Dual Arm Matco tailwheel?

[natemcm]

Has anyone tried the Dual Arm Matco on the Highlander to address the single arm shimmy problem? Suggestions for a steerable tailwheel that doesn't shimmy would be appreciated.

[messenger]

Most times , the shimmy in the tailwheel assly has nothing to do with the single or double arm. It has to do with the angle to which it is attached to the tail spring. If you would go to supercub.org or shortwingpipers.org and do a search about tailwheel shimmy, Steve Pierce has written extensively about how to eliminate shimmy problems in tailwheel assemblies. I know first hand because I used many of his suggestions to eliminate the shimmy problems I had. thanks R L Messenger

[aerochristian]

Most times , the shimmy in the tailwheel assly has nothing to do with the single or double arm. It has to do with the angle to which it is attached to the tail spring

I'm glad you said "most times". By changing the angle of the tailwheel spindle...all your doing is shortening the arm between the contact point and the spindle thereby raising the frequency of the system necessary to initiate shimmy beyond the operating range. No two situations are the same. Tire size, tire balance, tire inflation, tire wear, bushing/bearing wear, friction, mud, grease and tension can change this entirely. Just like a unbalanced control surface, a tailwheel will shimmy (flutter) regardless of the angle if all these things "hook up". This also has the negative effect of causing the tailwheel to be twitchy and "drop" off center as the weight is now trying to fall off the high trail position into a neutral resting position which is now 90 degrees to either side of the spindle axis.

The only way to truly eliminate shimmy is with a dampened system...(ie Outcast conversion kit, tailwheels.)

Just because you "fixed" shimmy with a angle change doesn't mean its not possible, its just moved, just like hundreds of airplanes that exist with no flutter and then boom its all over.
You're better off with a dual arm because at least the tire is in the center, unlike the single arms. But even the dual arms will shimmy, which is why I sold a conversion kit to Frank Soltis for his SS. After that he bought another one for his single arm.

Chris

[messenger]

I did not say I changed it with a single adjustment, I said read about tailwheel shimmy from an expert in the field who spends his entire life working on taildraggers. It sounds like you have a lot of knowledge about tailwheel dynamics, so my email would not be directed at people with your knowledge, but rather at people wit less experience in the field. go to his articles on supercub or shortwings and read and you will see what I am referring to, I am not an expert, but steve certainly is. thanks RLM

[aerochristian]

Fair enough....

I just didn't want the guy to get a single arm un-centered tail wheel, change the angle to make the thing even more divergent, all the time thinking he's doing the right thing, and then ground loop his life savings.

So in the effort to help others who are less experienced as you or I, and seeing that we don't agree on behavior after changing the spindle angle, what specifically did you do to your tail wheel to eliminate shimmy?

Chris

[danerazz]

Chris,

You ever get a website up?

[natemcm]

Dear Gentlemen:

Glad to stimulate a discussion......but I'm still waiting for steerable tailwheel suggestions that don't shimmy on the Highlander!

Nate

[aerochristian]

Still working on the website... Just been so busy, plus
I figured if Obama can take forever on his you guys would
Cut me some slack on mine.

Ok.... In answer to the original posters question...

There isn't any.
Your best bet is a smaller dual arm Matco.

Chris

[danerazz]

...I figured if Obama can take forever on his you guys would
Cut me some slack on mine...

His site is up, it just steals your personal information, gives it to felons, provides no service in return, and locks you into something you don't want. But at least it is still up.

[messenger]

When I first bought my highlander, it had an iron design tailwheel. Thru no fault of its own, it was shimmying like all get out. I finally got it working by following Steve Pierce's suggestions in his article on supercub.org . It took several small adjustments to get it working properly, but I did get it done. I had a talk with Billy Payne and he suggested getting an alaskan bushwheel, which is equivilant to a scott tailwheel. since I am more familiar with ABI- scott style tailwheels with my earlier experience, I went ahead and splurged and got the best steerable tailwheel money can buy for our size planes. I have had not one shimmy problem with the ABI, and would suggest getting one if your budget will allow it. If not, the iron design tailwheel is a good second for a steerable tailwheel. With the intended use of the highlander, the smaller matco might not be the right choice, altho they do make a larger design that I have no experience with at all. But no matter which tailwheel you wind up with, be sure to reference steve's suggestions on how to make your tailwheel perform the way it should. What I am suggesting is not the only way, but it has worked for thousands of certificated planes for years and years. good luck. RLM

[natemcm]

Dear RLM:

Many thanks! That's the type of experienced-based info I was hoping for!

Nate