the budget mechanic- field report- turbine fan will not rotate

captain reported that the core engine showed rotation when they went to start, but the fan never showed any rotation.

dual spool engines are how you get maximum efficiency, the core engine does the work of turning fuel into thrust, then right behind the engine turbine stage is a second turbine wheel, turned only by thrust from the core turbine engine.
this second power turbine drives a long shaft that extends through the center of the core engine and this turns the fan, which provides most of the thrust that propels the aircraft.
some designs have three spools, most two, old turbojets had one, and made lots of noise

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