jedelsky wing

cmulder Sun May 21, 2023 6:58 pm

aspeed wrote:The Duet has an undercamber with a couple ribs sticking out the bottom, so covering would be a bit tricky. It really is a nice looking wing though, all sanded at the factory.

This type of wing construction is called a "jedelsky" wing.
The original multiplex panda was a example as was the Robbe Habicht Glider.
The "underchamber" profile is part of the design and if you cover the bottom with film then the performance gets a lot worse.
My first rc model was that multiplex panda and did make the mistake to close the wing bottom. Once fixed it was a ok ish glider but likely best suited for flying at a slope

GallopingGhostler Mon May 22, 2023 4:49 pm

cmulder wrote:
aspeed wrote:The Duet has an undercamber with a couple ribs sticking out the bottom, so covering would be a bit tricky. It really is a nice looking wing though, all sanded at the factory.
This type of wing construction is called a "jedelsky" wing. The original multiplex panda was a example as was the Robbe Habicht Glider. The "underchamber" profile is part of the design and if you cover the bottom with film then the performance gets a lot worse. My first rc model was that multiplex panda and did make the mistake to close the wing bottom. Once fixed it was a ok ish glider but likely best suited for flying at a slope

Beauty of the Jedelsky wing is similar to the K-Flex wing of today in its simplicity. Because it was all balsa almost demanded that the wing be clear doped with a couple coats until grain sealed, then trimmed with a little colored dope. Otherwise, the plastic films added unnecessary weight.

Yes, it would be a little tricky to cover the undercamber with plastic film, so the covering hugged the undercamber surfaces. However, those able to do showed up in the skill of their application.

The Honker, Rocket and Bipe were prime examples posted in magazines this side of the pond, for a fun fly sport R/C aircraft.

https://outerzone.co.uk/search/results.asp?keyword=honker

The designer credited with this style wing, Erich Jedelsky has a plan on Outerzone of one of his Jedelsky wing towline gliders:

https://outerzone.co.uk/plan_details.asp?ID=11365 Ko C by Erich Jedelsky 86in span

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Outerzone photo.

aspeed Mon May 22, 2023 5:53 pm

I have a Honker Bipe covered with film. Flies ok with a .25, lots of power.

GallopingGhostler Mon May 22, 2023 7:23 pm

aspeed wrote:I have a Honker Bipe covered with film. Flies ok with a .25, lots of power.

That is quite a bit of power for such as small package. Very Happy

I shouldn't make light of this, because I oft had the same idea, too, like an Enya .19-VI TV to power a 46" Airco Aero Star single channel rudder with throttle, or the same on the 46" Hobby Shack Real Thing. Cool

My ideas on lightness of finish has to do with often marginal power used on our half-A's, just makes 'em fly that better. Surprised

My similar sized Airtronics Gere Sport by the late Lee Renaud, designer of the Q-Tee and S-Tee, recommended power by a .09 - .10 engine of the time with a .15 for sparkling performance. I put a Magnum .15 plain bearing (one by Thunder Tiger, not later one by China) Schneurle in my 45" Hobby Shack foam RTF, could do a loop from horizontal as strong pulling it was. (Was originally designed for .09 - .15 legacy cross scavenged engines.) Huh...

Thought comes from the extra power of a Schneurle. A .25 Schneurle plain bearing sport engine is often power for a .35 cross scavenge C/L plane. I'd think similar for R/C.

When using less power on weaker engines, the clear doped balsa trimmed in color can't be beat for having a good flying lightweight model. Eyebrows

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