420P9, Stahlring für F.N. Gerät (für Einbau in B) (FPzE 5034)
| Thickness on top | 125 mm |
|---|---|
| Weight | 2,5 t |
| Outer diameter | 540 mm |
| Inner diameter | 300 mm |
| Height (+ ceiling part) | 1646 mm (+ 300 mm) |
The 420P9 was designed for the Festungs Flammenwerfer also known as Festungsnahkampf Gerät. An armoured tube was also made for the F.N. Gerät in Baustarke A, the 457P01. However, it doesn't look like this part was ever used somewhere.
Probably because of the enormous fuel usage and the complexity of the weapon, the F.N. Gerät was not much used. They were part of the standard armament of the Oder-Warthe-Bogen Panzerwerke and Westwall B-Werke. Only two examples can be found in the Atlantikwall, built into a tunnel system at Ba 39 and 40 in Biarritz.
Below is a detailed description of the F.N. Gerät of Werkgruppe Seeckt (B-Werk No. 1520) near Irrel, also known as Katzenkopf, made by American Ordnance Technical Intelligence Team No. 3 (Capt. W.J. Lord, Sgt. John Jakovljevic and T/5 Otto Haas) and published on 3 June 1945. Except for several small changes this is the actual text from 1945.
a. This unit, the “F.N. Gerät”, is a disappearing type flame thrower unit designed for the neutralization of any assaulting enemy who might advance to the immediate neighborhood of the fort or who might be on top of the fort.
b. The range of this flame thrower, according to the instruction manual, is fifty-three yards (48 meters); traverse is 360°. The fuel is flame oil, ignited by acetylene, the oil being projected thru a one-half inch (13mm) diameter nozzle at the top of a circular steel shaft. The head of this shaft, normally covered by a mushroom shaped, armor steel, hood weighing about one hundred and fifty pounds (68 kg), is below the roof of the fort except when in the firing position when it is 16 inches above the earth on top of the fort roof.
c. The complete installation requires three levels: the roof, the control room (No. 27), and the fuel and pump room (directly below the control room). The main parts of the equipment are: the shaft or pipe, the mechanism for elevating and rotating the shaft, and the mechanism for throwing the flame.
d. The shaft (l) which projects from the control room, is seven and one-half inches (190 mm) in diameter. Inside, it carries the pipes for the flame oil and the acetylene, the ignition cable, and one reserve pipe. (Prisoner stated that this reserve pipe was for poison gas. No poison gas was found in this fort). The base of this shaft contains connections for the ignition cable and for hoses carrying flame oil and acetylene. The shaft is guided in an armored ring (2) which is set in the concrete of the roof, and in a flange (13). The upper part of the shaft is constructed of armor steel as is the hood (3). The head of the shaft contains the nozzle (4), three gasburners, and two sparkplugs.
e. The lower room contains the motor (3) operating the hoist mechanism for elevating and lowering the shaft and rotating it in traversel; in the upper room, No. 27, is a unit (15) for manual operation. In the corner of this upper room is the electrical control unit for operation of the flame thrower.
f. In the lower room, in addition to the hoist motor, are the 2500 liter (660 U.S. gallons) flame oil storage tank (23), rotary oil pump (27), pressure tank (16), nitrogen bottles (24), and acetylene bottle (25).
g. Operation:
- (1) The electrical control unit (Steuerung) permits the operation of the F.N. Gerät. By means of the motor (5) and drive (7) the shaft is elevated above the roof of the fort exposing the oil nozzle and the concentric gas opening in the head. When the head is in the highest position, the shaft begins to rotate by means of a transmission (10). An electro-magnetic valve (26) is opened feeding the acetylene (25) thru another flexible hose to its pipe in the shaft and thence to the burners in the head. At the same time the ignition unit is operated to fire the spark plugs, igniting the acetylene. The electric-magnetic valve (19) now opens allowing the flame oil under pressure from tank (16), to be forced thru the oil pipe (17), the flexible hose (18), and the pipe in shaft (1), to the nozzle in the head where it is ignited by the acetylene flame.
- (2) The maximum amount of flame oil thrown at one time is limited to 120 liters. (31.7 U.S. gallons). The F.N. Gerät is so adjusted that the flame oil will last thru three full revolutions of the shaft. After the oil is used up, the magnetic oil and acetylene valves are automatically cut off. At that time the rotary oil pump (21) is started, bringing 120 more liters of oil from the storage tank (23) to the pressure tank (16). Storage tank is filled from a pipe at one of the entrance doors to the fort.
- (3) The shaft rotates alternately clockwise and counter-clockwise each 360° of traverse, to prevent breaking of the hoses. The amount of traverse can be set and controlled, a mil scale being provided on the bottom of the traverse transmission unit (10), and the shaft can also be set to fire in one direction only.
- (4) In the event of failure of the power supply, the 24 volt emergency storage batteries can be used to operate the automatic oil and acetylene valves and the ignition unit. A hand pump (30) is provided to pump flame oil to the pressure tank (16). A hand crank is provided at (15) to operate the shaft elevating mechanism and traversing mechanism.
h. It appears, from the examination of the turrets and earth in the roof, that the flame thrower of this fort had not been used to defend it. No doubt the accuracy of the tank destroyer crews during firing on the machine gun turrets convinced the personnel in Panzerwerk Seeckt No. 1520 that surrendering was the better part of valor. The accuracy of the 76th Division, XII Corps, riflemen, whose small arms' fire against the mirrors of the disappearing telescopes of the mortar, artillery observer and machine gun turrets was so effective, no doubt increased the desire of the fort personnel to see again the open sky over their beloved Deutschland, past the border of which they were soon to journey to the protective enclosure of a prison stockade.
