Questions tagged [fuel-consumption]

The amount of fuel an aircraft burns during a specified time period or for a specified distance; also known as "fuel burn".

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Why cruise at 7000' in an A319?

I was on a flight from Philadelphia (KPHL) to Boston (KBOS), after some delay and some change of route due to weather, the captain announced that we will be cruising at 7000' due to delays in the area....
Brice's user avatar
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24 votes
9 answers
11k views

What is more environmentally friendly? An A320 or a car?

Presuming the A320 is at least 80% full (of passengers) and comparing it to a typical road car with 2 people inside, which one is more environmentally friendly, per passenger mile? I have attempted ...
Cloud's user avatar
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21 votes
2 answers
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Has a plane ever run out of fuel while taxiing?

When planning a flight, the pilots calculate the fuel load, allowing for diversions, delays, etc. While listening to an ATC recording of 30 minute taxi times at JFK, I wondered whether a plane has ...
Roger Lipscombe's user avatar
19 votes
1 answer
6k views

Why is the 777 fuel burn rate graph U shaped and skewed to the left?

I don't know math or physics. If I misuse terms, just edit my post, thanks! Presuppose a normal uneventful flight, such that as the plane climbs and cruises, the pilot reduces engine thrust to 69%-...
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18 votes
5 answers
5k views

Would an airliner climb higher late in the flight because of the consumed fuel (lighter airplane) to save more fuel?

Some people said airplanes would fly higher in the late period of each flight, because the fuel is consumed, and the airplane is lighter. Higher altitude and less dense air is enough to support the ...
Westack's user avatar
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18 votes
1 answer
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Why would a B-29 consume more fuel at 17 kft than at 9 kft?

According to Wikipedia, one of the factors which almost caused B-29 44-27297 (Bockscar) to run out of fuel and crash at the end of its 9 August 1945 strike mission was the selection of an excessively ...
Vikki's user avatar
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17 votes
5 answers
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Has there been any attempt to use an underground cable system, a la a cable car, to tow aircraft along taxiways? [duplicate]

I've been looking at some proposals to try to reduce the time that an airliner's main engines are run at idle or near idle when taxiing to and from runways--a situation that uses non-trivial amounts ...
lapsedwondering's user avatar
17 votes
3 answers
3k views

Can the plane Celera 500L be eight times more fuel efficient than a jet of similar size and capacity?

Celera 500L (see Otto Aviation site for more details) is a plane with a single propeller powered by a piston diesel engine. The constructor claims it is 8 times more fuel efficient than a jet of about ...
Robert Werner's user avatar
15 votes
2 answers
4k views

Does flying slower actually save fuel?

Following a discussion on travel.SE, I wonder: would flying more slowly actually save fuel? I suppose that it would save fuel on a volume of fuel per flight hour basis, but the flight would end up ...
jcaron's user avatar
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12 votes
10 answers
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What is the most 'environmentally friendly' way to learn to fly?

As this question indicates, I've been thinking recently about the environmental impact of flying (since when automated cars are the only means of ground transport, aviation will be responsible for ...
Cloud's user avatar
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12 votes
4 answers
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Which engine is more financially economical to operate, a turboprop or gasoline engine?

I've seen a discussion about this somewhere before. I'm aware that there's no real way to calculate this. So rather then comparing weight and volume for efficiency, let's compare prices. Which engine ...
Mateo's user avatar
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12 votes
2 answers
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How much fuel is burned to carry the trip fuel?

For rockets, there is a rule of thumb that says for each kilo of fuel put into orbit, 7 kilos is needed to get it there. For long and ultra-long flights, it feels intuitive that some very significant ...
Simon's user avatar
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9 votes
2 answers
3k views

What is the operating temperature of a turbofan engine, and how is it kept at that temperature?

What is the operating temperature of a turbofan engine? If advancements were made to materials through material science for the internal components would increasing the operating temperature result in ...
securitydude5's user avatar
9 votes
1 answer
939 views

What is the function of the aft stator in CFM's open rotor engine design?

CFM revealed their design for a open rotor propfan engine with two stages of blades - one active set of blades rotating in the forward and an static sets of blades on the aft. According to The ...
karthikeyan's user avatar
8 votes
2 answers
3k views

Which aircraft has the best fuel mileage per person?

I was looking at a BD-5 that got 32 miles to the gallon for one person and wonder: Which plane gets the most fuel mileage if you divide the number of passengers against the mileage of the plane? ...
Justintimeforfun's user avatar
8 votes
3 answers
689 views

Is it possible for a plane to be over fueled (and over-weight) to take off?

I've just reached my destination after 33 hours going from one European hub to another. A journey which usually takes a max of 6 from leaving my house! On the final leg of the journey, after boarding,...
Phil Shackleton's user avatar
8 votes
2 answers
371 views

Can quadcopters save energy by flying in formation?

If two or more quadcopters are aligned, would the effect of drag due to the lead quadcopter's slipstream lead to measurable energy savings? And if so, how would one determine the optimal distance ...
GreenIris's user avatar
7 votes
2 answers
2k views

What would be the range of a cargo 777 full of usable fuel up to MTOW?

