counter rotating props on a large 1/10 scale Lancaster 12 foot wing span

[Robert Jerome]

Do you set them by there position on the wing 1 through 4 1 and 4, 2 and 3. Or by the side they are on the wing 1 and 2, 3 and 4? Or does it really matter? Hope the question makes sense.

 

[CappyAmeric]

For counter-rotating props - the TOP ARC of the props should be turning inward toward the fuselage. For 4 motors, looking from the front of the airplane, the right motors turning counter-clockwise, and the left motors turning clockwise.

 

[Crow929]

The Aribus A400 (Looks like the C-130) has props that counter rotate on each wing. Looking from the front, left to right, it's CW, CCW, CW, CCW. The props turn toward each other on each wing. The C-130 props all rotate the same direction. You don't get massive torque roll with multi engine aircraft, so really it doesn't matter much.
From what I've read, having a twin engine rotate toward each other make it more stable and will have less roll authority. I've set up my twins that way, and honestly haven't tried it the other way to compare.

 

[CappyAmeric]

The Aribus A400 (Looks like the C-130) has props that counter rotate on each wing. Looking from the front, left to right, it's CW, CCW, CW, CCW. The props turn toward each other on each wing. The C-130 props all rotate the same direction. You don't get massive torque roll with multi engine aircraft, so really it doesn't matter much.
From what I've read, having a twin engine rotate toward each other make it more stable and will have less roll authority. I've set up my twins that way, and honestly haven't tried it the other way to compare.

The purpose for counter-rotating in multi-engine is to minimize P-factor as well to eliminate the “critical engine” performance hit. The reason the C-130 and other aircraft like the Beech King Air do not counter rotate is to minimize the expense of 2 engine variants - but otherwise non-counter-rotating multi-engine have no benefits. Counter-rotating is superior in every aerodynamic way.

 

[quorneng]

The power to weight of a twin is also a factor in determining the need for counter rotating props.
The DH Hornet and Grumman Tiger Cat are examples. Note the similar but bigger and heavier DH Mosquito did not counter rotate.

We have to remember that at smaller RC model sizes it is quite likely that the plane will have a power to weight ratio that exceeds even those high power full size types so non scale counter rotating can have a significant flight advantage.

 

[Robert Jerome]

The power to weight of a twin is also a factor in determining the need for counter rotating props.
The DH Hornet and Grumman Tiger Cat are examples. Note the similar but bigger and heavier DH Mosquito did not counter rotate.

We have to remember that at smaller RC model sizes it is quite likely that the plane will have a power to weight ratio that exceeds even those high power full size types so non scale counter rotating can have a significant flight advantage.

My Mosquito handles very differently when I tried it with non-counter rotating props did not like it one bit. Went back to counter rotating props and all the handling issues went away. I too have a F7F Tiger Cat, I donot think I will try this experiment with it.

 

[CappyAmeric]

In R/C planes unless the motors are not able to be easily switched in rotation, or you can’t find counter-rotating props, you should ALWAYS setup counter-rotating.

Learn about the effects of P-factor and the principles of moment and you quickly discover why you don’t want giant discs rotating the same direction while being located at an opposite distance from the longitudinal axis.

 

[CappyAmeric]

The power to weight of a twin is also a factor in determining the need for counter rotating props.
The DH Hornet and Grumman Tiger Cat are examples. Note the similar but bigger and heavier DH Mosquito did not counter rotate.

We have to remember that at smaller RC model sizes it is quite likely that the plane will have a power to weight ratio that exceeds even those high power full size types so non scale counter rotating can have a significant flight advantage.

The decision to not counter-rotate was an economic one, not an aerodynamic one.