Meillerwagen

After completing the process of fitting the warhead to the V-2 rocket, the Technical Troop used a 'strabo crane' at the transloading point to transfer the missile from the Vidalwagen to the Meillerwagen for transport to the launching point. Typically a Hanomag SS-100 tractor pulled the Meillerwagen up to 45 km/h (28 mph) forward with the rocket travelling tail-first – the maximum speed in reverse was 15 km/h since the Meillerwagen's pneumatic brakes could not be coupled to the tractor when being pulled backward.

After the Meillerwagen was close to the launch point, the Firing Platoon Truck Section took charge and removed the rocket's camouflage cover and rudder protection. The control compartment batteries, alcohol-filling connection, tools, and other equipment were loaded into a box on a strut at the top of the Meillerwagen's lift frame. The Meillerwagen was moved via hand winches to the firing stand and then levelled via the two extendable outriggers with end-jacks.[1]

Meillerwagen raising a V2 rocket

The rocket was raised via the Meillerwagen lift frame and hydraulics. When vertical, the rocket was suspended above the firing stand, which was raised to touch the rocket fins. Clamping collars were used to connect the rocket to the firing stand, and the Meillerwagen was withdrawn less than a meter and the rocket was turned a quarter turn for the fuel connections to face the Meillerwagen platforms, which were lowered into position for standing. A separate three-section extendable ladder, the Magirus ladder, was used for areas of an erected rocket not accessible via the Meillerwagen.[1]

The hydrogen peroxide tank on the Meillerwagen (126 litres) was filled from a 2120-litre tank truck with its own pump, then the rocket was filled from the Meillerwagen tank.[1] Additional Meillerwagen piping included the following.

The elevated lifting frame was fitted with piping to fuel the rocket with A, B, P, and T-stoff.

• A-Stoff: Liquid oxygen equipment consists of a pipe, which follows a circuitous route along the centreline of the lifting frame's lower half. The pipe is fixed on the lifting frame by brackets, and closed at each end by cast ramp-and-claw seals.
• B-Stoff: Ethyl alcohol equipment consists of a pipe which runs along the full length of the starboard beam of the lifting frame. The pipe is slung from the underside on straps, and closed at each end by threaded seals.
• P-Stoff: Compressed nitrogen (or compressed air) equipment to service the rocket consists of several batteries of compressed air tanks carried on the chassis frame, and a pipe fixed to the full length of the starboard beam of the lifting frame. The P-stoff batteries consist of one bank of six fixed tanks, and two banks of two removable tanks. (compressed air for the Meillerwagen pneumatic brakes was sourced from a separate set of two tanks across the front of the chassis frame)
• T-Stoff: High test peroxide equipment consists of a pipe which runs along the starboard beam of the lifting frame from the trunnion end to the halfway point. The pipe is fitted at the upper end to the triple valve assembly, consisting of two flow valves and a three-way valve. The triple valve assembly connects to two tanks, a large measuring tank and a smaller overflow tank. The measuring tank can be filled to the rocket's required amount of T-stoff, after which any excess flows down a stand pipe to the overflow tank. The measuring tank is fitted with a ventilation stud, which vents displaced air as the tank is filled. The ventilation stud includes a ball cock fixed to a frustum stopper, which blocks the vent stud in case of accidental overfilling so that T-Stoff does not spray from the air vent. Both T-Stoff tanks are fitted with an inspection window.

According to an official document of the time (5240/44GKdos) which describes a 110-minute launch, the Meillerwagen participates thus:

• arrival at launch site and dismount rocket; duration 20 minutes from X minus 110 to minus 90 minutes.
• fuelling of B-Stoff and T-Stoff; duration 20 minutes at X minus 55 minutes.
• fuelling of A-Stoff and Z-Stoff; duration 10 minutes at X minus 30 minutes.
• finalise rocket position, couple Meillerwagen to tractor, depart site; duration 5 minutes at X minus 13 minutes.

The lifting frame was fitted with outlet sockets and wiring for field telephones. A main connection from the armoured launch vehicle switchboard to inlet sockets on the lifting frame provided circuits for four field phone stations at the Meillerwagen – one each at the upper and lower folding work platforms and two at the launch table.

An early configuration of the Meillerwagen included hard-wiring of two electrical power circuits and two FLAK-plug circuits for the power and control needs of the rocket. The system included four sockets at the upper and at the lower end of the lifting frame, and the connective wiring fixed along the starboard beam. The four circuits were connected to two Stotz ejecting plugs, stowed with their cables along the side of the lifting frame. All of this wiring had become redundant by the time the rocket attacks began, but was not removed from the Meillerwagen.

