• Pawnee PA25 with Tost reel

    From Mark Palmer@21:1/5 to All on Thu Aug 4 09:55:08 2022
    Hello all,

    Our club has been operating a Pawnee with a Tost reel system for some years now. For the most part it works well, but it does have issues. It is not uncommon for it to jam on line retraction. Our biggest concern is the amount drag and amount of force
    need to pull the line out when we are about to hook up to a glider.

    I'd like to talk to members of other clubs/operations that use the reel. I know the St. Louis club uses a reel system and that Williams Soaring does also. What other clubs use a reel? What issues do you have? Have you done any modifications? Do you have
    the same issues we have?

    You can contact me off list if you wish at mfpalme AT gmail DOT com .

    Thanks,

    Mark Palmer
    Greenwood Village, CO

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  • From Roy B.@21:1/5 to All on Thu Aug 4 11:11:22 2022
    Mark:
    Below is a copy of my post from April 25, 2017 on this list relating to our problems with the system when I was Chief Pilot for GBSC. We had the system on 2 of our 3 towplanes and eventually stopped using it entirely.
    Roy

    Charlie:
    We used the system for several years on our 2 Pawnees and finally got away from it. I found that it was a useful system for situations of limited operations - particularly where the pilot wants to do a tow and then carry on to a new destination ( like a
    cross country retrieve) without landing to drop the rope. It also had all of the expected advantages of not landing with a rope hanging behind you. But - we also found a few very significant disadvantages:

    1) The system uses an electric motor that is operated by a manual switch. The tow pilot has a mirror that is focused on the tail cone so she or he can shut off the switch when the rope is fully retracted. The system depends on the tow pilot looking in
    the mirror at exactly the time & place where they need to be looking for traffic, checking cool down, etc. As a tow pilot I did not like that.

    2) The system is non compliant with FAR 91.309(a) since it uses only one weak link (the FAR requires 2: one at each end) and there is no way to use a weak link at the towplane end. In a towing accident that could be an issue.

    3) The system can't be used in cold weather. If the rope gets wet it freezes on the reel. If you switch over to use the manual Tost release you have to disconnect the guillotine cable and connect it to the Tost release. This is dangerous because if the
    reel is now used - the guillotine is disconnected. That happened to us twice and we had to tape over the housing to prevent a reoccurrence.

    4) It is possible for the reel to get tangled so that the rope stops close to the end - but the glider load is on the reel (and not on the airplane airframe). The reel is not designed to take that load.

    5) Tangles are frequent - and a PITA. Checking the portion of the rope that is hidden behind the guillotine is also a PITA. Changing the rope is a PITA.

    6) The system is expensive and parts are expensive. We had lots of rope breaks (almost never at the Tost weak link) and that weak link unit is expensive, we lost several tail cones (also expensive) and had a motor burn out (really expensive and a long
    wait).

    7) We had incidents were the tow plane "slack out" process was interrupted and the tow pilot didn't realize that reel was not fully played out. Then when the tow started it whiplashed the glider.

    8) A&Ps are not familiar with the system and some were reluctant to work on it.

    Bottom line - it's a complex system that makes sense in an operation where cost is not important, the same people are using it, and obstacle clearance is important. But in a busy club or commercial environment a simple rope/release system works better -
    I was happy to see it go.

    Roy B.(GBSC Chief Pilot)

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  • From Mark Palmer@21:1/5 to All on Thu Aug 4 12:08:42 2022
    Roy,

    Thanks for your post. Many of the items you list are ones we have experienced also. Unfortunately for us, use of the reel is mandated by the airpark we fly out of. Changing back to a fixed rope isn't an option.

    We have tried to develop and standardize our launch procedures the last couple of years. They're not perfect by any means. Having the wing runner hold the line while the towplane taxis away puts a lot of stress on the wing runner. Hooking to the glider
    and using that as an anchor does not appeal to private owners or the club because of the line's tendency to snag and grab.

