• Re: EVs may be the source of this ship fire - stay tuned

    From 2G@21:1/5 to Hank Nixon on Tue Apr 5 21:54:21 2022
    On Tuesday, April 5, 2022 at 9:10:51 AM UTC-7, Hank Nixon wrote:
    On Monday, April 4, 2022 at 10:56:18 PM UTC-4, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote:
    My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of mine
    cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute.

    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
    The MGM HBC series controllers that were being used(not sure if they still are), can have a nasty electrical fire if there is a short between board layers. I know this from first hand experience. The fire stops as soon as power is removed. Very stinky.
    FWIW
    UH

    Again, manageable by fusing.

    Tom

    --- SoupGate-Win32 v1.05
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  • From Hank Nixon@21:1/5 to All on Wed Apr 6 05:32:34 2022
    On Wednesday, April 6, 2022 at 12:54:23 AM UTC-4, 2G wrote:
    On Tuesday, April 5, 2022 at 9:10:51 AM UTC-7, Hank Nixon wrote:
    On Monday, April 4, 2022 at 10:56:18 PM UTC-4, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote:
    My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of
    mine cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute.

    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
    The MGM HBC series controllers that were being used(not sure if they still are), can have a nasty electrical fire if there is a short between board layers. I know this from first hand experience. The fire stops as soon as power is removed. Very
    stinky.
    FWIW
    UH
    Again, manageable by fusing.

    Tom
    The normal max operating current in my system is about 250 amps. I'm fused at 300. You can make a pretty impressive fire within normal operating current. Opening the main contactor breaks the circuit immediately.
    But what do I know
    UH

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From kinsell@21:1/5 to Hank Nixon on Wed Apr 6 07:23:00 2022
    On 4/5/22 10:10, Hank Nixon wrote:
    On Monday, April 4, 2022 at 10:56:18 PM UTC-4, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote:
    My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of mine
    cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute. >>
    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    The MGM HBC series controllers that were being used(not sure if they still are), can have a nasty electrical fire if there is a short between board layers. I know this from first hand experience. The fire stops as soon as power is removed. Very stinky.
    FWIW
    UH

    That's weird. MGM-Compro is sposed to be a world leader in electrical propulsion systems. If those guys can screw up, how are we going to get fool-proof zero maintenance ultra reliable electric motor gliders??

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Hank Nixon@21:1/5 to kinsell on Wed Apr 6 12:36:13 2022
    On Wednesday, April 6, 2022 at 9:23:06 AM UTC-4, kinsell wrote:
    On 4/5/22 10:10, Hank Nixon wrote:
    On Monday, April 4, 2022 at 10:56:18 PM UTC-4, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote: >>>> My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of mine
    cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute.

    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    The MGM HBC series controllers that were being used(not sure if they still are), can have a nasty electrical fire if there is a short between board layers. I know this from first hand experience. The fire stops as soon as power is removed. Very
    stinky.
    FWIW
    UH
    That's weird. MGM-Compro is sposed to be a world leader in electrical propulsion systems. If those guys can screw up, how are we going to get fool-proof zero maintenance ultra reliable electric motor gliders??

    More to the story. There was no indication in their documentation that proximity of metal to the edge of their boards would be an issue. In fact they implied it was not. I stupidly took them at their word and made my mounts out of sheet aluminum because
    it was quick and easy. Part way through testing, outside the ship , there was a short and a fire. $2500 mistake. The next mounts were fiberglass. You can't buy experience, but you do pay for it. I use another brand of controller now.
    UH

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eric Greenwell@21:1/5 to kinsell on Wed Apr 6 20:15:18 2022
    On 4/6/2022 6:23 AM, kinsell wrote:
    The MGM HBC series controllers that were being used(not sure if they still are), can
    have a nasty electrical fire if there is a short between board layers. I know this from
    first hand experience. The fire stops as soon as power is removed. Very stinky.
    FWIW
    UH

    That's weird.  MGM-Compro is sposed to be a world leader in electrical propulsion
    systems.  If those guys can screw up, how are we going to get fool-proof zero maintenance
    ultra reliable electric motor gliders??

    I have good news for you: we have that glider already! And, it uses an FES propulsion.
    Talk to FES owners, monitor their news groups, and you'll discover what I did: the owners
    are very happy, and the news groups have very little conversation. Why is that? One dealer
    summed it up this way: "What's to talk about? You charge it, you fly it, repeat as desired."

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eric Greenwell@21:1/5 to kinsell on Wed Apr 6 20:15:42 2022
    On 4/6/2022 6:23 AM, kinsell wrote:


    That's weird.  MGM-Compro is sposed to be a world leader in electrical propulsion
    systems.  If those guys can screw up, how are we going to get fool-proof zero maintenance
    ultra reliable electric motor gliders??

    I've started another thread for this subject: "fool-proof zero maintenance ultra reliable
    electric motor gliders"


    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eric Greenwell@21:1/5 to All on Wed Apr 6 20:38:13 2022
    On 4/5/2022 8:37 AM, 2G wrote:
    On Monday, April 4, 2022 at 9:31:11 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 8:04 PM, 2G wrote:
    On Monday, April 4, 2022 at 7:56:18 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote: >>>>>> My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of mine
    cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute. >>>>
    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    I would not be concerned about the motor controller - it doesn't have any fuel source that can burn, but generates heat only as long as an energy source (electrical current) is supplied. Interrupt the current and the "fire" stops. That is what fuses
    are for.

    Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.

    Tom
    That Taurus is a very different design than the Jetta, and was not as safe (in my
    estimation), for these reasons (and others):
    - The batteries were in the fuselage, instead of the wing like the Jeta
    - the batteries were foil pouches; the Jeta uses cells that are manufactured with a metal
    container
    - the Taurus batteries were routinely removed and potentially subjected to dropping

    Even so, I believe the changes made since that fire substantially improved the safety of
    the Taurus, and I'd willing fly it.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    One shouldn't immediately assume that cylindrical cells are safer than pouch cells. Besides the Tesla fire database I previously cited, here is Tesla battery farm fire in Australia:
    https://www.cnbc.com/2021/07/30/tesla-megapack-caught-fire-at-victorian-big-battery-site-in-australia.html
    https://stopthesethings.com/2021/07/31/battery-bombs-more-giant-renewable-energy-batteries-explode-in-toxic-fireballs/
    Tesla batteries, of course, use cylindrical cells, and are in a controlled, non-vibration environment. In other words, battery farms should be the LEAST LIKELY environment for a battery fire. Aircraft are subject to repeated positive and negative g-
    loading as well as significant vibration while flown in turbulent air.

    Placing the batteries in the wings may position them modestly further away from the pilot than the fuselage, but does it prevent fire fumes from reaching the pilot? In any event, a major fire in the wing(s) is a very serious situation, and would
    probably compromise the BRS.

