Re: Jet engine rpm

From: (C. Marin Faure)
Organization: Northwest Nexus Inc.
Date:         08 Oct 96 13:00:10 
References:   1
Followups:    1
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In article <airliners.1996.1960@ohare.Chicago.COM>, wrote:

> A recent Flight International magazine has an article and cutaway
> on the RR Trent engine. Maximum Shaft rotation speeds were given
> as 3,500 rpm for the Fan (LP Turbine), 7,700 rpm for the IP stage
> and 10,000 rpm for the HP stage. For the Fan the rpm results in the
> blade tips being supersonic - or near it.
> I was under the (miss)impression that jet engine shaft rpm were
> very much higher than this - like 70,000 rpm plus. Maybe I'm thinking
> of smaller older engines. I know that some of the model aircraft jet
> engines (based on turbochargers) have shaft speeds of around 90,000rpm.
> These engines are only a few inches across though.
> Can anyone comment on this with say rpm of the Conway, Viper, Olympus
> etc engines.

No, but the PT6A as used in turboprops like the de Havilland Twin Otter,
Pilatus Porter, etc. spins up around 30,000 rpm I believe.

C. Marin Faure
   author, Flying a Floatplane