My 46AX loves the 11x6 prop. Tachs out at 13K on the ground, and being on a slippery Mustang, winds way out in the air, and yet has vertical limited only by my eyes and my fuel. It's a good place to start.

If you find your plane flies too quickly, or if you'd like more vertical still (the 11x6 at 13K is good for about 7# thrust), you could try a 12x5. In the unlikely event you wanted more speed (with an 11x6, it's pretty quick!), a 10x8 might be a good choice.

Try to use props that hold the ground RPM to 13K or less, and it'll run a long, long time, and still have PLENTY of power for spirited flying.

This is the best engine I've owned yet, it's never deadsticked (about 70 flights on it), it always starts easily (started first flip when breaking in), and it tunes with ease. Oh, and it's really powerful. The LA you had should have been it's equal in everything but power, I find the AX's very similar to tune, excepting their superior non-air-bleed carb which is far better than the LA's bleeders.

You'll be amazed at the difference. Think 6cyl ford mustang vs 5.0L all tricked out....

J