If you keep finding yourself in a luftberry i think the best thing is to know how to win in that position. It sounds counterintuitive, but keep your flaps up. when you get slow its the person who maintains the best corner speed that turns the tightest. The person who can maintain it the longest also has a advantage. It's important not to blow your potential energy, because in the end that could be the difference. Badboy has graphs that show each planes best turning speed. It may be boring but if it happens during KOTH, or some other type of competition your opponent probably wont let you re merge.
Corner velocity is the speed that gives the optimum balance between turn rate and turn radius. Usually, it represents your best turn rate in degrees/second. Corner velocity is the minimum speed where you can pull maximum g. However, if you are at corner velocity, you are nearly blacked out at max g. Thus, this is great for instantaneous turn, but impractical for sustained turning. First, no WWII fighter could maintain corner velocity for more than a few seconds without trading altitude for speed. These aircraft simply lacked the thrust to maintain that velocity under high g loading. Eventually, your altitude will run out and it will be impossible to sustain anything close to corner velocity. Then what? Inasmuch as duels begin right on the deck, you can forget about corner velocity being a factor after your first hard turn or two.
You have to decide if you can offset a better turning pilot with a greater turn rate. You have to decide if you want to dump some or all of your flaps. Getting into a lufberry with a skilled pilot may not be a good idea. You have to discover if your opponent has greater skills at riding the stall. If he does, you will be dead in short order if you don't break out of the lufberry. To break out, you can't wait until the other guy gets much beyond your 9/3 line. You should retract some flaps and ease off the turn, getting the nose up. If the other guy doesn't do likewise, you may be able to build a quick E advantage while he goes around at minimum speed. If you do, you roll level, nose over and accelerate out of the circle. If you have timed it well, the other guy still has nearly 180 degrees to turn, level off and pull up flaps. That should give you enough distance to reverse back for another merge. However, if you are very good at riding the stall, stay in the circle and wear your opponent down.
Having flown literally thousands of duels, I've discovered that there are some pilots who will not immediately reverse off of the merge. These guys will blow by and run out 2k and then chandelle back with lots of E. Meanwhile, you burned off much of your speed with a hard reverse just as you passed each other. To avoid this problem, I used to do cage matches in the TA. Pick a large field. You take off in opposite directions. At the other end of the runway you both reverse into a merge. You cannot, at any time, fly outside the perimeter of the field. Thus, no running, no timid merges... You fight close in and usually on the edge of a stall. This, more than any other type of duel, will determine who has the better plane handling and dogfighting skills. One advantage to dueling in the TA is that when you get clobbered, you don't have to re-plane, which wastes a lot of time. Keep on fighting. Record everything in the event that there arises a dispute.