    I met you briefly last year at the Womens Soaring Seminar in Springfield. I very much enjoyed your talk on advanced cross country flying.

    Thanks,

    Mark

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  • From Sarah Anderson@21:1/5 to Mark Palmer on Thu Aug 4 14:25:53 2022
    That's unfortunate. Our club, (in Minnesota) operated a PA18 with a custom reel made by a master engineer club member
    years ago.

    The STC paperwork and winch goes with the supercub, which is for currently for sale.
    But I don't think 160hp would work out well in Colorado.

    We should have developed it into a product - apparently it's still better that Tost as we had none of those issues.

    Sarah



    On 8/4/22 11:55 AM, Mark Palmer wrote:
    Hello all,

    Our club has been operating a Pawnee with a Tost reel system for some years now. For the most part it works well, but it does have issues. It is not uncommon for it to jam on line retraction. Our biggest concern is the amount drag and amount of force
    need to pull the line out when we are about to hook up to a glider.

    I'd like to talk to members of other clubs/operations that use the reel. I know the St. Louis club uses a reel system and that Williams Soaring does also. What other clubs use a reel? What issues do you have? Have you done any modifications? Do you
    have the same issues we have?

    You can contact me off list if you wish at mfpalme AT gmail DOT com .

    Thanks,

    Mark Palmer
    Greenwood Village, CO

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  • From Hartley Falbaum@21:1/5 to Sarah Anderson on Sat Aug 6 16:30:35 2022
    On Thursday, August 4, 2022 at 3:26:00 PM UTC-4, Sarah Anderson wrote:
    That's unfortunate. Our club, (in Minnesota) operated a PA18 with a custom reel made by a master engineer club member
    years ago.

    The STC paperwork and winch goes with the supercub, which is for currently for sale.
    But I don't think 160hp would work out well in Colorado.

    We should have developed it into a product - apparently it's still better that Tost as we had none of those issues.

    Sarah
    On 8/4/22 11:55 AM, Mark Palmer wrote:
    Hello all,

    Our club has been operating a Pawnee with a Tost reel system for some years now. For the most part it works well, but it does have issues. It is not uncommon for it to jam on line retraction. Our biggest concern is the amount drag and amount of force
    need to pull the line out when we are about to hook up to a glider.

    I'd like to talk to members of other clubs/operations that use the reel. I know the St. Louis club uses a reel system and that Williams Soaring does also. What other clubs use a reel? What issues do you have? Have you done any modifications? Do you
    have the same issues we have?

    You can contact me off list if you wish at mfpalme AT gmail DOT com .

    Thanks,

    Mark Palmer
    Greenwood Village, CO

    We, at Mid Georgia Soaring Assn, Monroe GA, have used the TOST CRG system on our PA 25-235 (Pawnee) for about 20+ years. We have had some minor difficulties, but overall, a very good experience. We got it initially to stop taking out a phone line
    crossing the approach path. Occasionally, the rope cross-winds as the reel does not have a level wind system. It only requires a minor tug on the rope. We don't have a ice problem--that would be messy!
    WE attach the glider to the rope, and the glider pilot holds the brake for 3 wheel and CG hook gliders. A rope overrun requires a removal of that section of rope, as real damage is internal. The glider pilot releases the brake AS the takeoff roll begins--
    there is no jerking. We have a mirror to view the funnel---The last part of the rope is painted orange--three 1 ft stripes with 1 ft space between, then the final (fourth) stripe is 2 ft long, followed by a 6 inch unpainted area. The tug pilot thus
    knows the rope is full out.
    We do have an occasional (once or twice a year) jam on retraction. The tug pilot starts the retractor after the glider release is confirmed, and keeps the airspeed under 90 Kt until the rope is in. Above that speed, the load on the retract mechanism is
    too great.
    We stopped breaking funnels when we educated our members to pull the rope straight out. We educated our CFIG's to not do "extreme" lateral displacement on wake box, and slack line exercises. As long as we remain in the lateral area where the tailwheel
    and the opposite making gear are lined up, we are OK.
    We have had 2 rope breaks--both at the location where the rope enters the end piece. We have the proper 1200N weak link, but that didn't let go. (Our pilots failed to actuate the release, so we saved the end piece.!)
    Changing the rope is easy, if you know how. We change it after two years.
    We require functional check of the guillotine at annual. Unfortunately this was neglected :-( .. The mechanism DID NOT work, no matter how much force. Disassembly, cleaning and lubing restored order. We have a powered release, with large red industrial
    button switch on the panel. It is Verboten to sharpen the blade, and replacement is expensive. The blade is surface hardened only (Nitro Steel) and sharpening would soon remove the hardened edge. The more tension on the rope, the better it cuts.
    So-overall, we are happy with the CRG. It speeds up our operation and prevents leaving a rope on the runway (it has happened at end of day--everybody is hot and tired.)

