Can someone confirm whether the mil Chipmunks had a rather nasty spin if left to wind up? The civilian mods for a C of A included so-called 'anti-spin strakes' on the rear fuselage, presumably for this reason. I was told that in extremis it was discovered the spin could be stopped by pulling the yellow knob, jettisoning the canopy, unstrapping and standing up! - something to do with changing airflow over the tail I was told.