In this V-n diagram for an F-104 (source: this Wikipedia link), on the left-hand edge of the flight envelope, what is causing the "corners" that we see at the following points? (Numbers are approximate)
30,000', 375 knots IAS, and 5 G
40,000', 295 knots IAS, and 3.1 G
50,000', 230 knots IAS, and 2 G
60,000', 180 knots IAS, and 1.25 G
70,000', 140 knots IAS, and 0.95 G
Do these points simply represent the "corners" of what performance is possible while still maintaining horizontal flight at a constant airspeed (i.e. while maintaining both altitude and airspeed), and if more engine thrust were available, these "corners" would move higher up and to the right, continuing to follow the stall speed curves? I.e., do the actual stall speed curves continue upward from the corners following a path that is more or less continuous with the lines below the corners?
(Note-- re the last data point-- a G-loading of less than 1 is obviously incompatible with constant-altitude flight-- but the data point still could have mathematical or theoretical significance -- e.g., if the aircraft weight decreased by 5%, then the aircraft could maintain constant altitude.)
Wouldn't it be theoretically possible for a pilot to operate well outside the illustrated envelope, say, by pulling 4G at 340 knots IAS at 40,000'? Am I correct to assume that this could be done without stalling the aircraft, but the aircraft would be losing either altitude or airspeed continually? Because it is on the "back side" of the thrust-required curve? Whereas that would not be the case for a point further to the right, on the other side of the illustrated curve?
If the actual stall speed curves do in fact continue more or less smoothly upward from the "corners", this would imply that if, theoretically, we were setting a "maneuvering speed" to protect the aircraft from exceeding 6G's, it would need to be at about 430 knots IAS at 20,000' (the "cornering speed" shown on the diagram), but it would need to drop to about 380 knots IAS at 30,000' -- well outside the envelope of the figure as drawn. Is this in fact the actual situation?
Is this particular diagram really as much about achievable performance as about protecting the aircraft from excess loading, at least in the positive-G part of the flight envelope?
Is it therefore not strictly accurate to call this particular diagram a "V-n diagram"?
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