Rr Rb211-535e4 Engines
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The -535 uses "on-condition" maintenance principals so you only have to remove it for a life limited part going timex or else if you have a problem (e.g. turbine damage outside limits). However....most operators will have an expected life based on rating, average de-rate, stage length, route network etc.. This is true of all gas turbines though.
On the fan blade issue, the original RB211-22 had wide chord composite fan blades made from a carbon composite called Hyfil. While it survived most tests during development engine running in '69/'70, it wasn't up to a bird strike and this resulted in the switch to a Ti clappered blade. This late design change along with a number of other factors (general RB211 performance, exchange rates etc.) pushed R-R into bankruptcy in 1971. The wide chord blade was next introduced onto the E4, this time it was a Ti blade.
On the fan blade issue, the original RB211-22 had wide chord composite fan blades made from a carbon composite called Hyfil. While it survived most tests during development engine running in '69/'70, it wasn't up to a bird strike and this resulted in the switch to a Ti clappered blade. This late design change along with a number of other factors (general RB211 performance, exchange rates etc.) pushed R-R into bankruptcy in 1971. The wide chord blade was next introduced onto the E4, this time it was a Ti blade.
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I thought 411A was in this thread yesterday, if I'm not mistaken
My opinion, Rollers are very robust and fuel efficient engines.
Best in the business.
One does pay a penalty, however...they are heavier.
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What.....no reference to Lockheeds' finest......?
Next to my parked private twin engine airplane in Arizona, is a twin, owned by a retired Boeing design engineer.
He says, and I will quote...
'When we looked at the autopilot/systems integration on the L1011 in early 1973, we at Boeing then realised that we were well behind the design curve'.
Ha!
No surprise.
The Rollers were only a bonus.
The L1011....waaaay ahead of everyone else with aircraft systems automation, and, even more important, aircraft systems REDUNDANCY.
For the average line pilot...absolute perfection.
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I'm not sure of the weight of the -22B/earl 524's v the competition of the day but an installed Trent 800 (B777) does have a weight advantage over the competition (GE90 / PW4000). I believe it's more than 1000 lbs.
Another example of R-R benefiting from the shorter 3-shaft design.
Another example of R-R benefiting from the shorter 3-shaft design.
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I'm not sure of the weight of the -22B/earl 524's v the competition of the day
However...the Roller was considerably more fuel efficient (9%, actually) and....quieter.
Have to say, RollsRoyce....mightly fine engines.
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Just to clarify something from the original poster, that shows how godo/popular the 535 was/is, the fleet split RR/PW on the B757 was closer to 80/20. Consider the number of US B757 operators and they didn't all choose the home brand - tut, tut!
George 'Buy a Boeing' Bush would be so unhappy...
Regards,
N1 Vibes
George 'Buy a Boeing' Bush would be so unhappy...
Regards,
N1 Vibes
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Yes, the RR on the 757 is hard to beat. Is there a more reliable or lower operating cost engine anywhere?
That said, why are so many 757s being parked, and maybe scrapped?
Airlines can be more rational than militaries when it comes to loyalty. America West 757s came with RR because Indian Airlines had ordered them before going bankrupt.
Boeing and GE financed Continental's bailout from its second bankruptcy in the mid-1990s, with the agreement that CO would always buy Boeings with GE engines. RR was selected for CO 757s by GE, because they were the weaker competitor.
IF the militaries had any common sense, they would buy half-life airliners, including 757s, for tankers. They would save hugely, as the work could be done competitively by MROs all over the world. However, govt leaders everywhere are rewarded for spending money, not saving it.
GB
That said, why are so many 757s being parked, and maybe scrapped?
Airlines can be more rational than militaries when it comes to loyalty. America West 757s came with RR because Indian Airlines had ordered them before going bankrupt.
Boeing and GE financed Continental's bailout from its second bankruptcy in the mid-1990s, with the agreement that CO would always buy Boeings with GE engines. RR was selected for CO 757s by GE, because they were the weaker competitor.
IF the militaries had any common sense, they would buy half-life airliners, including 757s, for tankers. They would save hugely, as the work could be done competitively by MROs all over the world. However, govt leaders everywhere are rewarded for spending money, not saving it.
GB
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Any RB211-535C and E4 experts out there?
