Hello, I was just wondering how to tell what kind of aftermarket propellar to put on a plane. What do you judge to look at speed or slow flying or torque or what?
I have put a smaller more curved prop on my hobbyzone champ and it allows me to fly a little slower which is cool, but I also have a UM t-28 and a big t-28 and a f4f wildcat. All of them have the stock prop on them. If I were to look at getting a new prop, what would I look for? Size? shape? Thickness?

I am not new to flying planes, but I am new to exchanging props. Thanks for the help.