Rolls RB-211s
 

Will be checking out on a 757 with Rolls RB-211s. I've never flown Rolls engines before - only GEs and Pratts. Anybody have an tidbits on the good and bad points of the 211. The triple spool seems the expensive and heavy way to do things, but would be interested in anybody's experience with them regards good & bad characteristics, maintenance reliability, fuel economy etc.
Cheers.

ROADTRIP:

Have operated the RB.211 for twenty years, altho not the -535 model used on the 757. My experience is on the -22B and -524B402 models. Anyway, have found it to be VERY reliable, have only had one shutdown, due to high vibration (fan locator bearing). Yes, it is heavier but quieter and more fuel efficient. Be prepared for slower starts (and strange sounds) as the three shaft design takes longer to wind up. I became a convert a long time ago, the RB.211 is one FINE engine.

Got over a thousand hours in Rollers, and about a hundred in Pratts.
The Roller is a hugely better engine, especially on approach, as the spool-up time is much shorter. The Pratts need a much bigger handful of throttle, too, to get the same responce.
(This is comparing the RB-211-535-D4X to a JT9D-7A, FWIW. Perhaps not a totally fair comparison, but it's all I can offer)

Haven't flown a GE yet, but by all reports they're better than the other two. Unanymous agreement on that.

Watch out for hot starts, especially if you a wind up the tail pipe and the OAT is above 20C - otherwise a lovely motor.

Very low residual thrust compared to the Pratt (read - throttles off very close to ground. Otherwise, you can announce "welcome aboard the U.S.S. _________". In reverse, makes alot of noise, very little deceleration.

Shore Guy

reliability of -535 is excellent, far better than -22B (but can't be much worse (from -22B's era!)).
Only tip is that during start up, 535 accelerates to what seems flight idle & then slows down to ground idle. This is due to power change over to the EEC (aircraft power used until engine dedicated altenator is on line) during the start sequence.
Minor point I know, but it may be worth sumfing.

RB211 is a brill engine from maintenance and reliability point of view. Nice and easy to work on and very simple due to tripple spool design. You don't need so many bleed valves or any variable inlet guide vanes atall. Fuel efficiency and engine spool up times are much better, again due to tripple spool --I think Royces' have the patent for this design,hence Pratt plus G.E. can't use it!! Anybody know this for certain?

Must be a different RB211 to the one's I work on as they variable inlet guide vanes, if not what is the VIGV fluidic controller for!!!!I guess that will allow me to rip out test 4 from the MM as it is no longer reqd.

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"please report further"

Yes indeed, they DO have VIGV's, controlled by pneumatic rams. Work good too!