R44 article

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Just read the article on the 44, I've many turbine hours and as they are a constant speed engine I've never had to wait for one to 'spool up' other than when starting Think your getting confused with a 737 ?

-- Stan Lee, December 26, 2013


Thanks, Stan. Maybe it could be better worded. I was cautioned in the turbine helicopters that I flew not to attempt going from a condition where near-idle power was required to a condition (collective position) where near-full power was required. The power turbine is geared to the rotor, right? So it should be spinning at a constant speed. But the compressor turbine is not connected to the power turbine in most designs (JetRanger and R66, for example). So to increase power the engine might have to spool up the compressor, no?

http://en.wikipedia.org/wiki/Turboshaft has a drawing showing the conventional free turbine design.

-- Philip Greenspun, December 26, 2013