Having read about Rutan's Voyager and more recently about Virgin Atlantic GlobalFlyer I wondered how would some modern long haul airliner such as a cargo Boeing777 (or other airliner) perform at this ...
user721108's user avatar
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7 votes
2 answers
26k views

How much fuel is used for the different phases of the flight of a typical airliner?

An Airliner flies from LA to JFK in 5 hours. In the first 30 minutes the plane climbs to about 30,000ft. For the next 4 hours the plane flies at about 30,000ft. For the next 30 minutes the plane ...
user28043's user avatar
7 votes
1 answer
633 views

Why is my calculated seat-miles per gallon of small aircraft higher than of big aircraft?

I've calculated the seat-miles per gallon for three planes. This factors in the speed; it basically means how much does it cost to transport 1 person 1 mile. Plane Seats Cruise (MPH) gph seat-mpg ...
Isaiah Taylor's user avatar
6 votes
5 answers
6k views

Does a 120cc engine burn 120cc of fuel a minute?

I have heard that a 120cc engine burns 120cc or 120ml of fuel per minute. Is this true?
Lelotz's user avatar
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6 votes
1 answer
223 views

What are the engine-out implications of giant turbofans?

It seems that turbofans for civil airliners are improving fuel efficiency by building larger and larger fans that spin slower. For example, the RR Trent 800 introduced in 1993 had a diameter of 2.8m, ...
AshleyZ's user avatar
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6 votes
2 answers
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What passenger airplane has the lowest fuel efficiency?

What is the airplane with the lowest fuel efficiency? To set some parameters, let's limit it to the following: Must be manufactured between 1960 and modern day. Must be a non-military passenger ...
M28's user avatar
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6 votes
1 answer
828 views

Does one-engine cruise consume less fuel than two-engine cruise?

Scenario 1. A two-engine airliner experiences rapid depressurization and makes an emergency descent to 10,000 ft, and diverts to the nearest airport. Scenario 2. The same two-engine airliner ...
lemonincider's user avatar
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5 votes
4 answers
717 views

Can longer paths consume less fuel than the (shorter) great circle path?

Is the most fuel-efficient route between points A and B always along a great circle ? Although somewhat counter-intuitive, this comment on an aviation blog seems to suggest that longer paths (in ...
summerrain's user avatar
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5 votes
1 answer
246 views

Why use thrust reversers? [duplicate]

I see a lot of planes using thrust reversers and stopping in the middle of the runway in plane spotting videos, but I don't understand why they do it when they can obviously not use the reversers and ...
Air Canada 001's user avatar
5 votes
1 answer
888 views

What makes the loss of a flap track fairing strongly increase fuel consumption on Airbus planes?

Inspired from this question about the loss of a flap track fairing. In the answer by Thunderstrike, a part of the configuration deviation list of an Airbus A320 is linked. In it, it says: One ...
Noah Krasser's user avatar
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5 votes
2 answers
2k views

What is the most fuel efficient climb speed for a C172 SP?

Assuming ISA, sea level, no wind, max gross weight, what speed would be most fuel efficient per 1,000 ft of climb? Alternatively, if that converges to the most fuel efficient cruise speed, when there'...
GJ.'s user avatar
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4 votes
4 answers
3k views

What difference does altitude make on fuel efficiency? [duplicate]

Most commercial flights are between 29,000 and 42,000 feet in altitude apparently. But I realise I don't know why. My guesses are: If you fly too high the air pressure gets very low and you have to ...
Simd's user avatar
  • 193
4 votes
3 answers
2k views

How much does it cost extra to fly with one additional passenger?

How much does it cost to fly an airplane (like a Boeing or Airbus) when there's one extra passenger there, at an average speed of 475–500 knots (880–926 km/h; 547–575 mph)? That is, about 100kg extra,...
Quora Feans's user avatar
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4 votes
3 answers
3k views

Which is more efficient: a jet engine or a rocket-powered engine?

Knowing that rocket powered engines have higher speeds than jet engines, it raises the question: are jet engines more efficient than rocket powered engines? This is of course in terms of fuel ...
Super's user avatar
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4 votes
2 answers
696 views

What are the standard numbers for fuel consumption (kg), kg/NM, and kg/h, of Boeing 737-300?

I'm currently working on a school project regarding the analysis of Boeing 737-300 fuel consumption. I'm working on some parameters that my supervisor gave me, which are : Total fuel consumption (kg),...
Luthfi Ahmad's user avatar
4 votes
2 answers
2k views

Does endurance include the fuel reserve time?

I have been wondering if endurance time actually includes the fuel reserve time? For example: Total usable FOB = 84 litres Fuel burn rate = 16 litres/hour Aircraft's reserve fuel = 30 minutes ...
Hazim Husni's user avatar
4 votes
1 answer
867 views

Am I calculating the fuel consumption correctly?

I'm trying to calculate the fuel consumption for l550e engine. In its datasheet you can see this graph: At 6500 RPM, engine power is around 48hp and the SFC is 345g/HPh. Ok, then the fuel consumption ...
Roh's user avatar
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4 votes
2 answers
381 views

What is a jet engine's fuel flow at constant IAS?