    Tom
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Hank Nixon@21:1/5 to Eric Greenwell on Thu Apr 7 05:47:22 2022
    On Wednesday, April 6, 2022 at 11:15:22 PM UTC-4, Eric Greenwell wrote:
    On 4/6/2022 6:23 AM, kinsell wrote:
    The MGM HBC series controllers that were being used(not sure if they still are), can
    have a nasty electrical fire if there is a short between board layers. I know this from
    first hand experience. The fire stops as soon as power is removed. Very stinky.
    FWIW
    UH

    That's weird. MGM-Compro is sposed to be a world leader in electrical propulsion
    systems. If those guys can screw up, how are we going to get fool-proof zero maintenance
    ultra reliable electric motor gliders??
    I have good news for you: we have that glider already! And, it uses an FES propulsion.
    Talk to FES owners, monitor their news groups, and you'll discover what I did: the owners
    are very happy, and the news groups have very little conversation. Why is that? One dealer
    summed it up this way: "What's to talk about? You charge it, you fly it, repeat as desired."
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    I'm using the same controller that the FES gliders use. After troubles with the HBC controller I researched and identified the controller in the FES ships and migrated to that. Once integration issues were resolved it has worked very well. '24EL uses
    Sony VT6C cells . '25EL uses Samsung INR 25R due to lack of availability of VT6C cells.
    UH

    --- SoupGate-Win32 v1.05
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  • From 2G@21:1/5 to Eric Greenwell on Thu Apr 7 21:49:53 2022
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote:
    On 4/5/2022 8:37 AM, 2G wrote:
    On Monday, April 4, 2022 at 9:31:11 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 8:04 PM, 2G wrote:
    On Monday, April 4, 2022 at 7:56:18 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote: >>>>>> My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of
    mine cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute.

    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    I would not be concerned about the motor controller - it doesn't have any fuel source that can burn, but generates heat only as long as an energy source (electrical current) is supplied. Interrupt the current and the "fire" stops. That is what
    fuses are for.

    Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.

    Tom
    That Taurus is a very different design than the Jetta, and was not as safe (in my
    estimation), for these reasons (and others):
    - The batteries were in the fuselage, instead of the wing like the Jeta >> - the batteries were foil pouches; the Jeta uses cells that are manufactured with a metal
    container
    - the Taurus batteries were routinely removed and potentially subjected to dropping

    Even so, I believe the changes made since that fire substantially improved the safety of
    the Taurus, and I'd willing fly it.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    One shouldn't immediately assume that cylindrical cells are safer than pouch cells. Besides the Tesla fire database I previously cited, here is Tesla battery farm fire in Australia:
    https://www.cnbc.com/2021/07/30/tesla-megapack-caught-fire-at-victorian-big-battery-site-in-australia.html
    https://stopthesethings.com/2021/07/31/battery-bombs-more-giant-renewable-energy-batteries-explode-in-toxic-fireballs/
    Tesla batteries, of course, use cylindrical cells, and are in a controlled, non-vibration environment. In other words, battery farms should be the LEAST LIKELY environment for a battery fire. Aircraft are subject to repeated positive and negative g-
    loading as well as significant vibration while flown in turbulent air.

    Placing the batteries in the wings may position them modestly further away from the pilot than the fuselage, but does it prevent fire fumes from reaching the pilot? In any event, a major fire in the wing(s) is a very serious situation, and would
    probably compromise the BRS.

    Tom
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jfitch@21:1/5 to All on Fri Apr 8 06:36:52 2022
    Tom, were those Tesla walls using LiFePo4 cells, or some other chemistry? Pretty sure you already know the answer to that....
    On Tuesday, April 5, 2022 at 8:37:20 AM UTC-7, 2G wrote:
    On Monday, April 4, 2022 at 9:31:11 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 8:04 PM, 2G wrote:
    On Monday, April 4, 2022 at 7:56:18 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote: >>>> My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of
    mine cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute.

    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    I would not be concerned about the motor controller - it doesn't have any fuel source that can burn, but generates heat only as long as an energy source (electrical current) is supplied. Interrupt the current and the "fire" stops. That is what
    fuses are for.

    Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.

    Tom
    That Taurus is a very different design than the Jetta, and was not as safe (in my
    estimation), for these reasons (and others):
    - The batteries were in the fuselage, instead of the wing like the Jeta
    - the batteries were foil pouches; the Jeta uses cells that are manufactured with a metal
    container
    - the Taurus batteries were routinely removed and potentially subjected to dropping

    Even so, I believe the changes made since that fire substantially improved the safety of
    the Taurus, and I'd willing fly it.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
    One shouldn't immediately assume that cylindrical cells are safer than pouch cells. Besides the Tesla fire database I previously cited, here is Tesla battery farm fire in Australia:
    https://www.cnbc.com/2021/07/30/tesla-megapack-caught-fire-at-victorian-big-battery-site-in-australia.html
    https://stopthesethings.com/2021/07/31/battery-bombs-more-giant-renewable-energy-batteries-explode-in-toxic-fireballs/
    Tesla batteries, of course, use cylindrical cells, and are in a controlled, non-vibration environment. In other words, battery farms should be the LEAST LIKELY environment for a battery fire. Aircraft are subject to repeated positive and negative g-
    loading as well as significant vibration while flown in turbulent air.

    Placing the batteries in the wings may position them modestly further away from the pilot than the fuselage, but does it prevent fire fumes from reaching the pilot? In any event, a major fire in the wing(s) is a very serious situation, and would
    probably compromise the BRS.

    Tom

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  • From Eric Greenwell@21:1/5 to All on Fri Apr 8 06:43:25 2022
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote:
    ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom

    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

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  • From 2G@21:1/5 to jfitch on Sat Apr 9 23:40:19 2022
    On Friday, April 8, 2022 at 6:36:54 AM UTC-7, jfitch wrote:
    Tom, were those Tesla walls using LiFePo4 cells, or some other chemistry? Pretty sure you already know the answer to that....
    On Tuesday, April 5, 2022 at 8:37:20 AM UTC-7, 2G wrote:
    On Monday, April 4, 2022 at 9:31:11 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 8:04 PM, 2G wrote:
    On Monday, April 4, 2022 at 7:56:18 PM UTC-7, Eric Greenwell wrote:
    On 4/4/2022 4:58 PM, 2G wrote:
    On Monday, April 4, 2022 at 11:34:02 AM UTC-7, Eric Greenwell wrote: >>>> My Jeta will not have room for a personal parachute, or a canopy that can be ejected, as
    it would delay delivery significantly. Jetas built after mine will be the Jeta+ versions
    with the bigger wing and the option for using a personal parachute. Since I think the
    biggest fire risk is a fire caused by the failure of the motor controller electronics,
    which is mounted in the center fuselage and near the BRS. To mitigate that risk, I will
    order the optional motor controller fire suppression system.

    A fire suppression option is also available for the wing mounted batteries, and I am
    considering ordering that system, too.
    On 4/4/2022 11:02 AM, Dan Marotta wrote:
    ...And I have plans in place for the unfortunate eventually.
    ...
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Unfortunately, lithium battery fires can't be suppressed - they generate their own oxygen unlike gasoline fires (it's built into the chemistry). I have been repeating this warning most times that I post about lithium battery fires. A friend of
    mine cancelled his order for a Jeta for this very reason.

    Tom
    My main concern is electronic motor controller, for which there are several types of fire
    suppression systems. I don't have the details of that system or the battery fire
    suppression system, so I can't describe either of them, nor do I what "fire" they will be
    trying to suppress in the wing where the batteries are mounted. It may be a structure
    fire, and not the battery fire. If the structure could be protected for, say, 10 minutes,
    that would give the pilot time to descend and land normally, or deploy the parachute at
    about 1000' AGL, from where he can be on the ground in less than a minute.

    Before I order either system, I'll have the complete details to guide my decision.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    I would not be concerned about the motor controller - it doesn't have any fuel source that can burn, but generates heat only as long as an energy source (electrical current) is supplied. Interrupt the current and the "fire" stops. That is what
    fuses are for.

    Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.

