Originally posted by Mustaine
you know I gotta ask, how do you accurately measure the turn radius? it's not like there are tape measures built into AH.
It's a function of speed, time and distance. For example, if it takes you 53.45 seconds to make three complete circles and your average speed is 94 mph, you can calculate average turn radius and rate. Rate is easy. Simply multiply 360 x 3 / time in seconds. In the case of the TBM, this is 1080/53.45, or 20.2 degrees per second.
Radius is more complex, but I'll make it as simple as possible.
mph / 60 x 88 (which is 5280/60) = feet per second (FPS).
FPS x time = total distance traveled in three circles / 3 = circumference of one circle.
circumference / Pi (3.14) = diameter of circle. (note that rounding off Pi as I did will introduce a very minor error)
Dia / 2 = radius of circle.
So, for the TBM it takes 53.45 seconds to fly 3 circles at an average speed of 94 mph. Thus, 94 / 60 x 88 = 137.866 fps. 137.866 x 53.45 = 7368.9733 feet traveled / 3 = a circumference of 2,456.324 feet / 3.14 = 782.269 feet circle diameter / by 2 = 391.11 feet average turn radius.
Accurate data requires exceptional attention to maintaining speed and altitude. Test results will often vary from tester to tester, but the lowest figures are generally the most accurate IF the test methodology is carefully adhered to. Most of us who do this testing do at least three tests and average the results.
We simply provide data that allows pilots to gauge performance of each aircraft. How close a pilot can come to that performance in combat is wildly variable from individual to individual, as one would expect.
My regards,
Widewing