Thnx FLs , good and detailed explanation, but I see that you are focused on sustained turn anyway thanks again.
Let me ask my first question in a different way, I am looking for way to determine the speed to complete a single 360 turn with which will give the tightest possible turn radius in a plane.
Its ok to loose speed , (but is not ok loose alt or stall , or black out).
In other words:
Corner speed also affects the minimum turn radius. The size of the turn radius of an aircraft depends on the speed it is traveling. A faster aircraft requires a larger circle to turn in than a slower one. However, the turn redius isn't only a function of speed. It also depends on the number of Gs a pilot pulls during the turn. An aircraft at a constant speed will make a relatively wide circle at 1 G but will turn in a very tight circle at 7 or 8 Gs. The corner velocity is the speed that gives the optimum balance between turn rate and turn radius.
for other dependencies we can assume that we will always use a slick plane with %50 fuel at start of the turn.