SonexBuilders.net

Yesterday after much difficulty I fitted the flap push rods. Today I went to set the flap geometry and found that I am nearly out of thread in one side and to long on the other. On reflection it appears to me that the push rods must be different lengths however I can not find any reference to the push rods being different. It is possible I have fitted the left where the right should be and visa versa.
Could someone please confirm the length difference prior to me going through the painful process of reversing the installation.

Thank you in advance

I happened to have my two flap rods on my work bench. They are identical length. I just checked.


Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved

The pushrods are identical.
I believe the difference youre seeing is caused by the fact that on the Sonex one wing sits slightly forward comparded to the other, the spars slide into eachother remember.

Robbie and Michael took the words out of my mouth. I was going to say the same thing. One spar sits in front of the other, and I see no reference in wings to account for the difference. I welded my flap rods and they are the same length as well.

Thank you for the responses. The problem is that on the right wing there is insufficient thread to be in 'safety' at the rod end when the the flap is set to the correct (stated) position. One solution I have considered is moving the flat detent bracket backwards, that should allow for more thread at the rod end but then the flap handle in the 30 degree position will hit the spar tunnel.
Any ideas?

Peter, I would not do the same as you are thinking, it seems like more work. The easiest way I would do that would be to extend the flat part of the push rod end that attaches to the torque tube by about one inch. You could weld an extended flat extension to the push rod and re drill the hole further down to account for the needed length. Or you could lengthen the entire flap tube by by cutting the tubing in the straight area, and placing a steel tubing sleeve over the two cut tubes allowing you to lengthen that way as well. I would recommend welding the tubing sleeve to the tubing, but the tubing could probably be drilled and AN bolts could be used to bolt the tubing together.

Something isn't right. The rods should be the same length and should adjust left/right equally.
Is your flap torque tube square and parallel to the spar tunnel? Did you mount the detent angle in the correct position? Perhaps too far forward?

As others have indicated the right wing by design is actually slightly behind the left wing. The flap torque bar is however parallel to the spar tunnel. This means the distance from the flap push rod pivot to the flap is longer on the right then on the left. With both push rods the same length there is going to be less thread available on the right wing than the left. I my case maybe due to slight variances in my build that have compounded the distance I am three (3) threads short (1/8") of being in safety at the rod end on the right wing flap.
These variances can be very small at places like flap handle, detent bracket, torque bar bearing. flap rod end attached plate and flap hinge position but when added up easily make the 1/8" difference I am getting.
I have decided to remove the push rod and have it professionally extended by 1/4" to 3/8" using a cut, splice and weld method.