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na
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Which Engine Performs Best On The 744?

Fri Nov 03, 2000 1:48 am

I would like to know if there is a statistic somewhere that gives information which engine, if RR, GE or PW, has the best overall performance on the B747-400 (Reliability and Fuel efficiency as the most important features).

Thanks to everyone in advance.
 
Guest

RE: Which Engine Performs Best On The 744?

Tue Nov 07, 2000 6:08 am

Most of the European carriers like Air France, KLM, Lufthansa, & Alitalia have selected the GE CF6 series on their 747-400s, while in the USA airlines like Northwest & United have selected the P&W 4000 series. The only RR RB211 powered 747-400 operators I know of are British Airways, Qantas, South African Airways, & Air New Zealand.
 
Tarantine
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RE: Which Engine Performs Best On The 744?

Tue Nov 07, 2000 12:04 pm

according to janes, the CF6-80CB1F has the lowest fuel burn, followed by the PW4056.
 
TK
Posts: 222
Joined: Tue Oct 31, 2000 11:41 am

RE: Which Engine Performs Best On The 744?

Tue Nov 07, 2000 6:17 pm

Tedski, Cathay Pacific also operates a large fleet of RR powered 744's.

The RB211 is almost certainly the best engine for the 744 i.e. most powerful yet most fuel efficient. Because of this, Qantas is able to increase the MTOW on their RB211 powered 744 to 875,000lb.
 
FLY DC JETS
Posts: 191
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RR Has The Highest Fuel Burn.

Tue Nov 07, 2000 9:01 pm

The Rolls-Royce engine has the highest fuel burn of the three when based on specific fuel consumption. Some sources have the PW4056 as having a low SFC than the CF6, however, since there is a discrepancy, we'll call it even. Rolls has even had to retrofit engines for several airlines at THEIR OWN expense due to the engine not living up to performance garantees.

Also, here are the engines offered on the 747, unless the RR can eke out an extra 3,000lbs of thrust when installed, I'd say it is not the highest thrust either.
Pratt & Whitney PW4062
63,300 lb (28,710 kg)

Rolls-Royce RB211-524H
59,500 lb (26,990 kg)

General Electric CF6-80C2B5F
62,100 lb (27,945 kg)

The fact that the RR is not best engine, as evidenced by the higher SFC and less reliability than the PW or GE, is truly hammered home when one looks at the fact that the PW and GE are the more popular choice for engines and RR lags behind in third on the 744.
 
FLY DC JETS
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BTW Standard Mtow Is Now 875,000lb

Tue Nov 07, 2000 9:04 pm

According to Boeing, the standard MTOW for the B747-400 is 875,000lb. I have book that discusses the Quantas issue that you brought up, however, the book that I am referencing was made more than six years ago and the information is now out of date. -- And the author was British and had a bias.
 
widebodyphotog
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RE: BTW Standard Mtow Is Now 875,000lb

Tue Nov 07, 2000 9:32 pm

Not sure if you are correct about the Standard MTOW being 875,000lbs. The latest 747-400 book I have, published 1998, still lists standard MTOW as 870,000lbs with the higher gross weight as an option with wing and undercarriage strengthening. Furthermore 875KLB is only available with the highest thrust engines ie. CF6-80C2B1F2's (61,500Lbt) ,PW4062 (62,000Lbt), and RR-524G-H/T (60,300Lbt). And as far as the higher thrust GE and Pratts go, 62,100 and 63,300Lbt respectively, I am not sure if any aircraft has been delivered with thrusts above 62,000Lbt, although Boeing has them listed on their site. If anyone knows of the aircraft that have please let me know the tail number and delivery date.

TKS

Widebodyphotog
If you know what's really going on then you'll know what to do
 
TK
Posts: 222
Joined: Tue Oct 31, 2000 11:41 am

RE: Which Engine Performs Best On The 744?

Tue Nov 07, 2000 10:01 pm

It has been brought up many many from several sources that the RR is the best on the 744 and may I ask what your source was when you say that the RR has the highest specific fuel consumption?

You also mentioned that RR has had to retrofit engines at their own expense. Could you elaborate more on that because I've never heard of such a thing. I've only heard of Cathay upgrading the RB211's to RB211-524H/T at their own expense to add to what was already an exceptional engine and that after the retrofit (which improved SFC by 3%), they are now among the best.

2 books have brought up the Qantas issue. 1 by Robbie Shaw (the one you mentioned) and the other by Guy Norris and Mark Wagner and printed in 1997 in the US.

Also, its hard to judge the quality of an engine simply by looking at how many were sold. Many factors come into play when an airline chooses an engine, with a main one being commonality with the rest of its engines in its fleet.
 
FLY DC JETS
Posts: 191
Joined: Sat Feb 26, 2000 1:13 pm

RE: Which Engine Performs Best On The 744?

Wed Nov 08, 2000 5:44 am

I stand corrected, I was wrong. Went back and looked at the numbers I had and the SFC given for the PW4K was for .80 Mach and the SFC for the RR was .85 therefore if the two are equalized the edge will go slightly to RR. Differences in momentum will lead to higher engine thrust being used and more fuel being burned.
About the retrofit, I'm digging up my source for info on that. I'll post back w/i a few minutes.

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