I've had 2 Avistars in the family and we have over 10 at our field (grass field). The Avistar is a bit heavier than a lot of other trainers. Does the LA fly the plane? Certainly but there will be some limits in the plane's capabilites under different situations. At max throttle, you can pull the plane around ok, basic takeoffs, loops, rolls, etc but if there are winds involved or thick grass, the plane may have more difficulty pulling.

What we found with the Avistars and the .46fx was that you flew around at about 1/2 throttle 90% of the time but if you had to pull out of a "situation", the extra power you would need is there.

I wouldn't compare this to insanely overpowering the plane (e.g.a 1.80) but it does give slightly more power than you would use "most" of the time.

So, as others have said, for the price the .40LA engine will do the basic job. It's certainly the minimum power range I would recommend for the plane.

Don't throw it away, if you've got it, fly it

Bob aka Nuker