RE: Red Wing Sbach profile
Tim,
I gave my completed bird an engine test run last weekend. The firewall (if we can call it that since it does not really have one) was so weak that the motor shook very badly. After less than couple of minutes of goosing the throttle, the top engine mount broke.
I believe this is a rather big flaw in the airframe design. I tore off the covering to find that there was not much wood at all. The horseshoe shape piece of ply used for the engine rail was very thin and does not extend deep enough to reach the wing tube and landing gear sections of the fuselage.
I ended up pulling the horseshoe engine mount off the airframe and this took very little effort since the glue was minimal. I epoxied the mount and added a large piece of lite ply to beef up the entire port side of the fuselage from the engine back to the landing gear area.
I will finish covering the added side and remounting the engine tonight. Will test run this weekend. The new enforced mount is ten times stronger and I hope to be able to fly the plane without further rework. It's a very nice plane but the engine mount is not safe as it is designed.