American twins,Brit triple spool engines?
Emirates chose EA engines over Rolls for its A380's. They are unwise, and don't know the value of Fuel??
I don't know where you got this idea.
Compared to the Trent 900 on the A380s, Emirates are way ahead on sfc and block fuel on their aircraft, to the degree that Airbus is producing/has produced a new Performance Manual (by whatever name Airbus uses) to take full advantage of the actually achieved figures.
By comparison, the Trent 900 ( and traditionally since the RB211-22D through the -C,-D and -524) is still well below book figures and contract guarantees.
Incidentally, the "short" cowls of the various RB 211 produce some quite interesting drag problems, particularly above M0.855, not so the CF6-80C2 on many B744 and B767.
In every weight comparison "like for like" the RB 211 is heavier than the GE or PW equivalent, a function of the "three spool" design.
I would check the weight claims of the Trent v the rest very carefully.
All publicly available information.
Tootle pip!!
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I believe the Trent 800 offers the lowest takeoff consumption on the 777-200A/ER, which is in part due to the triple spool design. This combined with its light weight means it is more efficient than the GE90 for flights under ~3000nm, after this the GE takes over (not sure where Pratts come into this). But then again, if you want a 777 to be efficient under 3000nm you should buy an A330-300.
Another advantage of the triple spool design that an engine family is extremely scalable.
Note that the RB211 has ranged from the -535 at ~37klb to the -T800 with ~94klb. RR also hoped to supply an engine for the 777LR program which demonstrated 114klb in test but were denied a place due to engine exclusivity.
This scalability has proven crucial though as it has allowed RR to not only supply engines for the 787, but exclusively supply them for A350. So even though the 787 order books so far say the GeNX is a better package than the Trent, RR stands to dominate the upcoming generation of widebodies.
Another advantage of the triple spool design that an engine family is extremely scalable.
Note that the RB211 has ranged from the -535 at ~37klb to the -T800 with ~94klb. RR also hoped to supply an engine for the 777LR program which demonstrated 114klb in test but were denied a place due to engine exclusivity.
This scalability has proven crucial though as it has allowed RR to not only supply engines for the 787, but exclusively supply them for A350. So even though the 787 order books so far say the GeNX is a better package than the Trent, RR stands to dominate the upcoming generation of widebodies.
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For the B777-200ER fitted with the GE - Pratt - RR; here is the ICAO fuel burn data.
GE-94B - Take-off - 3.513 kg/s
Pratt 4090-Take-off - 3.926 kg/s
RR 895 - Take-off - 4.03 kg/s
GE-94B - Climb-out - 2.831 kg/s
Pratt 4090- Climb-out - 2.996 kg/s
RR 895 - Climb-out - 3.19 kg/s.
So from the above data, the RR burns the most fuel during take-off and also in the climb-out.
I have yet to see good data to prove otherwise.
GE-94B - Take-off - 3.513 kg/s
Pratt 4090-Take-off - 3.926 kg/s
RR 895 - Take-off - 4.03 kg/s
GE-94B - Climb-out - 2.831 kg/s
Pratt 4090- Climb-out - 2.996 kg/s
RR 895 - Climb-out - 3.19 kg/s.
So from the above data, the RR burns the most fuel during take-off and also in the climb-out.
I have yet to see good data to prove otherwise.
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Most engines are scaleable.
I'm interested in the scaleability of the new Pratt GTF series. So far indications are that it will be scaleable all the way from engines powering the Japanese MRJ 100 seat jet to wide bodies. Pratt may even knock GE from number one position on the A320NEO. I predict that Pratt will have a major come-back in wide body frames and will regain number two position in engine sales but it will take some time. This engine will be a 'game changer'. Long live the dependable flying Eagle symbol on engine cowlings.
I'm interested in the scaleability of the new Pratt GTF series. So far indications are that it will be scaleable all the way from engines powering the Japanese MRJ 100 seat jet to wide bodies. Pratt may even knock GE from number one position on the A320NEO. I predict that Pratt will have a major come-back in wide body frames and will regain number two position in engine sales but it will take some time. This engine will be a 'game changer'. Long live the dependable flying Eagle symbol on engine cowlings.
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Someone mentioned P&W doing stuff with geared fans. Rolls Royce did work on a geared fan engine in the late 70's early 80's using a modified M45 engine. called the silent demonstrator. I guess that they never needed the technology the project was scrapped.
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Doesn't a 747 have a maximum cruise mach of 0.88 and a MMO of 0.92?
