Hi guys, I have a Freestyle Rush thats about ready to maiden. I'm planning on putting a Magnum 52 engine on it. I was thinking about a 12.25 x 3.75 prop, 12 x 4 prop, or 13 x 4 prop. What do you think?

I have found the 12.25 X 3.75 to be a good choice for my OMP 47" profile. If you have all three props you mentioned I would try them. Each airframe is different and will use a different combo.

I would not recommend the 13X4 at all. I have had terrific results with the 12X4 and the 12.25X 3.75 APC's, depends on what you are trying to accomplish. The 12X4 with the narrow tips is very sensitive to even grass blades. The 12.25 with the wide blade can almost be used as a weed eater with great midrange pull out from a hover. Hope you have great luck with your Magnum .52. A tower .46 muffler on this engine also gives you about 300 to 500 more RPM's on the top end.

You will be revving the 52 engine higher than necessary with a 12 x 4 prop. The 12.25 x 13.75 is great for 46 engines, but rather a light load for a 52..

Use a 13 x 4 or even 13 x 4 wideblade. This engine works well with those props. I know, I have a 52 and a 46.

The 13/4W is too small a prop for the 61FX and too big for the 46.

Seems like it would be perfect for a 52.

On my 52xls the 13x4 narrow was ok but liked the 12x4 better.

The .52 will pull all those props and for climb, the 12.25-3.75 would probably give you more. For serious 3D where you will be modulating the power around mid range or slightly higher, the 12-4 will rev and slow quicker so will give you an easier handling plane, especially is it is light. I like an APC 11.5-4 on a .46 for the same reason. The thin blade 12-4 APC will rev a lot on the .52, but if you are going to run full power for a long time, you don't want that prop.