Hi Dave
Can you just fly with one aileron? I saw a drunk farmers fly like that
in
both a Piper and Aeronca!
Bending aluminium is EZ, but since you have the ball end it will allow
your kink to rock up and down. You may get away with it? Don't try
bending in a vise, chance of kinking is far greater than if you drill a
hole in a thick piece of wood, like work table or your basement stairs,
of course a proper bender is best. Filling with sand can also help
prevent kinking.
As far as rigidity and keeping things light, thin wall and large OD for
a
given weight gives you the most bang for your buck. In your case a
smaller OD and thicker wall will give you a little more clearance with a
slight weight penalty. 4130 is stronger than aluminium, you should even
be able to go smaller in OD and if you weld it it can get away without
heat treating, again with a slight weight penalty.
If your bow idea is not going to work, you could offset your mounting
stud on the end of your tube to move forward the front edge of the
smaller ID tube as far as you can, this would keep your tube
straight.
I'm not at my aeroplane, but off the cuff a small OD very thick
wall,
perhaps even a solid piece of 4130 (see McMaster Carr too for 4130 in
addition to ACS and Wicks) and a welded on piece of 4130 that is tapped
to give you needed offset, then install in it a threaded stud (tack the
far end to keep it from rotating) if you are close you could weld the
stud directly to the 4130 and space the ball end slightly aft.
I would first rig wings without the pushrod to make sure you can rig.
Then screw a piece of metal in place of the pushrod and determine what
clearance you have to your spars. Soft aluminium rectangular bar from the
hardware store comes to mind.
I am doing battle with making sure I can get my flaps to work post 78. I
had my son (going to CMU for mechanical engineering) grind some numbers
for me as far as the side force exerted when you put a bend in a tube. I
used a 4 foot example with the bend occurring at the middle 2 foot point
with a 100lb parallel force exerted on the two ends. May give you an
idea:
http://www.europaowners.org/main.php?g2_itemId=394508
Ron Parigoris
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