tailwheel compression springs

[N74DV]

how much preload tension should they be rigged with? Last week I removed the tension springs and swapped them for a new set of compression springs but they are a tad loose and not preloaded at all. I'm experiencing a shimmy and wonder if I removed a link in the chain to tighten things up if the shimmy would be reduced.

[Ron Babos]

Re: tailwheel compression springs

N74DV: Just take up the slack and maybe very slight compression of about 1/8" - 1/4". Springs won't cause or eliminate shimmy as a rule.
Ron

[Len Petterson]

Re: tailwheel compression springs

Tail wheel shimy can be very difficult to find the reason for, here is what we exerienced on my friends Thorp T18.
Everything is fine but one day as we came back from a flight the tire is ready to come of the rim.
New tire installed and the shimey starts!
Why ?
Springtension was tight, we lossend it , Shime still there !
At this time we take the aircraft home for the winter We read evrything we can find on Tailwheel shimmy.
We rounded of the sharpe edge in the tire to give it a rounder profile.
Tight springs, round profile, no shimmy.
Happy landings!
The zenith 300 what is parked on the other side of me has loose springs works fine ,but not with tight springs.
My Taylorcraft has the original springs or simmilar and no shimmy. (;f
Len

[flyguy]

Re: tailwheel compression springs

if you have a tire with air in it try changing the pressure. I had never heard about the tire edges before, but it makes sense as my spring twist slightly from tire tracking left to tire tracking right. That would put the weight on the edges of the tire. Best way is to try a bunch of different things and see what works. Every spring/tailwheel conbination is a little different. If you have Maule springs one should be bigger in diameter than the other which is supposed to help with shimmy. Good luck.
Darryl

[NY86]

Re: tailwheel compression springs

What kind of tailwheel? They're all different...

Castor angle has a lot to do with shimmy. If the "king pin" is angled forward at the top it'll shimmy no matter what...