# 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 22, 2018

### BBerson

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Primary training is primarily learning to land. I learned in a 2-22 with aero tow, doing about two landings each Saturday because others went up also. A quicker way to do circuits (landings) is needed. A motorglider is obvious, but not so simple to do in practice.

Later the club got a 2-33 which allowed advanced thermaling instruction which was a limiting factor with the 2-22, since one wrong turn and it needed to land.

Perhaps the primary trainer could have a switch for advanced glide ratio. Electric thrusters can provide any glide ratio relatively cheaply without the need for large wings that are heavy.

Last edited: Jun 22, 2018
2. Jun 22, 2018

### mcrae0104

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Affordability is a slippery, relative term. We have litigated this extensively here at HBA.

Recently I have become intrigued with paramotoring as a fascinating way to get in the air even though I can afford fly "real" airplanes with modest frequency.

OTOH, a good friend of mine finds the cost of warbirds--his life dream--to be a struggle and wouldn't consider a lowly paramotor.

I say fly what you can afford--anything that gets you off the ground is a victory over gravity that should be applauded by everyone here.

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3. Jun 24, 2018

### John.Roo

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Hello!
Idea to produce new trainer is good, however first of the two main questions is - what is expected final price?
As has been written - expected costs of development 500T - 1,3M USD are adding 5T - 13T USD to each airframe. It means there is expected need of 100+ pces?

There are already existing projects of new trainers.
For example new L-23NG (http://www.blanik.aero/l23ng-3) based on a very succesfull L-13/23 series.

Or upgrade of "old" L-13 trainers (http://www.blanik.aero/gliders-for-sale). And this gliders are nice and perfect for training. The only disadvantage is limited lifetime due to aluminium structure.
There is also Polish SZD-54 Perkoz (http://szd.com.pl/en/products/szd-54-2-perkoz) with 15T hours "design life". Price +- 75T EUR.

And "old" trainers like:
PW-6 - with cost arround 50T (for example here http://www.windpath.ca/index.php/products/szd-jezow) etc.

I definitelly support new designs and I definitelly support every idea increasing number of new pilots (especially glider pilots)
So second main question is - will new trainer help to train more pilots?

My personal experience is that glider training price is not a problem.
If you want to have a glider pilot license you need 15-20 hours and prices are affordable (even more affordable if you are aeroclub member, but than have also other duties).
Here is pricelist of glider pilot training in Czech Republic (1 USD = +-22 CZK)
https://www.aeroweb.cz/pilotni-prukazy/kluzaky/pilot-kluzaku-spl

So where I see real problem?
I see main problem how to build hours and experience AFTER training.
During training is always a lot of people on airfield helping with aerotow, winch starts etc.
Than you have license and you want to use your free afternoon during working day to fly and... nobody is on airfield.
Problem continues even if you have your own old or new glider - plenty of one-seaters are offered on market from low to high-end price (example here http://www.segelflug.de/osclass/).
But still you need a tow plane and help....
Do you want self-launch glider solving this problem? Than prepare your pocket that soon will be much lighter...

So what I want to say... my opinion is that market is missing "primary self-launch glider" - simple and "affordable" (this slippery and relative term
No high-end performance, light enough to allow simple manipulation and "nice" to fly - allowing to be flown by "pilot with wet/just printed pilot license".
Young pilots are from "gaming" generation. They generally don´t want to spent whole day on airfield for 2x winch start (in total 10 min in the air).
Honestly... I also prefer to be totally independent.
I was many time "pissed off" (and sad) when I arrived during morning to airfield and "old pilots" were drinking coffee, discussing about flights in past and than they (typically arround the lunch time) decided to release "young eagles" to the air...

I was enthusiastic about ultralight category of gliders.
However - soon this category went to "wrong" price range.
Beautifull GP gliders are starting from 43T EUR (no VAT) for GP11 Pulse (no self-launch).
https://www.gpgliders.co.uk/faq/

Unfortunatelly the same problem with Silent, Apis etc.

Do you want more simple way how to glide?
Don´t expect that you save money buing self-launch glider like very interesting Archeopteryx
Unit costs 83 800 - 108 500 swiss franks (+- is the same amount in USD)

By the way - where are projects like AXEL glider?

