As Randy Jackson says, â€śHey Dog, Check it out.â€ť
Matt â€“ 7th reply, page 1 â€“ 3/25/08,
What do you mean by "torque roll problems?"
Nearly all full-scale, multi-engine prop planes have all their props spinning in the same direction, for simplicity in manufacturing and maintenance.
Handling issues can be overcome with adequate vertical fin area, and adjusting the down/right thrust on each individual motor. A degree or two of down thrust on the starboard (right) engine will take a huge bite out of the plane's tendency to pitch up and/or roll to the left under power.
A conventional engine will tend to roll a plane left and lift the nose when mounted square to the airframe due to these factors. Down and right thrust counteract these factors.
Hughes Spruce Goose had four powerful engines on each wing with all 8 props spinning in the same direction. The Spruce Goose had a very large vertical fin to counteract the yaw from all 8 engines spinning in the same direction.
â€śThe vertical tail on typical twins vs. typical single-engine aircraft tend to have two or three times more vertical tail than singles. The need for enough rudder authority to counteract the yawing problems with critical engine dead is what usually determines the vertical size for a multi-engined aircraft.â€ť - Don Stackhouse
â€śThe bottomline is that for a typical electric model, especially backyard type, counter-rotating props are usually not worth the trouble. If single-motor planes donâ€™t need contra-rotating props on the same axis spinning in opposite directions to counteract P-factor and torque, a twin model of the same size and power will need counter-rotating props even less!â€ť â€“ Don Stackhouse
Matt â€“ 16th reply, page 1 â€“ 3/26/08,
That starboard motor appears to have some up and left thrust in it from the picture. It may be the cowling is on crooked, or an optical illusion. Up thrust and left thrust would explain the problems you are having.
BTW, the Catalina's engines both rotate in the same direction on the full scale version.
Can any one name even one twin engine civilian aircraft with counter-rotating props?
If counter-rotating props arenâ€™t necessary on a civilian aircraft why are they needed on a Catalina electric model. The Catalina is no WWII Lockheed P-38 fighter.
The comments by my flying buddy Swift427 made about as much sense as your need to use a right-handed tractor prop on one motor and a reverse pitch, left-handed pusher prop on the other motor for counter-rotating twin motors on your electric model Catalina.