Hi there,
I bench ran in my DH2 Beaver in my shop as the motor had not been broken in yet. I put the 8 foot wingspan bird on its floats on the table after sticking my "ground fork' into the table to fit right in front of the stabilizer to prevent the bird from shooting foreward while I ran in the motor.
I am getting vibration deflections of possibly 1/4-3/8 inches in my wing struts at a certain RPM (wide open). Wing struts are about 22 inches long. The prop has been balanced. Do you think the vibration could have something to do with the fact that the floats and plane were sitting on a hard table and the vibration would dissapear or not be as bad if the plane were airborne?
Anyways...I ran the plane for about an hour and a half total varying the RPM and everything worked fine. I checked the plane out and I have no cracks in anything due to vibration. BTW... the motor is a new .90 Super Tiger 2 stroke with a pitts style muffler.
Comments? Thanks...Jim