riff_raff, the venerable Harrier indeed did hold up to 495lbs of demineralised water. Operated or armed via an in-cockpit switch, the water was directly injected at high pressure onto the Pegasus turbine blades, cooling the JPT by around 25degC. That drop in temperature allowed more fuel to be added to reach the [now slightly higher] DECS JPT limit, whilst also increasing overall engine mass flow - i.e. increasing thrust. If used in one go it lasted 90 sec which was (normally) plenty of time to get the old girl on the deck or a pad in high OAT and/or high AUW recovery conditions, though it did concentrate the mind if you were "wet committed" and needed the water to land. Bit like the Countdown show clock running. This was routine for the Pegasus 105 engine (-406). For the more powerful 107 (-408) we hardly used the water in the UK but carried it anyway as ballast to maintain CofG margin.
Last edited by MSOCS; 28th Mar 2016 at 22:57.