On Monday, April 4, 2022 at 10:56:18 PM UTC-4, Eric Greenwell wrote:cancelled his order for a Jeta for this very reason.
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
TomMy 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.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.
--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
FWIW
UH
On Tuesday, April 5, 2022 at 9:10:51 AM UTC-7, Hank Nixon wrote:mine cancelled his order for a Jeta for this very reason.
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
stinky.TomMy 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.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
--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation" https://sites.google.com/site/motorgliders/publications
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.FWIWAgain, manageable by fusing.
UH
Tom
On Monday, April 4, 2022 at 10:56:18 PM UTC-4, Eric Greenwell wrote:cancelled his order for a Jeta for this very reason.
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
My main concern is electronic motor controller, for which there are several types of fire
Tom
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
On 4/5/22 10:10, Hank Nixon wrote:cancelled his order for a Jeta for this very reason.
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
stinky.My main concern is electronic motor controller, for which there are several types of fire
Tom
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
FWIWThat'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??
UH
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??
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??
On Monday, April 4, 2022 at 9:31:11 PM UTC-7, Eric Greenwell wrote:cancelled his order for a Jeta for this very reason.
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
are for.My main concern is electronic motor controller, for which there are several types of fire
Tom
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
loading as well as significant vibration while flown in turbulent air.That Taurus is a very different design than the Jetta, and was not as safe (in my
Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.
Tom
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-
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 wouldprobably compromise the BRS.
TomI was speaking specifically about the Taurus situation. After that accident, there were
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 propulsionI have good news for you: we have that glider already! And, it uses an FES propulsion.
systems. If those guys can screw up, how are we going to get fool-proof zero maintenance
ultra reliable electric motor gliders??
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
On 4/5/2022 8:37 AM, 2G wrote:mine cancelled his order for a Jeta for this very reason.
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
fuses are for.My main concern is electronic motor controller, for which there are several types of fire
Tom
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
loading as well as significant vibration while flown in turbulent air.That Taurus is a very different design than the Jetta, and was not as safe (in my
Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.
Tom
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-
probably compromise the BRS.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
TomI 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
On Monday, April 4, 2022 at 9:31:11 PM UTC-7, Eric Greenwell wrote:mine cancelled his order for a Jeta for this very reason.
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
fuses are for.My main concern is electronic motor controller, for which there are several types of fire
Tom
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
loading as well as significant vibration while flown in turbulent air.Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.
TomThat 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 ofOne 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:
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
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-
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 wouldprobably compromise the BRS.
Tom
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
Tom, were those Tesla walls using LiFePo4 cells, or some other chemistry? Pretty sure you already know the answer to that....mine cancelled his order for a Jeta for this very reason.
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
fuses are for.My main concern is electronic motor controller, for which there are several types of fire
Tom
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
loading as well as significant vibration while flown in turbulent air.Ten minutes wasn't available to the Taurus Electro pilot - he was incapacitated in seconds.
TomThat 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 ofOne 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:
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
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-
probably compromise the BRS.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
Tom
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.
Tom18650 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
On Friday, April 8, 2022 at 6:43:29 AM UTC-7, Eric Greenwell wrote: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.
On 4/7/2022 9:49 PM, 2G wrote:
On Wednesday, April 6, 2022 at 8:38:18 PM UTC-7, Eric Greenwell wrote:...
18650 cells are used by the military, NASA rockets them into space, and EASA and othersI 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
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
TomThe certification standards have changed substantially because of the Taurus fire, and as
On 4/9/2022 11:49 PM, 2G wrote: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.
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: >> ...18650 cells are used by the military, NASA rockets them into space, and EASA and others
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
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
TomThe 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
They should design electric gliders with the ability to drop the
batteries in an emergency (in Star Trek parlance … eject the warp core!)
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?
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.
On 4/9/2022 11:49 PM, 2G wrote: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.
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: >> ...18650 cells are used by the military, NASA rockets them into space, and EASA and others
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
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
TomThe 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
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.
On Sunday, April 10, 2022 at 6:28:18 AM UTC-7, Eric Greenwell wrote: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.
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: >>>> ...18650 cells are used by the military, NASA rockets them into space, and EASA and others
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
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
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 moreThe certification standards have changed substantially because of the Taurus fire, and as
Tom
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.
Tom
On 4/10/2022 9:49 AM, 2G wrote: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.
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: >>>> ...18650 cells are used by the military, NASA rockets them into space, and EASA and others
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
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
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 moreThe certification standards have changed substantially because of the Taurus fire, and as
Tom
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.
TomThe 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
On 4/10/2022 9:49 AM, 2G wrote: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.
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: >>>> ...18650 cells are used by the military, NASA rockets them into space, and EASA and others
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
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
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 moreThe certification standards have changed substantially because of the Taurus fire, and as
Tom
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.
TomThe 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
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. WhileThe 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
TomI haven't heard anyone speak of vibration while a glider is flying, unless the motor was
On 4/10/2022 6:22 PM, 2G wrote: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
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
TomI 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
On Monday, April 11, 2022 at 11:11:06 AM UTC-7, Eric Greenwell wrote:...
On 4/10/2022 6:22 PM, 2G wrote:
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
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
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 haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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
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:
On 4/11/2022 2:57 PM, 2G wrote: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.
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
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 haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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
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
On Monday, April 11, 2022 at 3:42:41 PM UTC-7, Eric Greenwell wrote: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.
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
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 haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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
words...I did not read about air transport regulations, because gliders are not transporting
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:
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
TomI think you should learn the certification requirements for gliders, learn what the glider
On Tuesday, April 12, 2022 at 7:35:34 AM UTC-7, Eric Greenwell wrote: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.
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
mind.I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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
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").
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
for words...I did not read about air transport regulations, because gliders are not transporting
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:
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
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 discountOf 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 asTomI 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
https://www.easa.europa.eu/light/topics/easas-type-certification-fully-electric-aircraftstandards 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).
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
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
On 4/11/2022 7:57 PM, 2G wrote: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.
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
I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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.
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").
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
words...I did not read about air transport regulations, because gliders are not transporting
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:
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
TomI 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
On Tuesday, April 12, 2022 at 7:35:34 AM UTC-7, Eric Greenwell wrote: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.
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
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 haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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
words...I did not read about air transport regulations, because gliders are not transporting
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:
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
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 discountI think you should learn the certification requirements for gliders, learn what the glider
Tom
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
https://www.easa.europa.eu/light/topics/easas-type-certification-fully-electric-aircraftstandards 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).
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
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
On Tuesday, April 12, 2022 at 4:49:55 PM UTC-5, 2G wrote: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
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
mind.I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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
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").
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
for words...I did not read about air transport regulations, because gliders are not transporting
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:
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
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 youOf 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 worseTomI 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
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).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
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+).
TomWhat ever happened to "I am truly at a loss for words...."
On 4/12/2022 2:49 PM, 2G wrote: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.
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
mind.I haven't heard anyone speak of vibration while a glider is flying, unless the motor was
Tom
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
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").
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
for words...I did not read about air transport regulations, because gliders are not transporting
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:
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
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 youI think you should learn the certification requirements for gliders, learn what the glider
Tom
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
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).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
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
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