I have an Avistar with an OS 46FX and it is an absolute honey with this engine. I usually fly it with 1/2 throttle and that gives me plenty of power and speed to do the regular Newbie things. I've been so impressed with this engine for it's size that I got another one for another Avistar I turned into a taildragger. I'll be sticking with the .46FX's for a while, as long as I can find them. You can't beat the cost effectiveness with fuel and the aircraft size.

As an experiment, I also got a Magnum XLS .46 (looks exactly like the OS) and put it on my Bipe, and it also does a great job of hauling the A/C around the field.

The only time I have seen something with a .40LA (Hobbico Superstar), it didn't seem to want to fly...slow as a dog on takeoff and just didn't seem like it wanted to run..........

A .46 on an Avistar? Go for it! You won't be dissappointed!