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Old 11th June 2005 | 00:50
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macho macho man
 
Joined: Apr 2005
Posts: 2
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From: Canada
Question Stall investigation

As part of my job a few times a year I have to compare stall speeds of aircraft in various configurations against their charted speeds. The direction out of our operating instruction for the aircraft (P-3) with respect to the rate of deceleration is that the ideal deceleration is 1 knot per second, which seems reasonable and manageable.

I have heard conflicting views on this: one technique, as apparently taught at the USN Test Pilot School, recommends a maximum of 1 knot per second - I think to allow smoother investigation of deceleration/stall characteristics, while a second technique (Jay Beasley's theory) advises avoiding a slow deceleration (even 1/2 knot per second) since doing so would introduce a greater vertical component to the flight path, and thus a higher angle of attack resulting in an accelerated stall.

I confess I don't understand the second view - while I understand that a slower decel will result in more altituded being lost due to this "vertical component", AOA is AOA. I'd think that slowing at 1 knot per second or 1 knot per 20 seconds would not change the ultimate buffet onset speed. While I'm happy with the way I currently investigate stall buffet I'm less happy with my understanding of basic AOA, if Beasley was correct.

Ideas? Thanks in advance, MMM
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