In the turn, the violent buffet is a double edged sword. There is no such thing as a free lunch especially in physics. In the NACA measured results, encountering the buffet represents a change in available angle of bank. The airplane goes from 78.5 degrees of bank to 60 degrees of bank in one second.
****5G @ 147.73KIAS:
ROT = 1091*tan(78.5) divided by 147.73 KIAS = 36.2 degrees a second
****2G @ 141.647 KIAS:
ROT = 1091*tan(60) divided by 141.647 = 13.34 degrees a second
As a quick ballpark using IAS to get an idea of the scope of the effect on turn performance, we see the rate of turn drop from 36.2 degrees a second to 13.34 degrees a second. That means our time to complete a 360 degree turn changes from 10 seconds to 27 seconds!!!
As the Operating Notes relate, you do not want to turn any airplane in the buffet. Energy cannot be created or destroyed, all the energy that was being used to achieve an instantaneous performance rate of turn of 36.2 degrees a second from our ballpark went to warn the pilot of an impending stall, taking the aircraft right down well inside its sustainable performance envelope of 13.34 degrees a second.
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07-18-2012, 04:24 PM
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