How do self-sealing fuel tanks work?

Factual Questions
1

The A-10 “Warthog”, among others, has self-sealing fuel cells. How do they work?

2

Via a specially developed and patented fuel-swellable foam.

3

There was anothe thread on this not too long ago.

Short story: There is uncured rubber sandwiched between two sheets of cured rubber. The cured rubber is unaffected by fuel. When the tank is punctured, the uncured rubber is exposed to the fuel and swells, thereby sealing the hole.

At least that’s the way the tanks made by Engineered Fabrics in Rockmart GA work.

4

Thanks for the answers. Is one technique preferred (foam vs. uncured rubber)?

BTW, I did trya search but came up empty-handed.

5

This is what you posted then:

There are two layers of cured (vulcanized) rubberized fabric that make up the tank. In between these layers are a layer of uncured (non-vulcanized) rubber. The vulcanized rubber is unaffected by jet fuel. If there is a penetration of the tank by an object, such as shrapnel from a cannon shell or missle warhead, the fuel flows through the hole and hits the unvulcanized rubber between the two layers. This rubber swells due to the fuel and plugs or at least greatly reduces the size of the hole.
Additional information I found interesting about fuel tank manufacture at no extra charge:

The tanks are layed up by hand over cardboard forms. Basically a cardboard box. After the tank has been manufactured you might wonder how thay get the form out? they fill the tank with water and the cardboard softens. Then someone reaches in through an opening and pulls out the cardboard.

Some tanks are built up over a plaster mold if the shape is too complicated for cardboard. Again after the tank has been manufactured, water is added and the tank is beat with rubber hammers to break up the plaster mould. Then the parts are removed through one of the access holes.

I saved the page on my HD because I thought it was interesting. All of the Above is Gary’s, not mine

6

Thanks for finding the post Pamflitt.

I was posting from work and it was almost time to go home. Didn’t want to get “whistlebit”!

The post you posted was based on a visit to the Engineered Fabrics plant in Georgia. They made/make the tank bladders for MD-11, F15 and F18 aircraft. I don’t know if they make all the bladders in each aircraft, but they make some.

In the MD11, at least on some models, there is a fuel bladder under the cabin floor. This bladder looks like a glove with long fingers. The whole assembly is actually laced to the aircraft structure with cords. Kind of a neat way to use the space. The fingers allow the use of space that would be difficult to incorporate into a fuel tank any other way.