Throughout the story of air fighting runs the quest for height, for the fighter on top had control of the air battle.
Air Vice-Marshal J.E. "Johnnie" Johnson, RAFThese tests are run by an outside program that gives input to the game. Each plane can take up to 5 hours to test. The process was to load each plane with 45 minutes worth of fuel and then auto launch them from a base. As soon as the auto launch circuit is complete, the plane is put into auto climb (speed). Data is taken every 10 seconds for the next 30 minutes and then the test re-ran with a different auto speed setting rate. Bad data points where the speed was over or under by more than 5 mph were removed. Even still you will see oscilations in the data as the plane adjusts the climb speed. Bombers were loaded with typical loads.
Note the climb speeds in these graphs are Indicated Air Speed (IAS).
Pick up to 5 planes to compare. Only planes that have been tested are shown.