It is interesting to read back over this old thread. I wonder if Bidule and his son ever built thier plane.

It's funny, because in my original advice above, I indicated that the only real money difference between the smaller trainer and the larger one would be in fuel consumption.

Since that post, I have had my kids training on my Alpha 40 with the .45 Evolution engine. On one training night, with two kids each getting in three flights (10 ounce tank), plus a flight for another kid who just wanted to try it out, plus one flight for Dad, because I just wanted to fly at least once, I burned about 3/4 gallon of fuel.

The .25 size Eaglet starts looking even better at that point

I hope the original poster and his son are having as much fun as we are.