Fuel tanks on an airplane. Where are they? Design. Aircraft fuel: what it is and where to buy it

From the moment the first aircraft was created to the present day, at least ten thousand various models airliners, whether military or civil aviation. Constantly emerging questions and progressive improvements are embodied in new elegant designs and patterns, which in a few years occupy their niche in the modern air fleet.

One of the most important tasks of the aircraft industry is the fuel consumption of an aircraft, because the higher it is, the more unprofitable the car is, which is directly opposite to any market progress. So what is the fuel consumption of an airliner, and what is it different aircraft?

At the moment, there are three technical indicators of this aircraft parameter:

Hourly fuel consumption;
Kilometer fuel consumption;
Specific fuel consumption.

Hourly fuel consumption is the amount of fuel used in one hour of flight. This calculation is always taken without exception when cruising speed and the maximum payload of the airliner and is calculated in the unit - kg / h.

Cruise speed is the speed at which all passenger traffic is carried out. It is approximately 60-80% of the maximum due to safety and additional weight.

The maximum payload is the maximum allowable weight of passengers, baggage, equipment and other cargo on board the aircraft.

On average, it is from 1 to 15 thousand kg per hour.

Kilometer fuel consumption

Kilometer fuel consumption is the amount of fuel used per kilometer of flight. It is calculated in the same way as for hourly - at cruising speed and at maximum payload.

It should be noted that for freight and passenger traffic it is much more logical to apply this particular calculation, since the main goal of such a flight is to deliver the cargo to the required distance at the lowest fuel consumption, and not to stay in the air as long as possible, however, in technical specifications the sentinel was fixed.

Calculated in kg/km.

Specific fuel consumption

Specific fuel consumption is the amount of fuel consumed per unit of time or distance, relative to power or thrust. aircraft provided by one or another engine, etc.

There are several different units of calculation, depending on the choice of parameters:

Mass or volume of fuel - gram, kilogram or liter (g, kg or l);
Travel time or distance - an hour or a kilometer (h or km);
Engine power or thrust - horsepower or kilogram-force (hp or kgf).

The result is, for example, g (hp h) or kg (kgf h).

In civil aviation, another calculation has also become entrenched - the weight of fuel consumed per kilometer of the way to the total number of passengers on the plane. Its unit of calculation is g/pass-km (grams per passenger-kilometre).

This metric works closely with fuel efficiency to help you determine the most cost-effective airliner to carry a given number of passengers while using the least amount of fuel.

What determines fuel consumption

The fuel consumption of an aircraft depends on several factors:

cruising speed;
The mass of the aircraft;
Commercial download;
weather conditions;
Type and number of engines (screw, jet or combined);
Airliner structures;
And another.

