Jet engine rpm

Date:         01 Oct 96 23:56:43 
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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. Thanks for answers.