The SIG KADET LT-40 is without a doubt the best .40 size Beginner Trainer on the market. We use 3 of them as Club Trainers. 71" Wingspan and will accept anything from a OS LA .40 to a O.S. or Super Tigre .61

If you want something just a little smaller, the SIG KADET LT-25 is a SUPER Easy to Build, Easy to Fly Tail Dragger. I just soloed two of our club students on my LT-25. I have a Saito 4 stroke .30 in mine, could use just a little bit more power, but I believe it is the best .25 size Trainer. 63" Wingspan, 4 pounds of Flying Fun.

Built it and learn how you might have to repair it.
Keep em Flyin,
Ken