MLG Pivot Rod pushing off Caps

02-06-2012, 12:45 AM

Russ Kotlarek | MLG Pivot Rod pushing off Caps

After hearing a number of thoughts on resolving the 5/8" stainless Pivot Rod backing out caps issue I decided to see if yet another answer could be found. Nylon spacers still do not 100% appear to resolve the issue and no real quick preflight inspection shy of crawling into the tail end, Set screw can have it's own issues in siezing up for the future which I could see being a huge problem if it did and still no easy way to visually inspect during a preflight.

What I elected to do is remove the Rod and cut two 7/16" wide 1/32" deep grooves just inside of the center missing section of the Aluminum gear plate. These slots will hold a 9/16" double split Stainless rod collar that will resist any movement of the rod as the collars have a shoulder in which to lock into. This with a 5/8" ID Bushing washer and a slight flatening of the gear plate appears to allow for a virtually wear free, guarenteed movement less answer to the problem. The Rod will never touch the caps so the only thing they need to do is collect grease and seal out water from inside the plane.

I did the math and the 1/32" grove reduces the rod maximum tensile strength from 26K to 21k going from 5/8 to 9/16. Assuming a 3000 lb aircraft landed on just one rod of this dimension instead of 2 much less at 4 sheer points would support a 7G landing assuming all that weight feel on just one 9/16" rod not in sheer. bottom line it is nothing is really compromised at all in making this modification so it appears. In addition it is very easy to visually inspect from outside the aircraft on a pre-flight for a loose collar or any movement.

Pictures attached

Russ Kotlarek

02-07-2012, 07:43 PM

Fred Lohr

elegant solution.

i just safety wired the caps. fitted em with grease fittings first though

02-10-2012, 10:43 AM

keithw | mlg pivot shaft @ bush

Hi Russ I found that when I lowared the pivot point per sna at the time the aft end of the bushing and shaft was almost at floor level and i had no room for the cap. Result is i greased up the end and glassed it in. Ha Ha Shaft not going aft and no leaking at that end. Then i caped the forward end per the book. Keith W N80CC