List of aircraft models and their fuel consumption

An-2: specific fuel consumption - 42 g / pass.-km, hourly fuel consumption - 0.131 thousand kg / h;
An-140-100: 24.4 g/pass.-km, 0.55 thousand kg/h;
An-38-100: 43.7 g / pass.-km, 0.38 thousand kg / h;
An-24: 36.0 g / pass.-km, 0.86 thousand kg / h;
IL-86: 34.5 g / pass.-km, 10.4 thousand kg / h;
IL-96-300: 26.4 g/pass.-km, 7.8 thousand kg/h;
IL-114-100: 20.8 g/pass.-km, 0.59 thousand kg/h;
Yak-40: 79.4 g / pass.-km, 1.241 thousand kg / h;
Yak-42D: 35.0 g / pass.-km, 3.1 thousand kg / h;
Tu-104B: 75 g / pass.-km, 6 thousand kg / h;
Tu-134A: 45.0 g / pass.-km, 3.2 thousand kg / h;
Tu-154M: 31.0 g/pass. km, 5.3 thousand kg / h;
Tu-204-300: 27.0 g/pass.-km, 3.25 thousand kg/h;
Tu-214: 19.0 g/pass.-km, 3.7 thousand kg/h;
Tu-334: 23.4 g/pass.-km, 1.7 thousand kg/h;
Tu-144S: 230.0 g / pass.-km, 39 thousand kg / h;
Boeing 707-320: hourly fuel consumption - up to 7.2 thousand kg / h;
Boeing 717-200: 2.2 thousand kg/h;
Boeing 727-200: 4.3 thousand kg/h;
Boeing 737-300: fuel efficiency - 22.5 g / pass.-km, hourly fuel consumption - 2.4 thousand kg / h;
Boeing 737-400: 20.9 g/pass.-km, 2.6 thousand kg/h;
Boeing 747-300: 22.4 g/pass.-km, 11.3 thousand kg/h;
Boeing 757-200: 23.4 g/pass.-km; 3.25 thousand kg / h;
McDonnell Douglas MD-83: hourly fuel consumption - 3.1 thousand kg / h;
McDonnell Douglas MD-90: 2.65 thousand kg / h;
Airbus A320-200: fuel efficiency - 19.1 g / pass.-km, hourly fuel consumption - 2.5 thousand kg / h;
Airbus A321-100: - 23.2 g / pass.-km, 2.885 thousand kg / h;
Airbus A380: specific fuel consumption - 2.9 per passenger and 100 km of travel, hourly fuel consumption - up to 13 thousand kg / h;
Fokker 50: hourly fuel consumption - 0.64 thousand kg / h;
Embraer EMB-120ER: fuel efficiency - 27.6 g / pass.-km, hourly fuel consumption - 0.39 thousand kg;
Bombardier CRJ 200: 35.9 g/pass.-km, 1.1 thousand kg/h;
Sukhoi Superjet 100: fuel consumption per hour - 1.7 thousand kg / h;
MS-21-300: specific fuel consumption -15.1 g/pass.km;
MS-21-400: 15.1 g/pass.km;
Concorde: hourly fuel consumption - 20.5 thousand kg / h;
Avro Canada C102: specific fuel consumption - 109 g / pass.-km, hourly 2.7 thousand kg / h;
Vickers Vanguard: hourly fuel consumption - 2.1 thousand kg / h;
Bristol Britannia 314: 2.2 thousand kg / h;
De Havilland Comet 4B: 5.2 thousand kg / h;
Breguet 941: 1.2 thousand kg / h;
Hawker-Siddeley Trident 3B: 4.65 thousand kg / h;
BAC One-Eleven 475: 2.3 thousand kg / h;
Sud-Aviation Caravelle 11R: 2.6 thousand kg / h;
Dassault Mercure: 2.8 thousand kg / h;
Convair 990A: 5.8 thousand kg/h.

How to calculate the amount of fuel for a flight

The amount of fuel that is filled into an airliner before takeoff is calculated using special formulas that are accessible to a narrow specialized circle of people and differ depending on the model of the aircraft.

However, there is an approximate calculation that consists of the following terms:

The mass of fuel required to fly from point A to point B at a certain payload.
The amount of fuel that will be expended in flying from point B to the outermost aerodrome indicated as an alternate in the flight plan.
The amount of fuel that would be used if the aircraft made two additional circle on landing.
And 5% of the total amount of fuel calculated in the previous paragraphs as a reserve.

This video shows fuel dumping during flight. This procedure is practiced by some models of airliners when emergency situations or before landing (much less often).

Conclusion

In conclusion, several main conclusions can be drawn:

Aircraft fuel consumption is one of the oldest and most urgent problems in aircraft design.
There are three main characteristics of fuel efficiency: hourly, kilometer and specific consumption fuel. Each of them participates in their calculations and helps to choose the most advantageous option in certain conditions (technical, weather, loading, etc.).
Fuel consumption is also not an exact value, it depends on external and internal factors (flight conditions, payload, cruising speed, etc.).
At different models Airliners and specific, and hourly fuel consumption varies in a fairly wide range (hourly from 1 thousand kg per hour to 11 thousand kg for subsonic, up to 40 thousand kg for supersonic).
The amount of fuel that needs to be refueled on an aircraft before departure is calculated using formulas that are specific to different models. The most approximate of them summarizes the fuel consumption for a flight up to end point, to the farthest alternate airport, two additional laps before landing and another 5% of the resulting amount in reserve.

