The Cessna 120-140 Association Forum

I have a Maule tail wheel SFS-p8a-1-2 P/N TW100 that I would like to use on my 1947 C120, born on date 12-31-1946. Is it ok to install on my C120 ? And what tail spring do I use? Early or late model spring on the install, I am removing a Scott 2000. Any help would be greatly appreciated! Thank you.

It's OK to install per item 203 of the aircraft specification.

Check with Maule for any specific installation requirements. You may need some adapters, but use the original spring.

Thank you for your help.

I installed one on my 120 and was not successful at eliminating shimmy. I freely admit that my inability to eliminate shimmy on this tailwheel might have been due to my own personal inability to do so coupled with a tinge of impatience. For what it's worth, a former 140 owner gave it to me free of charge saying he had given up on eliminating shimmy as well. All the best with your Maule tail wheel.

What worked for me, to eliminate the maule shimmy, was to take out the free slack at the arms -not tight, but just enough to eliminate the free slack with the wheel centered.

John K's post mirrors my experience...and, I'll admit, too, that impatience prob led me to go back to the "little" Scott TW, 'though I did like the larger Maule. Mine was a "gift" from a friend after I spied it laying under a work bench. He'd experienced similar frustration with shimmy. We phoned Maule for help...phone actually rang @ home of B.D. and June Maule and June answered...offered advice and took our order for some OH parts. My experience was that after OH (new bushings & swivel parts) the tailwheel didn't shimmy, but was a bit stiff on swivel. As it "wore in" it began to function perfectly...yay!...no shimmy & swiveled just right. Then, as it loosened up a bit more...back to the ole shimmy. They DO work for a lot of folks -- the special "anti shimmy spring kit" (above...note different spring size L & R)) and a read of Neal Wright's article (viewtopic.php?f=10&t=147) may provide the solution that really works(?).
Mac

The shimmy damping effect is due to the different spring rates, resulting in different resonant frequencies. There is a reported issue with those springs. They are called compression springs. As the chains "stretch" the springs compress, and they have a hard limit (solid length) as to how far they can compress. When you hit the limit, all the stress is suddenly transferred to the rudder bellcrank, and it is not unheard of for them to be found damaged. Not proof of cause and effect, but something to consider.

Jimmy: Why are you wanting to replace the Scott 2000?

I replaced all the tailwheel support springs, the rudder return springs and chains, and put on a new ABI/Scott 3200 tailwheel assembly. No more shimmy.

Note that there are several configurations of the tailwheel spring stack depending on year. Went with the stack for the year of the airplane - 1946.