    Tom
    That Taurus is a very different design than the Jetta, and was not as safe (in my
    estimation), for these reasons (and others):
    - The batteries were in the fuselage, instead of the wing like the Jeta - the batteries were foil pouches; the Jeta uses cells that are manufactured with a metal
    container
    - the Taurus batteries were routinely removed and potentially subjected to dropping

    Even so, I believe the changes made since that fire substantially improved the safety of
    the Taurus, and I'd willing fly it.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
    One shouldn't immediately assume that cylindrical cells are safer than pouch cells. Besides the Tesla fire database I previously cited, here is Tesla battery farm fire in Australia:
    https://www.cnbc.com/2021/07/30/tesla-megapack-caught-fire-at-victorian-big-battery-site-in-australia.html
    https://stopthesethings.com/2021/07/31/battery-bombs-more-giant-renewable-energy-batteries-explode-in-toxic-fireballs/
    Tesla batteries, of course, use cylindrical cells, and are in a controlled, non-vibration environment. In other words, battery farms should be the LEAST LIKELY environment for a battery fire. Aircraft are subject to repeated positive and negative g-
    loading as well as significant vibration while flown in turbulent air.

    Placing the batteries in the wings may position them modestly further away from the pilot than the fuselage, but does it prevent fire fumes from reaching the pilot? In any event, a major fire in the wing(s) is a very serious situation, and would
    probably compromise the BRS.

    Tom

    Not sure which dead horse you are beating. Tesla has been switching from NMC to LFP chemistries for their Megapacks and their shorter range cars. But the Tesla fire database doesn't indicate which chemistry was at fault, but it is very likely NMC.

    Tom

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  • From 2G@21:1/5 to Eric Greenwell on Sat Apr 9 23:49:42 2022
    On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote:
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote:
    ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom
    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    Eric,

    I would if I could - the manufacturers don't provide any specs on vibration or shock that I have seen, indicating that they don't test for this. NASA doesn't use large quantities of batteries, so they won't provide any useful information. EASA also
    certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    Tom

    --- SoupGate-Win32 v1.05
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  • From Eric Greenwell@21:1/5 to All on Sun Apr 10 06:28:13 2022
    On 4/9/2022 11:49 PM, 2G wrote:
    On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote:
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote:
    ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom
    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    I would if I could - the manufacturers don't provide any specs on vibration or shock that I have seen, indicating that they don't test for this. NASA doesn't use large quantities of batteries, so they won't provide any useful information. EASA also
    certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    Tom
    The certification standards have changed substantially because of the Taurus fire, and as
    I have pointed out before, it was a very different design than what Schleicher is
    producing. You have offered no evidence, much less proof, that the "actual fires" resulted
    from vibration or G loading. And, if NASA's experience doesn't provide useful information
    because their battery packs are smaller than glider pack, then I will continue to claim
    car fires or utility fires also do not provide useful information, since they use ten
    times to thousands of times as many batteries.

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
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  • From stephen.szikora.t3@gmail.com@21:1/5 to Eric Greenwell on Sun Apr 10 07:03:01 2022
    They should design electric gliders with the ability to drop the batteries in an emergency (in Star Trek parlance … eject the warp core!)

    On Sunday, April 10, 2022 at 9:28:18 AM UTC-4, Eric Greenwell wrote:
    On 4/9/2022 11:49 PM, 2G wrote:
    On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote:
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote: >> ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom
    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    I would if I could - the manufacturers don't provide any specs on vibration or shock that I have seen, indicating that they don't test for this. NASA doesn't use large quantities of batteries, so they won't provide any useful information. EASA also
    certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    Tom
    The certification standards have changed substantially because of the Taurus fire, and as
    I have pointed out before, it was a very different design than what Schleicher is
    producing. You have offered no evidence, much less proof, that the "actual fires" resulted
    from vibration or G loading. And, if NASA's experience doesn't provide useful information
    because their battery packs are smaller than glider pack, then I will continue to claim
    car fires or utility fires also do not provide useful information, since they use ten
    times to thousands of times as many batteries.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

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  • From Martin Gregorie@21:1/5 to stephen.s...@gmail.com on Sun Apr 10 14:44:09 2022
    On Sun, 10 Apr 2022 07:03:01 -0700 (PDT), stephen.s...@gmail.com wrote:

    They should design electric gliders with the ability to drop the
    batteries in an emergency (in Star Trek parlance … eject the warp core!)

    THAT will work well!

    "Be the first person on your block to claim for falling battery damage
    wrecking your roof, setting fire to your house and killing your cat."

    Or are you suggesting that each battery pack must be fitted with with a fireproof, self-deploying emergency parachute?

    --- SoupGate-Win32 v1.05
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  • From stephen.szikora.t3@gmail.com@21:1/5 to Martin Gregorie on Sun Apr 10 09:40:40 2022
    So you are opposed to ballistic parachute systems as well … in case the aircraft falls on a cat?

    On Sunday, April 10, 2022 at 10:44:12 AM UTC-4, Martin Gregorie wrote:
    On Sun, 10 Apr 2022 07:03:01 -0700 (PDT), stephen.s...@gmail.com wrote:

    They should design electric gliders with the ability to drop the
    batteries in an emergency (in Star Trek parlance … eject the warp core!)

    THAT will work well!

    "Be the first person on your block to claim for falling battery damage wrecking your roof, setting fire to your house and killing your cat."

    Or are you suggesting that each battery pack must be fitted with with a fireproof, self-deploying emergency parachute?

    --- SoupGate-Win32 v1.05
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  • From =?UTF-8?Q?Arne_Martin_G=C3=BCettler@21:1/5 to All on Sun Apr 10 09:49:44 2022
    On Sunday, 10 April 2022 at 08:49:44 UTC+2, 2G wrote:
    EASA also certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    No, the Taurus (electro or otherwise) is not EASA certified. The ones flying in Europe are registered as ultra light (which don't follow EASA rules) or experimental.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From 2G@21:1/5 to Eric Greenwell on Sun Apr 10 09:49:55 2022
    On Sunday, April 10, 2022 at 6:28:18 AM UTC-7, Eric Greenwell wrote:
    On 4/9/2022 11:49 PM, 2G wrote:
    On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote:
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote: >> ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom
    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    I would if I could - the manufacturers don't provide any specs on vibration or shock that I have seen, indicating that they don't test for this. NASA doesn't use large quantities of batteries, so they won't provide any useful information. EASA also
    certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    Tom
    The certification standards have changed substantially because of the Taurus fire, and as
    I have pointed out before, it was a very different design than what Schleicher is
    producing. You have offered no evidence, much less proof, that the "actual fires" resulted
    from vibration or G loading. And, if NASA's experience doesn't provide useful information
    because their battery packs are smaller than glider pack, then I will continue to claim
    car fires or utility fires also do not provide useful information, since they use ten
    times to thousands of times as many batteries.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    I have done nothing BUT provide "proof" of shock and vibration induced battery thermal runaways (also called "fires"). You may not accept this, but FES knows it to be a problem of such magnitude that they have put shock sensors on their battery packs. An
    excellent summary of the issues is presented in "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340), which references 27 other studies. Note that this was published six years ago, so I can assume that much more
    research has been done. Then, there is the McMicken battery farm fire which exposed systemic defects in the manufacture of lithium cells used in the farm (which has been extensively discussed on RAS).

    Tom

    --- SoupGate-Win32 v1.05
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  • From 2G@21:1/5 to All on Sun Apr 10 10:30:11 2022
    On Sunday, April 10, 2022 at 9:49:45 AM UTC-7, Arne Martin Güettler wrote:
    On Sunday, 10 April 2022 at 08:49:44 UTC+2, 2G wrote:
    EASA also certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.
    No, the Taurus (electro or otherwise) is not EASA certified. The ones flying in Europe are registered as ultra light (which don't follow EASA rules) or experimental.

