What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Rod end bearing installed wrong

tc1234c

Well Known Member
I am sure that no one made the dumb mistake I did. Just in case anyone did, my experience may save you. Yesterday I got an email from a 6A builder telling me that he saw my 9A at MERFI on Sunday and found my flap push rod end bearings were installed wrong (see picture below):
oldFlapRodend.jpg

When I think about it, it is so clear what the problem was. But I did not catch it over the past 230 hrs. My FSDO inspector did not catch it a year ago neither. I am grateful to Tony for his keen observation. It might have saved my life if one of the rod end bearings fails.

This morning I spent an hour correcting the problem and test flown the airplane. The bearings are still in good shape without any free play. Here is the correct installation:
FlapRodend.jpg

(new picture. Blue loctit on threads, lock washer added. Washer above the jam nut to be removed.)

Check your installation and make sure you did not make the same mistake I made.
 
Last edited:
Is there really supposed to be a stop nut on the side that attaches to the flap? Seems to me you'd just use washer(s) between it and the flap. Not sure what a nut would be doing in there. I haven't looked at the RV-9[A] drawings, however. Just sanity checking...
 
No, there isn't really supposed to be a stop nut there. Vans instructions say a maximum of two washers for more inboard spacing.
dan said:
Is there really supposed to be a stop nut on the side that attaches to the flap? Seems to me you'd just use washer(s) between it and the flap. Not sure what a nut would be doing in there. I haven't looked at the RV-9[A] drawings, however. Just sanity checking...
 
Also, the RV-7[A] calls for an AN936A416 internal tooth lock washer in there. I gotta assume the RV-9[A] is the same?
 
One other thing Ted. Not 'picking' on you. But, a washer is not usually used between a "jam" nut and the mounting substrate such as you used on the push rod and rod end. The "jam" nut is to lock the threaded connection. The washer, while probably not a problem, could reduce the locking function of the jam nut.
Dale Ensing
RV-6A
EAA TC & FA
 
Dale,
Yes, time to take that washer out above the jam nut. Thanks for reminding. By posting the picture here I got free inspections. Now errors discovered, problems solved and lessens learned. All comments and suggestions are most welcomed. :)
 
Since there is no jam nut on the flap side, just the internal lock washer, I elected to use some "Blue" LocTite there.

Just something else to think about for those of you still building. My flaps worked perfectly during assembly but in flight I found a minor issue. When deploying the last 10 degrees of flaps while flying straight and level, all was good. However, when deploying those same last 10 degrees while turning base to final the flap rod on the right side conttacted the edge of the hole and made a nice scraping noise. Five minutes with a small file and the problem went away.

I would not have guessed that the loads put on the flaps while turning would be that much different than going straight ahead but I guess they are. (When I tried this in flight, out of the pattern, it didn't seem to matter if the turn was coordinated or not.)
 
Dwg 19 zone D-9 calls for AN960-416L washer, AN36A416 internal tooth washer, and Loctite or equiv to ensure CM-4MS does not back out of platenut.

Bill RV-9A N930RV Flying
 
Back
Top