The RB211-535C and E4 have had a number of reported contaminated air events due to engine oil contaminating the bleed air supply. RR Service Bulletin RB.211-72-7651 of 1 Feb 1985 and others refer to the issue.
A 1999 article also states:"Oil related problems on the RB211-535E4 have multiple origins. First, high oil consumption can come from extended low power operation. "All the bearing compartments on the RB211 are sealed with air, so operating the engine at low power simply means that the available sealing air is less than it would be at high power or cruise settings. It has been shown that normal oil consumption can double when the engine is run at low power for an extended period of time, such as when taxiing or just sitting at the gate...."
Are there any engineers who could please explain a bit more about the relationship between increased oil leaks and the engine at idle and also the reported pilot reports of contaminated air events occurring in the decent again with the engines at idle?
Many thanks
The RB211-535C and E4 have had a number of reported contaminated air events due to engine oil contaminating the bleed air supply. RR Service Bulletin RB.211-72-7651 of 1 Feb 1985 and others refer to the issue.
A 1999 article also states:"Oil related problems on the RB211-535E4 have multiple origins. First, high oil consumption can come from extended low power operation. "All the bearing compartments on the RB211 are sealed with air, so operating the engine at low power simply means that the available sealing air is less than it would be at high power or cruise settings. It has been shown that normal oil consumption can double when the engine is run at low power for an extended period of time, such as when taxiing or just sitting at the gate...."
Are there any engineers who could please explain a bit more about the relationship between increased oil leaks and the engine at idle and also the reported pilot reports of contaminated air events occurring in the decent again with the engines at idle?
Many thanks
Last edited by FNFF; 13th Oct 2019 at 15:49.
Any RB211-535C and E4 experts out there?
The RB211-535C and E4 have had a number of reported contaminated air events due to engine oil contaminating the bleed air supply. RR Service Bulletin RB.211-72-7651 of 1 Feb 1985 and others refer to the issue.
A 1999 article also states:"Oil related problems on the RB211-535E4 have multiple origins. First, high oil consumption can come from extended low power operation. "All the bearing compartments on the RB211 are sealed with air, so operating the engine at low power simply means that the available sealing air is less than it would be at high power or cruise settings. It has been shown that normal oil consumption can double when the engine is run at low power for an extended period of time, such as when taxiing or just sitting at the gate...."
Are there any engineers who could please explain a bit more about the relationship between increased oil leaks and the engine at idle and also the reported pilot reports of contaminated air events occurring in the decent again with the engines at idle?
Many thanks
The RB211-535C and E4 have had a number of reported contaminated air events due to engine oil contaminating the bleed air supply. RR Service Bulletin RB.211-72-7651 of 1 Feb 1985 and others refer to the issue.
A 1999 article also states:"Oil related problems on the RB211-535E4 have multiple origins. First, high oil consumption can come from extended low power operation. "All the bearing compartments on the RB211 are sealed with air, so operating the engine at low power simply means that the available sealing air is less than it would be at high power or cruise settings. It has been shown that normal oil consumption can double when the engine is run at low power for an extended period of time, such as when taxiing or just sitting at the gate...."
Are there any engineers who could please explain a bit more about the relationship between increased oil leaks and the engine at idle and also the reported pilot reports of contaminated air events occurring in the decent again with the engines at idle?
Many thanks
First off, one of the big challenges of a 3 spool engine is bearing design and lubrication - it's simply far more difficult than with a more conventional 2 spool engine. Due to those complexities, oil going were it doesn't belong is more likely on a 3 spool, and Rolls has had more than their fair share of oil leak and bearing issues over the years on all of it's 3 spool engines.
Common design practice on large turbine engines is to use relatively simple oil seals on the bearings, and then use differential air pressure to help keep the oil from getting past those seals. They use air bled from various parts of the engine to provide those differential pressures - and at idle those pressure differentials are not large enough for this system to work as well as it does at power. That's also why fume events sometimes occur right after engine start - when the engine is shut down there is zero differential pressure so if an oil seal isn't up to snuff it can let oil into the flow path (it used to be common to see massive clouds of oil smoke out the tailpipe after engine start on the L1011).
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My experience of a number of oil-smell events on 535C's in the 1990's was that there were oil leakages at the front of the HPC rotor (i.e, from the rear of the IGB assembly) this then mixed with airflow that entered the interior of the HPC rotor, then out into the HPC airstream and entered the a/c through the off takes (HP3 and HP6?)
