Acceleration comparisons

[Woke Up Dead]

Originally Posted by JtD

The HUD tells you the water injection is active because it is. It works above full throttle altitude. It did in real life. There's just no increased boost any more, and therefore there's no meaningful extra power. As it is in real life.

I think IL2 Compare helps you figure out at what altitude boost no longer makes a difference. There are two lines on each maximum speed graph: the speed at 100% throttle, and the speed at 110%/boost. In some planes, like the Hurricane and Spitfire, the two lines meet at 4-5000m.