Shoestring, OS61FX on a Pitts. 112mph clocked flat run into a full-pull vertical climb to a super high hammerheadover into several snap rolls with a smooth pull out at the bottom with no worries of snapping a wing in half. Before my "dumb thumb" I was on fire every time I put this bird in the air. It has zero bad tendencies at any speed and was responsive at all attitudes and altitudes. Inverted was easy and light with great inverted climb ability, almost an instantaneous 90 degree inverted climb out from level flight. One thing I will say, due to the nature of this bird to maintain speed at landing, getting her on the ground was my only personal heart-attack time.