What fuel is used for aircraft? What, one might say, feed these flying machines? How to choose it? First of all, any aircraft fuel must be of high quality. The operation of the aircraft directly depends on this. As for the types of fuel, there are several.

One of them is gasoline for aircraft. It has little to do with motor gasoline. Completely different requirements and standards apply to it. The reason for this is simple: from bad gasoline, the car simply may not start. But the plane is likely to fall.

There are a number of brands of aviation gasoline. One of the most common of them is B-92/B-91. The main part of jet and passenger aircraft is sent to fly on kerosene. There are several types of it, but we will not dwell on them.

Answers to the most common questions

Piston aircraft (those with a propeller) fly on aviation gasoline. The car on it, theoretically, will go, but not as fast as we would like. What jet planes fly on has already been said. How fast can a car run on this fuel? At a speed of 0 km / h, that is, it will not go at all. There is only one exception - if you screw the engine from jet aircraft to the car. This is possible in fact, a similar experiment has already been carried out. The author and performer of this experiment received the Darwin Prize. But this is, of course, the exception rather than the rule.

How is gasoline obtained?

This fuel is obtained from crude oil. Oil is a black liquid known to most people, which is extracted from the bowels of the earth. What is in this liquid? Oil contains hydrocarbons, carbon atoms are connected in chains of different sizes and lengths. As a result of these compounds, various substances are formed.

Why do most planes fly on kerosene?

Why do most planes use kerosene to fuel them? Again, there are several reasons for this:

More low price. It is much cheaper than gasoline. Kerosene tends to burn smoothly, if I may say so about this process.

What is important to us in cars? It doesn't matter if they are trucks or cars. It is important that there is the possibility of a sharp switch of the engine, speeds. What is the aircraft designed for? To start it slowly enough, and long time keep the turbines moving at a predetermined speed. Of course, when it comes to passenger aircraft. If we talk about light-engine aviation, then it is mainly intended for the transportation of really huge cargoes. Gasoline is suitable for this type of aircraft. It is perfect for the type of turbines that are used in light aircraft. The most important question - from whom to buy fuel for aircraft? So much depends on its quality ... The best option will purchase this fuel from us. We are responsible for quality.

Imagine that sitting in the center of the Tu-154M cabin, under you there is at least 3 tons, or even all 8 tons of kerosene. It looks something like this:

Can you imagine 8 tons of kerosene? I agree, it's difficult. I assure you that much more is placed in the wings of the aircraft than in the center section, under the passenger seats. Moreover, there is fuel in the plane Always, merges completely only in cases of special maintenance. On the Tu-154M with installed engines, it is generally forbidden to drain all the fuel, otherwise it will sit on its tail. It happens, photo below;).

Shall we refuel?

The story in this article will focus on the fuel in the aircraft. Lots and lots of detail ;)

The cost of kerosene today varies from 17 to 35 thousand rubles per ton. A simple Google search yields the following sites:
http://www.riccom.ru/sale_market_r_np_12.htm
http://distoplivo.ru/prais/
There you will figure it out without me =).

At Pulkovo, we refuel two grades of aviation kerosene, which are considered interchangeable and can be mixed in any proportions: TS-1 and RT. Jet Fuel A, Jet Fuel A-1 (freezing point -47°C) and something else are refueled abroad. You can also pour and mix in any proportions. The main thing is what is written in the documentation for the aircraft. If the crew meets some unfamiliar brand, you need to consult with the base.

In winter, an additive is added to kerosene, liquid "I" so that it does not freeze at more than low temperatures(for -60°C exactly). They add quite a bit, 0.05% of everything. Another liquid "I" Prevents thickening and waxing of diesel fuel at low temperatures. prevents icing of the fuel filter. Promotes complete combustion of fuel. Removes water from the fuel system. Increases torque. Provides easy start of the engine in a frost.
http://www.masla.su/?Produkciya:Tehnicheskie_%0Azhidkosti

They say that pure kerosene can be drunk, and it helps to cure diseases (blood, gastrointestinal tract, genitourinary system). BUT! You can't drink kerosene with liquid "I"!. I don’t know why or how, but the only thing I ask is that you don’t try to ask familiar technicians or pilots to pour a jar of kerosene in winter, spring or autumn. It may contain this dangerous additive. What exactly is dangerous, I do not know, but it's better not to risk it.

