Rudder Pedal Bearing Friction

[Airhead]

I spent a good half day polishing the ends of the rudder pedal weldments with emery cloth to remove the coating and then realised they were still tight in the plastic bearings, so I kept going until I got a decent fit. Using emery cloth on the steel ends is very slow going (any other suggestions) and removing material from the inside of the bearing (again, with emery cloth) didn't seem to work well. Anyway, when I installed the assembly in the fuselage, I found that because the longeron on which the bearings are mounted have a slight camber, the bearings have a "toe in" position which causes an increased rotational friction in the rudder pedal shafts. I believe the hole was drilled at 90 degrees to the bearing, but that's not the way they end up aligning with the shafts when mounted.

How much friction is reasonable? For instance, if I pull the rudder pedals all the way to a horizontal position (with the brake cylinders & pedals on) they will stay in place. The rotational resistance is what I would term "firm". I would think that when they rudder cables are connected and you are effectively rotating both shafts by pushing on a pedal, this force will double. Did anybody else face this problem or decision?

[Brantel]

They are tight but will break in.

Mine were not drilled 90° I do not think. Seems I remember that they would work on one side not the other.

Here is a trick that I did on mine to loosen em up.....Works great!

http://www.vansairforce.com/communit...10&postcount=5

Entire thread:

http://www.vansairforce.com/communit...410#post304410

[Airhead]

Thanks Brantel for the reply and link to the other thread on the subject. I should clarify by saying that I am not so worried by the foot pressure required to push the pedal (they are not that tight) but was thinking more about the return to the neutral position in flight. It seems that after a rudder application the rudder should be able to easily return to the neutral position with the wind pressure on the rudder, rather than with a manual correction using opposite rudder. But I have no way of knowing what the wind pressure correctional force is until flight testing. At that point, removing the rudder assembly would be...lets just say a pain in the back. Maybe I should take them back out and try the "hot sockect" method loosen them up even more.

I noticed in the other thread with pics, it looked like some are putting the bearing blocks on with the rust preventative coating still in place (by tapping with a rubber hammer). I must say that mine would go on like that but would certainly have been unacceptably tight. As it is, I polished each end for 30 to 45 min. and obviously am still questioning the resistance.

[schristo@mac.com]

imagine the force from the air stream in flight... the rudder will find a trail position from the aerodynamic forces flowing across it that will far exceed the minor resistance from the wear blocks on the pedal pivots...