Hi,

I would vote for 4 stroke on trainers, reason being trainee tense require short take-off from all or any direction and they abort landing 10 times before rolling the plane to the nearby bush...

All this difficult stunts requires high torque on low rmp to help them get out of trouble, the menovure some trainees make are sometimes 3-D look alike.

Futhermore, 4 stroke drives a bigger dia props, which creates a bigger gyroscope effect on the plane making it more stable for beginners.

Last but not least, the low end high torque can help trim more grass off to clear for a wider run way before the engine come to a dead stick when they go for a bush landing.