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wadeg
07-16-2008, 09:46 PM
Getting close to being ready to fly.
Looking at my tailwheel from the side, the line vertically through the axle down is 'trailing' meaning the top is in front of the bottom. I understand this is a recipe for shimmy.
I have a Maule tailwheel with the steel leaf springs. I suppose the only way to deal with it is to increase the bend angle in the leaves so it brings the vertical line so the top is slightly behind the bottom.
If this is indeed the way to fix the problem, any ideas how to best bend the leaves other than renting a bulldozer?
Thanks!

84KF
07-16-2008, 10:29 PM
Wadeg,
Attached is a low quality picture of mine... but it's a Scott assembly I believe. It's not vertical, but I don't have any shimmy..., now.

Most of the flying has been done at light weights. The most was solo, sometimes with full tanks. (26 gals) The setup was always smooth on roll out with no shimmy.

Then I started adding weight in the empty seat and when I got up around 80 lbs more then normal I started to get a shimmy when the tail came down at landing. The initial response was to keep the tail up as long as possible, use the brakes to slow down quickly and by that time the forward speed was so slow the shimmy wouldn't start when the tail came down. But I knew something wasn't right.

Finally I got curious and spent some time inspecting the assembly. With only 75 hrs or so it was, and looked, brand new. I took everything apart and checked bushings, etc. The tire did not have any uneven wear and everything was tight.
Almost.....

What I realized was that as weight at the tail increased as I added weight in the cabin, the rake angle was slightly changing causing the steering springs to loose just a bit of tension. Not much, but just enough to put a bit of slop in the setup.

I went one link less in the chains making them tighter then they were before and now with any deflection change due to weight they still stay snug. No more shimmy at any speed.

I know this doesn't answer your question..., just thought I'd pass along the information

I want to say ...see what happens first, before any modifications, and make sure the chains/springs stay tight for any expected loading scenario.

wadeg
07-17-2008, 09:20 PM
Steve,
Thanks a bunch for your reply. I'll give it a shot as it is and see how it does. I will be flying off the grass at 7S9 for a while so that will give me a good testing ground. Appears my angle is about the same as yours. If I can get this shoddy photo to load, you can barely make out mine.
Thanks!

84KF
07-18-2008, 07:43 AM
Check out the last image on the last page (17/17) of this article dealing with Maule tailwheel assemblies repair and setup.


http://www.bowersflybaby.com/tech/Maule_Tailwheel.pdf

wadeg
07-18-2008, 09:49 PM
Thanks Steve!
Solves that riddle!