I want to preserve this information in the RV-3 forum, even though it is partially copied from a thread over on teh RV-4 forum - the RV-3 gear legs are wet noodles enough that some form of stiffener/damper is generally required, and the wooden ones have always been a bit marginal for us.
I just finished doing this modification on our -3, something I have contemplated for quite awhile, but never got around to doing. At ourt annual a couple of weeks ago, I noticed that the wooden stiffeners had de bonded, and weren’t doing much…so it was time. And with only one test flight in the box, I can still give a pretty definitive answer that the metal stiffeners are better! Our wooden stiffeners were on there from day one, and with almost 800 hours, and were doign very little. The truth is, we have always had a shimmy with these spindly RV-3 legs - we just controlled it with lower tire pressure, braking, and avoiding certain taxi speeds.
Installing metal dampers was probably a total of about six hour’s work - I spread it out over a couple of days, but it was straightforward. Based on notes from Dave Paule, I used 1/8” x 1-1/2” aluminum, and seven Adel clamps. I removed the rubber from the Adel clamps, mostly because I was worried about the outside diameter affecting the fit of our gear leg fairings. Largest Adel is -18, smallest is -12, and they are spaced to where they are naturally tight on the gear leg for their diameter - note that this is NOT evenly spaced. There’s a single wrap of Gorilla Tape under each clamp, just to seat them better.
Spacers were required between the clamp and the metal bar stock to put the center of the bar stock through the center of the gear leg. Screws are low-profile #10 Allen heads, 1” long, and fastened with low profile nylon lock nuts. Washers and s machined bushings were used for spacers, and there was approximately a single washer difference between adjacent clamps. The existing gear leg fairing fit right back in place!
View attachment 27479
I just finished doing this modification on our -3, something I have contemplated for quite awhile, but never got around to doing. At ourt annual a couple of weeks ago, I noticed that the wooden stiffeners had de bonded, and weren’t doing much…so it was time. And with only one test flight in the box, I can still give a pretty definitive answer that the metal stiffeners are better! Our wooden stiffeners were on there from day one, and with almost 800 hours, and were doign very little. The truth is, we have always had a shimmy with these spindly RV-3 legs - we just controlled it with lower tire pressure, braking, and avoiding certain taxi speeds.
Installing metal dampers was probably a total of about six hour’s work - I spread it out over a couple of days, but it was straightforward. Based on notes from Dave Paule, I used 1/8” x 1-1/2” aluminum, and seven Adel clamps. I removed the rubber from the Adel clamps, mostly because I was worried about the outside diameter affecting the fit of our gear leg fairings. Largest Adel is -18, smallest is -12, and they are spaced to where they are naturally tight on the gear leg for their diameter - note that this is NOT evenly spaced. There’s a single wrap of Gorilla Tape under each clamp, just to seat them better.
Spacers were required between the clamp and the metal bar stock to put the center of the bar stock through the center of the gear leg. Screws are low-profile #10 Allen heads, 1” long, and fastened with low profile nylon lock nuts. Washers and s machined bushings were used for spacers, and there was approximately a single washer difference between adjacent clamps. The existing gear leg fairing fit right back in place!
View attachment 27479
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