    Hartley Falbaum
    Loganville, GA, USA

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  • From bumper@21:1/5 to All on Sat Aug 6 20:22:29 2022
    Around 2007, I built 3 tow reels for Soaring NV at Minden. My design was based on tow reels made for or by Jim Indrebo, in fact, I purchased the guillotines from Jim, as he had extras. I had experience towing gliders with one of his reels, so looked to
    address the few issues I observed, one of which was his design used 1/4" polyurethane tubing for the drive belt on the reduction drive from motor to reel. It worked, but was sub-optimal, as you had to get slowed way up to retract the rope or the belt
    would just slip due to air drag on the rope. The belt was also prone to occasionally pull apart where the ends were joined to make the loop, or to come off the pullies. This necessitated slowing way up to initiate retraction, so the pilot would sometimes
    delay retraction until slowing down for pattern entry. Of course, this can also be a higher mental work load time that presented the opportunity for the pilot to forget. My design would retract the rope at VNE, no need to slow.

    I made the reel to mount forward of the pilot. The reel mount clamped onto the frame tubing at 4 points. Reduction drive was by chain and sprockets - no slipping and strong enough to "reel in" the golf cart I used for testing the design. There was a
    master On/Off switch and a large red momentary button on the dash to initiate rope retraction. Once initiated with a momentary push of the button, three magnets buried in the aluminum reel face were sensed by a Hall Effect sensor. The output of the
    sensor charged a capacitor/resistor delay circuit which kept the "run relay" energized. As soon as the rope came up to the tail stop, the magnets no longer were sensed by the Hall Effect sensor to allow the RC circuit to de-energize the "run relay" and
    the reel stopped. The run relay deenergizing, also removed power from the Hall Effect sensor so that the real would not "bounce" i.e. come up tight, then move a magnet past the sensor, repeat. (There was never a problem with this auto shut off, but if
    there were, the pilot holding the retract push button would override and retract the rope for redundancy).

    I'm retired from most of my making stuff days. Recent heart issue reinforces that. Happy to answer questions etc.

    bumper

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  • From Mark Palmer@21:1/5 to All on Sun Aug 7 08:56:04 2022
    It's good to hear every one else's experiences. It seems that the line fouling one way or another is not uncommon. For us, lately it has become very common, and thus my concern.

    Hartley notes that they hook up the line to the glider and then let the towplane taxi away while the glider holds the brake. We do not do this, instead, the line crew holds the bullet while the line plays out. This puts a lot of stress on the line crew,
    obviously. We're experimenting with some sort of bungee setup that the line crew would hook to the line while it plays out. We do not hook the line to the glider and let the towplane taxi away. This is because the line hangs and jerks and (more often
    than we like) the line fouls and stops. To us, this seems to put a lot of stress on the glider at the release location and many pilots do not like it.

