"Ed Rasimus" wrote in message
...
On Sat, 20 Dec 2003 09:31:05 GMT, Scott Ferrin
wrote:

As testing proceeds, airspeed, bank angles, altitudes, AOA ranges and
accelerations are expanded. Pushing the envelope involves moving those
lines on the performance charts gradually outward to expand the
capabilities of the airframe.

Basically a very good explanation of flight test procedure.
To be absolutely accurate, one can say that "pushing the envelope" in a
flight test context is a carefully programmed step by step process designed
to take the airframe/engine combination through the PROJECTED flight
envelope parameters and compare actual flight test data against that
projection; then adjust the envelope to a final set of limit parameters.
This process will either prove or disprove the design projection.
I should add that after all this has been done by the contractor's test
pilots, it's redone by the military flight test program for the involved
aircraft. The F14 for example, went through Grumman's flight test program,
then into an extensive flight test program at Strike Aircraft Test
Directorate at Pax River, where all aspects of the envelope were proven over
again by the Navy team. I can attest first hand that the "envelope" was
indeed "re-pushed" a bit at Strike! :-)
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
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