I forgot about that! God those engines were a beast in terms of weight. IIRC, they were planning on using some kind of composite which was to be used on at least the fan-blades if not some of the compressor stages. I do know they wanted to use wide-chord fan-blades (which would be excessively heavy if they used metal, so they instead decided to use composites) to do away with the mid-span shroud. It turned out to handle rain, sand, and FOd poorly, so they replaced it with a more conventional titanium fan which drove up the weight of the fan (possibly some compressor blades), and then required the engine to be strengthened around the extra weight.
FLAPS 10-100
I assume RR's geared-fan concept worked well...
Incidentally, the "short" cowls of the various RB 211 produce some quite interesting drag problems, particularly above M0.855, not so the CF6-80C2 on many B744 and B767.
In every weight comparison "like for like" the RB 211 is heavier than the GE or PW equivalent, a function of the "three spool" design.
FLAPS 10-100
Someone mentioned P&W doing stuff with geared fans. Rolls Royce did work on a geared fan engine in the late 70's early 80's using a modified M45 engine. called the silent demonstrator. I guess that they never needed the technology the project was scrapped.
Usual disclaimers apply!
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Not forgetting of course that the weight of the RB211 includes the complete pod. The CF6 and PW4000 the thrust reversers are a boeing part and stay with the airframe.
Reference the fan blades. RR got it wrong as the technology at the time was woefully inadequate. Some 30 years later composite knowledge had come on leaps and bounds and the GE90 composite fan blade is excellent albeit with a titanium leading and trailing edge and titanium in the root BUT it is heavier compared to the Trent Titanium blade and in something of a backward step the -115 blade is susceptible to birdstrike damage. As for maintenance I much prefer the RR (all varieties of the 211)as they are so simple.
One thing the RR motor has always been good at performance retention over its lifetime. The hightime engine achieved over 40k hours on wing. The mount bolts still had the boeing seal on them when it was eventually pulled for overhaul.
Reference the fan blades. RR got it wrong as the technology at the time was woefully inadequate. Some 30 years later composite knowledge had come on leaps and bounds and the GE90 composite fan blade is excellent albeit with a titanium leading and trailing edge and titanium in the root BUT it is heavier compared to the Trent Titanium blade and in something of a backward step the -115 blade is susceptible to birdstrike damage. As for maintenance I much prefer the RR (all varieties of the 211)as they are so simple.
One thing the RR motor has always been good at performance retention over its lifetime. The hightime engine achieved over 40k hours on wing. The mount bolts still had the boeing seal on them when it was eventually pulled for overhaul.
Last edited by gas path; 12th Mar 2011 at 17:39.
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An interesting use of the English language for a tech issue. So the RR is superb at retaining its performance whilst it is retaining its performance??
High time leader 40k on wing?? Excellent!! Your statements want data in support of what I think you mean. An anecdote, and an anomalous one at that, I fear.
An interesting use of the English language for a tech issue. So the RR is superb at retaining its performance whilst it is retaining its performance??
High time leader 40k on wing?? Excellent!! Your statements want data in support of what I think you mean. An anecdote, and an anomalous one at that, I fear.
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Sorry Rj111, I should have noted the link for the fuel burn data as it's always good to provide a link to back up ones notation(s).
Document Categories | Human and Environmental Issues | Safety Regulation
I hope the previously noted data clears up and misunderstanding with regards to fuel burn in the climb stage.
Document Categories | Human and Environmental Issues | Safety Regulation
I hope the previously noted data clears up and misunderstanding with regards to fuel burn in the climb stage.
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Airbus Payload Range graph for A330-200, A330-200F and A330-300.
http://www.airbus.com/fileadmin/medi...A330_Jan11.pdf
Note: The GE engined aircraft has the best range as indicated on the Airbus graphs.
ICAO fuel consumption data.
Document Categories | Human and Environmental Issues | Safety Regulation
Pratt 4164 - Take-off 2.721 kg/s - Climb 2.239 kg/s
GE CF6-80E1 - T-off 2.97 kg/s - Climb 2.337 kg/s
RR Trent 700 - T-off 3.2 kg/s - Climb 2.58 kg/s
Again, the RR triple spool loves her fuel.
http://www.airbus.com/fileadmin/medi...A330_Jan11.pdf
Note: The GE engined aircraft has the best range as indicated on the Airbus graphs.
ICAO fuel consumption data.
