Originally posted by Widewing:
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Testing for turn rate and radius is relatively simple in concept, but not so easy in practice. The aircraft must be flown with great precision right at the edge of the flight envelope. This takes some practice.
The method is as follows:
Set up a reference point to use as the beginning and end of each 360 degree turn. Most of us use the .target command set at some reasonable distance. I use 1,000 yards. Get into a turn, adding flaps as you need them. Engage WEP. You must maintain altitude, not letting the nose drop or wander up. You should have E6B enabled with the clipboard stowed.
When you are flying at the limit, time 3 full 360 degree turns. Check speed each turn. Average the 3 speed readings.
Let's say your average speed was 99 mph. Divide 99 by 60 to obtain Miles Per Minute, or 1.65. Multiply that by 5,280 feet, or 8,712 Feet Per Minute. Divide by 60 seconds, and get 145.2 Feet Per Second. Multiply 145.2 by the total time of the 3 turns. In this case, 54.84 seconds. This will produce 7,962.768 (total distance flown). Divide 7,962.768 by 3 to obtain the circumference of the average circle, or 2,654.256 feet. Divide this by Pi (3.14 will do) to obtain the diameter of the circle, or 845.304 feet. Divide by 2 to obtain the turn radius, or 422.65 feet for the F4U-1A
To calculate average turn rate, multiply 360x3/time, or 19.694 degrees/sec.
My regards,
Widewing
As WW states, getting consistent results is difficult. Requires flying on the edge of the stall without gaining or losing altitude. I believe Soda uses stall limiter and sets the angle as low as possible (.5 to 1.0 degrees), depending on plane.
Now, I'd like to know how instantaneous turn rate is measured -- how badboy generates the EM chart data???
Regards,
Optiker
