Most recent aircraft with water injection?

[Winemaker]

Originally Posted by B2N2

Sport Class Air racing allows water injection:

https://www.kitplanes.com/sport-clas...rules-rewrite/

Isn't that for pistons engines though? A different situation and common in WW2.

[Alpine Flyer]

Originally Posted by Winemaker

Isn't that for pistons engines though? A different situation and common in WW2.

No works for jets and turboprops as well.

This is what Wikipedia has to say about the subject:

Adding water increases the mass being accelerated out of the engine, increasing thrust; and it also serves to cool the turbines. Since temperature is normally the limiting factor in turbine engine performance at low altitudes, the cooling effect lets the engine run at higher RPM with more fuel injected and more thrust created without overheating.

[tdracer]

In piston engines, water (or water/alcohol) injection cools the intake charge and that helps prevent detonation at high compression rations/boost pressures. Not only does detonation kill performance, it can rapidly kill the engine (I used to have a nice collection of pistons from my racing showing just how much damage even a few seconds of detonation can do to piston - including pistons with holes through the crown).
Turbine engines also use water injection to cool the intake air to allow more fuel to be added and burned without over temping and melting the turbine blades - producing more power. Yes, there is a small delta in thrust due to the added mass of the water to the exhaust stream, but that's secondary and small. The big gain is that you can burn more fuel which means more power (thrust).