B1C17L1011
Topic Author
Posts: 96
Joined: Fri Jun 29, 2001 12:42 am

The Most Fuel Efficient Aircraft

Sat Sep 22, 2001 2:38 am

What is the most fuel efficient aircraft in terms of widebody's. From what know the tri-jet's like the DC-10, MD-11, & L-1011 are the leaset fuel efficient. Large twin jets like the 777 and A330 are more fuel efficient the the tri's. But some of the quad jets like the A340 are the most fuel efficient because of the fact that they require less thrust to comply with the engine out on take-off regulations. This then raises several important questions.
1. Does the higher initial cost of purchase and higher cost of maintenance of a quad jet over a twin jet offset the fuel savings.
2. Then why are airlines retring some of their quote "fuel inefficient 747-400's"?
3. On a slightly different note. Why is the 767 considered economical for passenger travel? It has the lowest ratio of seat's to internal volume of any widebody. 2-3-2, that is 7 seat's to two isles, opposed to a higher ratio on evey other widebody.
4. Then, what is the most fuel efficient engine number?
5. What is the absolute most fuel efficient aircraft?

I know the airlines will be looking for then during this hard time.


B1C17L1011
 
timz
Posts: 6160
Joined: Fri Sep 17, 1999 7:43 am

RE: The Most Fuel Efficient Aircraft

Sat Sep 22, 2001 4:26 am

Absolute most fuel-efficient aircraft! Now there's a can of worms. Presumably you mean measured by seat-miles (in the cruise) per pound of fuel. As I recall the Quickie (and whatever happened to it?) claimed to get 10 nm per pound, which is quite comparable to the seat-miles-per-pound of a 747. So there's lots of possibilities.
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: The Most Fuel Efficient Aircraft

Sat Sep 22, 2001 5:01 am

Your questions are roughly akin to deciding which type of car is best for you.

What is economical for one airline may not be for another; just as people with better credit can qualify for lower interest rates on their vehicle purchases. A brand new car (a/c) will have lower DOCs, but higher aquisition costs. The opposite is true for older equipment whether it's a car or an a/c.

For most of the 747's life, it has been purchased about half of the time for its range capability and not for its capacity, which has lead to the popularity of the 777.

WRT to the 767, seat configuration is one of thousands of options selected by the airlines, not Boeing. It's all a function of how an airline feels it can best utilize the available payload. And, like a lot of equipment, airliners are roughly priced according to take off weight, so an airline tries to buy what they need, and no more. On a 767 sized a/c, there is roughly a 50,000 lb variation throughout the product line, and up to about 25,000 lbs on a unique model like the 400er. The same with landing weights. I have seen many 727s recertified to land at higher weights simply by doing paperwork and sending a check to Boeing. Airlines buy the lightest a/c that will fit their needs. Are those needs near term? Or do you try to forecast demand in 10 years? One of the reasons NWA bought the A330 over the 777 was simply that the 777 was too much a/c in terms of a DC10 replacement. The 747-200s and 400s were both forecast to be around for a while at the time of that announcement.

As I've said before, the word "efficient" is the most overused term on this forum. It must be defined...How does the airline intend to use the a/c? At a min, one must state the mix of pax and payload over a specified stage length. Is ETOPs a factor for the route structure? If so, ETOPs cert costs big bucks on a twin, while it's not on issue on a 3-4 engine a/c. How about bely cargo and pallets? That's big. If it were simple, then the industry would only have 1 0r 2 airliner types with no sub variations...

BTW - "tris" and "seats" is plural, not possessive.

Cheers-

 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: The Most Fuel Efficient Aircraft

Sat Sep 22, 2001 5:09 am

PS-
You may check topic "Cost of Operation" 7May01 this forum...
 
