Good looking planes from DCS - I think the 'what is it' job is a Grumman F3? before they went monoplane. The '51' looks like an A36 the one they designed for the Brits. Had an Alison (GM) engine - good low level but not so much at altitude. Didn't come alive 'til a genius at Rolls Royce suggested the Merlin engine - the Brits had already named it 'Mustang' and the rest is history.