Flamethrower, Portable, No 2

The Flamethrower, Portable, No 2 (nicknamed Lifebuoy from the shape of its fuel tank), also known as the Ack Pack, was a British design of flamethrower for infantry use in the Second World War. It was a near copy of the German Wechselapparat ("Wex") from 1917.

The Mark 1 was used as a training weapon, while the improved Mark 2 was used in action. Over 7,000 units were produced from 1943 to 1944. They were ready for service during Operation Overlord (the Allied invasion of Normandy).

The Ack Pack was a harness carrying a doughnut-shaped fuel container with a capacity of 4 Imperial gallons (18 litres) of fuel on the operator's back. In the middle of the "doughnut" was a spherical container holding nitrogen gas as a propellant, which was pressurized to 2,000 lbf/in² (140 Bar). This was sufficient to propel the burning fuel 120 feet (36 metres). A hose from the fuel tank passed to the nozzle assembly which had two pistol grips to hold and aim the spray. One of the grips had the trigger. The Ack Pack nozzle was fitted with a 10-chambered cylinder which contained the ignition cartridges. These could be fired once, each giving the operator 10 bursts of flame. In practice this gave 10 one-second bursts. It was also possible to spray fuel without igniting it to ensure there was plenty splashed around the target, then fire an ignited burst to light up the whole lot.

At some 64 lb the flamethrower was considered heavy.

Popular Culture
One of these devices can be seen in the movie A Bridge Too Far, when the British troops decide to try a night assault on the Arnhem bridge, after their first daylight assault fails. The team sent misses the pillbox slit, instead igniting the shack behind the pillbox which explodes, as it has apparently been used to store ammunition. One of the operators is British actor Alun Armstrong.