The final dump-and-burn of a F-111 at the Williamtown Airshow 2010 in Sidney - dumping fuel and igniting it with the afterburner to look good

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SkirtComfortable952@reddit

A remarkable aircraft. Some of the low-level-flying stories about F-111's are the stuff of legend!

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Indifference_Endjinn@reddit

Good ol' dump and run, my favorite move when leaving the in-laws after taco night

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Puppy_1963@reddit

It was not, in fact, the final dump and burn

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iYAM_who_i_SAMiAM@reddit

How much fuel is dumped / used in this maneuver?

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BobbiePinns@reddit

About 200 litres when they did it in Brisbane

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TheFightingImp@reddit

Man, its nice to have the Super Hornet buzz the CBD in September like its an Axe Combat mission, but I still miss the dump 'n burn.

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iYAM_who_i_SAMiAM@reddit

That’s crazy! Stupid question, but does the sudden release provide a quick burst of thrust? I’ve just never seen or heard of this before.

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IlluminatedPickle@reddit

Nah it's just basically a big flame thrower. Looks cool though.

Iirc, discovered by accident when one pilot decided to dump fuel and turn the afterburner on at the same time to gtfo of a potentially hostile area. At which point his wingman was like "yo that was sick"

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Captain_Lolz@reddit

That's how all he beat militaries strategize

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BobbiePinns@reddit

Not a stupid question. I don't know, but I assume not because it all happens outside of the engine/exhaust area (unlike afterburners, which ignite extra fuel within the exhaust nozzles and do create extra thrust).

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ForbiddenExceed@reddit

Afterburners are able to direct the thrust into one vector and massively increase the temperature, accelerating the gas and subsequent mass flow via increased velocity, thus increasing the thrust.

You're correct with your assumption with the dump and burn, as despite it also heating and accelerating the gas, there is no useful vector and thrust generated is basically negligible if even existant.

It's like firing a bullet out of a gun's barrel vs detonating the cartridge on the ground without a way to direct the pressure. In the first case, the bullet goes fast in one direction; in the other, there's basically no effective bullet movement.

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BobbiePinns@reddit

Thank you for the confirmation! 😁

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BobbiePinns@reddit

First off, its Sydney. 2 Ys no Is.

Secondly, RAAF Williamtown is actually part of Newcastle 180ish km north of Sydney. But for the sake of international people I think we can give you a pass on that because its just way easier to go with Sydney.

Third and most important, fucking excellent clip.

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TheFightingImp@reddit

The Newcastle Knights and Newcastle Jets would hound OP down for assuming Williamtown is within Sydney lol

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_oohshiny@reddit

Feels like OP is a karma farming bot.

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DionStabber@reddit

I know him, he's not, he's just an extremely prolific Reddit user.

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natso2001@reddit

It's so interesting. There's nothing inherently Australian about the aircraft, but only Aussies will feel how iconic the dump and burn is. Love the F-111

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Simmo2222@reddit

We basically bought the planes just to buzz Grand Finals.

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747ER@reddit

Australia was one of only two operators of the F-111, and the other used the aircraft for a very different role. The Dump and Burn is very iconic for Australia because it was regularly performed for so many years in so many cities, much more than the US.

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Puzzleheaded-Ad-4883@reddit

I saw this done in the UK at an RAF Finningley airshow about 40 years ago, can't remember exactly, but it was low cloud and drizzle so most of the display was cancelled. The F111 did a very low pass along the crowd line with a dump and burn, then a fast low pass. Really felt the heat on my face. That, a low level harrier display and low A10 were really good in the bad weather, most other displays either cancelled or just fly pasts.

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erolbrown@reddit

Ahhh, when Airshows in the UK were decent.

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Puzzleheaded-Ad-4883@reddit

I went to every RAF Finningley airshow from about 1968 to 1994 with my dad, we lived nearby. Peak for me was 70s with multiple Vulcans scrambled and Lightnings still flown hard. The Spitfire and Hurricane displays were also flown more enthusiastically back then. Also just after the fall of the Berlin Wall with the Russian aircraft attending and still all the American air bases in the UK, plus French, Italian and German visitors.

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IlluminatedPickle@reddit

There is definitely something inherently Australian about it. The F-111C was only flown by us. We even had a different name for it. The seppos called it the Aardvark. We called it the Pig.

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mnp@reddit

Today I learned a new word for gringo.

https://fluentslang.com/seppo-meaning/

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Uniturner@reddit

Australia was the only operator of the F-111C, which this is.

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obskeweredy@reddit

My favorite aircraft!

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waldo--pepper@reddit

The third rule.

One. Lose sight. Lose the fight.

Two. Speed is life.

Three. Always look good.

Thank you Falcon 4.0 for teaching me these cardinal rules.

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StuffMaster@reddit

Falcon 4.0 yeah

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kyflyboy@reddit

The USN RA-5C Vigilante could do the same trick. Same idea. Fun stuff...

