I still have my Aircore 40 trainer it has a ST 51 these thing are durable but heavy. Mine once took the limbs off a pine tree. They land a lot faster than a balsa trainer, but you can stick it in the ground with little damage. I built the Cub one latter same plane as the trainer had much trouble with it being a tail dragger it will make you a pro War bird pilot. Check out the SPAD guys.