ah, don't ya just love aerodynamic questions....
saudipc-9,
Ahh not really true.
-I understand where your coming from, but I think you'll find it is really true, just not put in the way us pilot chappies normally think. I was simply trying to answer the original question.
I'm quite aware that in combat terms "rate kills". Aircraft g and airspeed. Rate and radius.
I was just putting it in a way the aerodynamics guys seem to favour.
tan bank angle equals tas squared over gR.
jetdriverwannabe
I suspect at exactly 90 Degrees, most airframes will have a tendency to yaw towards the ground and would be a handfull to fly....
your assertion here is flawed. Remember, at 90 degrees of bank the load factor becomes infinite, so the situation you describe is impossible in the real world. A 90 degree bank turn in level flight requires infinite g, so it's not "most" airframes as you assert, but all, although it doesn't necessarily mean they're a handful to fly. It's just that in aerodynamic terms, a level turn at 90 degrees of bank is impossible. Simple as that.
Intruder is correct in saying that you can be in "knife-edge" flight, ie 90 degrees of bank and still level, in a high performance aerobatic aircraft. But you are using the rudder and fuselage for lift in this case, so in proper aerodynamic terms it does not constitute a turn, as the wings are not loaded.