When selecting a Flat Pitch Prop for a smaller scale 3D aircraft like a Hangar9 Twist combined with a 61 size motor....what flat pitch prop is recommended? Are there any guidelines on the right prop used in 3D type aerobatics?

I think for that plane/engine combo, an APC 13X4W or a standard 13X6 would work well for 3D.

the only way to find out is to try, good luck!

I ran a 15x4W on my TT61 2C. It was okay, experimented it on my Harrier 90. A 13x4W is very little prop for the 61 2C for 3D, maybe a 14x4W as a minimum.

On another note, it is not worth it to fly the Twist with a 61 2C. The extra weight of the engine will increase the wing loading by heck of a lot. The increase in weight is more than the increase in performance. I tried this combo on quite a new planes. Best engine is something like the Twist is a SA82 turning a 14x4W.

Really have to agree with him about the .61 on a twist. I had a .52 magnum on one and it was overpowered, using either an APC 12X4 or 12.25X3.75 APC wide prop. A good running ball bearing .46 engine is more than enough power for this airplane, expecially here in Texas. If you think you need more power, then invest in a Tower .46 muffler for your TT, OS, or Magnum .46 sized engine. The plane is allot of fun, easy to see with a good color scheme, but isn't a good choice for hovering, since it is so close coupled.

A lot of prop selection depends on how you fly. Many people use an APC 11.5-4 on .46 engines. It revs more and gives slightly less thrust, but your control is better. The rpms seem to be in a better place on the power band so you can make 1 click corrections without the plane climbing or dropping rapidly. I have also seem a Master Airscrew 11-4 on .46s on 3D planes.

As for the .61, if you just want to go out and blast upward, by all means get a longer prop like a 14 or 15 inch. For fine control in low down 3D maneuvers, I'd go with the APC 13-4W prop. I would also try the 14-4W, but I think it will give you too much climb per throttle change. I have used a Zinger wood 14-4 and it spools up quickly.

There doesn't seem to be the same quantity of selection for the .61 as there is for a .46. It may be that the .46s rev quickly and have a lot of power for the weight, but I have never really liked a .61 in a 3D plane. .61s tend to be a heavy engine. Your .75s and .91s are built in the same case. Like I said, it's what you like.

Ed - I love the APC 11x5 for a 46 sized engine.