I'm not going to give my oppinion on how well the radial work. But I can say I have the Saito five cylinder on my Stearman and it does not have a ton of power, but is cool and very scale.

Yes, I flew off grass and had no problems. Make sure you position the gear wire so the door is at "Full Flex" when on the ground.

The flaps work extremely well. I only use half because full flaps will make it sslo down too much.

John