National Aeronca Association Bulletin Board

Is there any interest in a progressive rate spring for the Chief & Champ landing gears. If so, I am willing to research and develop a spring and, or piston orifice re-valve.

Charles

Bet the off airport guys would be interested.

My biggest question would be how would it affect slow-speed/taxi maneuvers? Touching-down isn't much of an issue for me, as the current oleos suck-up quite a bit initially. The sketchy part is rolling out. Bushwheels helped immensely on wheels, but skis are a different story...

Bob K.
Anchorage, AK

Bob,

What performance are you wanting at slow-speed/taxi maneuvers, or what is happening now with the skis.

I can take an Aeronca spring and dyno it (graph the rate), then work from there to your demands and have new springs wound.

We can also work with orifice size in the piston along with the spring to suit your needs.

Charles

Charles,

I don't know much about the internals of an oleo, but from what Ive read it sounds like the large spring absorbs the initial touchdown, assisted by the oil passing through orifices, etc... Once the plane finally settles down, the whole thing is riding on a smaller set of springs inside the oleo tubes. Am I thinking about this correctly?

The capability of the oleos at touchdown is great, they sure can smooth out a rough landing, but after the initial touchdown, and you are rolling to a stop, the uneven ground really pounds the gear/plane. For instance, if you liftoff at 35mph, then its rough as a cobb from 0-25mph, and then the wing takes enough weight off to get the oleos involved, and it smooths out a bit. Similarly on landings, the initial touchdown from 35-25 isnt bad, but one you slow beyond that, it gets rough.

Id gladly give up the soft and smooth landing personality of the oleos for a more rugged hydra-sorb setup like a Cub, but it doesn't make financial sense at this point. Ive been told that one can install a "spacer" under the taxi-spring inside the oleos to gain an extra inch or so of prop clearance, but other than that I haven't heard of any off-airport mods for oleo gear.

Its all about compromises...

Bob K.
Anchorage, AK

Bob,

There are several ways to work with those issues you are having.

Economical: K-Prene bushing with several different durometers. Just add as a wedge in the spring coil or to the ends of the coil.

Middle of the road: wind new springs.

High end: new springs with custom valves in the piston.

There is a local spring and shock specialist here that provides engineering, custom springs and shocks for the motocross and nascar industry.

If you want to try something let me know.

Charles