Sorry if this is already covered elsewhere - I found it interesting …
Flamethrower -
From http://www.canadiansoldiers.com/mediawiki-1.5.5/index.php?title=Flamethrower#Lifebuoy
While the use of fire as a weapon dates back to antiquity, the first modern mechanical flame-throwing weapons originated in the First World War. The first such weapon was used by the Germans in Feb 1915 at Verdun against French troops, and then at Hooge in Jul 1915 against British trenches. Allied armies experimented with, but never adopted, flame weapons.
The Canadian Army first used modern flame weapons during the Second World War.
Contents
1 Man Portable
2 Vulnerability
3 Vehicle Mounted
4 Notes
Man Portable Lifebuoy -
The Flamethrower, Portable, No.2 (nicknamed “Lifebuoy” from the shape of the fuel tank, and not after the popular brand of soap), was a British design of flamethrower for infantry use and was used extensively in the Second World War.
Mark I was a training weapon
Mark II was used in action.
Over 7,000 units were produced from 1943-1944.
A harness carried a ring-shaped fuel container with a capacity of 4 Imperial gallons (18 litres) of fuel, which was strapped to the operator’s back. In the centre of the ring was a spherical container holding propelling gas pressurized to 2,000 lbf/in³, sufficient to propel burning fuel 120 feet. A hose from the fuel tank passed to the nozzle assembly which had two pistol grips; one to assist holding and aiming the nozzle, and the other with a trigger. The nozzle was fitted with a 10-chambered cylinder containing ignition cartridges, and each could be fired only once. In practice the operator usually fired in 10 one-second bursts. It was also possible to spray fuel without igniting it, in order to provide combustibles to the target before using the flame.
The unit weighed 64 lbs fully loaded, making the weapon both heavy and cumbersome. During the attack on Kapelsche Veer, a number of Lifebuoy operators were killed due to difficulties moving over snow and ice with the weapons. The drawbacks of the weapons were many, including limited range and reduced mobility of the operators. Optimum conditions for their employment included close-in terrain and a covered approach to the target, either by concealing terrain or by supporting fire.
Vulnerability -
However, a Hollywood myth perpetuated by films like Saving Private Ryan bears some scrutiny here:
It should be noted that flame thrower operators did not usually face a fiery death from the slightest spark or even from having their tank hit by a normal bullet as often depicted in modern war films. The Gas Container is filled with a non-flammable gas that is under high pressure. If this tank were ruptured, it might knock the operator forward as it was expended in the same way a pressurized aerosol can bursts outward when punctured. The fuel mixture in the Fuel Containers is difficult to light which is why magnesium filled igniters are required when the weapon is fired. Fire a bullet into a metal can filled with diesel or napalm and it will merely leak out the hole unless the round was an incendiary type that could possibly ignite the mixture inside. This also applies to the flame thrower Fuel Container.(Weapons of the WWII Tommy)
Research by John D. Salt at the Public Records Office in the United Kingdom has unearthed other interesting operational research of flamethrowers in action with British forces in the Second World War.
Document WO 208/2112, “Translation of German flamethrower manual”, states:
In order to give the men a greater sense of security attention should be drawn to the fact that should the weapon be struck by an infantry bullet or shell splinter it will not explode.
Salt’s research also finds that operational research conducted during the Second World War found that the main effects of flame weapons were on enemy morale as opposed to physical effects. According to Salt:
The disproportion between prisoners and casualties resulting from flame attacks is mentioned in WO 291/308, “Effect of flamethrowers on military personnel”, which says that information from flame actions showed an average expenditure of 270 gallons per death, 9 gallons per prisoner.
Physical effects are discussed in WO 231/32, “Notes on Wasp and Lifebuoy”
An attack by flame depends largely on its terrifying effect for its success. Troops familiar with Flame Throwers will offer greater resistance than those inexperienced.
It is difficult to get large quantities of burning fuel in through the slits in a pill box. Anti-ricochet slits and flaps afford additional protection.
The occupants of a pill box are fairly safe if they retreat behind the partition wall.
As a counter measure to flame weapons, the report (according again to Salt) “advises that woollen blankets and greatcoats, especially if wet, give good protection against radiant heat, but should be easy to remove in case they do catch fire.”
Another PRO document, WO 291/986, entitled “The operational effectiveness of the flamethrower tank (Crocodile)” states:
a) Flame was most effective against houses and fortified buildings. There were invariably set on fire and gutted.
b) Open defences among woods, hedges and undergrowth provided good targets as the vegetation was easily set on fire.
c) As would be expected, flame was least effective against pillboxes and the like; only if it could be projected through apertures to the inside did the occupants suffer.
Salt further comments on his research
The difficulty of using flame against entenchments is commented on in WO 291/1060, “The A45 flame gun versus the Panzerfaust”. This report refers to earlier research using the Wasp flamethrower, which it says shows that “a frontal shot of ignited fuel does negligible harm to men in a slit-trench providing they keep their heads down.” The trench should either be enfiladed, or an unignited (“wet”) shot fired first. Because of the different ballistics of ignited and unignited fuel, it is likely that two unignited shots may be needed. It is also stated that, if wind conditions are such as to affect shooting, the first shot will usually be wasted, used for indicating wind direction.
The number of manpack flamethrowers required to reduce a pillbox or bunker seems considerable. WO 232/70, “Flame throwers – Exchange of information with Red Army” says “The number of flame throwers allotted to an assault group formed to attack a pillbox depends on the number of embrasures. On an average 3–4 flame throwers are allotted per pillbox.”
Nonetheless, WO 232/35 “Reduction of Japanese bunkers” says that “At Tarawa M3 tank flame throwers reduced pill boxes when all other attempts had failed.”
Finally, …effectiveness against AFVs was known to be poor. WO 291/1139, “Drop tank incendiary bombs used in the anti-tank role”, mentions that trials of flamethrowers against AFVs showed that it was difficult to get fuel inside the AFV. An open driver’s hatch would admit fuel; an open commander’s hatch with more difficulty, as it was harder to “loft” the fuel to turret height. Hits on the (internal) mantlet area of the Churchill admitted fuel. Vehicles with engine louvres on the rear deck could be disabled by flaming from the rear, which ignites fan-belts and damages ignition wires. It is pointed out that attack from above, as with an air attack, seems to be the most favourable aspect when using flame.