Originally posted by humble
Flying to the elbow is a phrase (and tactic) probably made famous by Robert Johnson. I believe the comment was specific to his famous "duel" with a spitfire but it was a tactic he commonly used in combat as well.
If you view a turn as a curve layed out with your bent arm what Johnson (and other jug pilots) would do is to pull up and roll away from the direction of the turn placing themselfs in an inverted position with there lift vector pointed at a spot ahead of the con. This placed them in a position that they could pull thru in the vertical and "drive for the elbow" of the turn. It allowed them to use the jugs tremendous roll and rudder and elevator authority to routinely defeat planes that could out turn them.
I've seen the reference to its representaion as flying to a point of lag pursuit many times on the net but never used that way by a WW2 aviator. It's original use was specific to using an out of plane manuever to defeat a better turning con by utilzing a superior roll rate to place your lift vector at the "elbow" of your bogies turn. This is an aggresive vertical lead pursuit.
We could debate the origins of slang ad nausium as it's continually changing and "elbow" may very well have meant something different 60 years ago; however, your description of this maneuver isn't very clear.
I'm assuming the attack is coming from within the target's turn circle (i.e., target turning into the attack). Saying the attacker would pull up and roll away from the direction of turn appears to describe a barrell roll attack (assuming you're saying he continues his roll away from the turn). If the end position of the maneuver is outside of the target's turn radius it's just a lag roll.
If, after the attacker "rolls away" from the turn he then reverses enough to go inverted he's simply doing a vertical reversal. All turns are tightened by going nose high so there's no magic there, and yes, a poorer turning aircraft can stay with the better turner by doing this and an airplane with good roll and pitch performance is using its strengths.
Also, it's not clear how the target's turn can be described as having an "elbow" unless you assume he's also using the vertical. The "elbow" in my description is simply describing a point in space, is this what you're doing or are you talking about the target's actual flight path? I can definitely see the attacker's flight path as having the perception of an elbow since his turn radius is signficantly reduced over the top giving the impression of a sharp turn (elbow) vice a steady radius arc.
