Stupid question about flight testing and "the envelope"

On 21 Dec 2003 13:26:43 GMT, (BUFDRVR) wrote:

It was a 777 and the wing bent something on the order of 28 feet before
failure.


28 feet...ahhh, that's nothin'


The B-52's probably flap like a friggin' albatros :-)



BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

From: Scott Ferrin
Date: 12/21/2003 9:52 AM Central Standard Time
Message-id:

On 21 Dec 2003 13:26:43 GMT, (BUFDRVR) wrote:

It was a 777 and the wing bent something on the order of 28 feet before
failure.


28 feet...ahhh, that's nothin'


The B-52's probably flap like a friggin' albatros :-)

That's what keeps it in the air. They beat the air into submission.

Dan, U.S. Air Force, retired


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it
harelips
everyone on Bear Creek"

In today's world, we can't afford to do a contractor test and a govt
test. We combine the testing as much as possible. Single seaters are
almost always flown first by the company test pilot followed by
military test pilots. From then on it is pretty transparent who is
flying the jet.

For multi seat aircraft, the first flight is usually a mix of company
and military test aircrew, and remaining flights are a random mixture.

Nowadays, the Operational testers are also mixed in early.

Also, test pilots will push the aircraft beyond flight manual limits.
We need to see how robust those limits are. Nice to know if the
aircraft will depart if it goes .00001% past some parameter.

Ross "Roscoe" Dillon
USAF Flight Tester
(B-2, F-16, F-15, F-5, T-37, T-38, C-5, QF-106)

On Sat, 20 Dec 2003 17:11:51 GMT, "Dudley Henriques"
wrote:


"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
For personal email, please replace
the z's with e's.
dhenriquesATzarthlinkDOTnzt