Hiya Peter!
Good to hear from you again.
Hope all is well with you and yours.

I'm not very familiar with the Polywagen. I've seen drawings of it,
but never had a chance to study the final product.

My first thought about the spring idea was that it seemed reasonable.
(read it yesterday)

But thinking about it for a while, I'm not so sure.

Two reasons:

First - it's seems it would take _two_ springs.
One to pull it down and one to pull it back up.
The activation force would be the difference between the springs?

Then - the possibility for flirting with flutter.
Springiness in any flight surfaces should be avoided at all costs!
Especially as fast as I'd like this one to go.

My Tailwind used Jim Clement's C model details for the flight controls.

1" x .058 steel torque tube for the aileron drive, with a 1-1/2" .058
6061-T6 "spar tube" centered over that(IIRC). A round spacer at each end
ties the two tubes together and the aileron ribs and skins are pop
riveted to the outer tube.

(Ok, there is a welded steel tube sleeve/spacer at the root end to
tie the tubes together as the torque tube stops at the inboard end
of the aileron. I think I'd just run this one full length).

The flap spar is another piece of 1-1/2" aluminum tube (built similarly)
but actuated via a horn just inside the fuselage.

Very simple, clean and much easier to build than the brazed steel
structure that Steve used. Also has been thoroughly flight proven on
most of the newer Tailwinds.

Well, for what ever it was worth.

It's just a daydream doodle...



Richard


I have had a set of plans for the Polywaggen, but currently can not seem to
find them.

Therefore, my recollection is from a construction project that I had an
opportunity to visit. The torque tubes were much smaller in diameter--at
most 3/4" for the flap torque tube. The builder was working on a means to
assure that the system would not fail under flight loads, as he told me that
he had heard of previous problems. I have no recollection of the alloy
used; but a much larger diameter tube, so that damage would be unlikely with
the length of flap handle in use, would certainly solve the problem--and
would probably be lighter and less complex than the spring idea that I have
envisioned.

Peter