Well the trick is, this is essentially a sucker move.
A defensive barrel roll is essentially a way to make the other guy overshoot by using a barrel roll to make your flight path longer. At the same time as you lengthen your flight path, you also roll around in a manner that is difficult to track, so you avoid getting shot most of the time. If your attacker sees what you are doing and understands how to counter it, he will either camp out on your six and blow you away when your E bleeds down from all the maneuvering, or if he has enough E he'll zoom up BEFORE he overshoots and set up another attack. Notice the capital letters.
It's no good to overshoot horribly and THEN try to zoom up and away. You have to see it coming beforehand, then either slow down and lengthen your flight path to follow him, or zoom back up before you overshoot and become a target.
If you have enough extra smash (speed) you can often simply blow through into a steep zoom before he can get to you. However, after the second or third attempt, that energy advantage will likely have dwindled, and you won't have the extra speed to overshoot without getting nailed for it.
It all boils down to understanding what the defender is trying to do, and what the available counters are. If you are going to try and shoot him anyway, you need to decide that early and go for it, then be ready to extend to his cold side (bottom of his plane) to zoom back up. If you don't think you can hit him, be prepared to either zoom away early and possibly try to sucker him in to following you up without enough E, or camp out on his six without overshooting.
Now, this is a very different move from a "barrel roll attack". That uses a barrel roll to generate separation to allow the attacker with more speed/energy to stay in the bogey's rear quarter without giving up his speed advantage. It's not an intuitive move, and pretty much the only way I every understood it was by buying Shaw's Fighter Combat and reading that section while practicing it online and dying a lot attempting it.
Now if you are using a barrel roll defensively, you need to do two critical things. 1. Estimate the attacker's energy level. 2. Hit a good barrel roll at just the right time. Both of these are tough to do. In order for the barrl roll defense to work, the attacker must have more energy than you, and at the attack point that means more speed. If he isn't already flying quite a bit faster than you are, he may be able to simply slow down a bit and stay on your six. Assuming he is quite a bit faster and is not going to be able to slow down and stay with you, it comes down to timing. You want to hit a big barrel roll with lots of back stick (so you make a big corkscrew in the air) at JUST the right time. Ideally you want to start it just before he is going to shoot you so that he lines you up for the shot (pulling lead pursuit and increasing his closure rate... ensuring an overshoot) but that you are rolling out of his gun sights before the bullets hit home. Getting the timing right is the hard part. Make sure you are pulling back on the stick enough to make a real barrel roll, practice this and film it, then review with trails on and make sure you displace your flight path lots, not just roll around your engine line.
Ok, lets say the attacker dives in to your six, and starts lining up for the shot. You start a very gentle break to the left and he lines you up for a nice deflection shot. Sucker!
As he gets in range, you suddenly pull into a hard barrel roll. His shot misses, and you watch him and see he is going to overshoot. Once he is going to blow through, you are unloaded (not pulling back anymore) and rolling onto his flight path. If he has blown it and you timed it right, you are now on his six as he zooms away, but you may get there in time for a nice snapshot opportunity before he is out of range. Now if you've got a shot take it, but otherwise you should be accellerating as much as you can, and building speed. You'll need more E to burn to defend his next attack.
One more thing, after he overshoots and you can't quite get guns on him, DO NOT try to follow him up. Assuming he had more E and was forced to overshoot, you will stall out below him if you try to go up with him. This is every E fighter's dream... that the guy who just evaded him will get sucked in to going vertical without enough E, and then stall and wallow helplessly below for an easy kill. Don't take the bait!
[ 08-08-2001: Message edited by: Lephturn ]
