Spit IIa is now so much more inferior to the 109

[Crumpp]

Most civil operating handbooks will denote a normal climb speed which is also known as Cruise Climb speed.

Very few list a cruise climb speed. Once again, it is something that changes with atmospheric conditions and the weight of the aircraft is a huge factor. That is what you are doing, climbing the plane at the optium speed as it sheds the weight of consumed fuel.

Cruise climb is calculated as it varies with conditions and is of most practical value in a turbine engine. There are two approaches. Optimum Climb speed produces the best overall fuel economy. It seeks to balance the most altitude over time using the least amount of fuel with the most distance covered over the ground. Best Economy Climb speed is the second method and it factors operating cost, maintenance, and crew cost. Neither one is applicable to a WWII piston engine fighter.

Piston engines the main benefit is engine cooling, visibility and comfort.