Is not only about cost of high-end materials. "Human work" is also not cheap (and this will not be better - in aviation you need experienced workers).
And... also certification requirements are more complex (flutter testing etc.).

OK, this post is already too long and not so optimistic.
Now I will prepare my morning coffe and think about solution
Have a great day!
Martin

Last edited: Jun 24, 2018
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4. Jun 24, 2018

### ypsilon

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Dobré ráno, Martin

When I was a kid, I had the urge to become airborn as soon as possible, which is why I got myself a paraglider as soon as I could talk my parents into it. It took a few more years and I started to fly sailplanes. I was a great time basically living on the airfield, flying whenever the weather permitted. Then I made the mistake to finish my studies, and get a real job. I met my wife, later the kids came, and now I find myself flying largely with the paraglider again, the sailplane sleeping comfortably behind the house in its trailer. I hear similar stories from many of my old flying companions, so this seems to be a common fate.
Living in the alps, I just put my glider in the car and go to the mountains after work, and still fly two or three hours in gentle evening thermals (video below we launched at 5:30pm, sometimes even much later)
[video=vimeo;223032362]https://vimeo.com/223032362[/video]
That doesn't really work out with sailplanes (unless you have a self-launcher AND a reasonable spot in the hangar, so you don't have to move 20 other ships before you can access your own.
So even when my paraglider offers only a 1/4th of the performance of my H201b (L/D 9 vs L/D 38) I fly about 4 times as much with it (maybe 150 vs 35 hours).
In a nutshell reality shows for me (and for many of my flying friends), that simplicity beats performance.

This was the main reason for my own little project (which btw. progresses very slowly only).

There are UL gliders that are cheap and self-launchers, like the Banjo, but they were all not very successful. Combustion-engines are probably too complex and too maintanance-intensive to be a real solution for the weekend-warriors out there. Electric drives are better, but expensive and come with their own limitations.

To me the SWIFT, more than 30 years after after its maiden flight seems still the best hangglider/sailplane hybrid out there. The electric drive gives you ~1500 meters of altitude which is enough for a self launch + some safety to avoid outlandings. It's almost the same performance as the Archaeopteryx, at a third of the cost. Plus the Archaeopteryx is as unwieldy as its name. You need a trailer almost as large as a sailplane trailer (To be fair, all SWIFT pilots I know personally also use sailplane trailers by now, no one uses the roof-top-box anymore).
The only thing I don't like about the SWIFT is the fact that you sit behind the wing. If you are used to the view in a regular glider or even a paraglider, this gives you headache (especially in crowded thermals).

Last time I heard of Darek, he told me that he sold the project to Werner Eck, who'd want to make build the thing commercially. Don't expect it to become super-cheap, though. Darek estimated that in a professional environment it would take at least 1000 hours to build it even at a moderate cost of 30€ / hour that's 30K€ without any material/engine etc.

I see, this is getting too long and hijacking Bob's thread. Martin, why don't you start an "most affordable Sailplane construction" thread, where we can continue this discussion?

5. Jun 24, 2018

### Hot Wings

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That to me is a pretty good summation of the "problem" in the US. It's not a lack of hardware, it's a lack of usable hardware that can be operated without a crew.
The only solutions I can imagine are either motorgliders or a winch that can be operated solo. Could be a failure of my imagination..............?

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6. Jun 24, 2018

### BBerson

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A typical certificated two seat motorglider is about twice the weight of a 40hp Cub. That is the dilemma of medium performance two seat motorgilders. Can't be low cost.
Why not teach glider pilots in Cubs (Taylor-craft/Champs)? Turn the engine off and land dead stick.
Get about 10 landings in an hour. Some spoilers could be fitted. Perhaps extend the span some. A starter would be nice.

I guess the student could ride along and learn in the SuperCub tow plane return for almost free.

7. Jun 24, 2018

### Pops

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Flying the Piper Super Cub tow plane back is how I started my flying lessons. If the SC was towing a single place sailplane, I could go. Worked in the ground crew and got fly the SC at different times. Then when my instructer had some free times in the middle of the week, we got to use the SC if I paid for the fuel. Ray had been a Sailplane, floatplane and landplane instructor since 1937. He got his rating in a Aeronca C-3 on floats. Don't know what sailplane for his rating, but when I met him he just finished building a Cherokee Homebuilt sailplane with a lot of drag clean-ups, different wing tips, etc. Latter he had a K-6.