Here is my assumption: In straight and level flight of a jet turbine engine: One IAS = One drag = One thrust = One fuel flow Therefore, the fuel flow will be approximately the same for a given IAS, ...
Arnaud BUBBLE's user avatar
4 votes
1 answer
380 views

How did the 767/757 reduce fuel burn relative to older aircraft (like the 727)?

When Boeing launched the 757 and 767 aircraft, they widely touted it's improved fuel efficiency relative to previous airliners. Notably: Delta stated that the 767 was "quieter and 30 percent ...
interested22's user avatar
4 votes
2 answers
454 views

How to compare two SFCs, one in thrust, the other in power (both turbofans)?

I want to compare some recent turbofan engines in terms of fuel efficiency, particularly the PW535A and FJ44-4. I found the SFC for the PW535A to be 0.44 lb/h/lbf. I couldn't find anything on the ...
rational-pi's user avatar
3 votes
2 answers
345 views

Does burning fuel to get to your max landing weight violate any regulations?

Consider a hypothetical situation where where an unexpected tailwind will cause a flight to arrive at its destination above maximum landing weight. After reviewing all reasonable changes to altitude ...
ryan1618's user avatar
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3 votes
1 answer
232 views

What would the effect be of flap deployment on a UAV such as the Reaper or Predator?

I've read answers that said that the climb performance is usually worse with flaps extended, and the pilots would, if they could, just retract them and get into a clean config as soon as possible. ...
Sharva Potdar's user avatar
3 votes
3 answers
573 views

How does the power distribution change for a turbofan engine from being stationary to going at full speed?

I have found out that a turbofan engine of say an F-16 is producing zero power when stationary since $Power = Thrust × Velocity$. But assuming that the engine is producing the same thrust, it appears ...
Abanob Ebrahim's user avatar
3 votes
1 answer
720 views

What is the fuel mass flow rate at stationary full power for the CFM56 5C2/3C1 engines?

Does anyone know what is the value of fuel mass flow rate when stationary at full power for CFM56-5C2 or CFM65-3C1 turbofan engines? I am doing a work on engine performance and it seems that only ...
Darjan's user avatar
  • 1,145
3 votes
2 answers
1k views

How does fuel economy quantitatively depend on altitude for a jet?

We already have a few questions and answers about the qualitative effects of altitude on fuel economy: How do I determine the best altitude to fly for fuel economy? Why does fuel consumption decrease ...
Bianfable's user avatar
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3 votes
0 answers
74 views

Are measures taken to deliberately increase the fuel burn rate to lower the landing weight? [duplicate]

Just recently the Air Canada flight AC837 from Madrid to Toronto had problems with the gear right after take-off and they decided to abort the flight and go back to Madrid. It was a B767-300 (C-GHOZ) ...
PerlDuck's user avatar
  • 3,176
2 votes
2 answers
827 views

On SEP airplanes, why does the fuel consumption decreases with temperature, pressure and airspeed being equal?

Looking at the cruise performance tables in the POH of the C150, C172 or C182, one can see that for the same pressure altitude, the same RPM and the same true airspeed, the fuel consumption is reduced ...
RedGlyph's user avatar
  • 123
2 votes
1 answer
677 views

How far could a KC-10 tanker fly if it consumed all of its internal fuel tanks?

I have read that the KC-10 tanker aircraft carries a maximum load of 356,000 lbs of fuel. It also consumes the same fuel that it carries for refueling other aircraft. So naturally, I am wondering: If ...
Neal's user avatar
  • 21
2 votes
1 answer
1k views

Why is the thrust-specific fuel consumption much worse for high bypass turbofans at cruise?

General Electric GE90 Takeoff: 0.278 lb/lbf/h (28.3 kg/kN/h) Cruise: 0.545 lb/lbf/h (55.6 kg/kN/h) Source: https://en.wikipedia.org/wiki/General_Electric_GE90#Specifications I assume this is typical ...
Abdullah is not an Amalekite's user avatar
2 votes
1 answer
3k views

What is the range difference between LEAP and PW1000 powered A320 and A321 NEOs?

Mounted on the same aircraft, PW 1000G and CFM LEAP are two very different engines, with different performances, that should have an impact on range. And we know range is a very important aircraft ...
the world is not flat's user avatar
2 votes
1 answer
1k views

What is the ground idle fuel flow of an A320 (CFM or IAE or neo)?

Standing on ground, what is the idle fuel flow of an A320? ISA conditions, both engines running?
Ulu83's user avatar
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1 vote
2 answers
207 views

What is the 'fuel cost' of a pneumatic braking system vs. a hydraulic one, in terms of weight?

A pneumatic braking system has indisputable advantages over a hydraulic braking system for large and heavy aircraft in terms of braking force and secondary perhaps in terms of weight (pipes and ...
securitydude5's user avatar
1 vote
2 answers
187 views

Was it ever considered to optimise a jet to normally operate with one engine shut off?

As I understand it, the current trend to reduce all commercial aircraft to no more than two turbofans has long-relevant reasons – the more engines, the higher the fuel consumption – and earlier jets ...
leftaroundabout's user avatar