In short, pilots being equal the P-38 will come out on top. The only real threat is in a rolling scissors where the FW 190A-5 can potentially use it's better roll rate to force the P-38 to squeeze out front. However, the P-38 pilot, if he spots it quick enough can use its superior slow speed handling to stay behind the FW190A-5 as the A-5 tries to force the P-38 out in front. If the P-38 driver manages to stay in back in a low speed rolling scissors, there is nothing the A-5 can really do to reverse positions as he'll not be able to match the P-38s low speed handling and at best can hope to roll the plane out of plane to throw off the aim and shots of the Lightning or hope the Lightning pilot makes a mistake that leads to him crashing.
In a match where the A-5 has an energy advantage, the fight will always favor the plane with the advantage regardless of plane type. As long as the FW 190A-5 uses proper BnZ attacks (by proper I mean aggressive BnZ, not this hand holding, limp wristed incorrect idea of BnZ that some people think means to run half a sector /rant off) and keeps up the pressure as to not allow the P-38 to regain any energy after the break turns, the A-5 should come out on top. However, if the A-5 driver becomes impatient during the BnZ passes and tries to force an angles engagement, the A-5 is going to die. Also, it is important that the A-5 driver maintains his advantage at all times and doesn't fall for the trap that just because he has more energy at the moment, doesn't mean he's got the fight won. Pretty much all of the dedicated, experienced P-38 drivers will use vertical breaks instread of break turns. What I mean by vertical breaks is that the P-38 driver will use the vertical to avoid, while at the same time meeting the BnZ attacker's pass. This allows the P-38 driver to gain altitude on each pass as they break to avoid the BnZ attack while at the same time "putting energy in the bank" to use later on. After a few passes, the P-38 driver will usually have equalized that altitude advantage the A-5 enjoyed though the A-5 will still have the slight energy advantage from his BnZ pass but the P-38 has the "potential" energy advantage because he's now at a higher altitude than the A-5 and can spend that altitude for energy at any time, effectively reversing positions and now in the driver's seat. Only option at this point is for the A-5 to try and run home because if he enters into the vertical, the P-38 will kill him. If he tries to turn at this point, the P-38 will kill him. If he dives and run, he might be able to escape long enough to find help from friendlies or cover from his acks. If he doesn't find safety, the P-38 will dive down and kill the A-5.
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