I have recently decided to buy and mount a FS91 Surpass II 4-stroke on my new CAP231. I have realized that I will need to mount this engine in at a 90 degree position. When I mount the motor mount in the center of the firewall, the engine has so much weight on the head that it throws the balance way off. Another-wards, it wants to roll when holding the plane up. Are guys just adding weight to one wing to balance? Also, can I use an extension on my pitts style muffler. It doesn't clear all the motor mount and will have to be mounted at a slight angle. Is this normal?

Matt

Matt,
You won't be able to really tell until you fly it and put it into a straight up climb. If it leans to right or left, it could be lateral balance or rudder. The engine torque usually counteracts the slight weight of the engine side mounted.
To check lateral balance, use a string from top of rudder and fingertip on nose of spinner and see which way the plane leans.

As it sits without the wing off, when I hold the plane in the horizontal position it once to roll over real bad. So you think this could be washed out when the engine is running. It just seems like as it sits that the plane would torque on take off?

Matt

This is not a big issue with the wing on and the engine running. In any case, it's better to laterally balance the plane with the wing on and add weight to the lighter wingtip.

Matt, read this article. Scroll down to the section on Lateral Balancing:

http://www.rcuniverse.com/magazine/a...?article_id=84