A path to an affordable trainer?

On Wednesday, July 31, 2013 2:23:46 PM UTC-7, WB wrote:
A similar concept, flat-panel, pre-fab composite version of a K-18 was make
by a Brit once upon a time and looked pretty good. Don't know what became of it.

That would be the Edgley EA9 Optimist, which I bring up here periodically:

http://www.flightglobal.com/news/art...ototype-24019/
http://www.retroplane.net/forum/files/optimist_195.pdf
http://www.faulkes.com/dfet/index.ph...sailplanes-ltd

I think the major mistake that they made (and I remember it being discussed at the time) was not coming up with a two-seater (think modernized ASK-13) as their first design. Even back then, there was a need for affordable training gliders to replace aging K-7s, K-13s, 2-33s, and Blaniks.

We've spent the past few years designing and building an "affordable" truck-based winch, making heavy use of CAD design and CNC fabrication, while minimizing the amount of skilled labor required (machining and welding). We start testing in the next few weeks. One big problem we're having is getting hold of a decent training glider with a CG hook for testing and training. If we want to get soaring back on its feet again in the US, we need a rugged training glider in the 30:1 or so range that is affordable out of pocket by a small group of people, say $50K (and, no, I don't think a clapped-out G103 with a 300 lb useful load is an option). It's time to explore lower cost fabrication techniques...

Marc

I think we need to convince Richard VanGrunsven to design a two place 30 to 35 l/d glider for training using the same wing style of the RV planes. Keep it simple to build and offer a fast build kit. Let clubs put in the sweat equity for a good basic trainer.

On Wednesday, July 31, 2013 10:43:25 PM UTC-7, Tim Taylor wrote:
I think we need to convince Richard VanGrunsven to design a two place 30 to 35 l/d glider for training using the same wing style of the RV planes. Keep it simple to build and offer a fast build kit. Let clubs put in the sweat equity for a good basic trainer.

He has looked at it. It really is not a viable business model to create it. Sales are too limited.

The big issue with a kit is that it is difficult to type-certify it. An experimental two-seater has very much less utility than a type certificated one that can be used for rides, sightseeing, demos, flight instruction, transition training, and other commercial purposes.

Furthermore, the type of wing construction used in the RVs does not scale very well up to the kinds of spans and aspect ratios required to make a glider that is worth building. When Dick was building a motorglider, he used wings from an HP-18. When I was deciding whether and how to move beyond the HP-18 and build kit sailplane wings, I settled on a Marske-style wing spar and European-style molded sandwich skins. No, not many people can do that in their garage. But it's not rocket science, and it has proven to be the most time- and cost-effective path to a set of glider wings worth having.

I'd be perfectly willing to work with clubs and even commercial operations on a sweat-equity basis. Given the right tooling and infrastructure, making sailplanes is not that hard, and I can get pretty much anybody doing it in just a couple of hours. I'm doing that today, in fact, up at the HP-24 Project 2013 Summer Akaflieg. The next Akaflieg is scheduled for the week between Christmas and New Years. If there's enough interest we can start laying out CNC cut parts for Aurora's big shells.

Thanks, Bob K.
https://www.facebook.com/pages/HP-24...t/200931354951

On Thursday, August 1, 2013 9:33:12 AM UTC-6, Bob Kuykendall wrote:
The big issue with a kit is that it is difficult to type-certify it. An experimental two-seater has very much less utility than a type certificated one that can be used for rides, sightseeing, demos, flight instruction, transition training, and other commercial purposes.



Furthermore, the type of wing construction used in the RVs does not scale very well up to the kinds of spans and aspect ratios required to make a glider that is worth building. When Dick was building a motorglider, he used wings from an HP-18. When I was deciding whether and how to move beyond the HP-18 and build kit sailplane wings, I settled on a Marske-style wing spar and European-style molded sandwich skins. No, not many people can do that in their garage. But it's not rocket science, and it has proven to be the most time- and cost-effective path to a set of glider wings worth having.



I'd be perfectly willing to work with clubs and even commercial operations on a sweat-equity basis. Given the right tooling and infrastructure, making sailplanes is not that hard, and I can get pretty much anybody doing it in just a couple of hours. I'm doing that today, in fact, up at the HP-24 Project 2013 Summer Akaflieg. The next Akaflieg is scheduled for the week between Christmas and New Years. If there's enough interest we can start laying out CNC cut parts for Aurora's big shells.



Thanks, Bob K.

https://www.facebook.com/pages/HP-24...t/200931354951

No dig at commercial operators as they are generally available more often than clubs, weather permitting. However, there may be about commercial entities using gliders in the US. AFAIK, there are two university academic gliding programs. There are about 144 clubs/chapters with public access and another 25 that are strictly private. There are about 6000 SSA members in chapters, and several hundred more in clubs that are not chapters, perhaps 1000 or more. Although a type-certificated trainer/ride gliders would seem more desirable from a designer/developer stand point, there are type certificated designs that aren't in production. The bigger hurdles and costs are establishing Part Manufacturing Authorization and Manufacturing Certification. Need an example? Peregrine Sailplanes. If it were easy, I think 2-32's might be in production today. Of course FAA restriction of allowing development of a design as experimental or SLSA and later granting a TC for the same design is a real problem and impediment to innovation. Perhaps some of the alphabet aviation organizations and their memberships would consider suggesting to the House and Senate General Aviation Caucuses that a change is needed. The House caucus just reached 200 members. Earl Lawrence (formerly of the EAA) now heads the small aircraft directorate. Perhaps there's a receptive ear there.

