re pushing the envelope in apr princeton edu lije cognito princeton edu elijah millgram writes a friend of mine and i were wondering where the expression pushing the envelope comes from anyone out there know every aircraft has flight constraints for speed aoa power when graphed these define the flight envelope of that aircraft presumably so named because the graphed line encloses envelopes the area on the graph that represents conditions where the aircraft doesn t fall out of the sky hence pushing the envelope becomes operating at or beyond the edge of the flight or operational envelope note that the envelope isn t precisely known until someone actually flies the airplane in those regions up to that point all there are are the theoretical predictions hence one of the things test pilots do for a living is push the envelope to find out how close the correspondence between the paper airplane and the metal one is in essence pushing back the edges of the theoretical envelope to where the airplane actually starts to fail to fly note too that this is done is a quite calculated and careful way flight tests are generally carefully coreographed and just what is going to be pushed and how far is precisely planned despite occasional deviations from plans such as the early first flight of the f during its high speed taxi tests i m sure mary can tell you everything you ever wanted to know about this process and then some insisting on perfect safety is for people who don t have the balls to live in the real world mary shafer nasa ames dryden fred mccall dseg ti com i don t speak for others and they don t speak for me