    So how smoothly does the line extend? A couple of years ago I was at the Women's Soaring conference in St. Louis. They have a reel on their Pawnee and the line always seemed to extend smoothly and easily. Ours has never acted like that. We're currently
    using the 6mm CRG rope from W&W. We've also tried a 4.5 mm poly rope. No difference.

    Bumper, you might not be in the building business any more, but if you had any pictures or diagrams, I'd love to see them.

    Mark

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  • From Hartley Falbaum@21:1/5 to mfp...@gmail.com on Sun Aug 7 10:01:08 2022
    On Sunday, August 7, 2022 at 11:56:06 AM UTC-4, mfp...@gmail.com wrote:
    It's good to hear every one else's experiences. It seems that the line fouling one way or another is not uncommon. For us, lately it has become very common, and thus my concern.

    Hartley notes that they hook up the line to the glider and then let the towplane taxi away while the glider holds the brake. We do not do this, instead, the line crew holds the bullet while the line plays out. This puts a lot of stress on the line crew,
    obviously. We're experimenting with some sort of bungee setup that the line crew would hook to the line while it plays out. We do not hook the line to the glider and let the towplane taxi away. This is because the line hangs and jerks and (more often
    than we like) the line fouls and stops. To us, this seems to put a lot of stress on the glider at the release location and many pilots do not like it.

    So how smoothly does the line extend? A couple of years ago I was at the Women's Soaring conference in St. Louis. They have a reel on their Pawnee and the line always seemed to extend smoothly and easily. Ours has never acted like that. We're currently
    using the 6mm CRG rope from W&W. We've also tried a 4.5 mm poly rope. No difference.

    Bumper, you might not be in the building business any more, but if you had any pictures or diagrams, I'd love to see them.

    Mark

    Our rope payout is usually quite smooth. Perhaps some dirt or debris embedded in the rope? Our members would not like the jerking you describe.
    We did have to adjust the clutch about 2 years ago. We are still using the original motor and clutch. We use the 60 m reel. what size do you have?

    Hartley

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  • From Mark Palmer@21:1/5 to All on Sun Aug 7 12:47:04 2022
    Hartley,

    I believe it's the standard 60 meter reel but I will check. I know our IA and Chief Tow Pilot have disassembled and check the entire system in the last year or so.

    If the line paid out smoothly I think we'd have less objections from pilots.

    Thanks,

    Mark

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  • From Tony@21:1/5 to mfp...@gmail.com on Sun Aug 7 13:22:07 2022
    On Sunday, August 7, 2022 at 3:47:06 PM UTC-4, mfp...@gmail.com wrote:
    Hartley,

    I believe it's the standard 60 meter reel but I will check. I know our IA and Chief Tow Pilot have disassembled and check the entire system in the last year or so.

    If the line paid out smoothly I think we'd have less objections from pilots.

    Thanks,

    Mar

    Miami Gliders at X51 has a Pawnee with a reel, surgical tube type belt mounted forward of the rudder pedals. Tommie and Carlos bought it with that rig out of somewhere West of the Mississippi ca. 2004. Works great. As the tube/belt ages it is necessary
    to get slowed up to 100mph or so to retract, but you can retract at Vno when it's fairly fresh. Never saw a wear or other issue in about 300 tows. No reason you can't put a weak link on the non-pulley end of the line.

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  • From bumper@21:1/5 to mfp...@gmail.com on Mon Aug 8 00:01:28 2022
    On Sunday, August 7, 2022 at 8:56:06 AM UTC-7, mfp...@gmail.com wrote:


    Bumper, you might not be in the building business any more, but if you had any pictures or diagrams, I'd love to see them.

    Mark

    Mark,

    Sorry, I have neither. I didn't put the project to paper as far as diagrams or blueprints, just sort of built it to fit with quite a few visits to the Pawnee with a tape measure. I did do what amounts to a tech write up for the FAA, that included circuit
    diagrams and how the system operated etc. You might contact SoaringNV at Minden to see if they can help.