    Ok, this seems to be the case, but the Electro has been certified by some countries:
    https://www.pipistrel-aircraft.com/aircraft/electric-flight/taurus-electro/#tab-id-4
    And the Electro was designed by aeronautical and electrical engineers, and manufactured by a respected aviation company, Pipistrel. This demonstrates that an aircraft's pedigree, by itself, is no guarantee of safety. The Boeing 787 was, and is, certified
    by the FAA, but had a notorious lithium battery fire after being certified: https://www.reuters.com/article/us-boeing-787-battery/design-flaws-led-to-2013-lithium-ion-battery-fire-in-boeing-787-u-s-ntsb-idUSKCN0JF35G20141202

    Tom

    --- SoupGate-Win32 v1.05
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  • From Eric Greenwell@21:1/5 to All on Sun Apr 10 10:45:38 2022
    On 4/10/2022 9:49 AM, 2G wrote:
    On Sunday, April 10, 2022 at 6:28:18 AM UTC-7, Eric Greenwell wrote:
    On 4/9/2022 11:49 PM, 2G wrote:
    On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote:
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote: >>>> ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom
    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    I would if I could - the manufacturers don't provide any specs on vibration or shock that I have seen, indicating that they don't test for this. NASA doesn't use large quantities of batteries, so they won't provide any useful information. EASA also
    certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    Tom
    The certification standards have changed substantially because of the Taurus fire, and as
    I have pointed out before, it was a very different design than what Schleicher is
    producing. You have offered no evidence, much less proof, that the "actual fires" resulted
    from vibration or G loading. And, if NASA's experience doesn't provide useful information
    because their battery packs are smaller than glider pack, then I will continue to claim
    car fires or utility fires also do not provide useful information, since they use ten
    times to thousands of times as many batteries.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    I have done nothing BUT provide "proof" of shock and vibration induced battery thermal runaways (also called "fires"). You may not accept this, but FES knows it to be a problem of such magnitude that they have put shock sensors on their battery packs.
    An excellent summary of the issues is presented in "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340), which references 27 other studies. Note that this was published six years ago, so I can assume that much more
    research has been done. Then, there is the McMicken battery farm fire which exposed systemic defects in the manufacture of lithium cells used in the farm (which has been extensively discussed on RAS).

    Tom

    The FES batteries are routinely removed for charging, and can be damaged by dropping them.
    After the fires, the FES company realized pilots do not always report those incidents, and
    do not always have the batteries examined after dropping them. The shock sensors are for
    that reason, not for loads encountered in-flight.

    My experience is gliders operate with very little vibration, and that's when flying from
    rough grass fields. The total duration of the vibration per flight is less than a minute
    (takeoff plus landing), and most motorgliders operate from smooth runways.

    No one expects the cells to be perfect, which is why the EASA certification requires a
    glider to safely endure a catastrophic cell failure.

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Hank Nixon@21:1/5 to Eric Greenwell on Sun Apr 10 12:18:00 2022
    On Sunday, April 10, 2022 at 1:45:43 PM UTC-4, Eric Greenwell wrote:
    On 4/10/2022 9:49 AM, 2G wrote:
    On Sunday, April 10, 2022 at 6:28:18 AM UTC-7, Eric Greenwell wrote:
    On 4/9/2022 11:49 PM, 2G wrote:
    On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote:
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote: >>>> ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom
    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    I would if I could - the manufacturers don't provide any specs on vibration or shock that I have seen, indicating that they don't test for this. NASA doesn't use large quantities of batteries, so they won't provide any useful information. EASA also
    certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    Tom
    The certification standards have changed substantially because of the Taurus fire, and as
    I have pointed out before, it was a very different design than what Schleicher is
    producing. You have offered no evidence, much less proof, that the "actual fires" resulted
    from vibration or G loading. And, if NASA's experience doesn't provide useful information
    because their battery packs are smaller than glider pack, then I will continue to claim
    car fires or utility fires also do not provide useful information, since they use ten
    times to thousands of times as many batteries.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    I have done nothing BUT provide "proof" of shock and vibration induced battery thermal runaways (also called "fires"). You may not accept this, but FES knows it to be a problem of such magnitude that they have put shock sensors on their battery packs.
    An excellent summary of the issues is presented in "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340), which references 27 other studies. Note that this was published six years ago, so I can assume that much more
    research has been done. Then, there is the McMicken battery farm fire which exposed systemic defects in the manufacture of lithium cells used in the farm (which has been extensively discussed on RAS).

    Tom
    The FES batteries are routinely removed for charging, and can be damaged by dropping them.
    After the fires, the FES company realized pilots do not always report those incidents, and
    do not always have the batteries examined after dropping them. The shock sensors are for
    that reason, not for loads encountered in-flight.

    My experience is gliders operate with very little vibration, and that's when flying from
    rough grass fields. The total duration of the vibration per flight is less than a minute
    (takeoff plus landing), and most motorgliders operate from smooth runways.

    No one expects the cells to be perfect, which is why the EASA certification requires a
    glider to safely endure a catastrophic cell failure.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    The FES gliders use "pouch" cells that provide higher stored energy per pound than 18650 type cells. The down side is that they are much more easily damaged as demonstrated by the fires that occurred. Contributing was a potentially conductive battery box.
    Additionally small metal shards resulting from the assembly process are thought to have contributed to possible cell damage. Once these cells go there isn't much to stop them. Containment is the only real option. The FES people have re done the
    enclosure, modified assembly, and added monitoring. Since that time I am not aware of any more fires.
    That said I have chosen to use the 18650 style cells that have been demonstrated to tolerate a single catastrophic damage(the nail test) without damaging adjacent cells. The way they are supported in the assembly leaves no room for movement so I expect
    no issues with shock or vibration.
    FWIW
    UH

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From 2G@21:1/5 to Eric Greenwell on Sun Apr 10 18:22:41 2022
    On Sunday, April 10, 2022 at 10:45:43 AM UTC-7, Eric Greenwell wrote:
    On 4/10/2022 9:49 AM, 2G wrote:
    On Sunday, April 10, 2022 at 6:28:18 AM UTC-7, Eric Greenwell wrote:
    On 4/9/2022 11:49 PM, 2G wrote:
    On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote:
    On 4/7/2022 9:49 PM, 2G wrote:
    On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote: >>>> ...
    I was speaking specifically about the Taurus situation. After that accident, there were
    major changes in design and manufacturing, and EASA regulations, that likely make pouch
    and cylindrical systems much closer in safety.

    A major fire anywhere on an aircraft is a very serious situation! Obviously, the
    manufacturers know this, and design the battery pack and it's installation reduce the
    risk. For example, the wing roots are sealed to prevent fumes from entering the fuselage,
    and venting is used to discharge the fumes from the wing. This shows a fume vent on the
    Antares:

    https://nordicgliding-com.translate.goog/opdateret-lange-antares-faar-tesla-batterier/?_x_tr_sl=da&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=nui

    Scroll down about half way to "Great demands on security".

    Vibration and G loads while operating a glider isn't a problem for the cylindrical cells,
    as they are very sturdy. Look up the specs for a typical 16850 cell, such as the
    Sony/Murata VCT6 cells used in the Jeta.

    This is a statement devoid of evidence. I, on the other hand, presented PLENTY of evidence to the contrary.

    Tom
    18650 cells are used by the military, NASA rockets them into space, and EASA and others
    allow their use in aircraft. So please, take the time to look up the physical specs
    (vibration, etc) on the VCT6 cells, or pretty much any 18650 cell of the same chemistry.
    Those are the ones used in gliders. Once you have those specs, you can compare the specs
    to the loads those batteries experience in glider use. That's the evidence you need to
    show us if you want to persuade anyone a glider is a "rough ride"!
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    I would if I could - the manufacturers don't provide any specs on vibration or shock that I have seen, indicating that they don't test for this. NASA doesn't use large quantities of batteries, so they won't provide any useful information. EASA also
    certified the problematic Taurus Electro. This falls into the category of absence of proof is not proof of absence. The ONLY proof I recognize are actual fires.

