Originally Posted by
allan907
IIRC the cockpit canopy jacks were fairly powerful beasts which extended to about 18 inches. In a static jettison they would undoubtedly blow the canopy a fair way up. I certainly remember the canopy whizzing into the air before it started its descent to mother earth.
I also remember a safety lecture where we were shown a graphic pic of a jettison jack neatly inserted into some riggers elbow and exiting out of the wrist. Apparently the canopy was off, he was resting his arm on the cockpit edge when the system (presumably there were no seats in) went orf and bang went his arm! Gruesome stuff. It was a fairly standard lecture - anybody else remember it?
I remember the photograph and I have an idea you're thinking of the ejection seat drogue parachute bolt, rather than the canopy jacks. During aircraft servicing it was possible to accidentally snag the drogue cartridge lanyard and fire the drogue bolt without the main seat charge being affected. The bolt was just that - a steel cylinder half inch by ten used to pull the stabilising drogue chute out after the seat had fired. I'm pretty sure the canopy jettison jacks were pneumatic, probably from the same source as the door closing air system. Could be wrong.