Ejaymd11 From United States of America, joined Feb 2001, 193 posts, RR: 0 Posted (11 years 7 months 4 days 11 hours ago) and read 6255 times:
The numbers are for the standard version.
Under these conditions fuel burn for the MD-11 standard version is as follows.
T/O weight max (602,500)
Range 4,500 (I used the range chart I found on Boeing)
Flight time would be 9:25:48
Burn 27,435.9 ponds per hour
I used a flight calculator to get the TAS, flight time, and FPH. I know the MD-11's cruise Mach is around Mach .83 but I was told I should even the playing field.
Under these conditions fuel burn for the 777-200 standard version is as follows.
T/O weight max (545,000)
Range 3,300 nm (I used the range chart I found on Boeing)
Flight time would be 6:54:55
Burn 30,034.9 ponds per hour
I used a flight calculator to get the TAS, flight time, and FPH.
Are my numbers correct if not let me know where I messed up.
Ejaymd11 From United States of America, joined Feb 2001, 193 posts, RR: 0 Reply 6, posted (11 years 7 months 4 days 4 hours ago) and read 5833 times:
Okay you wish the 777-200 burned 12,000 ponds an hour. My info comes from Boeing check it out. The take off weight of the standard MD-11 is 602,500 lbs. One more thing before you say the info do your research and tell me why my numbers are wrong.
LMP737 From , joined Dec 1969, posts, RR: Reply 9, posted (11 years 7 months 3 days 23 hours ago) and read 5713 times:
I'll be the first to say that the MD-11 is a fine looking aircraft. I know, I worked on it a little while with Boeing. However, it's kind of a moot point comparing the fuel burn of the MD-11 to the 777. We all know which one was successful in the market place and which one was not.
If you look at the chart on the MD-11 you will also notice the disclaimer "Not To Be Used For Flight Planning Purposes". The only way to get an accurate idea of fuel burn is to look at the flight test data. Boeing is not in the habit of making it's flight test data public however.
For the sake of argument lets say the MD-11 has a better fuel burn than the 777. While fuel burn is important there are other factors to consider. Such as, which airplane can carry the most passengers the farthest. The 777 is the winner in this area. Maintenance is another important area. Two engines are cheaper to maintain in terms of manpower and material (spare parts) than three. It is also less time consuming (time is $$$$$$ in the airline industry). You have a problem with the number two on a 777 you pop open the cowling or TR and take a look. On the MD-11 you have to crawl up the tail compartment, open the patio and THEN open the engine.
Tsentsan From Singapore, joined Jan 2002, 2016 posts, RR: 16 Reply 10, posted (11 years 7 months 3 days 21 hours ago) and read 5661 times:
From what I've witnessed and heard from both fuel loaders and pilots, the 777 burns about 8-9 tons an hour at MTOW, and as it gets lighter, about 6.5-7.5 tons an hr.
I've heard a fuel load for a SIN-AMS 777 being 110tons of fuel. Considering that journey is about 13 hours, that gives a fuel consumption of 8.46tons (18600 lbs per hr) if all the fuel was used, bearing in mind that these long haul jets dont get high altitudes until about 1/2 way through the journey.
From what I've read and heard, the Md-11 is a good a/c but apparently the range was a problem in the first few production models so thats why it wasnt tooo popular initially. I'm no expert in MD-11/777 characteristics, but its just what I've heard in life.
Timz From United States of America, joined Sep 1999, 6634 posts, RR: 7 Reply 12, posted (11 years 7 months 3 days 17 hours ago) and read 5608 times:
Okay, Ejaymd11, look again at the Boeing graph for the 777. You got a range of 3300 nm at MTOW 545,000 lb-- but that's at a zero-fuel weight of 420,000 lb. So the 777 is supposed to do 3300 nm on 125,000 lb (including reserves) instead of the 207,700 lb you apparently assumed.
By the way: why did you assume temp -30? And where did you assume that, anyway?
At any rate though, we know who won the battle. Besides, whether or not an aircraft is successful (if that is what you're trying to get at) is not totally dependent on fuel consumption. It is other factors like seat cost per mile, cargo/pax capacity, mx costs, reliability of dispatch etc....
Just my two cents worth.
is that a light at the end of the tunnel or just a train?
Ejaymd11 From United States of America, joined Feb 2001, 193 posts, RR: 0 Reply 16, posted (11 years 7 months 3 days 13 hours ago) and read 5498 times:
Timz I just picked -30 degrees, my flight instructor said to subtract 2 degrees every thousand feet from sea level from the standard temp of 15 degrees Celsius but the number I thought the number was too low, also the zero fuel weight includes payload but if you look at the end of the chart is says 31,000 US gallons. If that is wrong let me know. Thanks for you response.
Delta737 A 777 would burn more fuel than a 737-200, is it 10 times more I don't know.
Ben88 I'm not telling you how much a 777-200 burns I'm showing you what I got from the info I gathered, I didn't hear you explaining why my info is wrong.
Thanks I got some major points from a lot of you, that is the type of response I was looking for. One more thing I not trying to offend anyone, just trying to receive, and make a point.
Timz From United States of America, joined Sep 1999, 6634 posts, RR: 7 Reply 18, posted (11 years 7 months 2 days 15 hours ago) and read 5343 times:
...say the MD11 with a zero-fuel weight of 400,000 lb can make a 5100+ nm trip (at MTOW of 618,000 lb). So, with a payload of 112,400 lb they need 218,000 lb of fuel including reserves. The baseline 777 carries a payload of about 120,000 lb; the 3300-nm trip calls for 125,000 lb of fuel including reserves.
The "31,000 US gallons" refers to the tail-end of the graph (beyond 6500 nm), which is the only part that assumes full fuel.
I still don't see where the temperature got into your calculation, but standard temperature is -50 degrees Celsius at 10 km altitude.
Areopagus From United States of America, joined Sep 2001, 1364 posts, RR: 1 Reply 19, posted (11 years 7 months 2 days 13 hours ago) and read 5312 times:
ATC requirements. KL/BKK Atc only gives FL280 for SIN-Europe flights.
OK, thanks for the clarification, Tsentsan. I am a little puzzled, though. I thought I read that SQ selected the 777 for its ability to get to full cruising altitude before entering KL/BKK airspace, and they would let it stay there. I guess I missed something.
Ejaymd11 From United States of America, joined Feb 2001, 193 posts, RR: 0 Reply 21, posted (11 years 7 months 1 day 4 hours ago) and read 5217 times:
Timz Read my response, I said I just chose that number. I've figured outwhere I went wrong, the MD-11 or the 777-200 canot take-off with full payload and full fuel, it excedes MTOW. So when I get the new numbers I'll post them.
Konstantinos From Greece, joined Jun 2001, 389 posts, RR: 0 Reply 22, posted (11 years 7 months 12 hours ago) and read 5155 times:
MD-11's and 777, they are the same to me.
A 777 is an MD-11 without the 3rd engine and winglets.
Even if the MD11 was more fuel efficient than the 777, do you think
that Boeing would let you now this? How do we know that the
777 was not developed from the MD11 and how do we know
that Douglas's next aircraft wasn't going to be a 777 type?