Re: Whys and Hows of Water Injection on Jet Engines

From:         ldrew@sdcc13.ucsd.edu (PETE)
Organization: University of California, San Diego
Date:         13 Apr 96 16:44:52 
References:   1 2
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>Although methyl or ethyl alcohol (or a mixture of one or both of these and
>water) has been used in the past for injection to augment jet engine
>thrust, water has a higher heat of evaporation, and is therefore the only
>liquid generally used for thrust augmentation today.  The effect upon
>engine thrust depends upon the rate of water flow into the engine.
>

With all due respect to Mr. Wingedhoof, alcohol is still used in water
injection systems for his opposing company's engine.  The version of
the Garrett TPE-331 that is installed in the common, but finally fading
Fairchild Metro commuter airliner uses a water-meth mix. As much as 60 or 80%
meth in fact!  We use it all the time when hot and high, and it works
beautifully well.  Of course who wouldn't rather have gobs of extra power or
massively flat-rated engines instead!

Pete
current Metro III pilot
BS, Mech. Engineering
former Twin Otter pilot (PT6)
soon to be EMB120 Brasilia pilot (PW118A)

ps. I love Pratt's PT6 and PW118A too!