The Meillerwagen chassis was fitted with a Notek tail light[2] at the rear, its patch plug at the front, and the connective wiring in a conduit along the chassis frame.

The lifting frame erected the rocket from horizontal to vertical, using hydraulic power. The hydraulic lifting equipment consisted of a hydraulic pump and its drive motor, a hydraulic fluid tank, a control valve group with manometers, and the lifting pistons themselves.

The drive motor was a petrol KdF (Volkswagen) 14 ps (hp) engine, adapted for stationary industrial use by the fitting of magneto ignition and a centrifugal governor to the throttle; besides these modifications, the engine was otherwise identical to those found in Volkswagen Beetles, an air-cooled flat-four boxer. The engine was housed in a metal box fixed to the chassis frame. A three-piston eccentric-cam hydraulic pump was coupled to the engine flywheel. (Meillerwagen at Operation Backfire were fitted with electric motors as hydraulic drive in place of the petrol engine.)

A 70-litre (15 gal) oil tank was fixed to the chassis frame as hydraulic fluid reservoir.

Oil under pressure flowed from the hydraulic pump to the control valve group consisting of three valves in a common housing, manipulated via one large cross-handle and two small hand taps. The large cross-handle regulated the speed of raising or lowering the lifting frame. One hand tap selected direction to either raise or lower the lifting frame. The second hand tap controlled oil flow to the lowering piston (see below), to begin lowering of the lifting frame from its vertical position.

The two hydraulic lifting pistons each consisted of one stationary cylinder and four extending telescopic cylinders. The largest extending cylinder included a flange halfway along its length, against which hydraulic pressure could be selectively applied from either above or below; it was used during raising to delay its extension until all other cylinders had extended, and also to begin the lowering process when the lifting frame was vertical (once lowering had thus been initiated, gravity finished the job).

All components of the hydraulic system were products of Meiller-Kipper GmbH, except the KdF drive engine from Volkswagen.

Acting as gantry, the lifting frame included a number of work platforms from which crewmen serviced the rocket. Three (later two) platforms folded flat against the lifting frame, and could be folded out from the elevated lifting frame with the use of a hand winch. Each folding platform included a safety rail of folding posts and chains.

Two side platforms or catwalks were inserted into holders for deployment on each side of the lifting frame, otherwise stowed together on brackets near the turntable. A rotating platform could be suspended from the rocket nose, to provide access to the rocket control compartments on the far side of the rocket.

The port beam of the lifting frame was fitted with around 40 rungs along its full length, with which crewmen climbed to the working platforms.

The lifting frame included two accommodations for the rocket, a nose clamp around the warhead and a pivoting clamp around the rocket midsection. Both accommodations included a saddle, and various mechanisms to assist dismount of the rocket onto its launch table. The mechanisms were operated with two drive shafts running up the port lifting frame beam. The drive shafts ran within the integral rungs, and were operated by a crewman with a ratchet hand tool. The two drive shafts comprised a short shaft and a long shaft; both starting at the trunnion end of the lifting frame, one running half the length of the lifting frame while the other ran the full length.

The short drive shaft operated the pivot clamp around the rocket midsection, which could move the rocket 28 mm (~1") forward or backward along its centreline. The rocket midsection was fitted with a band which included trunnion pins placed in opposition; the pivot clamp held the rocket by the trunnion pins. The pivot clamp was able to rock on a transverse shaft, thus causing the rocket to move along its centreline. After erection of the rocket to a vertical position, it was held suspended above the launch table; by use of the pivot clamp, the weight of the rocket could be gently lowered onto the launch table until fully taken up, allowing the rocket to be unsecured from the lifting frame, thus dismounting it from the Meillerwagen.

The short drive shaft operated a screw sleeve, which extended to work a bell crank. The bell crank turned a transverse shaft fitted with an eccentric cam, which would push or pull the pivot clamp, thus moving the rocket forward or aftward along its centreline.

The long drive shaft ran along the full length of the port beam of the lifting frame. It entered a worm gear at the pivot clamp, then continued to the nose clamp where it entered another worm gear. A shift lever at the nose clamp disengaged the drive shaft to allow either simultaneous or independent operation of the two worm gears. The worm gear at the pivot clamp operated a pair of scissor arms, one on each side of the lifting frame to insert or extract the trunnion pins from the rocket. The worm gear at the nose clamp operated the jaws of the nose clamp to either open or close, thus enclosing or releasing the rocket.