CX 777 Variants Engines

[howitzer]

I'm having some trouble narrowing down the exact Trent series on the different variations that CX has for the 777

I understand the -300ER has only the GE90-115B, my question pertains to the -200, -200ER, and the -300

I show the -200 having 890's with 90,000 lbs of thrust.

The -300 having 877s with 77,000 lbs of thrust.

Are these correct? If so, why does the -300 have less power than the -200?

Thanks for any info you're able to offer.

[cx252]

those 200s are equipped with Trent 877 and providing 77,000 lbf as you stated, and 300s equipped with Trent 892 and giving 90,000 lbf.

[BuzzBox]

777 engines and thrust ratings as follows:

777-200: RR Trent 877, rated at 76,900 lb thrust

777-300: RR Trent 892, rated at 84,000 lb thrust (the basic engine is rated at 92,000 lb thrust, but CX engines are rated at the lower thrust. The full thrust isn't needed for the CX operation because the aircraft have a lower MTOW of 263T. The lower thrust rating reduces costs.)

777-300ER: GE90-115BL2, rated at 115,000 lb thrust

[geh065]

Actually the 777-300s used to have Trent 892s but when they were derated to 84,000lbs of thrust, the engines were technically no longer Trent892s. A new designation was given to the engines that CX operates which are unique in that they provide only 84,000lbs of thrust for take off, but then as the aircraft climbs into higher altitudes where 84,000lbs is not enough to keep a good rate of climb going on a max weight aircraft, the engines slowly increase their thrust rating to 92,000lbs.

The designation by Rolls Royce for these engines is the Trent 884b.

[howitzer]

Thanks for the help.

[BuzzBox]

A bit more background to the RR Trent 892/884 used by CX on the 773:

The 777-300 initially came to CX with Trent 884 engines.

Although the Trent 884 thrust rating is adequate to cover takeoff, MCT and go around thrust requirements, its climb thrust is marginal.

After discussion with RR and Boeing, an agreement to use the Trent 892 max climb thrust rating was reached, with takeoff thrust remaining at 84,000 lb.

At the time of the agreement, the only thrust ratings available for the 777-300 were the Trent 884 and Trent 892, so the only way to implement the use of Trent 892 max climb thrust was to use the Trent 892 rating plug.

In order to comply with the 84,000 lb takeoff thrust rating certification, the 777-300 fleet was restricted to only use TO1 and TO2 (TO1 closely approximates 84,000 lb thrust).

In the longer term a unique thrust rating was created to incorporate the take-off thrust of the Trent 884, with the climb thrust of the Trent 892.

Hence the Trent 884B thrust rating:

Takeoff
- Same rating as Trent 884 TO (equivalent to Trent 892 TO1)

Climb
- Same rating as Trent 892

MCT
- Hybrid rating Trent 884/Trent 892
- Below 21000' same as Trent 884
- 21-25000' Trent 884-Trent 892
- above 25000' Trent 892

Go Around
- Same rating as Trent 884

Clear as mud?