In aerodynamics, the flight envelope, service envelope, or performance envelope of an aircraft refers to the capabilities of a design in terms of airspeed and load factor or altitude. The term is somewhat loosely applied, and can also refer to other measurements such as maneuverability. When a plane is pushed, for instance by diving it at high speeds, it is said to be flown "outside the envelope", something considered rather dangerous.
Flight envelope is one of a number of related terms that are all used in a similar fashion. It is perhaps the most common term because it is the oldest, first being used in the early days of test flying. It is closely related to more modern terms known as extra power and a doghouse plot which are different ways of describing a flight envelope.
Read more about Flight Envelope: Extra Power, Doghouse Plot, Velocity Vs. Load Factor Chart, Sidenotes, "Pushing The Envelope"
Famous quotes containing the words flight and/or envelope:
“When we are high and airy hundreds say
That if we hold that flight they’ll leave the place,
While those same hundreds mock another day
Because we have made our art of common things ...”
—William Butler Yeats (1865–1939)
“... all my letters are read. I like that. I usually put something in there that I would like the staff to see. If some of the staff are lazy and choose not to read the mail, I usually write on the envelope “Legal Mail.” This way it will surely be read. It’s important that we educate everybody as we go along.”
—Jean Gump, U.S. pacifist. As quoted in The Great Divide, book 2, section 10, by Studs Terkel (1988)