Analysis of real life 109E performance for CloD

[Crumpp]

Climbed from sea level to FTH at 140mph IAS, full throttle, 6.2psi, 2700rpm

That looks like a problem. According to the Operating Notes, Vy for the Spitfire Mk I is 185mph ASI below 12,000 feet, 179 mph ASI to 15,000 feet, and 169 mph ASI to 20,000 feet.

Climbing at such a reduced airspeed will limit the cooling of the engine at a very high manifold pressure and rpm.

If your oil temperature and coolant temperatures are high, you won't last as long at any overboosted condition.

Try climbing at the faster speed. You should get to altitude quicker and have a cooler engine.

But 2700rpm to 3000 rpm at FTH gave no hint of speed increase prior to the engine failure.

In reality it won't either so that actually sounds realistic. In fact, on a summer day, the aircraft will slow down instead of speeding up. That is why I was saying many folks will be mad if they realistically model density altitude effects.

Once the propeller tips begin to approach their mach limits, the ability of the propeller to make thrust diminishes. So you get less thrust the faster your propeller turns at high density altitudes.