Hi Tim
Yes you are of course correct!
However FWIW...
I sanded out the delrin on 119 and still it seemed like a lot of
friction. (Don't leave any grit behind)
My tube was oval by at least 0.040" as I recall and I never did manage
to reduce that much and I don't think it really matters much once the
tube is loaded and/or riveted together anyway.
Adding some "CROWN" brand silicone as recomended by Wayne (plastics
expert) helped a bit but it still seemed too tight and it got a bit
tighter after closing the wing. (See archives on caution not to use any
other brand of silicone.)
However it seems to be a non issue once I got flying. Note that unless
you go to ball bearings. the things are definitely going to have
noticeable friction with the flaperons down anyway but even that does
not seem objectionable to me. Perhaps partly because it is so effortless
to pick up a wing with rudder on a Rebel. Perhaps partly because I'm
used to heavier controls. Most pilots have commented on how stable the
Rebel is and how it does not need constant aileron corrections like the
cessna/zenith/grumman that they normally fly.
Ken
Tim Hickey wrote:
Norm:
The following is worth just what it will cost.
The best one might hope for on this subject is a control system that is
frictionless. In other words, zero friction is good.
I should think that if you have any friction in the system you should do
your best to minimize it at this time. You mentioned that you think that one
tube is out of round. Can you measure the tube in several spots to determine
if this is true, and how much out of round it is?
Before you get to the point of not being able to work on this area, I would
try to run down what is going on.
I should think that in flight, the friction will be something that you will
have to fight forever.
There may be enough mechanical advantage on the torque tube from the air
loads on the flapperons that it easily over-rides any friction in the tube.
I don't know about that
Maybe some flying builders can shed more light on this.
But I do know that zero friction would be the goal.
Tim (you get what you pay for) Hickey
R 808.
----- Original Message -----
From: <
Newcog@aol.com>
To: <
rebel-builders@dcsol.com>
Sent: Friday, November 16, 2007 8:40 PM
Subject: Re: [rebel-builders] Friction in aileron torque tube
I have more friction in one wing than the other. The root cause seems to
be
a torque tube that is slightly out of round. I tried polishing the delrin
bearing blocks and using various lubricants with little improvement.. I
decided
that when the complete control system is hooked up it should be OK. A
little
friction might be helpful. Rebel #200.
Norm Wandke
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