8. Jun 24, 2018

### BJC

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I like your idea, BB. Two students per tow. Cuts the cost in half.

BJC

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9. Jun 25, 2018

### John.Roo

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Hello!

I see, this is getting too long and hijacking Bob's thread. Martin, why don't you start an "most affordable Sailplane construction" thread, where we can continue this discussion?

Absolutelly right! I apologize to Bob.

By the way - thank you to remind me and sorry that I forgot SWIFT and BANJO in the list of super light gliders. I was watching SWIFT pilots many times in French Alps and it was impressive

Best regards!
Martin

10. Jun 25, 2018

### ElEsido

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I remember reading an interview with an engineer of one of the German sailplane manufacturers said that developing a "new kind of ASK 21" was not worth it. If you do the whole design work (including a crash safe cockpit) you can as well apply modern aerodynamics on the outside and add a new wing profile for little extra cost; and in the end have very different, and probably better plane than the ASK 21. Or putting it the other way round: Developing a low performance glider is not significantly cheaper than developing a medium to high performance glider. I googled around but I can't find the transcript anymore.

The Archaeopterix has been mentioned. Keep an eye on this thread to follow the story of a significantly cheaper and probably more capable alternative. This might indeed be the future of basic training.

What to do? Develop a "dual seat Tetra" with an FES AND a jet?

11. Jun 25, 2018

### Victor Bravo

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All of that is undoubtedly 100% correct from the German sailplane company point of view. But this discussion exists because there is a need in America (and perhaps elsewhere) for a much much lower-tech training glider that can be club-built or low-production manufactured at a far lower cost than anything resembling the (wonderful) K-21.

IMHO, and not to displace what the OP was thinking, I think we are discussing something with little or no tooling cost, other than the CNC cut files. Whether wood, sheet aluminum, tube & gusset, steel tube, or perhaps even old-style wet moldless Rutan style foam and glass like a Long-EZ. We're not talking about a "better" training glider, we're talking about a much cheaper training glider that is safe enough and flies well enough to train students, give rides, and be soarable in average conditions. IMHO re are solving this equation for initial development cost and initial purchase cost, not long-term cost over the course of thousands of students trained.

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12. Jun 25, 2018

### plncraze

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It would be nice if the buyers could help build the sailplane to save on labor cost. Labor is the killer.

13. Jun 25, 2018

### Topaz

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I completely agree with the notion that a trainer motorglider would be a nice thing to have, but there's another issue, at least in my part of the USA: A nearly complete lack of CFI-G's that are able to give self-launch endorsements. As of five years ago, I knew of exactly two actively working as CFI's in the entire southern half of California. And only one of them had an actual motorglider that could be rented for training - at the mere pittance of $250/h plus fuel. I'm sure there are more out there, but they're not exactly dime-a-dozen, in the best of cases. Perhaps toobuilder is right in this regard - it may not be completely an equipment problem that we're facing. A lower-cost self-launching trainer might help, but if you can't get qualified instructors to do the training, they'll just sit on the ground gathering dust. That may well be true in the abstract, but manufacturing a low-performance glider can be significantly less expensive on the simple basis that the tooling doesn't have to hold the extreme tolerances that a higher-performance one would require. Again, using the SGS 2-33 as a perfectly serviceable example of the kind of performance needed (or not needed, depending on how you want to look at it), stressed-skin sheet metal construction is perfectly adequate for this kind of sailplane. Tooling costs alone would be less, since only jigs are needed, not full molds. The idea that "it's just as inexpensive to develop a high-performance sailplane as it is a low-performance one" is something that I feel has been used to rationalize building only high-performance ships, with accompanying high-performance prices. That and the attitude I see from a lot of sailplane pilots, where if it's not 50:1 or more, it's not worth flying at all. And, for the engineer, "design to increased performance" is always going to be a lot more exciting than, "design to cost." Designing a low-cost airplane just isn't as much fun. We're fighting this particular battle on multiple fronts, from within and without. 14. Jun 26, 2018 ### Hot Wings ### Hot Wings #### Well-Known MemberHBA Supporter Joined: Nov 14, 2009 Messages: 6,442 Likes Received: 2,353 Location: Rocky Mountains Not for all of us. Designing to maximize a small set of parameters, no matter what they are, has it's own intrinsic attraction and reward. But that is still attacking the "problem" from the flying hardware side of the equation. The other side of the equation needs to be modified as well to put everything in balance. dsigned and Topaz like this. 15. Jun 26, 2018 ### Victor Bravo ### Victor Bravo #### Well-Known Member Joined: Jul 30, 2014 Messages: 6,217 Likes Received: 5,012 Location: KWHP, Los Angeles CA, USA Get all the brilliant European sailplane engineers and designers together, with all their brains and experience and knowledge, and give them parameters to design a safe 2 seat rigid wing training glider with a maximum retail price of$25,000 US, and see what they can come up with. I bet that they will very quickly abandon the advantages of molded composites in favor of sheet or tube aluminum.

