by =69.GIAP=MALYSH » Sat Oct 08, 2011 1:20 pm
that's a good description of the geometry (and a nice picture, but the two-circle doesn't have to end in a head-on, it largely depends on the initial lateral distance between the fighters as they pass)
the thing to remember is that the two-circle is a rate fight, the fighter with the fastest turn rate will win. It's safe, less to muck up, but the enemy has a larger escape window. A small turn rate advantage is enough to secure the win, for a good pilot.
The one-circle is a radius fight, the fighter with the significantly smaller turn radius will win. Less safe. A small advantage in turn radius is not enough to secure the win, against a good pilot. But the enemy has a smaller escape window, and it can be quite frightening to see it for the first time, it's a very quick and aggressive move.
The two-circle is the standard way to merge most of the time. Safe, easy, but predictable.
The one-circle is useful against a very poor turner, like Utvara said, or can be useful to thrown off a better turning opponent, such as a 109 against a yak or when the enemy has good sutained but poor instantaneous turn rate, such as a 109 against a mig. It can also be a faster way to get onto the six of a less able opponent, but that's a gamble...
The second fighter to turn determines which of the two fights it will be.