'Diesel fuel as a filler of composite armour' & 'variable form charges' info please

[Pioneer]

G'day all

Last night I spent the even reading up on the Soviet Object 490/490A tank program.
A couple of think I was fascinated with and in vain attempted to research further into was the 'Diesel fuel as a filler of composite armour'; as well as the 'variable form charges' to have been employed as part of its 152mm smooth bore gun armament.
http://btvt.info/7english/490_eng.htm

If anyone has any information/links on the research and finding of these two subject matters it will go someway in helping me understand these principles somewhat better.

P.S. Am I right to think and understand that the Israeli Merkava MBT incorporates this 'fuel composite armour' configuration?

Thanks in advance.

Regards
Pioneer

 

[Apophenia]

A link in that article - Diesel fuel as a filler of composite armor (in Russian) - does give a few, minor details.

Test articles were comprised of two angled armour plates spaced 100 mm apart. Fuel was placed between those steel plates in polyethylene containers. Conclusions were that the outer plate should be of high-strength armour steel - to protect against sub-calibre projectiles - while the inside (and side) walls of this 'sandwich' could be of steel, aluminum alloys, or plastic.

https://www.secretprojects.co.uk/threads/kharkovs-object-490-buntar-bokser-and-object-477-molot-advanced-tanks.22005/page-3

In this thread, Andrei_bt confirmed stealthflanker's supposition that variable-form charges meant flexible casings.
https://www.google.com/search?q=can...Du54KHUFkAtwQ9QF6BAgKEAE#imgrc=oS1RSgnOINjYcM

 

[Pioneer]

Thank you for the links Apophenia
They are helpful and go someway in helping me understand a little more in these fields.

Regards
Pioneer

 

[overscan (PaulMM)]

Diesel as a filler for arnour is basically related to spaced armour. Spaced armour is effective against shaped charges by detonating the charge on the outer armour plate and then putting a lot of air between it and the rear plate. Filling the gap with diesel serves two purposes.

Firstly, diesel is more resistant to the shaped charge (actually, more efficient than steel, per gram, you just need a lot of diesel) than air and therefore disrupts the shaped charge more than the air gap. How efficient is debatable - I've seen a figure of 30% more protection for the spaced armour with diesel, for example.

You obviously have to use some kind of plastic cell arrangement to contain damage.

Secondly, spaced armour is space-inefficient, as it means your tank contains large void areas you can't use. Sticking fuel in the spaces potentially means a smaller tank as you won't need a separate fuel tank.

 

[Pioneer]

Thank you overscan.
So in effect, you'll almost need a sophisticated fuel management system to manage the fuel usage that ensures that your frontal fuel is used last....so as to ensure your principle armour level is retained...

Regards
Pioneer

 

[Grey Havoc]

G.S.O.R. 1008. thread.

 

[Charlesferdinand]

In the Dark Age of Tanks, David Lister details the tests of using diesel as armour for the British Contentious project. The concept seems to have worked very well. When a partially filled fuel tank was penetrated, a light explosion occurred. This was too weak to do any damage to the tank itself, but immediately used up all the oxygen, and so prevented any fire starting in the fuel tank itself. It was calculated that 3 inch of fuel thickness equalled 1 inch of armour plate.