Robert Baslee offers pretty complete airframe kits for single and two seat WW1 replica airframes, and sells them for $10,000 to$15,000. They are more or less well engineered, have acceptable flight characteristics, and have been built in large numbers by un-skilled labor. IMHO THAT is the closest thing to what we're talking about here.... something that looks like an SGS 2-22 that came out of Baslee's shop, with enough wing area and aspect ratio to stay aloft with a 2-33 in modest or average lift. Deviations from the Baslee / Graham Lee construction method will include struts instead of wire bracing, and at least the front 1/3 of the wing sheeted in aluminum, and (probably) a sheet metal / AL extrusion main spar.

The strutted monoplane versions may well be less expensive (lower parts count) than the wire braced biplanes. No engine mount, one wheel landing gear, no fuel tanks, etc. The wing and tail outloines can all be straight lines like the 2-33, requiring less fabrication/forming than the rounded tails of the WW1 stuff.

The big point I'm trying to make is, if someone like Baslee were convinced to design such an aircraft and offer kits, it is quite possible that the airframe kit coudl be sold at a profit for \$15K to private clubs or pilot co-ops, or non-profit org's that are set up to be able to legally do flight training with an un-certified aircraft.

16. Jun 26, 2018

### Rienk

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I'll come by for a lesson or two this week - as I'm visiting my son in Seattle at the moment!

Last edited: Jun 26, 2018
17. Jun 26, 2018

### Rienk

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What about AutoReply's idea of a composite "fold-a-plane"? All flat wrapped composite panels that have simple molds with self jigging fixtures?
Personally, I think making molds for a low performance design would be relatively quick and inexpensive, but not necessary to utilize the advantages of composites?

18. Jun 26, 2018

### BBerson

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Sorry, I meant I would have given some free lessons if someone had asked in the past. My Grob is in storage now waiting for restoration.
I did give several free rides, but none wanted lessons. A more populated area like Seattle might be different. But I don't want to live in Seattle.
I think you can get a ride from another Grob based at Arlington north of Seattle. Try: "glider-rides.com"

19. Jun 26, 2018

### ypsilon

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Sure there are differences in history and (flying) culture between the U.S. and Europe. It seems that there is simply no market for gliding in the U.S. Here in Austria you can fly a motorglider for 75€/h (including Fuel). FIs are typically working voluntarily in the clubs, so you pay another 20-30€ per hour for the club. There's a lot of voluntary work involved, but for whatever reason, this works over here (In radius of about 50km here, there are a 9 or 10 clubs offering sailplane rides & lessons) , and I don't think it has anything to do with the availability of gliders. The primary motorglider dicussed here exists:

It's a SF 25E (or a SF28). You get these machines used in good condition for about 15K€. They are simple to operate and perfectly suitable for lessons (in fact I had my first lesson on a SF25). WIth the SF25E you can thermal as well (I once flew 200km out and return after a self launch with only 7 minutes on the engine).
If there'd be a market for these machines in the U.S. I am sure someone would ship those gliders over there.

20. Jun 26, 2018

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