    Tom
    The certification standards have changed substantially because of the Taurus fire, and as
    I have pointed out before, it was a very different design than what Schleicher is
    producing. You have offered no evidence, much less proof, that the "actual fires" resulted
    from vibration or G loading. And, if NASA's experience doesn't provide useful information
    because their battery packs are smaller than glider pack, then I will continue to claim
    car fires or utility fires also do not provide useful information, since they use ten
    times to thousands of times as many batteries.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    I have done nothing BUT provide "proof" of shock and vibration induced battery thermal runaways (also called "fires"). You may not accept this, but FES knows it to be a problem of such magnitude that they have put shock sensors on their battery packs.
    An excellent summary of the issues is presented in "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340), which references 27 other studies. Note that this was published six years ago, so I can assume that much more
    research has been done. Then, there is the McMicken battery farm fire which exposed systemic defects in the manufacture of lithium cells used in the farm (which has been extensively discussed on RAS).

    Tom
    The FES batteries are routinely removed for charging, and can be damaged by dropping them.
    After the fires, the FES company realized pilots do not always report those incidents, and
    do not always have the batteries examined after dropping them. The shock sensors are for
    that reason, not for loads encountered in-flight.

    My experience is gliders operate with very little vibration, and that's when flying from
    rough grass fields. The total duration of the vibration per flight is less than a minute
    (takeoff plus landing), and most motorgliders operate from smooth runways.

    No one expects the cells to be perfect, which is why the EASA certification requires a
    glider to safely endure a catastrophic cell failure.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and ground
    operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses. While
    we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eric Greenwell@21:1/5 to All on Mon Apr 11 11:11:01 2022
    On 4/10/2022 6:22 PM, 2G wrote:

    The FES batteries are routinely removed for charging, and can be damaged by dropping them.
    After the fires, the FES company realized pilots do not always report those incidents, and
    do not always have the batteries examined after dropping them. The shock sensors are for
    that reason, not for loads encountered in-flight.

    My experience is gliders operate with very little vibration, and that's when flying from
    rough grass fields. The total duration of the vibration per flight is less than a minute
    (takeoff plus landing), and most motorgliders operate from smooth runways. >>
    No one expects the cells to be perfect, which is why the EASA certification requires a
    glider to safely endure a catastrophic cell failure.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and ground
    operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses. While
    we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From 2G@21:1/5 to Eric Greenwell on Mon Apr 11 14:57:16 2022
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote:
    On 4/10/2022 6:22 PM, 2G wrote:

    The FES batteries are routinely removed for charging, and can be damaged by dropping them.
    After the fires, the FES company realized pilots do not always report those incidents, and
    do not always have the batteries examined after dropping them. The shock sensors are for
    that reason, not for loads encountered in-flight.

    My experience is gliders operate with very little vibration, and that's when flying from
    rough grass fields. The total duration of the vibration per flight is less than a minute
    (takeoff plus landing), and most motorgliders operate from smooth runways.

    No one expects the cells to be perfect, which is why the EASA certification requires a
    glider to safely endure a catastrophic cell failure.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and ground
    operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses. While
    we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that if the
    battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:
    *Asiana Airlines 747 near South Korea in July 2011 https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_991#:~:text=On%2028%20July%202011%2C%20Asiana,people%20on%20board%2C%20were%20killed
    *UPS 747 in Dubai https://en.wikipedia.org/wiki/UPS_Airlines_Flight_6#:~:text=On%20September%203%2C%202010%2C%20the,air%20crash%20for%20UPS%20Airlines
    *UPS DC-8 in Philadelphia, PA in February 2006 https://skybrary.aero/accidents-and-incidents/dc87-philadelphia-usa-2006#:~:text=On%207%20February%202006%2C%20a,the%20emergency%20services%20were%20alerted

    I recommend that auto and aircraft manufacturers using electrical propulsion include high frequency transient recording instrumentation to detect microfaults occurring internal to the battery pack. I have personally measured high frequency noise being
    emitted by a failed lead-acid battery that was not there on a new battery. Any shorting in an individual cell will produce detectable current spikes that can be measured and recorded.

    Personally, I think they will find that the Felicity Ace ship fire was caused by a lithium battery fire (if the cause can be isolated).

    Tom

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eric Greenwell@21:1/5 to All on Mon Apr 11 15:42:37 2022
    On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote:
    On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and ground
    operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses. While
    we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that if the
    battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly.

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From 2G@21:1/5 to Eric Greenwell on Mon Apr 11 19:57:23 2022
    On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote:
    On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and
    ground operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses.
    While we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that if
    the battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    WHY didn't read about those regulations? Do you think that what they are worried about concerning battery safety SOMEHOW doesn't apply to you?? A battery fire IS a battery fire whether it occurs on a 747 or on a GP-15.

    The chemistry of the batteries involved on fires on ships, planes and cars are IDENTICAL to what you will be flying with in your GP-15. I am astounded by your denial of the very real safety risks concerning these batteries. I am, truly, at a loss for
    words...

    Tom

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eric Greenwell@21:1/5 to All on Tue Apr 12 07:35:32 2022
    On 4/11/2022 7:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote:
    On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and
    ground operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses.
    While we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that if
    the battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    WHY didn't read about those regulations? Do you think that what they are worried about concerning battery safety SOMEHOW doesn't apply to you?? A battery fire IS a battery fire whether it occurs on a 747 or on a GP-15.

    The chemistry of the batteries involved on fires on ships, planes and cars are IDENTICAL to what you will be flying with in your GP-15. I am astounded by your denial of the very real safety risks concerning these batteries. I am, truly, at a loss for
    words...

    Tom
    I think you should learn the certification requirements for gliders, learn what the glider
    manufacturers are doing to meet these regulations, examine the problems electric gliders
    have had, and discuss the issues with as many knowledgeable people as you can. Only then
    will you have the knowledge needed to give us credible advice.

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Dee@21:1/5 to All on Tue Apr 12 15:11:15 2022
    On Tuesday, April 12, 2022 at 4:49:55 PM UTC-5, 2G wrote:
    On Tuesday, April 12, 2022 at 7:35:34 AM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 7:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote: >>>> On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and
    ground operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses.
    While we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to
    mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that
    if the battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    WHY didn't read about those regulations? Do you think that what they are worried about concerning battery safety SOMEHOW doesn't apply to you?? A battery fire IS a battery fire whether it occurs on a 747 or on a GP-15.

    The chemistry of the batteries involved on fires on ships, planes and cars are IDENTICAL to what you will be flying with in your GP-15. I am astounded by your denial of the very real safety risks concerning these batteries. I am, truly, at a loss
    for words...

    Tom
    I think you should learn the certification requirements for gliders, learn what the glider
    manufacturers are doing to meet these regulations, examine the problems electric gliders
    have had, and discuss the issues with as many knowledgeable people as you can. Only then
    will you have the knowledge needed to give us credible advice.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
    Of course I HAVE been presenting "problems electric gliders have had," but you discount each and every one of them, claiming that those problems have been solved or minimized. All of those gliders are still being flown. These problems will get worse as
    electric gliders age since battery failure mechanisms are age related. It is very interesting that the EASA electric aircraft certification standard was developed as a collaboration between EASA and Pipistrel, one of the manufacturers that you discount
    and the producer of one of the electric glider fatalities:
    https://www.easa.europa.eu/light/topics/easas-type-certification-fully-electric-aircraft

    Note that the EASA certification process for electric aircraft is still in its embryonic stages, and will change with time. I located the EASA applicable documents:
    https://www.easa.europa.eu/light/topics/electric-sailplanes
    One pertinent document on this page (https://www.easa.europa.eu/downloads/16912/en) contains the following disclaimer:

    "EASA Position

    The proposed use of Li-Batteries has prompted EASA to review the adequacy of the existing
    battery requirements with respect to that chemistry. Lithium-Ion (Li-Ion) / Lithium Polymer (LiPo) Batteries, have specific failure and operational characteristics that could affect safety of
    those battery installations and cause hazards to safety. On the other hand it is understood that
    the characteristics of existing propulsion systems have contributed to quite a number of
    accidents and electric propulsion systems with a simple and reliable start procedure can improve
    safety significantly.