So, most of the fuel tanks are caisson tanks. This means that kerosene is simply poured into the wing cavity, there are no special containers, everything is located in a sealed compartment of the structure.

Let's see, where is the fuel stored and how is the fuel used on board? On different aircraft, the tanks are located differently, but in general the trend is the same - three tanks (the central one, which is also consumable, fuel is taken from it to the engines, and wing tanks).

Let's see A-320:

Boeing 737 Classic (the most popular type of 737s in Russia, manufactured in the 90s).

Well, now the highlight of the Tu-154M number:

At the "fifty kopecks" the tanks are arranged quite cunningly. The supply tank is called: "First", and is located in the middle, behind. The fourth tank is filled first and is very often used to maintain alignment.

What is a storage tank? This fuel tank, from which the fuel goes directly to the consumers-engines. From all other tanks, the fuel is pumped into the consumable and only then sent to the engines.

On some aircraft (for example, the A330, in my opinion, it is also allowed to use it on the latest modifications of the Tu-204) there is an additional tail fuel tank to adjust the balance of the aircraft in flight. They can be located both in the keel (Tu-204) and in stabilizers (A330).

Any tank must communicate with the atmosphere, in other words, be "leaky". For what? Try drinking Duchess (Coca-Cola, whatever you like) from a glass bottle without taking your lips off (to prevent air from getting inside). You won't be long enough. The pressure inside the bottle will plummet and you won't be able to drink.

Therefore, instead of outgoing fuel, air must enter the tank in its place, from behind the side of the aircraft. For this on foreign aircraft common practice of creating drainage tanks. They are located at the end of the wing. And their exit to the atmosphere looks like this:

Such a tricky entrance (often used) in order for the oncoming air flow to crush the kerosene in the tanks.

In the case of the Tu-154M, there are no drainage tanks. They are connected directly to the atmosphere through tricky pipelines encircling the fuselage. The pipes first go up, then go around the contour of the fuselage and have an outlet at the bottom. This is done so that when the aircraft tilts (rolls), the fuel does not spill out. The picture is complicated, I recommend to enlarge it.

In a magazine, I already once wrote about refueling an aircraft before a flight. I'll try not to repeat myself.

So, before refueling the aircraft, it is necessary to drain the sludge of fuel in order to check the presence of water in the aircraft tanks. It is just designed to drain sediment into it in the field.

The sludge drain by the technician is often controlled by the flight engineer (pictured is the sludge drain from the IL-76):

Then a tanker pulls up.

The technician must tell the tanker driver how much fuel to fill, so while the tanker connects the hose (it happens that he connects two at once to speed up the process), the technician goes to look at the remaining fuel:

The remainder is determined by the instruments of the aircraft, and is also recorded in the logbook. As you can imagine, these data sometimes do not converge. The temperature on the street has changed - the density of the fuel has changed, the instrument readings have changed. The thing is that in an airplane it is measured in kilograms, and in a tanker in liters. The price of division of the arrow is 1 ton. From the voltage in the aircraft's electrical network, the readings of the arrows may float. The photo shows the Tu-154M fuel system control panel (needle indicators show the amount of fuel in each group of tanks):

A bunch of light bulbs and switches help control the flow of kerosene in flight from various tanks. Light bulbs show on or off in this moment each tank pump. In general, I got used to this system for a long time, at first it was difficult to figure it out =). At the dawn of the operation of the Tu-154 aircraft, there was a disaster when the engines turned off in flight due to the fact that the supply tank ran out of fuel, and the flight engineer forgot to turn on the transfer from others to the supply tank. The engines stopped, the plane fell = (. After that, changes were made and when a certain level in the supply tank drops, fuel starts to flow from others automatically.

