A path to an affordable trainer?

See: http://makerplane.org/

Just ran across this crowd-sourced campaign to design and build an
open-source airplane. They are shooting for $15,000 US including engine.
I think they could make the airframe for $15k. I have my doubts about a
safe, reliable powerplant AND airframe for anything near $30,000. I
would dearly love to be proven wrong.

The website is worrisomely short on details, but the overall design
doesn't look far-fetched (no twin boom, pusher, three lifting surface
homebuilt F-22 fantasy). They propose a conventional looking plane built
of foam-cored composite panels cut out with CNC mills and non-structural
stuff made with 3d printing. 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.

If Maker Plane can make this work at even twice their projected cost,
could the same method be used to produce a reasonably priced training
glider? Even $25,000 for a new, two-seat trainer in the 28:1
neighborhood would be a fantastic bargain these days. Certification is a
glaring issue for a glider destined for commercial training. However, if
the glider only cost $25,000, it would be cheap enough to be viable in
the non-commercial club market where an experimental cert. would be OK.

On Wednesday, July 31, 2013 3:23:46 PM UTC-6, WB wrote:
See: http://makerplane.org/



Just ran across this crowd-sourced campaign to design and build an

open-source airplane. They are shooting for $15,000 US including engine.

I think they could make the airframe for $15k. I have my doubts about a

safe, reliable powerplant AND airframe for anything near $30,000. I

would dearly love to be proven wrong.



The website is worrisomely short on details, but the overall design

doesn't look far-fetched (no twin boom, pusher, three lifting surface

homebuilt F-22 fantasy). They propose a conventional looking plane built

of foam-cored composite panels cut out with CNC mills and non-structural

stuff made with 3d printing. 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.



If Maker Plane can make this work at even twice their projected cost,

could the same method be used to produce a reasonably priced training

glider? Even $25,000 for a new, two-seat trainer in the 28:1

neighborhood would be a fantastic bargain these days. Certification is a

glaring issue for a glider destined for commercial training. However, if

the glider only cost $25,000, it would be cheap enough to be viable in

the non-commercial club market where an experimental cert. would be OK.

https://www.facebook.com/AuroraTrainingSailplaneProject

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.

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!

In article ,
Bill D wrote:

https://www.facebook.com/AuroraTrainingSailplaneProject

Thanks, I forgot about the Aurora project. Wonder if "crowd-sourcing"
would help move that project along?

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.

On Thursday, August 1, 2013 9:14:35 AM UTC-5, WB wrote:
In article ,

Bill D wrote:



https://www.facebook.com/AuroraTrainingSailplaneProject



Thanks, I forgot about the Aurora project. Wonder if "crowd-sourcing"

would help move that project along?

i bet about 2 or 3 million would help it move along a lot faster.

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

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

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