Self Sealing Fuel Tanks

Thanks. I hope to be doing this for a very long time. I love the work.

If its in your blood, you're always be in this business. At times its been rough, but I can't imagine doing anything else, well maybe Bordello Management

Yeah I thought about renting myself out!

Its just a living, someones got to do it.

What Italian and Soviet aircraft from WW2 had self-sealing fuel tanks?

As a general rule it seems Italian aircraft did.

I don't have any production narratives but as early as November 1940, the crashed CR.42s and BR.20s examined in England all had self-sealing tanks (though no armour plate).

You might try looking at this document: http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-T/download.php?spec=MIL-T-5578C.013565.PDF

It is a pdf of the spec for self-sealing tanks. Basically, it specified a tank that withstands the vibration from flight, takeoff and landing (Protection A) and from the hydraulic effect of gunfire and engine damage (Protection B). Interesting read.

Glider said:

Matt. My understanding is basically the same as yours as to how it works, ie the rubber melting back to fill the hole. There is an example in Duxford of a Typhoons self sealing tank which works on the same principle. As to who had them first I don't know but Germany and the UK seems to have developed the basic idea at the same time. In the Battle for France the British suffered heavy losses because of the lack of self sealing tank and armour for the pilot. By the BOB both the Germans and ourselves had the same solution so I would call it a draw. Proof I suggest that necessity is the mother of invention.
The gas was different. I could be wrong here but my belief is that it wasn't there to stop the tank from leaking, more to stop the explosive gas from blowing up.

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Some Russian aircraft had a system that ducted engine exhaust gas into the fuel tank voids, the MiG 3 for sure. There are two requirements for getting an explosion in terms of fuel/air vapour concentration. 1 by being above the LEL (Lower Explosion Limit) and 2 by being below the UEL Upper Explosion Limit. By putting in an inert gas you greatly reduced the chance of having an explosion. Modern fighter aircraft generate their own oxygen from an oxygen concentrator system. I imagine the by-product nitrogen is channelled into the fuel tank voids.

Early uses using nitrogen were on the Handley Page Halifax III and VIII, Short Stirling, and Avro Lincoln B.II, which incorporated inerting systems from around 1944 according to Wikipedia.

I think many aircraft also had bladder tanks. If these were penetrated they might rapid form an explosive atmosphere when they leaked into the void of the tank space.

From recollection the self sealing walls of the Do 217 were an inch thick but again used rubber. It's worth mentioning that the Germans had a terrible time getting natural rubber, although they were able to manufacture buna-s and buna-n synthetic rubber it worked much better when a proportion of natural rubber was added (10%-20%).

A CIOS report I read said that the Germans had developed explosion and fire resistant gasoline fuels and this mentioned that the allies had as well. They were never implemented due to cost. This of course conforms to what we know about explosion resistant jet fuels which have never been commercially deployed despite being developed. The SR71 used a jet fuel which has such properties since the fuel tended to leak and was used as a heat sink for hypersonic flight. Kerosene and diesel is of course generally safer than gasoline due to its lower vapour pressure but I have been told that pure iso-octane can be used to douse out fires it so reluctant to ignite. (don't try at home, its hearsay)

Matt308 said:

As many of you know the self sealing fuel tank was quite a leap in technology in the early last century. I have a couple of questions.

1) Who (person/country/company/etc) invented self sealing fuel tanks?

2) When?

3) In what airplane were they first installed?

4) Can you describe the technology used?

Here is what spawned my question. I do know that the Germans made use of self sealing fuel tanks in Do17s during the BoB. The fuel tanks were surrounded by a 1cm liner that consisted of alternating layers of vulcanized and non-vulcanized rubber. The final outer layer was actually leather. Apparently, a rifle round would penetrate this outer 1cm thick liner and the resultant fuel leak would set up a chemical reaction that would literally melt the rubber back together. I am assuming the leather was an expedient means of containing the inner layers and prohibiting a "runaway" chemical reaction.

The above questions are hopefully going to stimulate some discussion of the origin of self sealing techniques and where they originated from.

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Hi

Although this is an old thread that has re-appeared I thought I would just add some information on the origins of 'self-sealing' fuel tanks from a report by the USAS at the end of WW1. There is a list of various tanks plus some detail of the 'Imber' tank.

Mike

Vahe Demirjian said:

What Italian and Soviet aircraft from WW2 had self-sealing fuel tanks?

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Soviet.
Some of those types:
R-10
I-153
DB-3/Il-4
MiG-3
Yak-7
Yak-9 (Yak-9DD from the start)
Pe-2
LaGG-3
Yer-2
La-7
probably:
latest SB-2 after modifications done by the team of Arkhangelsky and Ar-2.
Su-2 of later production, after summer 1941.

And more thread necromancy ...

See Exploding Fuel Tanks by Richard L Dunn. Seems to be a self-published volume.