How Does A Fighter Jets Fuel System Function?

It varies, but adding in some of the general principles. Most planes store fuel in the wings at least, often times more complex aircraft will have additional tanks, some planes even have a tank in the vertical stabilizer. Planes with high wings can often gravity feed fuel to the engine, and like you pointed out these would not normally work upside down. Most other planes, including probably all modern jets, have fuel pumps. These can work to send fuel to the engine or transfer it to other tanks.

Many planes have what they call a feed or header tank which is a smallish tank the engine draws from and it is constantly replenished by other tanks, so it is always completely full, and through creative fuel pickup design it can be made to reliably deliver fuel in any orientation. So even if fuel from the other tanks is disrupted it will be a while before the fuel in this tank falls enough to be a problem. Additionally, large fuel tanks will often have many compartments and there are a series of one way flaps between them that tend to let fuel move toward the pickup, but not away from it. This helps the fuel flow better, but also helps keep the fuel from sloshing around and affected the CG.

While even the C-130 can gravity feed, the pumps are always on during flight. Fuel pumps are used to deliver fuel from different tanks. Whether they feed to the engine directly or to another tank, fuel is pumped. Fighters are different depending on the company that designed them. but it is all the tubing in the tanks that get the job done.

to add to "Rolomatic" for some reason Y wont let me give you a tumbs up. so consider it done anyway.

since scavenging fuel was addressed,

nutshell on actual delivery,

multiple sealed injection systems at varrious points.

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and an auto electric fuel pump, or even a mechanical one, can work upside down. it's supplying it with fuel when inverted that's the issue. which hopefully no car has to endure. for any length of time where fuel is still needed. upside down in a car, prolly not expecting to simply drive off after that. so whats the point.

ex USAF. oh, and auto gear head.

with positive G, the fuel sits at the bottom of the tanks, no matter what the attitude relative to Earth.

with negative Gs, the aerobatic tanks and various plumbing systems work.

no plane, regardless of its type, will be allowed full aerobatic envelope below certain fuel capacity that ensures proper function during gload that's less than +1G

Just like a weed-whip or chain saw, there is a tube that stays in gravity contact with the fuel.

Most everything you wish to know about one can be found here:

http://www.dtic.mil/dtic/tr/fulltext/u2/a126832.pd...