Re: B747 technical questions

Date:         01 Aug 97 04:04:17 
From:         dqc@aol.com (DQC)
Organization: AOL http://www.aol.com
References:   1
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>	When the 5th engine is installed, it is inactive - it gets no
fuel.  To
>prevent the engine from windmilling, which is a very high drag state, a
>special inlet is fitted to change the inlet area and hence, massflow.

I've installed several "5th pods."  Actually, the fan blades are all
removed and a large mushroom shaped dome is attached which "locks" the
(bladeless) fan hub and thereby the low compressor/turbine module
preventing rotation, and fairs the now blunted inlet.  In addition, a cone
shaped "plug" is attached to the exhaust "tailpipe" and attached via a
smaller cap at the end of the "tailplug." Together these fixtures close
off the inlet to the "core" (or "hot-stream") section of the engine, close
the exhaust nozzle and provide the best anti-drag fairing for the
installation.
Joe W, TWA Ret.