    A safety assessment according (CS 2x.1309) is not required for Sailplanes and Powered
    Sailplanes. The engine control units for these kind of aircraft are normally not qualified according
    relevant EUROCAE/DO standards. Thus it is difficult to demonstrate that potentially hazardous
    or catastrophic failures are improbable. It also cannot be expected that the effect of a thermal
    runaway of Li batteries could be contained without any effect on the structural integrity of a
    powered sailplane, but with good engineering judgement all potentially critical items should be
    addressed to reduce the risk.

    As the result of this review, EASA has determined that the amended special condition as
    attached does adequately address installations of electric propulsion units and Li-Batteries and
    due to the positive effect of reliable and simple electric propulsion units improves overall safety.
    Additional requirements and notes introduced in this SC should help to identify relevant failure
    modes and operational characteristics that have to be addressed with good engineering judgment
    and necessary tests and qualification."

    This is INCREDIBLE: EASA is basically saying "fly electric gliders at YOUR OWN RISK as we cannot certify their safety!" Another EASA Special Condition document does not specify any standards for the battery system but refers you to relevant safety
    standards such as RTCA DO 311 (https://www.easa.europa.eu/downloads/16912/en). These aren't free, but you are welcome to buy them yourself (https://www.docuwebs.org/61467-RTCA-DO-311.html).

    And you can also confirm whether or not the GP-15 that you are going to receive is EASA certified (I don't think it will be because it is not a GP-15+).

    Tom

    What ever happened to "I am truly at a loss for words...."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From 2G@21:1/5 to Eric Greenwell on Tue Apr 12 14:49:53 2022
    On Tuesday, April 12, 2022 at 7:35:34 AM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 7:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote: >>>> On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and
    ground operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses.
    While we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to mind.


    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that if
    the battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly. >> --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    WHY didn't read about those regulations? Do you think that what they are worried about concerning battery safety SOMEHOW doesn't apply to you?? A battery fire IS a battery fire whether it occurs on a 747 or on a GP-15.

    The chemistry of the batteries involved on fires on ships, planes and cars are IDENTICAL to what you will be flying with in your GP-15. I am astounded by your denial of the very real safety risks concerning these batteries. I am, truly, at a loss for
    words...

    Tom
    I think you should learn the certification requirements for gliders, learn what the glider
    manufacturers are doing to meet these regulations, examine the problems electric gliders
    have had, and discuss the issues with as many knowledgeable people as you can. Only then
    will you have the knowledge needed to give us credible advice.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    Of course I HAVE been presenting "problems electric gliders have had," but you discount each and every one of them, claiming that those problems have been solved or minimized. All of those gliders are still being flown. These problems will get worse as
    electric gliders age since battery failure mechanisms are age related. It is very interesting that the EASA electric aircraft certification standard was developed as a collaboration between EASA and Pipistrel, one of the manufacturers that you discount
    and the producer of one of the electric glider fatalities: https://www.easa.europa.eu/light/topics/easas-type-certification-fully-electric-aircraft

    Note that the EASA certification process for electric aircraft is still in its embryonic stages, and will change with time. I located the EASA applicable documents:
    https://www.easa.europa.eu/light/topics/electric-sailplanes
    One pertinent document on this page (https://www.easa.europa.eu/downloads/16912/en) contains the following disclaimer:

    "EASA Position

    The proposed use of Li-Batteries has prompted EASA to review the adequacy of the existing
    battery requirements with respect to that chemistry. Lithium-Ion (Li-Ion) / Lithium Polymer (LiPo) Batteries, have specific failure and operational characteristics that could affect safety of
    those battery installations and cause hazards to safety. On the other hand it is understood that
    the characteristics of existing propulsion systems have contributed to quite a number of
    accidents and electric propulsion systems with a simple and reliable start procedure can improve
    safety significantly.

    A safety assessment according (CS 2x.1309) is not required for Sailplanes and Powered
    Sailplanes. The engine control units for these kind of aircraft are normally not qualified according
    relevant EUROCAE/DO standards. Thus it is difficult to demonstrate that potentially hazardous
    or catastrophic failures are improbable. It also cannot be expected that the effect of a thermal
    runaway of Li batteries could be contained without any effect on the structural integrity of a
    powered sailplane, but with good engineering judgement all potentially critical items should be
    addressed to reduce the risk.

    As the result of this review, EASA has determined that the amended special condition as
    attached does adequately address installations of electric propulsion units and Li-Batteries and
    due to the positive effect of reliable and simple electric propulsion units improves overall safety.
    Additional requirements and notes introduced in this SC should help to identify relevant failure
    modes and operational characteristics that have to be addressed with good engineering judgment
    and necessary tests and qualification."

    This is INCREDIBLE: EASA is basically saying "fly electric gliders at YOUR OWN RISK as we cannot certify their safety!" Another EASA Special Condition document does not specify any standards for the battery system but refers you to relevant safety
    standards such as RTCA DO 311 (https://www.easa.europa.eu/downloads/16912/en). These aren't free, but you are welcome to buy them yourself (https://www.docuwebs.org/61467-RTCA-DO-311.html).

    And you can also confirm whether or not the GP-15 that you are going to receive is EASA certified (I don't think it will be because it is not a GP-15+).

    Tom

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Eric Greenwell@21:1/5 to All on Tue Apr 12 20:22:46 2022
    On 4/12/2022 2:49 PM, 2G wrote:
    On Tuesday, April 12, 2022 at 7:35:34 AM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 7:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote: >>>>>> On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and
    ground operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses.
    While we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that if
    the battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly. >>>> --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    WHY didn't read about those regulations? Do you think that what they are worried about concerning battery safety SOMEHOW doesn't apply to you?? A battery fire IS a battery fire whether it occurs on a 747 or on a GP-15.

    The chemistry of the batteries involved on fires on ships, planes and cars are IDENTICAL to what you will be flying with in your GP-15. I am astounded by your denial of the very real safety risks concerning these batteries. I am, truly, at a loss for
    words...

    Tom
    I think you should learn the certification requirements for gliders, learn what the glider
    manufacturers are doing to meet these regulations, examine the problems electric gliders
    have had, and discuss the issues with as many knowledgeable people as you can. Only then
    will you have the knowledge needed to give us credible advice.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Of course I HAVE been presenting "problems electric gliders have had," but you discount each and every one of them, claiming that those problems have been solved or minimized. All of those gliders are still being flown. These problems will get worse as
    electric gliders age since battery failure mechanisms are age related. It is very interesting that the EASA electric aircraft certification standard was developed as a collaboration between EASA and Pipistrel, one of the manufacturers that you discount
    and the producer of one of the electric glider fatalities:
    https://www.easa.europa.eu/light/topics/easas-type-certification-fully-electric-aircraft

    Note that the EASA certification process for electric aircraft is still in its embryonic stages, and will change with time. I located the EASA applicable documents:
    https://www.easa.europa.eu/light/topics/electric-sailplanes
    One pertinent document on this page (https://www.easa.europa.eu/downloads/16912/en) contains the following disclaimer:

    "EASA Position

    The proposed use of Li-Batteries has prompted EASA to review the adequacy of the existing
    battery requirements with respect to that chemistry. Lithium-Ion (Li-Ion) / Lithium Polymer (LiPo) Batteries, have specific failure and operational characteristics that could affect safety of
    those battery installations and cause hazards to safety. On the other hand it is understood that
    the characteristics of existing propulsion systems have contributed to quite a number of
    accidents and electric propulsion systems with a simple and reliable start procedure can improve
    safety significantly.

