The fortress flame thrower - FN device
Due to erroneous descriptions of the fortress flame thrower in some books (also in that of the self-proclaimed Ostwallexpertin Christel F. from B.) we take this as an opportunity to describe the structure and operation here in more detail. The following text has been taken from the Waffen-Revue 98 with the kind permission of DWJ-Verlag.
"The fortress flamethrower was installed during the Second World War between Schartentürme in the fortifications (Westwall, Atlantikwall). He had the task, if it infantry, infantry, pioneers, paratroopers, etc., should manage to push forward to the towers, to drive them out or destroy them. But it could only be effective if, before it went into action, it was not recognized as such by its opponents. Therefore, the upper end of the flame thrower system was closed only with a small and flat dome and camouflaged accordingly. Only when the approach of the enemy was reported, drove the jet pipe out under pressure, the dome opened, when the jet pipe has taken the correct position, a sign is automatically triggered in the control room, whereupon the launcher is operated.
The flame thrower system consists of:
1. hydraulic part,
2. machine part
3. electrical part.
The Flammenwerfergerät consists of a reservoir with about 2400 liters of flame oil, a bottle with 400 liters of nitrogen, a hand-pump, with the flame oil from the reservoir is pumped into the pressure vessel over, to which also a nitrogen cylinder is connected to the electrically auszufahrenden jet pipe another nitrogen cylinder for the ignition. The nitrogen bottle must remain permanently attached to the pressure vessel to prevent pressure drop.
The casting time is 420 seconds = 7 minutes.
The filling per litter is 3 minutes.
The total duration of the fight is 64 minutes.
With a standard charge of 80 liters, a pressure of 18 atm. produced, with 120 liters is a pressure of 25 atm. generated.
The launcher reaches a throw range of 40 to 50 m, the maximum throw is about 65 to 70 m.
From the pressure vessel with a capacity of 200 liters, about 120 liters of flammable oil can be thrown in about 21 seconds, which means that 3 circles of 7 seconds each can be smeared. Since the jet can be swiveled 360 ° sideways, the terrain can be painted all around, but it can also be delivered in one direction bursts of fire.
The pressure vessel can be refilled in 2.5 minutes, and the system is ready to be re-used after about 3 minutes.
To ignite the flame oil is sufficient a pilot flame of 20 to 30 cm, which is generated by spark plugs at DC 24 volts.
The electrical system is designed for 220 volts AC and 24 volts DC. There are five lamps on the right and left. The signals mean:
- red lamp = not ready to throw
- white lamp = pressure vessel filled
- green lamp = jet tube extended, device ready to throw.
In case of power failure, the power is taken from batteries.
Furthermore, a rectifier for ignition and operation of DC and emergency battery is available. ... "
As far as the text from the weapons revue.
In total, the fortress flamer was installed 26 times in the OWB, of which 24 times in the middle section. The flamethrower was protected by a steel ring 420P9, which in principle was a strong steel tube with a plug at the top. The steel ring was bolted to the substructure of the ceiling during installation and then embedded in concrete. These tank components are preserved for the most part, despite demolition and metal removal (Pz.W. 864?).
Based on the well-preserved flame thrower in Pz.W. 720 we explain the basic installation in a bunker. The flamethrower was set up in two superimposed rooms of equal size. These are connected by a rectangular opening in the bottom of the upper room. Access is only via the upper room, which served as the control room. An inward opening, two-piece reinforced door, and a gas door to the corridor separated this area from the rest of the bunker. When you enter the control room, you immediately notice the beam pipe. It is located on the left side of the wall, partly in the opening to the lower room and in the ceiling in 420P9 steel ring. Two bars attached to the underside of the steel ring served as a guide for the extension of the jet pipe and extend to a wall console in the lower room. The jet pipe was extended by means of an electric motor (power transmission via chain) or by hand. On the wall opposite the entrance are also the holder of the nitrogen bottles and remnants of the old pressure line available. By way of crampons embedded in the wall, one arrives in the lower room, which for reasons of safety did not have access at ground level. Here are the reservoir for the flame oil and the pressure vessel. In addition, parts of the pressure line have been preserved here as well.
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