EA772LR From United States of America, joined Mar 2007, 2836 posts, RR: 11 Posted (2 years 3 months 2 weeks 2 days 1 hour ago) and read 6657 times:
Does anyone on here have SFC differences between the CF6-80C2B6 (60,800lbs*) the PW4060 (60,000lbs*) and the newer generation Trent 560 (60,000lbs*)?? I was wondering because they're all in the same thrust class but are from difference generations.
CF6-80C2B6:
PW4060:
Trent560:
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njxc500 From United States of America, joined Dec 2007, 185 posts, RR: 0 Reply 2, posted (2 years 3 months 2 weeks 1 day 20 hours ago) and read 6619 times:
tdscanuck From Canada, joined Jan 2006, 11032 posts, RR: 72 Reply 3, posted (2 years 3 months 2 weeks 1 day 16 hours ago) and read 6587 times:
Quoting EA772LR (Thread starter): Does anyone on here have SFC differences between the CF6-80C2B6 (60,800lbs*) the PW4060 (60,000lbs*) and the newer generation Trent 560 (60,000lbs*)??
I don't have a copy at hand, but if you can find Aviation Week's Sourcebook (any recent year), there's a gas turbine table that has this data.
tdscanuck From Canada, joined Jan 2006, 11032 posts, RR: 72 Reply 4, posted (2 years 3 months 2 weeks 1 day ago) and read 6497 times:
Quoting EA772LR (Thread starter): Does anyone on here have SFC differences between the CF6-80C2B6 (60,800lbs*) the PW4060 (60,000lbs*) and the newer generation Trent 560 (60,000lbs*)??
tdscanuck From Canada, joined Jan 2006, 11032 posts, RR: 72 Reply 8, posted (2 years 3 months 2 weeks 12 hours ago) and read 6406 times:
Quoting trex8 (Reply 6): wouldn't you expect TO thrust to burn more fuel than cruise????
It does. Takeoff fuel flow is way higher than cruise. But SFC is normalized by thrust ("S" = Specific), so it's lbs fuel per hour *per pound of thrust*. At takeoff, the engine is operating at its highest pressure ratio, and the efficiency of gas turbines goes up with increasing pressure ratio.
thegeek From Australia, joined Nov 2007, 2163 posts, RR: 0 Reply 9, posted (2 years 3 months 2 weeks 11 hours ago) and read 6391 times:
Quoting tdscanuck (Reply 8): It does. Takeoff fuel flow is way higher than cruise. But SFC is normalized by thrust ("S" = Specific), so it's lbs fuel per hour *per pound of thrust*. At takeoff, the engine is operating at its highest pressure ratio, and the efficiency of gas turbines goes up with increasing pressure ratio.
I thought the highest pressure ratio was achieved at top of climb, where the cool air would allow a higher fuel/air ratio.
brons2 From United States of America, joined Sep 2001, 2927 posts, RR: 5 Reply 10, posted (2 years 3 months 2 weeks 9 hours ago) and read 6374 times:
Quoting cobra27 (Reply 5): The CF6 I think is the least popular engine choice. PW4000 is the only big PW engine that sells
Depends on what platform you are talking about. The CF6 was popular on the 747 and 767, not so much on the A330. It is not offered on the 777.
The Trent 560 is available only on the A340NG and is the only engine available for that development. The Trent 700 is only on the A330 and is the market leader for that aircraft. The RB211-524 was on the 747 and 767. The Trent 800 is on the 777.
The PW4000 is popular on the 747, 767 and A330. Not so much on the 777, for which it has a bigger fan.
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EA772LR From United States of America, joined Mar 2007, 2836 posts, RR: 11 Reply 11, posted (2 years 3 months 1 week 6 days 21 hours ago) and read 6314 times:
tdscanuck From Canada, joined Jan 2006, 11032 posts, RR: 72 Reply 12, posted (2 years 3 months 1 week 6 days 16 hours ago) and read 6278 times:
Quoting thegeek (Reply 9): I thought the highest pressure ratio was achieved at top of climb, where the cool air would allow a higher fuel/air ratio.
Higher fuel/air ratio should allow a higher temperature ratio, but unless you actually spin the compressor faster you shouldn't get a higher pressure ratio. I'm not sure about all of them, but I've never seen an engine with top-of-climb N1 higher than takeoff N1.
cobra27 From Slovenia, joined May 2001, 934 posts, RR: 0 Reply 13, posted (2 years 3 months 1 week 5 days 9 hours ago) and read 6179 times:
Pressure output from compressor is relativetly easier to achieve technology. But in order to increase efficiency at the same time you have to increase the inlet temperature of the turbine, which is a limiting factor
747classic From Netherlands, joined Aug 2009, 1481 posts, RR: 6 Reply 14, posted (2 years 3 months 1 week 5 days 6 hours ago) and read 6168 times:
IMO, you are comparing two engines from the same generation (GE and PW) with one engine from a later generation(RR).
GE-CF6-80C2B6 is a turbo fan engine with conventional fuel control (MEC) and PMC supervisory, certificated in Feb 1987
SFC (CRZ) approx 0.607-0606, later that year improved with fadec (0.605)
PW 4060 is a fadec controlled engine, certificated in June 1987 from the same generation as the CF6-80C2
SFC (CRZ) approx 0.606-0.605
The RB-211-524G/H is also developed in the same time frame.
