New mystery model

[tiptipflyer]

This time it´s not a new replica transmitter but a new model. My latest project build from scratch. It was one of the first R/C kits available here well over 60 years ago.
Can anybody identify it ?
I hope to finish it within the next two weeks. It will be flown on the button as intended and on reeds.

Cheers
Frank

[Tobe]

I would guess Graupner Electra....

[tiptipflyer]

Yes Tobe, of course you are right.
Here on this forum al least 50% of the members would know it. In my club about 5 out of 300 would recognize this plane, that is less than 2%.
This plane was on my to-do-list for years. It will be electric powered with a Taifun dummy engine.
I dream to fly it sometime with my Bellaphon or Standard 30 transmitter.

Cheers
Frank

[Wayne_H]

Looks great Frank

I shall follow this one with interest as I actually downloaded the plan for it late last year, having discovered it while searching through old Graupner designs.

[Tobe]

Frank...you are German and Graupner addicted so it was a safe guess!
My only Graupner kit I ever built was the Hi-Fly, lovely airplane but the building was like putting together a 1000 pcs. puzzle with immaculate instructions and if a piece didn't fit you were sure one of the pieces was not the right one and all this well before laser cutting! As I grew up in Italy the classic first trainer was the Taxi II and Amigo II. Here is a picture of my dad flying Graupner Cup in Gorizia, Italy 1963. Graupner used to have its own representative in Italy and his name was Schnabel if I remember correctly.

[tiptipflyer]

The Electra is almost ready now. The maiden flight took place prior my holiday. It has now three test flights, but the rudder still needs improvement.

.
Cheers
Frank

[PaulJ]

It looks a lovely model Frank but for Rudder control it doesn't appear to have much dihedral. If the rudder needs "improvement", I think you would get better Rudder response with more dihedral....... Is there any way you could increase the dihedral angle, perhaps by making slightly longer wing struts?

Paul

[tiptipflyer]

Thanks Paul,
not the rudder response is the problem, but the yaw stability. I am thinking of adding more rudder area.
Also I noticed a slight warp in one of the wings, which I need to eliminate, which I will do first. The next flights, hopefully with less wind, will show.
Frank

[tiptipflyer]

This morning I did several test flights.
First I removed the warp out of the wing. Not much improvement.
Second I increased the dihedral. This makes it even worse. Very touchy to fly.
Third I increase the rudder area by about 50% and decreased the throw by 40%. Much improvement.
Fourth I removed the excess diheadral again to the inital value. Again more improvement.
Now the Electra is a nice model to fly and cruises lovely around.
The original fin has a very thick symetrical airfoil, I think a thinner airfoil with an area increased by 30 to 40% and a rudder increased by 40 to 50% with decreased throws would make the deal even better.

Cheers
Frank

[Martin]

Maybe you could add a small under-fin, like a tail skid, to add some extra side area at the rear without deviating too much from the "official" outline. You could use a piece of transparent plastic, so that it's almost invisible.