not using flaps but unknowingly had elevator trim maxed.
Ideally, you want to use your flaps to get your plane to loop. The flaps in the P-38 generate enough lift that you can just use those to loop your plane. As you come over the top, lower flaps and as your nose swings down, raise the flaps. This will generate enough energy that when you're on the downside of the loop, you'll have enough energy to loop again. Just repeat those steps and you'll loop endlessly.
Unfortunately, I no longer have the film but leviathn had made me one showing how well the flaps work in the P-38, think it was around 10 minutes long and that entire time he was just using flaps to loop, no other stick input.
ack-ack