    A safety assessment according (CS 2x.1309) is not required for Sailplanes and Powered
    Sailplanes. The engine control units for these kind of aircraft are normally not qualified according
    relevant EUROCAE/DO standards. Thus it is difficult to demonstrate that potentially hazardous
    or catastrophic failures are improbable. It also cannot be expected that the effect of a thermal
    runaway of Li batteries could be contained without any effect on the structural integrity of a
    powered sailplane, but with good engineering judgement all potentially critical items should be
    addressed to reduce the risk.

    As the result of this review, EASA has determined that the amended special condition as
    attached does adequately address installations of electric propulsion units and Li-Batteries and
    due to the positive effect of reliable and simple electric propulsion units improves overall safety.
    Additional requirements and notes introduced in this SC should help to identify relevant failure
    modes and operational characteristics that have to be addressed with good engineering judgment
    and necessary tests and qualification."

    This is INCREDIBLE: EASA is basically saying "fly electric gliders at YOUR OWN RISK as we cannot certify their safety!" Another EASA Special Condition document does not specify any standards for the battery system but refers you to relevant safety
    standards such as RTCA DO 311 (https://www.easa.europa.eu/downloads/16912/en). These aren't free, but you are welcome to buy them yourself (https://www.docuwebs.org/61467-RTCA-DO-311.html).

    And you can also confirm whether or not the GP-15 that you are going to receive is EASA certified (I don't think it will be because it is not a GP-15+).

    Tom

    THe most interesting remark in your posting was this: "On the other hand it is understood
    that the characteristics of existing propulsion systems have contributed to quite a number
    of accidents and electric propulsion systems with a simple and reliable start procedure
    can improve safety significantly."

    Until you understand the current situation, you will be unable to understand why electric
    gliders are so attractive, and ineffective in persuading people that they are too
    dangerous. The major reason is the promise of increased safety of operation over gas
    powered gliders; secondly, the reduction in maintenance. Most of us understand electrification will introduce some risks different from gas powered gliders, but we think
    the tradeoff will result in increased safety and more enjoyable soaring. No one is
    requiring you to follow us into the future, you've made your point repeatedly, so, please,
    relax and enjoy your glider, and let us enjoy the gliders we choose.

    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From 2G@21:1/5 to phlyi...@gmail.com on Tue Apr 12 20:22:29 2022
    On Tuesday, April 12, 2022 at 3:11:17 PM UTC-7, phlyi...@gmail.com wrote:
    On Tuesday, April 12, 2022 at 4:49:55 PM UTC-5, 2G wrote:
    On Tuesday, April 12, 2022 at 7:35:34 AM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 7:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote:
    On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering
    and ground operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure
    stresses. While we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to
    mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that
    if the battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    WHY didn't read about those regulations? Do you think that what they are worried about concerning battery safety SOMEHOW doesn't apply to you?? A battery fire IS a battery fire whether it occurs on a 747 or on a GP-15.

    The chemistry of the batteries involved on fires on ships, planes and cars are IDENTICAL to what you will be flying with in your GP-15. I am astounded by your denial of the very real safety risks concerning these batteries. I am, truly, at a loss
    for words...

    Tom
    I think you should learn the certification requirements for gliders, learn what the glider
    manufacturers are doing to meet these regulations, examine the problems electric gliders
    have had, and discuss the issues with as many knowledgeable people as you can. Only then
    will you have the knowledge needed to give us credible advice.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
    Of course I HAVE been presenting "problems electric gliders have had," but you discount each and every one of them, claiming that those problems have been solved or minimized. All of those gliders are still being flown. These problems will get worse
    as electric gliders age since battery failure mechanisms are age related. It is very interesting that the EASA electric aircraft certification standard was developed as a collaboration between EASA and Pipistrel, one of the manufacturers that you
    discount and the producer of one of the electric glider fatalities:
    https://www.easa.europa.eu/light/topics/easas-type-certification-fully-electric-aircraft

    Note that the EASA certification process for electric aircraft is still in its embryonic stages, and will change with time. I located the EASA applicable documents:
    https://www.easa.europa.eu/light/topics/electric-sailplanes
    One pertinent document on this page (https://www.easa.europa.eu/downloads/16912/en) contains the following disclaimer:

    "EASA Position

    The proposed use of Li-Batteries has prompted EASA to review the adequacy of the existing
    battery requirements with respect to that chemistry. Lithium-Ion (Li-Ion) / Lithium Polymer (LiPo) Batteries, have specific failure and operational characteristics that could affect safety of
    those battery installations and cause hazards to safety. On the other hand it is understood that
    the characteristics of existing propulsion systems have contributed to quite a number of
    accidents and electric propulsion systems with a simple and reliable start procedure can improve
    safety significantly.

    A safety assessment according (CS 2x.1309) is not required for Sailplanes and Powered
    Sailplanes. The engine control units for these kind of aircraft are normally not qualified according
    relevant EUROCAE/DO standards. Thus it is difficult to demonstrate that potentially hazardous
    or catastrophic failures are improbable. It also cannot be expected that the effect of a thermal
    runaway of Li batteries could be contained without any effect on the structural integrity of a
    powered sailplane, but with good engineering judgement all potentially critical items should be
    addressed to reduce the risk.

    As the result of this review, EASA has determined that the amended special condition as
    attached does adequately address installations of electric propulsion units and Li-Batteries and
    due to the positive effect of reliable and simple electric propulsion units improves overall safety.
    Additional requirements and notes introduced in this SC should help to identify relevant failure
    modes and operational characteristics that have to be addressed with good engineering judgment
    and necessary tests and qualification."

    This is INCREDIBLE: EASA is basically saying "fly electric gliders at YOUR OWN RISK as we cannot certify their safety!" Another EASA Special Condition document does not specify any standards for the battery system but refers you to relevant safety
    standards such as RTCA DO 311 (https://www.easa.europa.eu/downloads/16912/en). These aren't free, but you are welcome to buy them yourself (https://www.docuwebs.org/61467-RTCA-DO-311.html).

    And you can also confirm whether or not the GP-15 that you are going to receive is EASA certified (I don't think it will be because it is not a GP-15+).

    Tom
    What ever happened to "I am truly at a loss for words...."

    Ask Eric...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From 2G@21:1/5 to Eric Greenwell on Tue Apr 12 22:24:57 2022
    On Tuesday, April 12, 2022 at 8:22:48 PM UTC-7, Eric Greenwell wrote:
    On 4/12/2022 2:49 PM, 2G wrote:
    On Tuesday, April 12, 2022 at 7:35:34 AM UTC-7, Eric Greenwell wrote:
    On 4/11/2022 7:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote: >>>> On 4/11/2022 2:57 PM, 2G wrote:
    On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote: >>>>>> On 4/10/2022 6:22 PM, 2G wrote:
    ...