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BrtFrkwr@reddit

Well, we all knew the F-111 had to be good for something.

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Mr_Horizon@reddit

Whats the point of dumping fuel? What is that function even for? It doesn't extend range, and eventually you need to refuel again anyway.

Is it for agility? Is weight a concern?

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DeathrayToaster@reddit

Normally fuel dumping is used in an emergency. If you need to return to an airport and you are too heavy to land you need to dump fuel.

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Mr_Horizon@reddit

I didn't know that "too heavy to land" is a thing. If you can take off, you should be ok to land as well?

Or is there a risk of gear failure if you're too heavy and don't land perfectly smooth?

I googled... an empty F16 weighs 9000 kg. A full tank adds another 3000kg. That is admittedly more than I thought (25% of weight is fuel), but still - shouldn't the gears be made with varying weight in mind?

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Miuramir@reddit

The Max Landing Weight (MLW) of many aircraft is significantly lower than their Max Take-Off Weight (MTOW); and both can vary due to circumstances. Additionally, for carrier-based aviation, there's a Max Trap Weight to consider; and for land-based aviation the available runway length. Aircraft with variable geometry and/or thrust vectoring add additional variables.

According to the Standard Aircraft Characteristics for the Navy model F-111B, revised 1 July 1967 (NAVAIR 00-110AF111-1), the following weights are listed:

Loading	Weight (lbs)
Empty	46000
Basic	47519
Flight Design	60700
Combat	68365
Max. Take-Off, Field	77724
Max. Take-Off, Catapult	77724
Max. Landing, Field	64000
Max. Landing, Arrest	62000

Note that not only is the MTOW significantly higher than the MLW, even the expected combat loadout weight was higher than the MLW. If you had some sort of failure shortly after takeoff, you needed to shed weight before landing if possible, and burning off fuel is significantly cheaper and safer than ditching expensive weapons... especially if those are nuclear bombs!

Another table points out that the F-111B had 3383 gallons of internal fuel, plus possibly another 900 gallons on the fixed pylon tanks. The density of JP-4 or JP-5 varies, but 6.8 lbs./gal. seems to be a reasonable average; so that's potentially ~23,000 lbs. of internal fuel plus ~6,120 lbs. in the fixed pylon tanks. If you take the Basic weight of 47,519 lbs. and just fill all the fuel tanks, that takes you up to 76,639 lbs., quite close to the MTOW and well over the MLW.

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Tojb@reddit

It makes more sense than you would initially think. You're always going to be lighter when you land because you're burning fuel while you fly.

Landing is more structurally intense on the plane than taking off is, think of some videos you might have seen where the pilot absolutely slams the plane onto the runway. If you build an airplane that can land at its maximum takeoff weight you're adding in strength and structure that will only be needed in rare emergencies, but the additional weight of all of that will affect every single flight, and wasted payload is a huge cost in aviation.

To solve this issue they design planes to be able to takeoff with a full payload of cargo and/or passengers, burn off an "average" amount of fuel on whatever the designers have decided is an "average" flight for the aircraft, and then land safely at the destination. It may not seem like a big difference, but every pound matters in aircraft design, and you might save a few hundred pounds of payload in larger aircraft by doing it this way. That's not a huge number for a single flight, but for an airline if all of your planes can carry say, 250lbs extra on every single flight they do for the entire lifetime of the airplane, that adds up.

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IlluminatedPickle@reddit

If you can take off, you should be ok to land as well?

When you take off, you're unloading the weight from the gear at a fairly gentle rate. When you land, you're rapidly applying the weight of your aircraft as well as the momentum you're landing with.

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eatsmandms@reddit

Consider that when starting you are going from slow to fast, and lift is reducing the pressure on longing gear as you increase in speed.

On landing, you go from fast to slow, or in other words, high energy scenario into an abrupt impact. You need to have the energy go somewhere.

Think of your car - when you go up to highway speedyou use the engine and the suspension. But only when breaking from highway speed to zero you need the brakes. Your brakes need to be dimensioned to stop you. And so does the hardware (flaps, chute, longing gear, brakes and more) that slows you down before you run out of runway. And the runway itself needs to withstand being hit by 15 tons or more at 150 miles per hour.

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nigelxw@reddit

In at least some cases I'd imagine it's the runway that'd get damaged

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pesca_22@reddit

and lower fire risks in an emergency landing

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Pinky_Boy@reddit

It's an airshow. It's to look cool

The irl application is when you have more fuel than you expect whe you're about to land. Wether just because you packed too much, or you needed to divert. Because just like maximum takeoff weight, maximum landj g weight also exists

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Xeelee1123@reddit (OP)

Source: https://youtu.be/WpPEdOMSIgQ

Source. https://www.abc.net.au/news/2010-07-27/one-more-time-for-the-dump-and-burn/921168

Source: https://en.wikipedia.org/wiki/General_Dynamics_F-111_Aardvark