If the readings of the fuel gauges and the entries in the logbook match at least +/- 200 kg, then refueling can begin. The main thing at this stage is not to forget to control the tanker driver so that he connects his car to the aircraft with a ground cable (electrical potentials must be equalized through it, and not through the refueling hose, because this can cause a sickly spark of static electricity). Also, another ground cable must be connected from the machine to the ground point on the platform (usually a piece of pipe buried in the ground).

Open the filler neck (usually in the wing):

And connect the hose:

Or hoses (pictured Boeing-767):

The neck differs from the car in that there are check valves. You don't have to worry about fuel spilling out. The whole process is "dry", the valves open only when pressure is applied:

Fortunately, both on the Tu-154 and on foreign aircraft - everywhere this connection is unified and no adapters are needed. The spring presses the plate so that the fuel does not flow back.

At the tanker, the meter costs liters. Therefore, before refueling, we need to calculate how many liters we need. The density of the fuel depends on the ambient temperature and varies from 0.779 to 0.791 (the numbers may not be accurate, I forgot everything) and is written on the control coupon, which confirms the condition of the fuel. The last check must be made no more than six hours ago, otherwise fuel cannot be refueled. All necessary signatures and hours of verification are indicated on the coupon. If everything is in order, we count the liters and call them to the tanker.

But before you say "let's go", you need to perform one more procedure: checking the fuel in the TK for the presence of water. We kindly ask the refiller to provide a sample in a jar. If no water is found (in my lifetime I have never seen water in the TK), then you can refuel.

We open the taps of the tanks we need (where we will fill at the moment). All is ready.

Go!

Kerosene rushes into the tanks of the aircraft with great speed. This all happens before the arrival of passengers. In Russia, there are special procedures for refueling an aircraft with passengers, but everyone tries not to do this. Why take the risk?

Of course, the tanks have overpressure protection so that it does not burst when refueling. The protection is a small valve that opens when the pressure is exceeded and bleeds the air. A simple and common mechanism.

You can control the refueling on foreign aircraft right next to the hose connection point, you can also control the taps there (to select the filling of the tanks we need):

The A330 refueling panel is located on the fuselage in the tail section:

A320x family:

Sometimes the panel is located directly on the wing, sometimes on the fuselage, at the request of the aircraft customer.

On the Tu-154M, you can only control the cranes from the outside, while all the indication is inside, in the cockpit. Only. It always annoyed me, I had to run from the cockpit under the wing and back.

You can, of course, use measuring rulers outside, but their minimum value is not sufficient to show the desired level. Pulled straight out of the wing:

It turns out that a magnet floats in the tank, which at the right time picks up the ruler and prevents it from falling below the level of kerosene. Thus, it is possible to determine the filling of the tank without any electronics. To be honest, I have never used this method. It has always been safer for me to look in the cockpit.

Is it possible to refill the tank, fill too much? It is forbidden. Automation will close the taps and will not let you fill the plane with more than you can. But automation tends to fail. In this case, the mechanic works:

There are valves in the wing, which at a certain moment begin to drain excess kerosene directly to the ground. Open during refueling from the pressure of incoming kerosene:

In aviation, everything is provided;).

In the cockpit, pilots always have the opportunity to see the readings of the instruments about the fuel level. For example in 737:

In-flight pump control:

Everything is simpler on airbuses, fuel information is generally displayed on one of the pages of the multifunction display:

Compare with fuel system control panel 154=). That's where the power =).

Actually I'm kidding. Of course, that is why the flight engineer does not fly on new foreign aircraft as part of the crew. He's just not needed there. The plane does everything itself.

Especially on big planes refueling must be carefully monitored so that much more fuel is not pumped into one wing than into the other. It's called a "fork". You understand that if there is more than several tons of fuel in one wing, then this can not only affect the pilot's comfort (the plane will pull to the side), but also flight safety.

Worst of all, the situation is very difficult to fix. If you get a large fork, you need to drain the excess fuel and refuel in another wing. And this is not less than an hour (if everything coincides successfully, and the necessary ground equipment is at hand, which never happens) time. Accordingly, the delay. And for delays due to personal fault, the technical staff will not be patted on the head ... Drained fuel is no longer refueled on aircraft. It goes to airfield equipment, tractors and something else.