I'm not sure this goes far enough to help the gliding community.

http://www.kansas.com/2013/07/16/289...alization.html

Frank Whiteley

On Saturday, August 3, 2013 9:42:22 AM UTC-6, Frank Whiteley wrote:
On Thursday, August 1, 2013 9:33:12 AM UTC-6, Bob Kuykendall wrote:

The big issue with a kit is that it is difficult to type-certify it. An experimental two-seater has very much less utility than a type certificated one that can be used for rides, sightseeing, demos, flight instruction, transition training, and other commercial purposes.







Furthermore, the type of wing construction used in the RVs does not scale very well up to the kinds of spans and aspect ratios required to make a glider that is worth building. When Dick was building a motorglider, he used wings from an HP-18. When I was deciding whether and how to move beyond the HP-18 and build kit sailplane wings, I settled on a Marske-style wing spar and European-style molded sandwich skins. No, not many people can do that in their garage. But it's not rocket science, and it has proven to be the most time- and cost-effective path to a set of glider wings worth having.







I'd be perfectly willing to work with clubs and even commercial operations on a sweat-equity basis. Given the right tooling and infrastructure, making sailplanes is not that hard, and I can get pretty much anybody doing it in just a couple of hours. I'm doing that today, in fact, up at the HP-24 Project 2013 Summer Akaflieg. The next Akaflieg is scheduled for the week between Christmas and New Years. If there's enough interest we can start laying out CNC cut parts for Aurora's big shells.







Thanks, Bob K.



https://www.facebook.com/pages/HP-24...t/200931354951



No dig at commercial operators as they are generally available more often than clubs, weather permitting. However, there may be about commercial entities using gliders in the US. AFAIK, there are two university academic gliding programs. There are about 144 clubs/chapters with public access and another 25 that are strictly private. There are about 6000 SSA members in chapters, and several hundred more in clubs that are not chapters, perhaps 1000 or more. Although a type-certificated trainer/ride gliders would seem more desirable from a designer/developer stand point, there are type certificated designs that aren't in production. The bigger hurdles and costs are establishing Part Manufacturing Authorization and Manufacturing Certification. Need an example? Peregrine Sailplanes. If it were easy, I think 2-32's might be in production today. Of course FAA restriction of allowing development of a design as experimental or SLSA and later granting a TC for the same design is a real problem and impediment to innovation. Perhaps some of the alphabet aviation organizations and their memberships would consider suggesting to the House and Senate General Aviation Caucuses that a change is needed. The House caucus just reached 200 members. Earl Lawrence (formerly of the EAA) now heads the small aircraft directorate. Perhaps there's a receptive ear there.



I'm not sure this goes far enough to help the gliding community.



http://www.kansas.com/2013/07/16/289...alization.html



Frank Whiteley

About 50 commercial entities...

Tim Taylor wrote:

I think we need to convince Richard VanGrunsven to design a two place 30 to 35 l/d glider for training using the same wing style of the RV planes. Keep it simple to build and offer a fast build kit. Let clubs put in the sweat equity for a good basic trainer.

Not a Vans, but similar technology from Sonex.
From the Xenos test flights report: "...this puts the L/D at
approximately 24/1"
Could be slightly higher with a more streamlined front, (without
engine and prop.)
Of course, it would need a large dead weight in the nose to keep the
CG between limits.

http://www.sonexaircraft.com/aircraft/xenos.html
http://www.sonexaircraft.com/aircraf.../spintest.html
--
Roberto Waltman

[ Please reply to the group,
return address is invalid ]

On Thursday, August 1, 2013 9:58:40 AM UTC-7, Roberto Waltman wrote:


Could be slightly higher with a more streamlined front, (without

engine and prop.)

Of course, it would need a large dead weight in the nose to keep the

CG between limits.

Isn't that what the student is for?

Kirk
66

In article ,
wrote:

On Wednesday, July 31, 2013 2:23:46 PM UTC-7, WB wrote:
A similar concept, flat-panel, pre-fab composite version of a K-18 was make
by a Brit once upon a time and looked pretty good. Don't know what became
of it.

That would be the Edgley EA9 Optimist, which I bring up here periodically:

http://www.flightglobal.com/news/art...es-the-floor-t
o-build-prototype-24019/
http://www.retroplane.net/forum/files/optimist_195.pdf
http://www.faulkes.com/dfet/index.ph...sailplanes-ltd

I think the major mistake that they made (and I remember it being discussed
at the time) was not coming up with a two-seater (think modernized ASK-13) as
their first design. Even back then, there was a need for affordable
training gliders to replace aging K-7s, K-13s, 2-33s, and Blaniks.

We've spent the past few years designing and building an "affordable"
truck-based winch, making heavy use of CAD design and CNC fabrication, while
minimizing the amount of skilled labor required (machining and welding). We
start testing in the next few weeks. One big problem we're having is getting
hold of a decent training glider with a CG hook for testing and training. If
we want to get soaring back on its feet again in the US, we need a rugged
training glider in the 30:1 or so range that is affordable out of pocket by a
small group of people, say $50K (and, no, I don't think a clapped-out G103
with a 300 lb useful load is an option). It's time to explore lower cost
fabrication techniques...

Marc

Yes, that's it, the Edgley Optimist. Great looking glider. I think you
are right. Should have gone with a 2 seater first.

Best of luck with your winch project. I used to drive the winch for my
club, back when we had winch. Driving the winch was fun and gave me a
great sense of satisfaction. Of course, being on the other end of the
Spectra is fun, too!