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An afterburner is a secondary combustion system which burns additional fuel downstream of the combustion chamber, to further increase thrust at the expense of much higher fuel consumption. This is the Pratt & Whitney F100 afterburning turbofan, variants of which power the USAF's 4th-generation fleet of F-15s and F-16s: The final spoke-looking thing ...


37

The first photo is from the Tornado Role Demonstration Team's display at RAF Leuchars in September 2012 (source). That Sep '12 show or its preparation is on YouTube. Most of the instances of the air brakes as seen from the cockpit (looking behind) are followed by the swing-wing extending and the afterburner turning off (you can tell from the sound of the ...


24

The afterburner, of course. In simplest sense, the afterburner is just an extension attached to the engine where the fuel is dumped into the exhaust, resulting in an inefficient but huge increase in thrust. Turbojet with and without afterburner; image from aerospaceweb.org In the above image, you can see the basic schematic of the afterburner- it ...


22

Military aircraft takeoff with afterburner when it is safer to do so with an exception- carrier pilots always light their cans while taking off (and also when the pilot wants to show off, but lets leave it at that). The main consideration for using after burner in operational land based aircraft is the available runway length. When the aircraft is loaded ...


17

By using the afterburner, fuel is injected into the downstream of the turbine. Exit velocity gets higher -> More thrust. Comparison of the generated thrust in an F/A-18C Hornet: Maximum thrust without afterburner 10,440 daN (each 5'220 daN) Maximum thrust with afterburner 15,660 daN (each 7'830 daN) (The F/A-18C Hornet uses 2 General Electric F404-GE-...


13

While the pictures above are most likely a result of the reason posited by ymb1 (showing off max blast while staying subsonic for the crowd), using afterburner with speedbrakes to reduce weight is a known practice in the fighter community, in line with Kolom's answer. Even if an aircraft is equipped with a fuel dump system, environmental restrictions and ...


13

It is possible to design an aircraft that can cruise at supersonic speeds without using afterburners (for example Concorde, the British TSR-2 strike/reconnaissance aircraft, and the Tu-144). The aerodynamic drag force is higher at transonic speeds than when supersonic, and using afterburners to accelerate through the transonic speed range qucker may actually ...


12

No, no restrictions on using an afterburner. There are a few F104 Starfighters on the civil registration that must use the afterburner to take off. However, most countries forbid supersonic flight by non military operated aircraft in their airspace. The only time Concorde went supersonic was over the ocean.


11

fooot has pointed out the GE F101 (powers the B-1 Lancer) has a BPR (bypass ratio) of >2:1 and comes with an afterburner. Other examples are the Turbo-Union RB199 (1.1:1) and the Volvo RM8 (0.97:1). Generally, anything below 4:1 is a low BPR, and bypass air is needed for cooling. Pure turbojets resort to other means of cooling, such as the ram air inlet on ...


10

A friend has a demilitarized warbird. The full propulsion system remains intact. Sometimes, in full view of the FAA, at airshows, he will light the afterburner. I know of no regulation which prohibits augmented thrust from afterburners.


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My first guess based on the sound repeating when the thrust is idled near the end of the video is that's the sound of the actuators of the variable geometry nozzle. Googling that actually auto-completed it to Great F-16 Actuator Sound (video). Bonus answers to the bonus questions: It's a ground test of the engine, making sure it's working fine with no ...


9

Can you add reheat to a high bypass turbofan engine? Sure. The real question is what is the purpose for doing so? The bypass ratio of a turbofan is based largely on its operation regime. Turbojets or low bypass turbofans are excellent choices for operations above Mach 1 to around Mach 2-3. Larger bypass ratios are more suitable to high subsonic and ...


9

I flew B-1B's for 7 years. I've also had flights in F-15s and F-16s. The B-1 has 4 afterburners, but a lot more gas than the fighters, so I rarely had to stay out of burner due to fuel. There's lots of reasons to minimize burner usage, though: Operationally, AB makes you highly visible to all. At night, you put a spotlight on yourself. Daytime, ...


9

Afterbuner simply injects fuel directly into the jet pipe (i.e. beyond the turbine) in order to greatly increase thrust. The way throttle levers are normally set up, afterburner is engaged once the lever is advanced past maximum dry thrust, but I can't imagine why, theoretically, you couldn't set one up to be engaged at less than maximum dry thrust. Mind ...


8

A jet engine afterburner is an extended exhaust section containing extra fuel injectors. Since the jet engine upstream (i.e., before the turbine) will use little of the oxygen it ingests, additional fuel can be burned after the gas flow has left the turbines.—Wikipedia Also additional igniters.


