Jet Turbine generators

[MMEMatty]

Hi all

I was visiting Lougborough university on Wednesday, and inbetween being shown the facilities managed to have a look at the EAP, and several jet turbine engines which were on display for the guests. Now my question is this:

On my VW Beetle, electrical power is provided by a belt running from the engine to a dynamo. A similar system is used in piston engined aircraft. How is power generated from a jet turbine? obviously there can't be a belt running from the central shaft of a turbine, as presumably the temberatures would be too high. so how is the electrical power provided?

Many thanks

Matty

[FlyingForFun]

By gears, maybe?

Incidentally, what makes you think the shaft of a turbine engine is any hotter than the crankshaft of a piston engine? Piston engines get pretty hot inside, too - but the shaft protudes outside the engine, and there is a pulley bolted typically onto the front of the engine. Can't do this with a turbine engine, since the air-flow around the front and rear of the engine is essential - I'd have thought that's why there's no belt-drive. That and the fact that the turbines turn much faster than most piston engines.

FFF
-----------------

[Vizsla]

A number of fast Naval Patrol Boats in the 70's were powered by Jet Turbines linked by gearboxes.
The best use I've seen for a Mamba is at Malta Film Studios as a wind generator

[mustafagander]

Most gas turbine engines within my ken have a drive taken off the compressor drive shaft to power a gearbox (often under the engine). The customary accessories - fuel pump, fuel metering controls, hydraulic pump and electrical generator/alternator etc are driven from this wheelcase.

[Willit Run]

Just about all turbo jet engines that are installed on transport airplanes have 3 phase generators driven from the N2 accessory gearbox. Since Voltage and frequency need to be kept within fairly close tolerence, the generator is kept at a constant speed, being actually driven by a constant speed drive unit, very similar to an automatic transmission in your car. We are talking about 115 volts and 400 Hz. This is a very short and not very detailed description. but hope this helps!

[RomeoTangoFoxtrotMike]

A number of fast Naval Patrol Boats in the 70's were powered by Jet Turbines linked by gearboxes.

Indeed, but not just patrol boats. HMS Ark Royal is powered by 4 x Rolls Royce Olympus gas turbines, just like Concorde (OK, nearly ;) ) to two propellors.