From: Chuanga@cris.com (H Andrew Chuang) Organization: Concentric Internet Services Date: 07 Jul 96 14:09:01 References: 1 2
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In article <airliners.1996.1129@ohare.Chicago.COM>, Robert & Linda Wilson <email@example.com> wrote: > >If the engine has separate hot and cold nozzles like on the P&W JT9D or >ROLLS RB211-524 you will have zero mixing. The older RB211-524C/D found on the B747-200/300 has zero mixing, but the newer RB211-524G/H found on the B747-400 and the B767-300 does mix the bypass and core flows before exhaustion. >On engines with mixers, i.e. >the fan and core streams are mixed and ejected through a common final >nozzle like ROLLS RB211-535E4 mixing numbers can be of the order of 70% >with a well designed mixer. This gives a worthwhile reduction in noise >and specific fuel consumption > However, the engine becomes heavier, and there is more drag.