What am I doing wrong? 2-stage prop spitfires.

[justme262]

I'm sure I could have gone faster...
I was trying to fly as even as I could with just rudder and elevator trim. with out aileron trim I couldn't get it dead straight.

I had half a tank of fuel and full guns... radiator half open... and didn't even touch the boost cut out.

With 5% fuel, empty guns, fully closed radiator, and throttle pushed through the gate I think it might do 355mph TAS.

http://www.spitfireperformance.com/spitfire-I.html