I have heard of 'canopy breakers' but also heard they do not do the job. The late Spencer Flack had to get out of his crashed Sea Fury after an engine failure near RAF Waddington. I think he used his bonedome to smash the canopy. Charlie Hillard in the States and Paul Morgan in the UK in the same type of aircraft were not so lucky and both died. It would be a problem in our Skybolt but at least the biplane top wing would probably keep the canopy off the ground.