Radius of turn is equal to TAS squared, divided by (g multiplied by the tangent of bank angle).
Bugger - that sounds too difficult. So let's simplify it. First of all, use nautical miles per minute rather than knots and also assume that you'll always use 25 deg for the angle of bank. Then your radius of turn in nautical miles is is simply your (TAS in miles per minute squared) divided by 8.89. OK - make it even simpler. Radius of turn at 25 deg angle of bank is one ninth of your TAS squared in miles per minute. So at 180 KTAS it's 1 nautical mile.
OK??
[This message has been edited by BEagle (edited 05 June 2001).]