54ED, the trim changes (and subsequent stickforce changes) were sometimes so high in WW2 planes, that a trim change were necessary in order keep the desired attitude.
On the other hand, in aerobatic planes, the aim is to make the stickforces as light as possible. In most of them, you can do any manuever with one hand on the stick, where as in a WW2 plane, you could be exposed to stickforces in excess of 50lbs.
I've read several accounts, in particular from P-40 and P-51 pilots, where they changed trim during the manuever.
Also, it was the norm to leave the throttle against the firewall.
Daff
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CO, 56th Fighter Group
"This is Yardstick. Follow me"