Jam Nuts

15 Sep 2003 Jam Nuts

A builder experienced control problems, caused by jam nuts loosening. Another builder offers a pretty good solution.
Date: Jun 08, 2000 “RV”matronics.com
From: Ralph Koger
Subject: Re: RV8 Control Problems

I have found after building several RVs, 6s and a 4 that the jam nuts will
loosen because of the over rotation of the hemie bearing that they are to
lock. To have the given up and down degrees of the controls they have to
rotate more than a regular hookup with a bolt and possibly washers will
allow. Van sells a special washer that is 3/16” or bolts size with a
outside diameter that is small enough for the bearing to freely rotate over
it and will correct your problem. If you donot use the washers you will
always loosen the jam nut or twist the control tube if you lock everything
tight. I am not in my shop withmaterial information to give you the
numbers of the washers, but if you want more information just return mail.
I don’t know if Van sends them in the kit and we don’t find them, but I
have always orders a dozen or so for each airplane that I have put together.
This is a necessary item to check on all of the RV series planes.
Ralph Koger RV-6A N16RK

> 1.5 hours into 3rd test flight, my RV8 developed a slight play in the
> aileron channel. Landed aircraft immediately and investigated. Found the
> forward end of the cockpit control horn assy loose. The jam nut had backed
> off the forward attachment bearing allowing the forward end of the control
> horn assy to sway. Tightened jam nut and corrected problem. Inspected all
> flight control fittings and attachments. Found left outboard end of
> aileron push/pull tube bearing jam nut loose. Tighten nut and replaced all
> panels. Checked all flight surface deflections. Released aircraft for
> flight. This occurred with less than 3 hours time in service.
> You 8 flyers might want to check this before your next flight.

> Bobby Hargrave
> 80706 N426NC
> Cell. 901.834.1281
> home 850.473.9105