Here's what I do to take away a higher plane's E advantage-
The numbers I'll give are not "actual" top speeds, just rounded for easy math...
Let's say your plane is capable of a 10k level top speed of 300mph. Lets start at that speed and alt.
If you roll inverted, and pull into a dive for say 2000ft (450mph?), roll back level and then pull out of that dive and go back up without pulling hard G's, you'll end up at nearly your beginning alt and beginning speed, for a very low net E loss.
If, however, you dive down to 8k (speed picks up to say 450mph) and then level out, your speed will eventually drop back down to 300mph (more or less). You will now be at 8k and 300mph, for a significantly higher net E loss. See the difference?
If you can position yourself directly above (more or less) your opponent, and dive nearly vertically on your opponent, being careful to avoid going below him, and avoiding sharply pulling up (NO BLACK-OUTS!), you can make repeated passes without killing your E advantage (IF YOU STAY ABOVE HIM). You'll lose some, but he will lose at least as much by pulling hard to dodge your shot. The high plane will keep an E advantage in this instance. If the attacker drops below his opponent he'll need to waste some E getting back up to an alt equal with his victim before he can climb back up above him again. That will cause him to lose his advantage quicker. If the attacker lets the defender get off to one side (horizontal separation), he'll have to dive down and chase him, losing E in the process.
So- as the low guy, you want to avoid letting him do this (preserve his E advantage). You don't want him above you, and you don't want him to make you burn lots of E dodging his shots. As the attacker, he'll do best by staying above you (MINIMIZING HORIZONTAL separation. As the defender, you want to do the opposite- MAXIMIZE HORIZONTAL separation.
So- here's how I do that.
1-Think ahead, and think aggressively. Don't just try to dodge and stay alive, try to avoid getting shot while you increase your E, or at least preserve it. At the same time, take away his E advantage. Consider him as your next kill- just patiently set him up to die.
2-Preserve your E! To do that you need to dodge his shot without killing your E! So, if he's going to drop onto your six for a shot, DON'T wait until the last instant to start dodging. If you wait until the last second, you'll need to dodge hard, burning E, and he'll just go back up for another try(staying above you, with little horizontal separation). That'll get you killed. Start reversing earlier, I like him 2.5 to 3k back when I start reversing. I turn back fairly gently, avoiding any sign of blackouts, and make my turn slightly nose down to preserve speed. Level back out heading back towards the high attacker, but not quite nose-nose. Try to "merge" going a bit nose up. This will do a couple things. One, you'll recover the alt you lost in your initial turn. Two, you'll almost always get him to merge nose-down with you, which puts him in a position of wasting E to get back up to your alt( he'll usually dive past you, lower than you). He'll be fast in his dive too, and will probably waste E by pulling back up too hard.
3-After your merge, level back out and just keep flying away (maximize horizontal separation, and make him chase you down for another pass). He's now behind you, pulling through a 180 degree turn. Immelmann if he has a clue, flat turning if he doesn't. He'll waste more E then you either way, considering you're just flying straight.
I make my merges with the goal to make him turn 180 degrees, NOT to get position for a shot. If he goes past me and climbs "north", I want to extend "south". I want to get as much horizontal separation between us as possible, so he'll waste E by chasing me. If this goes on long enough he'll be behind me, but without any significant E advantage. After a few of these turns, he'll probably lose patience and start pulling very hard in his turns. This just helps me out...
4- Keep your speed reasonable! Don't get to slow, OR too fast! In my F4U, I stay about 275-300mph. If I have more speed, I climb very shallow (putting E in the bank.) I level out as soon as he's pointing back at me, and NEVER get too slow while I'm climbing. If you're too fast, you'll have to pull into the blackouts to dodge him, and will turn a wider radius while scrubbing more E in the process. Keep your speed at a reasonable level at least until you've approximately equalized your E states (his and yours).
Net result so far- You reversed carefully, at your leisure almost losing very little E in the process, and very likely able to climb a tad (building E, or at least maintaining it). He dove in, pulled up fairly hard, and in all likelihood scrubbed a chunk of his E. He's now behind you again, slow at the top of his immelmann, and you're accelerating away. Guess what? He now needs to dive down a bit to catch you. Remember about the E loss associated with that?
5- He'll catch you again, so repeat the process. Maybe again after that. Each time he does it he'll lose some of his advantage, and you may even be able to build some E in the process. I often start out at say, 2000ft, and find after 2-3 dodges I'm up to 3000ft, which is often about co-alt with the guy that started above me. You may also be able to get behind him on one of your merges and latch onto him. Just watch your E and don't get too aggressive too soon if he still has you at a significant advantage. Watch out for "ropes" etc. You may be able to get behind him with a bit of an E disadvantage and "scare" him into turning by shooting at him, etc. That may finish the fight. If not, continue as described...
6- At this point, your probably about co-alt with him, at a comfortable speed. Just merge and kill him (whole different topic at this point). He may realize whats happened, and leave if he's in a faster plane. That's OK, you beat him...
Now, if you spot him close behind you at first, you'll need to try a different beginning move. I like the "barrel roll defense" type move to get him to overshoot. I may try for a kill shot as he goes by, but if that fails I'll use the same strategy outlined above. It'll be hairy at first because I've let him minimize the horizontal separation already. If you can dodge twice though, watch him real close on his third attempt. Often as soon as you break right, he'll go up into a yo-yo. That's my signal to nose down a tad and get some speed and separation (I'll skip the barrel roll if he does this). I'll adjust my direction of extension here to maximize the turn he needs to make to chase me. I'm now back to the original scenario...
Read this in reverse to improve your ability to pressure lower opponents. DON'T let them get horizontal separation. If you do, you'll end up in an equal E tail chase. If your opponent can take away your E advantage, he can probably do the same thing with your angles advantage...
MtnMan