Document Categories | Human and Environmental Issues | Safety Regulation
Pratt 4164 - Take-off 2.721 kg/s - Climb 2.239 kg/s
GE CF6-80E1 - T-off 2.97 kg/s - Climb 2.337 kg/s
RR Trent 700 - T-off 3.2 kg/s - Climb 2.58 kg/s
Again, the RR triple spool loves her fuel.
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K 9
As Bear said, leakage of air around blade tip results in degraded performance. In the LP turbine the blade tip shroud seal teeth wear down creating leakage. Also, compressor blading tends to pick up dust that sticks to the aifoil surfaces and over time builds up changing the aerodynamics from what is desired. In the HP turbine, residue also builds up on the blade airfoils, probably coming from the fuel burn in the combustor that changes performance/efficiency for the worse. Today, some airlines have their engines water washed to restore the intended aerodynamics.
As Bear said, leakage of air around blade tip results in degraded performance. In the LP turbine the blade tip shroud seal teeth wear down creating leakage. Also, compressor blading tends to pick up dust that sticks to the aifoil surfaces and over time builds up changing the aerodynamics from what is desired. In the HP turbine, residue also builds up on the blade airfoils, probably coming from the fuel burn in the combustor that changes performance/efficiency for the worse. Today, some airlines have their engines water washed to restore the intended aerodynamics.
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unmanned transport
I would think the GTF engine would be capable of being scaled larger or smaller than that targeted for the A-320NEO. So far all looks well in the testing phase. Much will depend on the robustness of the gear feature and whether or not required maintenance of this feature is minimal.
Don't forget about the GE "LEAP" engine. It too is going to offer 15% or better fuel utilization verses current engine technology.
I'm interested in the scaleability of the new Pratt GTF series. So far indications are that it will be scaleable all the way from engines powering the Japanese MRJ 100 seat jet to wide bodies.
Don't forget about the GE "LEAP" engine. It too is going to offer 15% or better fuel utilization verses current engine technology.
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For sure Turbine D, this is the prime goal for Pratt, to scale an engine for wide bodies. Hey, maybe a twin decker twin engine monster of a lifter.
(Sorry, I don't know how to copy and paste a previous poster's comments)
Help!
(Sorry, I don't know how to copy and paste a previous poster's comments)
Help!
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unmanned transport
I have an iMac. What I do to copy & paste is:
1. Pick the spot for the "quote" in your reply and click on the "Wrap(quote)tags" icon which is the third icon tab from the right (toolbar above).
2. Scroll down to the "Topic Review" and copy the comment you want to paste.
3. Scroll back up to your reply box and place your curser between the two quote boxes, click and then click paste.
Hope this works!
Turbine D
(Sorry, I don't know how to copy and paste a previous poster's comments)
Help!
Help!
1. Pick the spot for the "quote" in your reply and click on the "Wrap(quote)tags" icon which is the third icon tab from the right (toolbar above).
2. Scroll down to the "Topic Review" and copy the comment you want to paste.
3. Scroll back up to your reply box and place your curser between the two quote boxes, click and then click paste.
Hope this works!
Turbine D
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Why didn't RR try diffusion bonded titanium fan blades?
The GE-4 which was designed for the failed SST program used wide-chord titanium compressor blades that were formed this way (it's effectively like glass blowing with hot metal) and it was pretty much as light as if it was a honeycomb blade except it wasn't. As far as I know the blades worked fine (the plane simply didn't)
The GE-4 which was designed for the failed SST program used wide-chord titanium compressor blades that were formed this way (it's effectively like glass blowing with hot metal) and it was pretty much as light as if it was a honeycomb blade except it wasn't. As far as I know the blades worked fine (the plane simply didn't)
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JaneDoH
The question is, how do you know (100% positively sure) the bond has been made? Perhaps today there is adequate inspection technology to survey the bonds and detect abnormalities now, but then inspection technology wasn't as advanced as today. The plane never got a chance to work, the contract (funding) by the US government was cancelled before any planes were built.
Turbine D
Why didn't RR try diffusion bonded titanium fan blades?
The GE-4 which was designed for the failed SST program used wide-chord titanium compressor blades that were formed this way (it's effectively like glass blowing with hot metal) and it was pretty much as light as if it was a honeycomb blade except it wasn't. As far as I know the blades worked fine (the plane simply didn't)
The GE-4 which was designed for the failed SST program used wide-chord titanium compressor blades that were formed this way (it's effectively like glass blowing with hot metal) and it was pretty much as light as if it was a honeycomb blade except it wasn't. As far as I know the blades worked fine (the plane simply didn't)
Turbine D