Hi, I am building a big Dornier DO-335 and it had 2 motors. ( http://www.rlm.at/profil/11/do335_v3.jpg ) The motors im using need 6X5.5 props, and I wanna do a counter rotating setup. Where can I fund a 6X5.5 reverse roation prop?! APC dosent make one! They have a 6X4 reverse rotation prop, but not the 6X5.5 Should I just use an 6X4 reversed one for one motor, and keep the 6X5.5 on the other? Help!

6X4 on the front and 6X5.5 on the back? The higher pitch prop would be operating in the faster air-flow.
Or don't bother.
A FB has a Beaufighter that with its 2 conventional props wanted to roll left. He eventually managed to track down counter-rotating props and... it still wanted to roll left.
He says it made no difference. Seems strange, but there you are.

You should use the 6x4 and the 6x4r.
BP hobbies also has these props.
http://www.bphobbies.com/view.asp?id=V748425

sounds like a cool project please post building pics.

Since this aircraft is push/pull, it shouldn't matter. You don't need a reverse pitch prop, just run the rear motor in reverse and make sure the prop is facing the direction of flight.

Azarr

Originally Posted by Azarr

Since this aircraft is push/pull, it shouldn't matter. You don't need a reverse pitch prop, just run the rear motor in reverse and make sure the prop is facing the direction of flight.

Azarr

WHen you say reverse, do you mean if you were look at the back of the plane, one motor is spinning one way, and the other is spinning the other way? Or you look at the back opf the plane; and the front motor is spinning one way, then you look at the front of the airplane and the rear motor is spinnig the other way?

The front motor is mounted normal and the back motor is mounted like a pusher prop.

Thats how I have it setup now. I hope it won't flip over when I gun it!

Originally Posted by PinkYakRC

WHen you say reverse, do you mean if you were look at the back of the plane, one motor is spinning one way, and the other is spinning the other way? Or you look at the back opf the plane; and the front motor is spinning one way, then you look at the front of the airplane and the rear motor is spinnig the other way?

Looking from the rear towards the nose, both props spin in the same direction. You need to reverse the rear motor since you've turned it around.

Azarr

Should I angle the rear motor up and to the left? Hehe, I have almost no exp. with pusher props! (my 3D foamies have 1 motor!)