So the refill is over. The driver of the TK writes out a requirement in which liters of kerosene are written on the counter. This is a very crucial moment when all calculations need to converge, otherwise there will be problems. Liters in the requirement are translated into kilograms and added to the balance before refueling. If this value is equal to the one required for the flight, then everything is fine, we put the necessary murals (as you thought, everyone answers with his head, especially in the matter of fuel).

How much kerosene does the plane take? I will not name specific figures for flights, because I have already begun to forget them. I can say that usually the Tu-154M refueled 25-35 tons. B-737-500 no more than 15 tons. A320 approximately 15-25 tons. These data are given for approximately the same routes. It is better to ask the pilots how fuel is calculated, I have never done this and have not been particularly interested. I know that an air navigation reserve is included in the refueling, allowing the aircraft to fly for several more hours, and for each type it is calculated in its own way.

15 minutes after refueling, you need to drain the sediment from the aircraft again. During this time, possible water should have sunk to the bottom of the tanks, where we check it through the drain points:

We bring a jar and look at the state of kerosene. Everything is fine?

And now I better couple I’ll say a word about how it is spent in flight. So, from the supply tank, fuel is supplied by pumps. As a rule, these pumps are centrifugal:

This type of pump is simpler than others and allows you to idle, even if there is nowhere to pump fuel (the fuel supply valves to the engines are closed). Pumps are pumping and pumping. Some help move the fuel through the tanks, while others send it to the engine power line.

But to start the engine, it is not enough to turn on the pumps. It is also necessary to open the "fire hydrants" (as they are called on domestic technology, because they overlap in the first place in the event of an engine fire). When the valves are opened, the fuel enters the engine, where it is filtered and heated (usually there is a radiator that cools the oil circulating in the engine and simultaneously heats the fuel) and is fed to the injectors. This is already the driving part, so about it in detail in the following posts. I can only say that there are several degrees of filtration, and even if all the filters are clogged, the fuel will bypass. The main thing is to maintain uninterrupted operation so that the plane can be landed.

Finally, I would like to show you what happens when mistakes are made with refueling on the Tu-154:

Photos from the Internet

Yes, yes, the plane can just land on its tail!

Photos from the Internet

In fact, this is a nightmare for every Tu-154 technician and flight engineer. The tail of the aircraft is very heavy. The exit of passengers is desirable in order - the second salon, the first salon, especially if there is little fuel left in the fourth tank.

Photos from the Internet

About how fuel is stored at the airport was recently written here: http://community.livejournal.com/sky_hope/180444.html#cutid1
I highly recommend watching.

IN passenger liners, whether it's aircraft production Boeing or Airbus, or domestic aircraft Tupolev or Ilyushin companies, aviation is used. In Russia, kerosene grades TS-1 and RT are used. IN foreign countries used kerosene brand Jet Fuel A and Jet Fuel A-1. Such kerosenes are used only in gas turbine engines.

These grades of fuel have slightly different characteristics, but can be mixed in any proportion. In winter, a special additive is added to aviation kerosene, which serves to prevent the fuel from freezing. Such an additive is indicated by the letter "I". This additive also contributes to a more complete combustion of kerosene and its better fluidity at low temperatures.

On light aircraft with piston engines, gasoline is used as fuel. But such gasoline, unlike automobile, has an increased octane number. This is necessary to increase the engine power and, accordingly, the torque on its shaft.

Where is fuel stored on an aircraft?

Most modern liners fuel is located in the wings and the compartment located in the central one. Wing tanks are a cavity filled with sealant. In such a cavity, the fuel is in a free state, overflowing inside one tank. The tanks are vented to atmosphere to prevent collapse when fuel is used up. In the middle of the aircraft at the level of the wings is a central or supply tank. From it, fuel is taken to the engines of the liner.

On some models of modern aircraft, fuel may be located in the tail or stabilizer. This is due to the need to make the rear of the aircraft heavier to facilitate takeoff.