OpenTrainer: New crowd-sourced open-source two-seat primary training sailplane

Discussion in 'Soaring' started by BoKu, Jun 15, 2018.

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  1. Jun 15, 2018 #1

    BoKu

    BoKu

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    I've just started a Facebook page to discuss and promote the idea of an open-source crowd-sourced two-seat primary trainer certified as SLSA or whatever makes it eligible for commercial ride, instruction, and rental use. I envision something about halfway between the ASK13 and ASK21 in performance and complexity, and designed to fill in for the declining 2-33 population.

    I'm not extremely optimistic about this effort, but as one of the few sailplane developers with a vested interest in the future of soaring in the US I thought I'd get the conversation going and see where it leads.

    https://www.facebook.com/SoarOpenTrainer

    --Bob K.
     
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  2. Jun 16, 2018 #2

    Victor Bravo

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    Bob if you haven't already done so, get with Murry Rozansky, he is very very much interested in this sort of idea, and filling that 2-33 mission.

    For whatever my opinion is worth, IMHO the mission you speak of is best addressed with a low-tech aluminum tube and gusset fuselage and an aluminum wing. I can hear Autoreply angrily screwing a silencer on the end of his camo Barrett rifle, but the development cost of production tooling would be a significant barrier to the type of crowdfunding and open source effort you are referring to. Developing that tooling for your (smaller) ship was an enormous effort over a long period.

    My OTHER reasons for suggesting the tube and gusset method are twofold:

    1) Same reason the Hawker Fury and Hurricane fuselages were built out of replaceablee tube sections. Almost any single part can be replaced without taking the entire fuselage apart. For a club training ship that will be used for students, there will be wear and tear, and damage, and fieeld repairs. Design for that reality, especially since your mission does not really require a laminar airplane.

    2) Schleicher, Grob, and Schempp-Hirth have all produced two seat composite training airplanes. They have 40+ years of experience doing it, with German efficiency. A new startup trying to do what the Germans and Europeans are doing, but do it a lot more cheaply, ain't gonna happen.

    Additionally, with the capabilities of CAD and CNC manufacturing, it would be simple to replace any tube or gusset in the entire fuselage using a Cleco-ready part that would fit perfectly.

    No major tooling would be needed. No huge weld jigs, no comp[osite molds, no aluminum skin stamping or forming dies. This means that the "tooling" is the CAD file and the CNC tube cutting machine.

    Basically my take on it would be something like a little heavier Graham Lee / Baslee tube fuselage and a modern aluminum bolt-together Cub style wing of higher aspect ratio, in the rough shape of a 2-33

    Another interesting idea is that a variation of the Kolb Mark3 two seat E-AB powerplane with no engine and lengthened wings, and the "full enclosure" cockpit, would be a very quick and dirty and inexpensive starting point. Several modificatiosn tot he existing design would have to be made, but the bg parts are already there and proven. The Kolbs fold the wings back, and the airplane takes up less than a four foot wide space, BTW. 5 or 6 of them in a standard T-hangar.
     
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  3. Jun 16, 2018 #3

    pictsidhe

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    As an outsider looking interestedly in at the gliding world, I'd suggest a cheap trainer. Gliders are eye-wateringly expensive for the average guy.
    I can see the average glider guy having a hard time accepting that a mediocre performer is a good idea, but us non-flyers wouldn't know the difference.
    So, Bob, how about a glider that costs less than, say, a small car?
     
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  4. Jun 16, 2018 #4

    gtae07

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    I'd go a different approach entirely, and suggest either:

    - A winch that is affordable and breaks the American cultural reliance on aero-tow (and the consequent $20-30/flight tow fees)

    or

    - The trainer Mr. K is proposing, but with a self-launch motor (which frees you from the need for a support crew and a winch or tug)
     
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  5. Jun 16, 2018 #5

    pictsidhe

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    The Spitfire was designed to be the best fighter in the world. The Hurricane was designed for mass production. The Hurricane scored more kills in the Battle of Britain as they outnumbered the hard to build Spitfires...

    A self-launcher could also be worth considering as tow fees will add up.
     
  6. Jun 16, 2018 #6

    Mad MAC

    Mad MAC

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    PW-6 is pretty close to the required specs and it was cheaper than a ASK-21 (I did my training in both).

    I think out field landing damage is being overrated somewhat, a fuse built out of glass for the same fuse weight as a space frame would come pretty close to flatting a brick out house. plus the fuses seem to be critical in the torsional load case (ground loop) which isn't a strong point of space frames.
     
  7. Jun 16, 2018 #7

    Hot Wings

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    Overall I like the idea but:

    Is a certified version really necessary? Club ownership of, and training in, an Experimental is perfectly legal with the right club structure. Instruction in one owned by the student is also legal. The only real advantage to an LSA is to get rid of the 51% rule.

    Damage is a real concern but not to the same extent as a primary glider. Ease of inspection is probably more important than ease of repair - provided it is robust enough to survive a typical student's poor landings?

    I agree with gtae07 that economy of operation is just as important as availability and cost. ASTM rules allow for single ignition systems for glider engines giving more choices of essentially off the shelf engines as candidates for a self launch version.

    An open source dual drum winch is probably a good idea as well, but a completely different project. There was at one time an active Yahoo group related to this but as far as I know it never lead to anything significant.
     
  8. Jun 16, 2018 #8

    bmcj

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    Side by side might make a better trainer but may be more prone to CG shifts between dual and solo. With tandem, you can always put one seat on the CG

    Performance doesn’t matter so much because, like the 2-33, students learn and then move on to better ships.
     
