Thanks eddieC
I'm stuck with paved runways and fly 38 lb plus 1/3 scale Sopwith pup and Fokker dr1. Both ground loop and my fear is they may ground loop into someone. I think landing on the mains and holding the tail up with power until plane slows down to descend on tail skid is the best way to reduce the amount of ground looping. Both planes are set up with straight 1/4 steel axle rod fixed at the center to allow for a sprung shock. Could bend the rod ends to push wheels in toe-in position but these gears are narrow may not do much and make the ground loop more aggressive when it starts.