SSTjumbo
Posts: 2579
Joined: Sun Jun 17, 2001 3:29 am

RE: The Most Fuel Efficient Aircraft

Sat Sep 22, 2001 6:18 am

Timz, forgive me but what exactly is the "Quickie"?
I don't know, so this is my signature.
 
timz
Posts: 6160
Joined: Fri Sep 17, 1999 7:43 am

The Quickie

Sat Sep 22, 2001 7:10 am

A Rutan design from 1980 or so. It started out as an 18 hp (?) single-seater of somewhat bizarre appearance, with a forward wing (?) beneath the fuselage with the landing gear at its tips, and a rear wing above the fuselage behind the cockpit. Dunno if it was the most fuel-efficient single-seater ever built, but I assume efficiency was one of its aims.
 
timz
Posts: 6160
Joined: Fri Sep 17, 1999 7:43 am

More On The Quickie

Sat Sep 22, 2001 7:35 am

It actually appeared in 1978, it seems. Jane's says length 17 ft 4 in, span 16-8, OEW 240 lb, MTOW 480 lb, 18 hp originally, 8 US gallons fuel, max cruise 121 statute mph, economical cruise not given but claims 100 statute miles per gallon.
 
mandala499
Posts: 6460
Joined: Wed Aug 29, 2001 8:47 pm

RE: The Most Fuel Efficient Aircraft

Sat Sep 22, 2001 11:38 pm

a glider pulled to the top by a hot air balloon would be the most fuel efficient !  Smile

Mandala499
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
B1C17L1011
Topic Author
Posts: 96
Joined: Fri Jun 29, 2001 12:42 am

Let Me Re-phrase The Question

Sat Sep 22, 2001 11:59 pm

OK let me rephrase. Assuming that you always fill an aircraft up to capacity, which type will be the most fuel efficient. The large twin such as the 777 or A330 or the quad jet such as the 747 and A340. Taking into account both the higher initial cost of the quad + the fuel savings from it.

PS. Sorry for the previous grammer errors"!:!
 
SSTjumbo
Posts: 2579
Joined: Sun Jun 17, 2001 3:29 am

RE: The Most Fuel Efficient Aircraft

Sun Sep 23, 2001 1:48 pm

Timz: Thanx

Also let me add that number of engines and type of engines don't completely change seat/mile costs. There are a HUGE load of factors that could change it, even with the same engines. Also, certain planes are optimized for certain routes. The A330 is a medium to semi-long range aircraft and the A340 is specifically designed with the long range market in mind. The 777 which lacks winglets is capable of long range flights but can also be optimized for shorter US domestic routes (just not LA-LV Big grin )
I don't know, so this is my signature.
 
lewis
Posts: 3581
Joined: Thu Jul 08, 1999 5:41 am

RE: The Most Fuel Efficient Aircraft

Sun Sep 23, 2001 11:02 pm

I think the 340 is very fuel efficient.
 
Gregg
Posts: 313
Joined: Sun Jun 18, 2000 12:49 pm

RE: The Most Fuel Efficient Aircraft

Mon Sep 24, 2001 5:26 am

On a per seat mile, the 747-400 in all charter layout. I think the 777 and A330 is more fuel effiecient per seat mile then the A340.
 
timz
Posts: 6160
Joined: Fri Sep 17, 1999 7:43 am

RE: The Most Fuel Efficient Aircraft

Mon Sep 24, 2001 10:44 am

A long-range aircraft like the 747-400 or A340 is always at a disadvantage when you're comparing seat-miles per kg/pound of fuel; on a long trip it's carrying all that extra fuel, and on a short trip it's still carrying the extra metal that it needs to be able to carry the fuel for a long trip. I suspect an A330-300 (and maybe an A300-600) will get more seat-miles per pound than any four-engine aircraft-- but I'm no expert.
 
EssentialPowr
Posts: 1646
Joined: Wed Sep 06, 2000 10:30 pm

RE: The Most Fuel Efficient Aircraft

Mon Sep 24, 2001 12:52 pm

"Tris and seats are (not is) plural, not possessive."

Whoops...good thing this isn't the Eng grammar forum...
 
srbmod
Posts: 15446
Joined: Tue Mar 20, 2001 1:32 pm

RE: The Most Fuel Efficient Aircraft

Mon Sep 24, 2001 4:30 pm

The 717 definitely could be termed a very fuel efficient aircraft. Original fuel savings estimates compared to the DC-9-32, were of between 5-9% more fuel efficent than the DC-9-32, after being put into service, it has turned out to be more between 17-23%, now that's fuel efficient.
 
cobra27
Posts: 939
Joined: Wed May 23, 2001 6:57 pm

RE: The Most Fuel Efficient Aircraft

Tue Sep 25, 2001 2:46 am

FOLK
Just answer the question!
Tell me how much liteers booste engine per second!
Don't discuss about horse races here

thanks

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