a solution to gear-leg shimmy

[highflight42x]

I've got an RV3 with 650 hours. Wood dampner strips glassed to the gear legs. I've always had some form of gear-leg shimmy (sometimes bad, sometimes not) at around 30mph on landing. The only thing that seemed to reduce it was keeping tire pressure at or below 25psi. But I could not eliminate it entirely. Until now.

I had been flying with Goodyear Flight Custom II tires over its entire service life. The tread on these tires was pretty flat-surfaced. Since the gear axels are angled downwards, the outer edge of the tire makes more contact than the inner edge.

I recently put on new tires, but this time the Goodyear Flight Special II. This tire has a noticably rounder cross-section.

After ten takeoff and landings, my gear-leg shimmy is gone! I put in 32psi. I had put the same pressure in my earlier tires for hundreds of hours, always with shimmy present on ldgs. And now: no shimmy. Must be the new tire with its rounder cross-section, that's all that I changed.

Hope this helps someone!

- Steven

[gasman]

In section 10 page 1 of my 6 construction manual it explains the tire profile needed.

[aerhed]

Yeah, the FC (flat bottom) type tires are designed for like oleo strut gear that stands straight. Flight specials and other "round" tires are intended for spring gear. Think PA28 vs skyhawk.