i also think it to be a WWII era jet test word.

Jets made there appearance in WWII, and after the war, there were many test about there capabilities. these were plotted, (what speeds could they attain at what altitude, what was engine stall speed, etc., and these paramiters were called the envelope (why?) and when test pilots attempted to do thing the planes hadn't been designed to do, (ie, breaking the sound barrier) they were pushing the envelope. (first used extensively in print in "the right stuff"--authors name, is gone for the moment, same guy who wrote bonfire of the vanities, and electric kool ade something.. tom..??)


my other obsession