I have been a great fan of the Dubro Motor mounts http://www3.towerhobbies.com/cgi-bin...&I=LXD630&P=SM , and have them on most of my planes. An interesting issue came up on my Ruperts Dad.

I found myself doing donuts if I got on the throttle to quickly. However the donut is to the right, not the left as I would expect. I first chased a radio issue, then just scratched my head for lack of a possible cause. During my last day flying, I peaked the needle valves and was testing the transision on the Mag 70 Four stroke. I noticed that when I punched it, the engine twisted to the right, to the maximum move of the rubber mounts. I fly a 13x4W APC prop and the engine/prop gives a lot of torque, apparently to much for the mounts.

I can cut some hard rubber replacement groments, but I was wondering if any one had any other ideas or had experienced this. I flew these mounts on my trainer, and a couple scratch builds, all with O.S. 52 four strokes truning a 12 1/4 x 3 3/4 APC, and my 4*60 with a Mag 91 turning a 14x4W APC, and never saw this issue before. Or at least they didn't behave the same. The Ruperts Dad has 2 degrees right built in, and I'm guessing the mount is shifting another three to four degrees when I punch it.

Don