Tailwheel assemble for a Luscombe 8A

[Luscombe8dk]

What is the best pneumatic tailwheel assembly for my Luscombe 8A?

 

[Magman]

My thought is you should start with the Type Cert Data Sheet and determine

what is approved for your aircraft as well as what is currently available.

Your choice may also vary with what is currently available as well as

the surfaces you operate off of. Scott seems to be a good product and Maule

not so good. There are also new brands in the mix. Perhaps a

“Baby Bushwheel”?

 

[Dan Thomas]

Scott tailwheels are expensive, and Alaska Bushwheel (now McFarlane Alaska) sells PMA'd clones for less. I have never cared for Scotts, as their anti-shimmy is a swivel brake that just makes steering harder during taxi. Tailwheel shimmy, like nosewheel shimmy, is often due to a dynamically imbalanced wheel/tire assembly. The rest of the problem is usually a weak and distorted tailspring pack letting the swivel axis tip forward, like the bent caster on a shopping cart. Geometry matters.

Maules are a bit cruder and suffer shimmy for the same reasons any other tailwheel does: dynamic imbalance and a tipped-forward swivel axis.

I had a homebuilders tailwheel on my Jodel. It originally had no castering function, so I made the bits I needed for that. I eventually modified it again and made a much better castering-locking mechanism for it, and steering was easy and crisp and it never shimmied. The mechanism was open and dirt was a bit of a hassle, but it never quit working.

 

[Tusayan]

In my experience on an 8A, the best tail wheel is a Scott 2000 (previously known as the 3-24, for example on the Luscombe TC), which is not pneumatic but works very well. They come in and out of lock very smoothly, use springs that aren’t too stiff and are generally a nice piece. Also much lighter than a 3200 and every ounce counts on an 8A. They are not available new so getting a nice one often involves buying used and rebuilding. Parts are available, but nothing will be cheap.

Maules are rough operating junk IMHO and do not measure up to what’s needed for a sensitive plane like the Luscombe. The pneumatic ones shimmy.

 

[Dan Thomas]

Avoid the cheap knock-offs; they shimmy like crazy on pavement.

The pneumatic ones shimmy.

A few posts back I said this:

Tailwheel shimmy, like nosewheel shimmy, is often due to a dynamically imbalanced wheel/tire assembly. The rest of the problem is usually a weak and distorted tailspring pack letting the swivel axis tip forward, like the bent caster on a shopping cart. Geometry matters.

I have cured shimmy on many airplanes by just dynamically (NOT statically) balancing that wheel, and on tailwheels, that spring pack has to hold the tailwheel so that its steering axis does not go forward of vertical under load.

When you get new tires on your car, the tire shop dynamically balances each wheel. They put it on a machine that spins it and determines exactly where and how much the imbalances are, then weights are attached to the wheel to remove the imbalance. A static balance only removes vertical imbalance, and cannot cure shimmy, which is a dynamic imbalance. A static imbalance can actually make shimmy worse if the weights are attached to the side of the wheel that already has a heavy spot.

 

[GeorgeC]

I may be a hamfisted brute that doesn't know any better, but the Lang (which I understand to be similar to / the same as the Maule?) on my 140 has been fine.

 

[Tusayan]

A Lang tailwheel will hit the bottom of an early 'round' Luscombe rudder unless the bottom of the rudder is removed per a factory service bulletin. Interference can also be an issue with the springs/chains used on other tailwheel types because the early rudder was originally designed for non-steerable castering tailwheels that had no springs or chains. Nobody used non-steerable tailwheels postwar and eventually the later square rudder resolved the issues but is a bit ugly.