Sunday, August 21, 2016

Vehicle of fire

Due to real life circumstances, and this article in its original form being quite a bit longer than anticipated, I'll be splitting it into two parts. 

Last week we had a look at handheld flamethrowers. Well the documents I read also covered vehicle mounted flamethrowers. This week, and next, I'll be covering those, although the information was only on Allied designs.

The British had the most famous vehicle mounted flamethrower, and it was the most efficient and successful. The following is a brief run down of the Crocodile so you can get an idea of its standards and then we'll have a look at some of the US designs.
The Crocodile started life as a Churchill Mk.VII infantry tank. An armoured trailer was attached to the back to carry the fuel and pressurisation gear, while an armoured channel ran along the underside of the tank. This channel had a plough attached to the leading edge to keep any debris away from the fuel pipe. The fuel pipe itself ran up through a hand-out hole, built into all Mk.VII's. This was normally used for cleaning and getting rid of waste. The hand-out hole was just behind the hull gunners position, from there this fuel line split into two pipes leading into the flame gun.
The flame gun itself was electrically powered with the tank commander having a control on the circuit. This enabled him to arm the gun or make it safe. The same circuit also allowed him to jettison the trailer.
The flame gun itself had three settings on it: "Safe", which rendered the trigger lifeless. "Ignition", which fired an ignited round, and just to be confusing, "Fire", which fired a unignited stream of fuel. The latter were termed "Wet" shots. The gun could elevate +15/-10 degrees and traverse seven degrees left and eleven to the right.
The six ton trailer was made out of 14mm armour plate, apart from the roof which was only 6mm. The 20" tyres were run flat designs and it had a ground clearance of one foot nine inches. The mount to the tank was a marvel of engineering. It allowed the trailer to rotate through 180 degrees in any direction, and still supply fuel, and could be jettisoned on command. When the trailer turned to far to the left or right a red or green light would light up in the driver's compartment informing him of the rotation of the trailer.
Inside the trailer lay five nitrogen bottles, each charged to 3000 lbs/sq. inch. These notoriously started leaking almost immediately and so charging was normally left to the last moment.  These all fed into a common hub which then fed into one of the fuel tanks.
Both the fuel tanks were located on either side of the trailer. They were seven feet, five inches long with a two foot six inch diameter. These contained the 400 gallons of fuel carried by the tank. Each fuel tank was linked in series, with the gas charge feeding in  the back of the series, and the fuel pipe to the flame gun out the front. Range was 140 yards and the Crocodile could fire between 80-85 shots, each lasting one second, this gave a discharge rate of about 4.5 gallons per second. To give you an idea of how much that is, that's about the same amount of water as comes out of a normal shower in three minutes fired out in one second.

Next week we'll have a look a three US projects, and another British flamethrower project. Plus the effect of flame throwers.