  9. Jun 16, 2018 #9

    Vigilant1

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    If it is to be purpose-built to train those who will go on to higher-performance single-place sailplanes, it would seem important that students learn about aero-tow and winch launches. If so, maybe a self-launch capability isn't a desirable feature in such a craft. Similarly, handling and basic characteristics similar to higher-performance sailplanes should probably be a design criteria (mono-wheel gear, etc).

    OTOH, if a self-launching two-place glider of modest performance (L/D of 24:1) and trigear/TD gear is all that is needed, is there something that rules out the Xenos motorglider? The kit is about about $40K with engine, instruments, upholstery, etc (approx $14K more for the quick-build version). Anyway, the existing Xenos filling one marketplace niche might be something to consider as this new project starts--differentiation of the new design from the Xenos and other existing available aircrat may be desirable.
     
    Last edited: Jun 16, 2018
  10. Jun 16, 2018 #10

    gtae07

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    Admittedly, I'm looking at this from the perspective of "what's keeping me from doing a glider rating".

    My only realistic option for glider training is the local (~45min away) club. They are exclusively aero tow, so not only is the minimum fee per flight $30 (rental plus tow) but that requires a couple of other people (instructor, tow pilot, ground crew). That adds up quick when practicing landings.

    Plus, this being a club, one can't just fly and then cut and run--one is expected to do one's turn as ground crew. That's all well and good, but it presents a problem (well, two problems) for me. First, I can't afford to be spending an entire day out at the airport right now. Maybe when my wife has finished recovering from her surgery and my son is a couple years older, I'll be able to, but right now I'm grateful for an hour or two a week to work on my project. The other is that, being a club, the only days they're "open for business" is on weekends. And I work weekends.

    A self-launch option reduces the number of people required to two--the student and the instructor. You don't need other people there for ground crew, you don't need a tow pilot or winch operator, and you can go any time is convenient for just the two of you without having to wait around and let everyone else take their turn. It would also really speed up landing practice and make it cheaper, since you won't be paying per flight and having to wait for a new tow hookup. One could subsequently do your tow/winch endorsement later on in another aircraft (or do it in the trainer if it's designed to allow it...)
     
  11. Jun 16, 2018 #11

    proppastie

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    well good luck...reading all the responses I come back the my statement of "there can only be one designer" that is not to say that suggestions are ignored as really now there is not much that has not already been done in aviation. I think that crowd funding might be new to aviation though. I am not sure what exactly that means. If any one can pull it together though Bob might be the one. Another phrase I seem to remember too is "never volunteer".
     
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  12. Jun 16, 2018 #12

    Vigilant1

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    As a bonus, the self-launch option also virtually eliminates the chances of "landing out," with attendant possibility of damage to the aircraft and costs of recovery. That's important if the plane will be operated across a wide geographical area, but probably not very important to a club if the aircraft will always be doing its training flights in designated areas chosen to have good access to airports or hospitable landing sites.
     
  13. Jun 16, 2018 #13

    bmcj

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    Wait a minute!!! Winches and self launchers, all just to avoid having to seek out a tow plane? Isn’t that what the new self-driving cars are for? ;)
     
  14. Jun 16, 2018 #14

    proppastie

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    good thing about self-driving cars when they crash it is a better "media story" than an aircraft crash.
     
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  15. Jun 16, 2018 #15

    TFF

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    Oh my. Self driving launches. I want to see the first insurance claim if there is a crash doing that! As for the Spit and Hurricane , they had slightly different targets. Bombers was the main target, but the Spit was sent to tangle with the fighters while the Hurris went straight for the bombers. There was a strategy on what got shot at.
     
  16. Jun 16, 2018 #16

    pictsidhe

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    The Spits got first dibs on fighters as they were a better fighter. But there weren't enough of them, so plenty of fighters were shot down by the merely competent but much more numerous Hurricanes. I had the pleasure of seeing Hurricanes and Spits flying today. The Spits were faster, but the Hurricanes did tighter turns.
     
  17. Jun 17, 2018 #17

    Pops

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    Last weekend was the big WW-2 military reenactment at Reading , PA. First Friday, Sat, Sunday of June of each year. Want to sit in a Spit or Hurricane, just ask if its OK. You would love it. Been about 4 years since I've been there and like to make it next June. Lots of movie shots are done there. I watch a movie this winter of Spit's in WW-2 and had a shot of the pilots getting a quick new briefing before getting in the airplanes. I was left and behind the cameras and my neighbor was on the other side. Like being on a huge movie set of Tora, Tora, etc, and watching WW-2. Large battle everyday out in a field with tanks, etc, America reenactment troops against the Germany reenactment Troops. So much going on.
     
  18. Jun 17, 2018 #18

    pictsidhe

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    I saw an av36 fly yesterday. It did come down fairly quickly, but wow, it put on an amazing show! It's pretty simple construction and storage would be relatively easy. Would need significant enlarging for 2 US seats, though.
     
  19. Jun 17, 2018 #19

    billyvray

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    Where did you see this ? I'm a sucker for Fauvels..

     
  20. Jun 17, 2018 #20

    Hot Wings

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    :emb:

    Box lid closed in on me and I didn't notice. :ermm:

    Completely forgot about the electric option. Still not a viable option for heavy training. As a backup when using a winch as the primary method of launch it gives the options for instruction in a motorglider and solo use when needed.
     

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