Tailwheel Shimmy and Spring Arch

[Lownslow]

Ok. I'd like to ask this question again. My Univair kit was purchased in November of '08. I am assuming the spring supplied for the Alaska Bushwheel doesn't have enough bend. Can someone share a recommendation on the amount of curve needed ?


Lou S.

[smcnutt]

I know Andy's site has some info on Tail Spring Re-arching. http://home.earthlink.net/~andy2220/id4.html

We recently redid ours. I would guess that when the rebuild/conversion was done before we purchased it they simply purchased and installed the spring that they got. From what I understand it does not come properly arched.

[Lownslow]

Thanks, that's where I forgot I saw it.

Lou S.

[Andrew K]

Just wanted to say thanks for the spring template. I had a shop re-arch my spring using the template last year and I haven't had the shimmy since.

I do have another question though, in the notes on Andy's site it says not to heat the spring or it could change the properties which I understand. But if one were to powder coat the springs, is the heating involved in powder coating substantial enough to mess up the spring properties? Just trying to find a finish that will last a little while so I am open to suggestions.

[Steve Pierce]

Andrew, Most powder coaters heat to no more than 400 degrees for the powder to melt so I don't think you have anything to worry about. Let me know how it works, those rusty looking tailsprings always bug me too.

[MrWayne]

I agree with Steve, a normal spring temper is in the neighborhood of 800 deg. F. plus or minus depending on the material the spring is made of. But never any lower then 600 degrees F. A spring would be very brittle tempered at 600 degrees. You will be plenty safe powder coating the spring.

[JrBirdman]

Hello Folks,

I'm tagging onto this 2010 thread rather then starting a new one (I searched and did not see anything more recent on the issue. I'd like to upgrade to a 1 3/4 width tailspring, and as Steve mentions in the quote below AK Bushwheels has a nice PA-18 single-hole 4-leaf that has a nice tight arch and strong temper. However, I just talked to Jason up there who said they did not end up making an adaptor to fit the std PA-22/20 tail post bolt spacing. I know several of you out there are using the wider AKB or Pawnee springs, but I suspect most welded on a wider foot while they were in rebuild or conversion.
But I'd like to ask if any one has come up with a design for an adaptor or ground half moons in the wider spring to pick up the original bolt pattern.

Thanks, REID

The Husky spring originated from the Piper spring and as they went up in gross weight the spring got more leaves but lost it's arch quickly. I hear Univair made them for Aviat. Bill Duncan at AK Bushwheels was selling Aviat tail wheels and they kept bending the steering arms. He would not warrant the bent arms because their tail spring arch was at the wrong angle thus the steering arms were bending trying to turn the tailwheel. Bill started supplying Aviat with tail springs and added a little more arch and changed the temper to make them last. The thing I am waiting on right now it the two bolt clamp that attaches the tail spring to the tailpost. The Husky is wider than the Piper one. Wup at AK Bushwheels is working on one to fit the Piper fuselage using their Husky tail spring which is wider thus the Piper bracket won't fit.

[Steve Pierce]

The Pacer is no different than the Cub or Super Cub. The bracket that comes with the spring bolts right on.

[JrBirdman]

Steve,

Thanks for the fast reply. Just to be clear before I order; you are saying that the Alaska Bushwheel SuperCub Tailspring & U-clamp they sell will bolt straight on to the Univair Converted PA-22/20 tailpost. If that is the case I will order one and all the other internal parts for the Scott 3200 I need and be back flying soon. If there is complications I'll post it, but it sound like you've seen and maybe even installed the AKB spring.

Great Day, REID

[Gilbert Pierce]

It bolted right up to my Clipper, no problem