Turbine Engines - Differences between types?

[Freek Flyer]

Just wondering if someone can point me in the right direction of a site or book that will explain the differences between Rolls-Royce Vs P&W and GE engines on the 747? or if someone could explain some of the basic differences, pro's con's etc, it would be of great benifit!

Thanks

[Bally Heck]

Try this (http://www.pprune.org/forums/showthread.php?s=&threadid=61239) for a start.

[Flight Detent]

My pennies worth: (for the B747)
Rollers are not reliable enough, and are way to heavy, and fuel efficiency is a problem.

P&W are much more of a 'hardier' machine, but are not very powerful, and not very fuel efficient, by comparison.

GE seem to make a good allround machine, light weight, fuel efficient, and able to stand the occasional bird down the intake.
They just seem to last for a long time. (MTBF)
And, of course, they don't use EPR for output indication.
For me, the best choice, all round!

Cheers

[acheo]

There are sub-categories of turbine engines:

1- turbo-prop
2- turbo-jet
3- turbo-fan

All these engines use a turbine but for different reasons. Start from this:)

[Flight Detent]

Hi all,
As far as I am aware, the B747 has only two "sub-catagories" of turbine engines, a/ turbofan x 4, and, b/ APU!;) ;)

[acheo]

soryy guys...I guess I misread the question:) :)

[Freek Flyer]

Thanks guys, getting there,

I've read elswere the major benifit of the rb-211 was it's reliability, anyone else with experience heard this? I realise the RR is by far the most expensive, what would be the benifit of an operator choosing this type of eng? I've heard rumblings about the length of the engine (RR being shorter) and therefore increasing efficiency? Or is this Nonsense?

Thanks for the continued help!

[gas path]

There is very little difference to choose between all 3 engine types when it comes to out and out reliability ie engine failures.
The RB211 is the heaviest of the 3 but when you take the weight of the powerplant, the Royce includes the complete pod, thrust reverser and the rest of the associated junk:) The other two types the thrust reverser is Boeing, part of the airframe and stays attached to the same during an engine change for example.
The Royce has a better S.F.C over the life of the engine with a lower deterioration in efficiency.
FWIW it is a delight to work on very straight forward and no unneccessary complications.
The Royce is a three shaft layout the other two have two shafts.
One minor point the other two rotate the wrong way:D :D :D

[tinyrice]

The reverser is part of the P&W JT9D engine and goes with it when it's changed - like the Roller

[gas path]

Doh!!!!....Sussed:D :D :D