Hum. The D-9 is hands down the 'best' German plane in the game, in my opinion. That said, a decently flown la-7 will kick your bellybutton every single time. I rarely go above 15k in any plane, sometimes I cruise at 20k, but that is fairly rare. From the deck to 10k, I'd say the D-9 is superior to the 109G10 in a 1 on 1 situation. The Dora is faster, rolls much better, and packs a more concentrated punch (in my opinion). If you are in the Dora, you want to use your speed and rollrate, and try to keep the fight above 300mph- the G10 doesn't handle at its best above 300mph (it doesn't get positively sluggish until around 400mph though). Be aware, however, that the G10 outaccelerates you once the fight gets slow, and it turns better as well.
Against a Mustang I don't have much advise. I rarely have trouble killing Mustangs, but there aren't to many skilled pilots flying the plane (which is a shame, because the P-51 is a fine airplane). I'd try to get the fight low against a Mustang, near the deck the D9 outclimbs, outaccelerates, and outruns the P-51. The P-51 has a slight edge in turning (which grows larger as the fight slows down). Also, don't be afraid to give the Mustang a snapshot if it means you will end up with a positional advantage.. the .50 caliber MG's are great, but you have to really hit with a sustained burst to kill someone with them.
Basically, you can fly the Dora as aggresively as you want to- I do. Just use the vertical instead of the horizontal- also, know when you have to run. It is OK to turn a few times with a 109, or a P47 if you think you are going to pull lead on them and get the shot- but if you stay in that circle they WILL wrap around onto your tail eventually. I've always thought that you can make a fast plane seem manueverable with good timing, but it is impossible to make a manueverable plane catch a faster one
. For that reason I think the Dora is the best German plane there is in AH right now. It also 'feels' lighter than the 109G10 on the controls, which makes it easier to adjust your aim on a pass (good thing there
). Anyway, just fly it, you'll get the hang of it
.