So I'm watching the History channel and they are talking about the japanese Zero not have self sealing fuel tanks. How does a self sealing tank work?

Made of rubber?

Rubber lined  and foam filled bladder inside of the fuel tank

but how does the rubber seal itself?

Quoted: but how does the rubber seal itself?

Ever shoot a tire?

Quoted: Quoted: but how does the rubber seal itself? Ever shoot a tire?

no, but I've seen the Firestone? self sealing tire display

Read this:


www.army-technology.com/contractors/protection/tss/

sort of get it, a non reactive soft rubber compound fills in the hole

Quoted: but how does the rubber seal itself?

The rubber is elastic enough that the projectile will not really punch a circular hole in the liner. The result will generally be a slit. The hydrostatic pressure of the fluid in the tank will push the rubber back down, and the slit will, for the most part, close back up. Now, you poke enough holes in the liner and you won't have any real integrity to the membrane. But one or two holes will be survivable. There may be some seepage through the slit, but the fuel won't go pouring out. Modern specialized self-sealing tanks employ a foam between the liner and the skin which further helps seal the puncture.

cool. thanks for the explanation

i understand the idea but i dont know exactly what they did.

Im thinking what was done is to have a smaller tank inside a larger tank.
The space in between the two was (i guessing) filled with some sort of semi liquid material under pressuse. When a hole is put into the tank  the material under pressure is pushed out, turns hard and seals the leak.

Similar to putting a can of fix a flat in a tire and running over a nail.

If that makes any sense.....

edite to say i didnt read dzl's post

This only comes from my experince working with Naval aircraft for 20 years....

Self-sealing fuel cells for military aircraft, not a fuel tank, (a fuel tank is a part of the structure of the aircraft, IE wet wings, there is no "fuel cell") are a Goodyear patented product.


Self-Sealing Fuel Cells
A self-sealing cell is a fuel container that automatically seals small holes or damage caused during combat  operations.  

A  self-sealing cell is not bulletproof, merely puncture sealing.

As illustrated in figure 3-31, the bullet penetrates the outside wall of the cell, and the sticky, elastic sealing material surrounds the bullet.
As the bullet passes through the cell wall into the cell, the sealant springs together quickly and closes the hole.
Now some of the fuel in the tank comes in contact with the sealant and makes it swell, completing the seal.
In this application, the natural stickiness of rubber and the basic qualities of rubber and petroleum seal the hole.

This sealing action reduces the fire hazard brought about by leaking fuel.

It keeps the aircraft’s fuel intact so the aircraft may continue operating and return to its base.

The most commonly used types of self-sealing fuel cells are the standard construction type and  the type that uses a bladder along with the self-sealing cell.

Of the two, the standard construction cell is used the most.  

It is a semiflexible cell, made up of numerous plies of material.

The combination bladder and self-sealing  cell is made up of two parts.
One part is a bladder-type cell, and  the   other   part   is   identical   to   the   standard construction  cell.  
It  is  designed  to  self-seal  holes  or damage  in  the  bottom  and  the  lower  portions  of  the side areas.
The bladder part of the cell (nonself-sealing) is usually restricted to the upper portion.
This type of cell is also semi flexible.


SELF-SEALING CELL (STANDARD CONSTRUCTION)
There  are  four  primary  layers of  materials  used  in  the  construction  of  a  self-sealing cell.   These   layers   are   the   inner   liner,   nylon   fuel barrier, sealant, and retainer.

All self-sealing fuel cells now  in  service  contain  these  four  primary  layers  of materials.    

If    additional    plies    are    used    in    the construction  of  the  cell,  they  will  be  related  to  one  of the primary plies.

The inner liner material is the material used inside the cell.
It is constructed of Buna N synthetic rubber. I
ts  purpose  is  to  contain  the  fuel  and  prevent  it  from coming  in  contact  with  the  sealant.  This  will  prevent premature swelling or deterioration of the sealant.
Buna rubber is an artificial substitute  for  crude  or natural  rubber.  
It  is  produced  from  butadiene  and sodium, and is made in two types, Buna S and Buna N.

The  Buna  S  is  the  most  common  type  of  synthetic rubber.
It is unsuitable for use as inner liner material in  fuel  cells.  
It  causes  the  petroleum  fuels  used  in aircraft to swell and eventually dissolve.

The Buna N is not affected by petroleum fuels, making it ideal for this application.  

However,  the  Buna  N  is  slightly  porous, making it necessary to use a nylon barrier  to  prevent the fuel from contacting the sealant.
The nylon fuel barrier is an unbroken film of nylon.

The purpose of the nylon fuel barrier is to prevent the fuel  from  diffusing  farther  into  the  cell.  The  nylon  is brushed, swabbed, or sprayed in three or four hot coats to   the   outer   surface   of   the   inner   liner   during construction.

The  sealant  material  is  the  next  material  used  in fuel  cell  construction.  
It  remains  dormant  in  the  fuel cell   until   the   cell   is   ruptured   or   penetrated   by   a projectile.  
It  is  the  function  of  the  sealant  to  seal  the ruptured  area.  
This  will  keep  the  fuel  from  flowing through to the exterior of the fuel cell

The  mechanical  reaction  results  because  rubber, both natural and synthetic, will “give” under the shock of impact.
This will limit damage to a small hole in the fuel cell.

The fuel cell materials will allow the projectile to enter or leave  the  cell,  and  then  the  materials  will return   to   their   original   position.  
This   mechanical reaction is almost instantaneous.

The  chemical  reaction  takes  place  as  soon  as  fuel vapors penetrate through the inner liner material and reach the sealant.

The sealant, upon contact with fuel vapors, will extend or swell to several times its normal size.  This  effectively  closes  the  rupture  and  prevents the  fuel  from  escaping.  
The   sealant   is   made   from natural gum rubber.

The retainer material is the next material used in fuel cell  construction.  
The  purpose  of  the  retainer  is  to provide  strength  and  support.  
It  also  increases  the efficiency of the mechanical action by returning the fuel cell to its original shape when punctured.
It is made of cotton or nylon cord fabric impregnated with Buna N rubber.

very cool explanation, you learn something new on ARFCOM everyday

the knowledge base here consistently floors me...