    To state there is little to no vibration in flight just isn't believable. Certainly, there is in any turbulent flight. Just entering and exiting a thermal is turbulent. Plus, the glider is exposed to substantial vibration during trailering and
    ground operations. And lithium battery thermal runaways have occurred in a vibration-free environment (i.e. battery farm fires). Plus, the batteries are being exposed to extreme altitude fluctuations, which subject them to atmospheric pressure stresses.
    While we still don't know the cause of the Felicity Ace fire, there were rough seas prior to its start.

    Tom
    I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
    running. To clarify what I mean by vibration, I'll use an automobile analogy: vibration is
    what you feel when driving on a washboarded road. Turbulence in glider is felt as G
    loading, not vibration. In cars, an analog to glider turbulence is speed bumps and strong
    wind gusts.

    I do agree that trailering effects on batteries in the glider are likely similar to what
    cars experience with their batteries. I skimmed three studies on "vibration testing" 18650
    cells used in cars; typically, they found some degradation in electrical performance and
    some mechanical damage (observable with CAT scanning or similar), but made no mention of
    fires. The strength, duration, the directions of test accelerations, and the chemistries
    tested varied considerably between the studies I looked at.

    I have not seen anything about altitude pressure issues for 18650 cells, and I don't
    expect an 8 psi ambient pressure reduction (sea level to FL180) to affect a 16850 cell
    that can withstand much higher internal pressures. The effects I did read about are
    reduced cooling due to thinner air, and reduced capacity due to lower temperatures.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Eric,

    Flight safety is similar to guarding the President: the Secret Service has to be right 100% of the time, an assassin only has to be right once. If we decide some factor is irrelevant and are wrong, then accidents can occur. The 737Max comes to
    mind.

    Did you read "Evaluation of Batteries for Safe Air Transport" (https://www.mdpi.com/1996-1073/9/5/340)? Section 4.2, Thermal and Mechanical Stress Testing, covers altitude pressure tests for batteries to be shipped by air. The situation is that
    if the battery case is sealed at sea level, and there is any air inside, it can create stress on the case when exposed to high altitudes. A manufacturer not listing a spec doesn't mean that spec is irrelevant ("absence of proof is not proof of absence").

    I can't understand why electric glider batteries shouldn't be subjected to the same tests required for shipment by air transport. Note that these regulations were developed following several major air disasters involving lithium batteries:

    I did not read about air transport regulations, because gliders are not transporting
    batteries, and the regulations for commercial carriage are hugely different EASA
    regulations for gliders. The altitude tests you refer to are for the case, not for the
    batteries.

    Seriously, Tom: fires in cars, fires in utility scale power banks, fires in ships carrying
    thousands of cars, regulations for shipping batteries in commercial aircraft? These are
    very tenuously related to what Schleicher, et al, are trying to do. They must follow the
    regulations for our aircraft, and not for these other uses. Please spend most of your
    effort on systems for gliders, their regulations, and how they are working out for soaring
    pilots, and we will be better informed about the gliders we want to fly.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    WHY didn't read about those regulations? Do you think that what they are worried about concerning battery safety SOMEHOW doesn't apply to you?? A battery fire IS a battery fire whether it occurs on a 747 or on a GP-15.

    The chemistry of the batteries involved on fires on ships, planes and cars are IDENTICAL to what you will be flying with in your GP-15. I am astounded by your denial of the very real safety risks concerning these batteries. I am, truly, at a loss
    for words...

    Tom
    I think you should learn the certification requirements for gliders, learn what the glider
    manufacturers are doing to meet these regulations, examine the problems electric gliders
    have had, and discuss the issues with as many knowledgeable people as you can. Only then
    will you have the knowledge needed to give us credible advice.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation"
    https://sites.google.com/site/motorgliders/publications

    Of course I HAVE been presenting "problems electric gliders have had," but you discount each and every one of them, claiming that those problems have been solved or minimized. All of those gliders are still being flown. These problems will get worse
    as electric gliders age since battery failure mechanisms are age related. It is very interesting that the EASA electric aircraft certification standard was developed as a collaboration between EASA and Pipistrel, one of the manufacturers that you
    discount and the producer of one of the electric glider fatalities:
    https://www.easa.europa.eu/light/topics/easas-type-certification-fully-electric-aircraft

    Note that the EASA certification process for electric aircraft is still in its embryonic stages, and will change with time. I located the EASA applicable documents:
    https://www.easa.europa.eu/light/topics/electric-sailplanes
    One pertinent document on this page (https://www.easa.europa.eu/downloads/16912/en) contains the following disclaimer:

    "EASA Position

    The proposed use of Li-Batteries has prompted EASA to review the adequacy of the existing
    battery requirements with respect to that chemistry. Lithium-Ion (Li-Ion) / Lithium Polymer (LiPo) Batteries, have specific failure and operational characteristics that could affect safety of
    those battery installations and cause hazards to safety. On the other hand it is understood that
    the characteristics of existing propulsion systems have contributed to quite a number of
    accidents and electric propulsion systems with a simple and reliable start procedure can improve
    safety significantly.

    A safety assessment according (CS 2x.1309) is not required for Sailplanes and Powered
    Sailplanes. The engine control units for these kind of aircraft are normally not qualified according
    relevant EUROCAE/DO standards. Thus it is difficult to demonstrate that potentially hazardous
    or catastrophic failures are improbable. It also cannot be expected that the effect of a thermal
    runaway of Li batteries could be contained without any effect on the structural integrity of a
    powered sailplane, but with good engineering judgement all potentially critical items should be
    addressed to reduce the risk.

    As the result of this review, EASA has determined that the amended special condition as
    attached does adequately address installations of electric propulsion units and Li-Batteries and
    due to the positive effect of reliable and simple electric propulsion units improves overall safety.
    Additional requirements and notes introduced in this SC should help to identify relevant failure
    modes and operational characteristics that have to be addressed with good engineering judgment
    and necessary tests and qualification."

    This is INCREDIBLE: EASA is basically saying "fly electric gliders at YOUR OWN RISK as we cannot certify their safety!" Another EASA Special Condition document does not specify any standards for the battery system but refers you to relevant safety
    standards such as RTCA DO 311 (https://www.easa.europa.eu/downloads/16912/en). These aren't free, but you are welcome to buy them yourself (https://www.docuwebs.org/61467-RTCA-DO-311.html).

    And you can also confirm whether or not the GP-15 that you are going to receive is EASA certified (I don't think it will be because it is not a GP-15+).

    Tom

    THe most interesting remark in your posting was this: "On the other hand it is understood
    that the characteristics of existing propulsion systems have contributed to quite a number
    of accidents and electric propulsion systems with a simple and reliable start procedure
    can improve safety significantly."
    Until you understand the current situation, you will be unable to understand why electric
    gliders are so attractive, and ineffective in persuading people that they are too
    dangerous. The major reason is the promise of increased safety of operation over gas
    powered gliders; secondly, the reduction in maintenance. Most of us understand
    electrification will introduce some risks different from gas powered gliders, but we think
    the tradeoff will result in increased safety and more enjoyable soaring. No one is
    requiring you to follow us into the future, you've made your point repeatedly, so, please,
    relax and enjoy your glider, and let us enjoy the gliders we choose.
    --
    Eric Greenwell - USA
    - "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications

    You didn't read the EASA disclaimer:

    "Thus it is difficult to demonstrate that potentially hazardous
    or catastrophic failures are improbable. It also cannot be expected that the effect of a thermal
    runaway of Li batteries could be contained without any effect on the structural integrity of a
    powered sailplane"

    What I "understand" is that the safety of the current crop of electric gliders is UNPROVEN and can ONLY be flown AT YOUR OWN RISK! There is no aspect of a glider so enticing that it is worth dying over. BTW, electric gliders ARE NOT simple and can shut
    down unexpectedly for a variety of reasons.

    Tom

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)