    Our procedure was to stop the tug a reasonable distance from the glider to prevent sand blasting and let the line crew pull the line and hook up, test the release etc. Then taxi away to pay out the line, no problem. Payout was actually too easy IF the
    motor leads are not shorted when off (my first tow reel had the motor leads simply shorted by the motor power switching relay when off. This proved to be too difficult for the line crew due to too much braking action. A suitable resistor was then used in
    the motor lead shorting circuit to moderate payout braking so the drum won't freewheel and cause line overwrap. The resistive load has the motor working like a generator into the load to cause light braking. This also serves to prevent any tendency for
    the rope to pay back out in flight after retraction. I will say using a narrower drum results in less tendency to have line overwraps (tangles if you will) in general. The first two tow reals I made were relatively narrow (the same as Indrebo's, guessing
    5 or 6 inches wide), and worked fine. The last reel i made was, due to a screw up on my part, a couple of inches wider which made it more picky in the rope selection that could be used without overwrap glitches. (I did notice the width goof before
    finishing the reel and offered to make it the same width while it was relatively easy to do so . . . they said go ahead with it as is, as we didn't realize the negative effect it would have at the time.)

    bumper

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  • From Morgan Hall@21:1/5 to bumper on Mon Aug 8 08:12:44 2022
    Bumper,

    Thanks for some details on limitations you saw on the Indrebo design. We just acquired an old Indrebo Pawnee with the reel system. It indeed requires slowing to a minimal speed to retract the rope. Additionally, when we add a weak link with a
    Schweizer ring on it, it will pull the line out on the descent.

    Sounds like we need your resistor braking upgrade and maybe a new poly tubing belt to reduce slipping based on others feedback as well.

    I will try reaching out to SoaringNV to see if they have any records of your diagrams or work. But it sounds like a deep dive under the panel is going to be required to document what we currently have anyhow. Always fun during these 100 degree days.

    If you remember any specifics, shoot me an email to: morhall at gmail

    Thanks,

    Morgan

    On Monday, August 8, 2022 at 12:01:29 AM UTC-7, bumper wrote:
    On Sunday, August 7, 2022 at 8:56:06 AM UTC-7, mfp...@gmail.com wrote:


    Bumper, you might not be in the building business any more, but if you had any pictures or diagrams, I'd love to see them.

    Mark
    Mark,

    Sorry, I have neither. I didn't put the project to paper as far as diagrams or blueprints, just sort of built it to fit with quite a few visits to the Pawnee with a tape measure. I did do what amounts to a tech write up for the FAA, that included
    circuit diagrams and how the system operated etc. You might contact SoaringNV at Minden to see if they can help.

    Our procedure was to stop the tug a reasonable distance from the glider to prevent sand blasting and let the line crew pull the line and hook up, test the release etc. Then taxi away to pay out the line, no problem. Payout was actually too easy IF the
    motor leads are not shorted when off (my first tow reel had the motor leads simply shorted by the motor power switching relay when off. This proved to be too difficult for the line crew due to too much braking action. A suitable resistor was then used in
    the motor lead shorting circuit to moderate payout braking so the drum won't freewheel and cause line overwrap. The resistive load has the motor working like a generator into the load to cause light braking. This also serves to prevent any tendency for
    the rope to pay back out in flight after retraction. I will say using a narrower drum results in less tendency to have line overwraps (tangles if you will) in general. The first two tow reals I made were relatively narrow (the same as Indrebo's, guessing
    5 or 6 inches wide), and worked fine. The last reel i made was, due to a screw up on my part, a couple of inches wider which made it more picky in the rope selection that could be used without overwrap glitches. (I did notice the width goof before
    finishing the reel and offered to make it the same width while it was relatively easy to do so . . . they said go ahead with it as is, as we didn't realize the negative effect it would have at the time.)

    bumper

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