Flap Pushrod Length

December 27, 2007

The flap pushrod, connecting from the hinge to the flap drive in the wing is made out of tube with a "T" on one end and "heavy" nut (5/16 -24tpi) welded to the other end to hold a rod end bearing.

 
The plans clearly say "check length on assembly".  Well, since the airplane and wing were in another county when I made the flap pushrods, I just made them to the length shown on the drawing.  After all, everything else has fit perfectly so this should as well.  

Not so fast friends.  Mine ended up 1/2" too long.  With the rod end bearing screwed all the way in (even with out a check-nut) to the pushrod, the flaps were still about 5 degrees down, when in the full up position.  Easy fix, but a pain in the rear because these had already been painted.  The fix was to cut the nut off  the end, plus 1/2" off the tube, then weld on a new nut.  With them re-painted, I'm ready to go.  I'm just glad they weren't too short as I would have had to re-make the whole thing.

Moral of this story - If it says "check length on assembly"  - do it.

Thankfully, the aileron pushrods were the perfect length so no problems there.

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