yup, game =/= reality at all.
However, I will say that the A5 is not that much slower then th late war rides - sure, its slower, but I think acceleration, roll rate, and climb rate are more important factors in dogfighting then top speed. But thats just me, I think the A5 can compete with th 51 perfectly fine unless the opponent really takes his/her tim to reset the fight, but then again, you get to re-asses your situation too. . .