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DHL B757s and contaminated air
Maybe that is because DHL have fitted the Pall Aeropsace 'Cockpit Filter Unit' (CFU) to all their Rolls-Royce powered Boeing 757 aircraft so there should be less contaminated air issues in the cockpit?
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http://www.vc10.net/Files/BOAC_EngNews_3403_red.pdf
After watching the beeb doc on Rolls Royce I looked a little further into the Hyfil Blades that were one of the Major causes of the Bankruptcy . I had never realised that they had actually flown these blades on a smaller engine .I still find it hard to believe that such a great engineering company could not have foreseen that the anisotropic properties of unidirectional carbon might have been a problem .
After watching the beeb doc on Rolls Royce I looked a little further into the Hyfil Blades that were one of the Major causes of the Bankruptcy . I had never realised that they had actually flown these blades on a smaller engine .I still find it hard to believe that such a great engineering company could not have foreseen that the anisotropic properties of unidirectional carbon might have been a problem .
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http://www.vc10.net/Files/BOAC_EngNews_3403_red.pdf
After watching the beeb doc on Rolls Royce I looked a little further into the Hyfil Blades that were one of the Major causes of the Bankruptcy . I had never realised that they had actually flown these blades on a smaller engine .I still find it hard to believe that such a great engineering company could not have foreseen that the anisotropic properties of unidirectional carbon might have been a problem .
After watching the beeb doc on Rolls Royce I looked a little further into the Hyfil Blades that were one of the Major causes of the Bankruptcy . I had never realised that they had actually flown these blades on a smaller engine .I still find it hard to believe that such a great engineering company could not have foreseen that the anisotropic properties of unidirectional carbon might have been a problem .
The anisotropic properties of Hyfil meant that it could be layered as appropriate and as I recall there was a belief that issues would be resolved. Anyhow it is unlikely that any project would have got off the ground if the weight saving benefits could not be shown to be there.
Again from memory there was strong sense of belief that it suited a Conservative uk government to allow RR to go bankrupt and then rescue it rather than simply put finance into it because of the situation with the EU/Common Market.
It was all a long time ago, a job I loved but was only in for a short 3 years at the start of my working career before being put on the scrap heap - I still have the "Dear Sir or Madam" redundancy letter somewhere. But had the original decision to go ahead with Hyfil not been taken I doubt that RR would be the important player it now is.
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The first of the RR RB211 family of engines was the -22 as fitted to the L1011 Lockheed TriStar. The engine was a development by Rolls of the first, that I know of, to have three spools. (Fan, LP Compressor, HP Compressor) all with their own Turbine sections and all on seperate shafts rotating at different RPMs. RB comes from Rolls Royce Barnoldswick where the engine was designed.
The biggest problem with the entrance of these blades was the resistance to FOD, The other big engine manufacturers were also keen to develop composite blades and needed to address the serviceability of these after they entered service. The FAA at that point had already noted the sensitivity of the early GE gun drilled fan blades and was shall we say gun shy of the ruggedness of the now developing composite blade following the RR lead, I seem to recall a funded developments through the Dayton Ohio folks in the 60's. The idea was concentrating around a protective covering at the leading edge to resist erosive properties of fine sand as well as a sacrificial resistance to larger particles such as small stones, hail etc.. and of course stay around long enough to get home after eating birds up to 1.5 lbs.
I believe that history suggests it took another 20 years of industry wide development before these problems were addressed.
I believe that history suggests it took another 20 years of industry wide development before these problems were addressed.
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Somewhat on the same topic , my first aviation job after leaving college around 1976 was at Westlands in the Composite Development . We built a tail boom for the Westland Scout from HIgh Modulus unidirectional carbon fibre ( Ciba Geigy product ) . I witnessed the final destructive test , I do not recall if it exceeded design limit but I will never forget the loud crack when it failed and the numerous pieces of carbon fibre that flew all through the hangar. Thankfully the woven fibres now available have much better properties.
I once made up a scale 1/2 size engine fan disk out of a styrofoam block and lashed it to the side of the bathyscaphe Trieste diving to a 10000 ft depth to see how uniform it would miniaturize. It turned out a horrible mess,.I was trying to demonstrate the HIP process of forging with a show and tell model.