7

Yes the specific fuel consumption of the afterburner, lbs of fuel used per lb of thrust, is much higher than the core engine. This is because the fuel is being added to a part of the engine where the air is less compressed, so the energy conversion is a lot less efficient. The bright orange flame coming out the tail pipe when in reheat is pretty much all ...


6

Yes, when the AB is lit, the nozzle needs to be opened, because the increase in exhaust temperature causes a decrease in density (pressure remains about the same), and so the same mass flow needs a bigger nozzle area to flow through. In AB, the engine mass flow is about the same as in max dry operation. The AB basically sits behind the core, and operates ...


6

The afterburner is aft of the gas core of the engine in the jet pipe and bypass air from the fan would have already been mixed with the exhaust gases from the core prior to passing through the afterburner flame holders. Supercruise is by definition supersonic cruise flight without the use of afterburning, so augmentation would not be in use here Counter ...


5

The aircraft fuel system does not distribute fuel equally among the afterburner and the engine's core (i.e. the compressor-combustion chamber-turbine part). It distributes fuel in such a way that the combustion is maintained in both the combustion chamber and afterburner and the required thrust is produced. Consider the case of F-15 E/I/S or F-16 C/D ...


5

What is EPR? [It] is the total pressure ratio across a jet engine, measured as the ratio of the total pressure at the exit of the propelling nozzle divided by the total pressure at the entry to the compressor. Placing an EPR probe in the A/B (afterburner) tube would not be a wise choice, and therefore in an A/B aircraft you wouldn't find an EPR reading. ...


4

The short answer is very much "no" -- afterburners are not at all required to launch from an aircraft carrier. Longer answer: Fred Larson's comment is correct: it really depends. Ultimately a given aircraft, at a given weight, with a given wind-over-the-deck, and a few other things, requires a given amount of thrust to get airborne -- whether it comes from ...


4

According to Wikipedia, the BAC TSR-2 was capable of supercruise (no reheat) at Mach 1.1 at 200 feet (~60 m) altitude. The TSR-2 first flew in 1964. The English Electric Lightning had demonstrated supercruise several months earlier, but only at higher altitudes (above 20,000 feet, appr. 6 km).


4

To be sure to not use more runway than available. It is also good to have runway to spare in case take-off has to be aborted. Look at this image as an example from another fighter. Notice the two X-axis. The top MIL is for without afterburner and the bottom FULL AB is with afterburner. Notice how the numbers for the MIL is almost double that of the FULL AB ...


3

If you look at it in terms of thrust vs fuel flow, then yes, they're very inefficient. However, if you just look at the amount of fuel burnt to get an interceptor from the runway to 30,000ft, then they can be more efficient. Without afterburners the same climb would take significantly longer and could use more fuel. Without afterburners, you'd need much ...


3

A normal jet engine has subsonic flow throughout. This avoids shock problems such as choking or excessive acoustic noise. A conventional afterburner accelerates the exhaust flow to supersonic speed, allowing it to push the plane past the speed of sound. It is placed after the turbines in order to avoid those shock problems. A supercruise engine must deliver ...


2

In the late 60s/early 70s, P&W proposed an engine (the JTF17) for the projected USA Supersonic Transport (SST) which would have introduced afterburning in the fan-generated section of the airflow: a fan-burner. This doesn't quite match the sense of the questioner's description but you should always beware of assuming that the most trodden paths are the ...


2

https://www.nasa.gov/centers/dryden/pdf/88117main_H-1449.pdf Scroll down there's some useful graphs that can give you some idea. AB increases exhaust temperature and thus allows for an increase in exhaust speed. By actuator disk theory this means the in flight thrust at MAX will be closer to the static number than in flight thrust at MIL for any given speed....


2

It depends on the aircraft type, loadout, fuel aboard, required endspeed, weather and winds, etc. Some jet aircraft or carriers e.g. the S3 Viking, A-6/EA-6B, A-7 etc. did not use engines equipped with re-heat, so that was not an option. Earlier incarnations of the F-14 required the use of reheat during cat launches due to the low thrust and ...


2

It's because on a jet engine the flame in the burner can is carefully controlled and contained by airflow that is guided in from the sides to keep the flame in the center of the burner can so it doesn't touch metal (only maybe a 3rd to half of the airflow out of the compressor gets burned; the rest is for temperature control - which is why there is enough ...


2

The nozzle position is automatically adjusted according to the current engine state to maintain optimal exit flow conditions at the end of the nozzle. The difference in nozzle actuation you are referring to is caused by a slight difference in activation time of the afterburner between the engines. Please see the following Aviation Stack Exchange question ...


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