ORIGINAL: MuSo
Hello Guys,
Just wondering how people set-up the propped tension in pull pull systems, I will be more than happy if some one can explain to me a good way to do it because I don't feel comfortable with just touch and feel "that's how I actually do it"
For sure there are other ways.
There are principles to follow in a pull - pull installation.
The following is my idea and might not be agreeable to all readers.
There should not be any tensions creating a constant pull on the control surfaces horns and on the servo shaft.
The above mean that the lines should have a mminimum of any elasticity (should not be stretched).
Avoid nylon strings because they stretch too much.
The best material to use is stainless steel tiny wire available as material to hang picture frames on the wall.
At the control surface the horns should be installed so that the center of the horn connections are on a line passing through the hinge line and 90 degrees to the control surface.
The use of a threaded clevis or ball joint should be used at one end or the other so that the length of the wire can be set without loosenes and without much tension ; just not loose.
At the servo the axis of rotation should be just a bit behind (closer to the tail of the fuselatge) the points of attachment to the horn..
How much behind ?
That would depend on the horn radius being used at the servo.
The idea of having the servo axis of rotation a bit behind is so that the wire going back has a tiny more movement than the one pulling but without going slack.
If the length is quite long there should be some stabilizing points on the wire about every 6 inches..
Something like passing through a little tube that may be 1/4 inch long.justto prevent the wire from going into resonance like a wire could if under tension.
voila ___it is simple
Best of luck 2 U.
Zor