One for the Sooties ....

[Barch]

How much engine power at the turbine (% ish) is used to ...

Drive the compressors on a turbojet?

Drive the compressors and fan on a turbofan?

Drive the compressors and propeller on a turboprop?

 

[propersplitbrainme]

Read a ball park figure somewhere that approximately 60% of the energy produced by a turbojet is used to power the engine itself leaving 40% to produce thrust.

Again, a ball park fugure, approximately 90% of the energy produced by a turboprop is used consumed powering the engine itself and prop which can leave 10% to produce jet thrust. How thats split between the core engine and the prop I don't know.

I don't doubt that those figures have probably improved as technology has improved.

 

[Late & Tired]

Crickey Barch, that's a deep question.
I think, considering the wage and pension the HR Trade is on, They should search their wealth of JPA docs and answer this one...
DT_Xtremez_25:

 

[dumbsumpy]

The power required to drive a compressor depends on the efficiency of the compressor being driven. Most modern compressors work at around 80-90% efficiency, so a turbine will have to equal the power required to drive the compressor to achieve this plus the additional 10-20% of power required to overcome losses through the compressor.

In a turbojet, realistically all Power generated by the turbine is put back into driving the compressor, as the efficiency of an turbojet engine is determined by the pressure raise through the compressor. However, Thrust, which drives the aircraft forward, is unaffected by the power extracted from the gas flow by the turbine and is dependent on the mass flow of air, the velocity of the gas stream leaving the jetpipe and the forward speed of the aircraft.

Not sure exactly how much power is extracted for turboshaft/props but as the main propulsive elements are driven from the power turbine, i would imagine that it will be a trade off between propulsive efficiency from the prop/blades and the 'air standard' efficiency of the compressor.

Probably this hasn't actually answered your question, but it might? be of some use.

 

[Tin basher]

For turboprops Wiki reckons a little as 10% from the exhaust

http://en.wikipedia.org/wiki/Turboprop