hey guys what prop do you think would be the best used for this plane it is from general hobby and it has a 56inch wing span and about 52 inches long i have a os 55 ax on it so what prop do yall think will be best i ran a 12 x 8 on it and it didnt act over powered at all didnt even have very good vertical....</p>

A prop with a pitch of 8 isn't going to give you vertical performance, it's going to be used more for speed. If you want more vertical "omph" you will need to use a lower pitch prop. A good way to remember prop pitchs is to think of them like gears in a car. Lower gears are for pulling power and higher gears are for speed. Same with props, lower pitch gives you more power and higher pitch gives you more speed.

As for your plane. It's hard to tell somebody what the best prop is for their setup. The best thing to do is buy several props and then start experimenting until you get the prop that best suits your flying and your plane. I do this for most of my planes until I find the prop that suits what I'm doing.

Ken</p>

what Ken said.But i would add that the Yak has an enormous cowl with loads of drag so you may want to consider only props in the 12 and 13 inch range.Try;

11x6 (good starting point for small engines)
12x4
12x5
12x6
13x4
13x5

I use a 12.25 X 3.75 APC with my 55 AX in my super dectrhlon with 60 inch wing span. unlimted vertical and it will hover and fly slow as well.

Im running that prop on my 55 AX also and like it very well.

For my decathlon. anything bigger than 12 inch prop would cause dead sticks with my 55 AX. Not sure why, but eventually settled on the APC prop I mentioned earlier and have had no more dead sticks.

Like everyone says, try a few props and pick what you like best. In my experience, a 13x4 works great on the .55-AX on your type of airplane. It gives a lot of pull but keeps the speed down. I've had great luck with both APC and Xoar 13x4. That's just my experience though; you might like something completely different.

12 x 6 or 13 x 4 just like have been said.

well i got a xoar 13x4 in today i will try it out this weekend looks like its going to be a nice weekend for flying