All were very competitive, but RR had a higher OEW.
RR RB211 Trent 560-61 is a later generation engine, certificated in may 1998, however an improved version is already certificated in January 2003, the RB211 Trent 560A2-61.
It's very difficult to get reliable SFC quotes about current engines. And all three manufacturers are continuously improving their engines by installing new technologies.
The best way to compare them is to look at the payload/range diagrams from aircraft with engines from different manufactures installed.
Example : B767-300ER is available with GE CF6-80C2B series and PW 4000 series engines.
Look at the Boeing website for detailed technical Characteristics for the 767-300ER and compare both diagrams for the relevant engines. http://www.boeing.com/commercial/airports/767.htm
choose : 3.0 airplane performance
scroll to 3.2 payload range
compare different airplane - engine combinations.
A better comparisson between 3 engine generations from different manufactures would be between :
PW JT9D-7R4 series (H1 56.000 lbs)
GE CF6-80C2B(F) series (4F 57.280 lbs)
RR Trent RB211-500A2-61 series (553 55.780 lbs)
Zeke From Hong Kong, joined Dec 2006, 6800 posts, RR: 74 Reply 15, posted (2 years 3 months 1 week 3 days 15 hours ago) and read 6075 times:
Quoting EA772LR (Thread starter): Does anyone on here have SFC differences between the CF6-80C2B6 (60,800lbs*) the PW4060 (60,000lbs*) and the newer generation Trent 560 (60,000lbs*)?? I was wondering because they're all in the same thrust class but are from difference generations.
Quoting tdscanuck (Reply 4): Unfortunately, RR doesn't provide their takeoff power SFC to allow an apples-to-apples comparison.
Considering most of the time aircraft are in the cruise, comparisons are normally made with cruise, not takeoff TSFC.
Quoting tdscanuck (Reply 8):
It does. Takeoff fuel flow is way higher than cruise. But SFC is normalized by thrust ("S" = Specific), so it's lbs fuel per hour *per pound of thrust*. At takeoff, the engine is operating at its highest pressure ratio, and the efficiency of gas turbines goes up with increasing pressure ratio.
SFC is normally applied to engines with propellers, TSFC is normally applied to turbojet/turbofan engines.
Quoting brons2 (Reply 10):
The Trent 560 is available only on the A340NG and is the only engine available for that development. The Trent 700 is only on the A330 and is the market leader for that aircraft. The RB211-524 was on the 747 and 767. The Trent 800 is on the 777.
RR also looked at putting the Trent 500 onto the 744NGa few years back.
tdscanuck From Canada, joined Jan 2006, 11032 posts, RR: 72 Reply 16, posted (2 years 3 months 1 week 2 days 17 hours ago) and read 5992 times:
Quoting Zeke (Reply 15): Quoting tdscanuck (Reply 4):
Unfortunately, RR doesn't provide their takeoff power SFC to allow an apples-to-apples comparison.
Considering most of the time aircraft are in the cruise, comparisons are normally made with cruise, not takeoff TSFC.
True, but it's easier to find one missing number for RR (takeoff TSFC) than to find two missing numbers for PW & GE (cruise TSFC). Either one would give you a valid comparison, albeit for different operating conditions.
ea772lr From United States of America, joined Mar 2007, 2836 posts, RR: 11 Reply 17, posted (2 years 3 months 1 week 1 day 22 hours ago) and read 5927 times:
Quoting 747classic (Reply 14): IMO, you are comparing two engines from the same generation (GE and PW) with one engine from a later generation(RR).
Sorry, bad wording on my part. I knew that the PW4000/CF6-80C2 are from the same vintage, but that the RR Trent 500 was newer tech.
Quoting Zeke (Reply 15): I have covered a similar line of enquiry in this thread 767 RR Vs PW/GE Fuel Burn
I know which is what got me wondering about the PW4060/GE CF6-80C2 vs. the Trent 500. About how much more efficient is the Trent 500 over the PW/GE above?
We often judge others by their actions, but ourselves by our intentions.
747classic From Netherlands, joined Aug 2009, 1481 posts, RR: 6 Reply 18, posted (2 years 3 months 1 week 1 day 20 hours ago) and read 5914 times:
Quoting ea772lr (Reply 17): I know which is what got me wondering about the PW4060/GE CF6-80C2 vs. the Trent 500. About how much more efficient is the Trent 500 over the PW/GE above?
Advantage in TSFC of Trent 500 is caused by :
- increased bypass ratio, using fan size of Trent 700, with a scaled down Trent 800 core engine. Optimized for long range aircraft.
- more advanced fan blades, diffusion bonded/superplastically formed (DB/SPF) wide-chord fan with less fan blades.
- 3D designed advanced aerofoils
- latest-generation single crystal high-pressure turbine blades for higher operating temperatures or longer engine life.
After installation also the lower engine weight gives an additional payload/range advantage.
You have to use the formula R = U/g / TSFC x (L/D) ln(mi/me) assuming that L/D is takeoff weight *gravity / cruise thrust
have fun
Jam
I'll leave you to spot some (deliberate?) data entry errors e.g. where L/D changes significantly for same wing! Also TSFC very different for same engine
EA772LR From United States of America, joined Mar 2007, 2836 posts, RR: 11 Reply 20, posted (2 years 2 months 3 weeks 2 days 1 hour ago) and read 5557 times:
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