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Motor-glider RV-12?

WingedFrog

WingedFrog

Well Known Member
I have a hangar neighbor who is building a Xenos which is two seats motor-glider from Sonex aircraft using quite a bit of the parts of the Waiex, the V-tailed Sonex. This made me mulling the idea of an RV-12 based motor-glider. I am actually wondering if it would be possible to just have a different pair of wings more adapted to gliding. Some additional changes to improve the gliding ratio could be ... (not being a glider specialist I will let the forum complete, secretly hoping that the most famous RV-12 builder and glider pilot will do us the favor of giving his input :cool:).
 
As appealing as the idea sounds, there are a few aerodynamics issues that come to mind-----------namely tail surfaces having the needed stability and authority.

I suggest you get someone trained in aircraft design to look at the concept.
 
i would think the wing would be the main issue. get the glide performance. the great thing about a motor glider is you could fail a medical and still fly.

look something like this.;)
RF0026.jpg
 
Thoughts about an RV motorglider (RV-11?)

Van the man himself is an experienced glider pilot, having competed in some serious sailplane competitions. I'm sure he has thought of designing a motorglider, and at one time, we were tantalized by the RV-11, which apparently is reserved for a single seat motor glider design. But Van, being the practical businessman he is, may not see the financial return on investment for it. Seems like I remember seeing a progress report with some photos in an old issue of the RV-ator. (That used to be a bi-monthly publication from Van's but it's been superceded by VAF news, Facebook, etc.)

I would certainly like to see an RV motorglider. You'd think it would have to be based on some of the existing RV designs. A random thought of mine, totally unsubstantiated, is that the RV-12 spar attachment design may not be robust enough for the long wings of a motorglider. But that's just a guess.
 
rv7boy said:
A random thought of mine, totally unsubstantiated, is that the RV-12 spar attachment design may not be robust enough for the long wings of a motorglider. But that's just a guess.
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Actually Don,
The RV-12 wing attachment design is loosely based off of what is commonly done on more recent high perf. sailplane designs.

It wasn't specifically designed for a future upgrade to longer wings though, so that would require some detailed analysis (along with looking at tail volume, etc.)

The first question that would need to be answered though, is how big of a market is there?
I would bet that very few sets of sailplane wings have been sold for the airplanes that currently have alternate wings available (here in the U.S. anyway, they might be more popular elsewhere).
 
Mike S said:
Different aircraft-------same physics.

https://www.youtube.com/watch?feature=player_embedded&v=OWgq_u_KHKY
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Jeremy Monnett in a brillant marketing/pilot role (in addition to his Sonex CEO job). John Monnett is very fortunate (and probably proud) to have such a promising successor.

What I like with the Monnett's approach to their airplanes kit market is that they give the impression that they are looking for fun projects more than for market shares. I would bet that their enthusiasm helps finding these market shares that would not show-up in marketing surveys. Is it enough to sustain their business? One can at least say so far, so good!
 
With a Xenos taking shape in our hangar, and based on a visit to Sonex last summer where I flew most of their planes, I can tell you that the Xenos is not just a Waiex with longer wings - the tail is much longer, and the stabilators much bigger. I haven't done the math on the RV-12, but I bet you'd need more tail volume just as the Waiex did when it turned into a glider.
 
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rvbuilder2002 said:
Actually Don,
The RV-12 wing attachment design is loosely based off of what is commonly done on more recent high perf. sailplane designs.

It wasn't specifically designed for a future upgrade to longer wings though, so that would require some detailed analysis (along with looking at tail volume, etc.)

The first question that would need to be answered though, is how big of a market is there?
I would bet that very few sets of sailplane wings have been sold for the airplanes that currently have alternate wings available (here in the U.S. anyway, they might be more popular elsewhere).
Click to expand...

Would be quite interesting to at least do so table/napkin design looksee....to check out "if" possible!!! Boy...some leisurely local area soaring would be a hoot! Just for building an extra set of wings....sold me��
 
Ironflight said:
With a Xenos takign shape in our hanagr, and based on a visit to Sonex last summer where I flew most of their palnes, I can tell you that the Xenos is not just a Waiex with lnger wings - the tail is much longer, and the stabilators much bigger. I haven't done the math on the Rv-12, but I bet you'd need more tail volume just as the Waiex did when it turned into a glider.
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Okay, and we have to build a second horizontal sab...still not that much $$$ for the "hoot"!!
 
Phantom30 said:
Okay, and we have to build a second horizontal sab...still not that much $$$ for the "hoot"!!
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It's not just a pitch control issue....

Longer wings can also influence yaw stability, spin recovery, etc.

Vertical tail would also have to be part of the design considerations.
 
Someone just mentioned to me that Rutan has been working on his latest design: 2-seat 2-engine motorglider that can land on snow, water, grass, paved called Ski-gull, apparently. Since he retired to Idaho, it sounds like something purpose built for that part of the country.
 
Longer wings

Adding span -- or longer wings-- without beefing up the center section can kill you! As span is added-- even if chord is reduced to keep total lift the same-- the center of lift moves outboard, increasing the moment arm and thus the wing bending moment at the carry-through or wing attach point. A friend here killed himself by adding just 2 feet to each wing in an attempt to make his own-design airplane, which had been flying for 12 years, a motor-glider so he could fly without a medical. After about a year the left wing separated at the attach point-- puller the attach bolts through the root attach point. DO NOT change anything significant on an airplane without a thorough structural analysis. Even a simple one would have shown him the problem.

Wayne 120241/143WM
 
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