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FM/DM threads Everything about FM/DM in CoD |
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![]() Quote:
V = TAS/SMOE = EAS Standard Means of Evaluation at 12,000 feet = 1.2011 Flaps up TAS at 12,000 feet = 160 mph TAS 160/1.2011 = 133 mph EAS 133 mph EAS * .869 = 115.6 KEAS Oh check it out....They give you EAS on the report. Gee, wasn't that another 100 page discussion on these forums? Anyway, once you have EAS you can easily convert the performance to any atmospheric condition you want. I like working with BGS but the units do not matter. Just don't put the correction factors like "1091" and "11.26" if you are using metric and keep your units straight. Our formula becomes: Radius = (VKeas * SMOE)^2 / 11.26tan <theta> <theta> = angle of bank which is a fixed relationship with load factor irregardless of altitude If you use the above formula and knots, our radius calculates out to be 693 feet and the RAE measurement is 695 feet. Pretty good agreement. Radius is not the primary turn characteristic in a fighter. It not so important how small the circle but how fast we can bring the nose around to put guns on target. So lets check our rate of turn based on the document: Flaps up = 160 TAS * .869 = 139 KTAS 1091(tan 68 ) / 139 KTAS = 19.42 degrees a second 360/19.42 = 18.56 seconds to complete a 360 degree turn 18.6 and 18.56 are a match.... Now let's see what it does at 20000 feet: 160 TAS at 12000 feet = 133 mph EAS 133 mph EAS * .869 = 115.6 KTAS SMOE @ 20000 feet from our Standard Atmospheric Data = 1.3700 Radius = (VKeas * SMOE)^2 / 11.26tan <theta> Radius = {115.6*1.3700}^2 / 11.26tan <68> = 899.97 or just 900 feet @ 20,000 feet Rate = 1091(tan 68 ) / (115.6KEAS*1.3700) = 17.05 degrees a second = 360/17.05 = 21 seconds to complete a 360 degree turn at 20,000 feet |
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