Me and my brother are at a loss, we understand the basics of how the upside down thing works, but how does the engine get fuel when the tank is turned around, is it a vacoom and how would that work or is the intake from the tank in the back of the it, so the fuel is forced into the engine? Thanks.
In: Engineering
You know how you can pump water uphill with a water pump?
It’s like that.
Fighter jets fuel intake does not work on gravity like a Cessna 172. They have fuel pumps to pump the fuel.
They have fuel pumps
If ur upside down for long enough at one point the engine will stall depenidng on the plane
Look into a chainsaw gas tank sometime. The fuel hose is flexible and always falls to the low side of the tank regardless of the position of the chainsaw.
https://aviation.stackexchange.com/questions/21452/how-does-fuel-get-to-the-engine-during-acrobatics
A few possible explanations here. They mention two primary ways:
1: Flop tube, a flexible tube with a weight at the end, making sure the tube follows the liquid around inside the tank.
2: Balloon, an internal pouch or rubber lining that shrinks with the amount of fuel. No air no problem, right?
Your question alrready answered by more educated people here but your question was[ once a problem in WWII](https://en.wikipedia.org/wiki/Miss_Shilling%27s_orifice).
Fuel pumps will maintain flow into the engine at least in the short term, but prolonged flight upside down can cause problems on some aircraft if the pumps aren’t capable of drawing fuel from the tanks when they’re inverted.
Most of these comments are off base, a fuel pump alone doesn’t mean that a fuel system can operate upside down. Do they think that there’s anything out there that just drips the fuel into the engine via gravity?
The problem is that the pickup for the fuel pump intake is normally at the bottom of the fuel tank (in a narrow spot called a sump), and if the airplane is upside down the fuel is at the top of the tank.
You need to either have a flexible pickup that can move around the tank or something called a maneuvering can which can store a limited amount of fuel. It could be something like a baffle with spring loaded flaps on it above the fuel pickup, so that when the airplane is in normal flight the fuel can push down through the flaps but if the aircraft is inverted the flaps close and the fuel within the baffle stays in the sump while the rest of the fuel goes to the top of the fuel tank. Then you only have a little bit of time to fly inverted before you have to roll back over.
My understanding is that modern aircraft use a fuel pump. The issue you mentioned was a problem in WW2 and one really cool lady had a solution.
https://www.kenleyrevival.org/content/history/women-at-war/beatrice-shilling-revolutionising-spitfire
IIRC, the F-16 has an additional boost pump on top of the fuselage fuel tank. All other tanks feed that one, so it should be full unless you’re low on fuel. The limiting factor on the Viper is the oil pump.
The F-15 has baffles to keep some fuel at the sump, but can’t stay negative g for more than a few seconds.
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