I have a 55AX in my SPAD Talon and I have it set up for speed. I have tried all sorts of different props on it and by far my favorite is the evolution 11x6. I have the Tower Hobbies pipe on it and it will pull this heavy plane straight up all day long but idles nice and slow. I have been a big fan of the evolution props for my sport planes. Plus the Tower muffler sounds awesome! Wouldn't reccomend it if you are in a noise sensitive are like CGRetired though. It is LOUD!