Luftwaffe Gunner's Trainer: The German Training Camera-Gun MBK 1000
By Michael Heidler
The training of aircraft gunners is an important but difficult task. In order to avoid the risks associated with shooting on towed flying targets and reduce the consumption of expensive ammunition, the German Air Force looked for a suitable training aid. In cooperation with the aeronautical authorities, the well-known optical company Zeiss Ikon AG from Dresden developed two special “camera-guns” (Lichtbild-MG) before the Second World War: the “MBK 1000” for mobile installation in bombers and the quick-film camera “ESK 2000” designed for fixed installation in place of the machine gun in fighter planes. These two devices were used not only by Germany, but also by foreign air forces.
The Zeiss Ikon camera-guns capture the entire aiming process on film as long as the gunner is “shooting” with his machine gun from an airplane. In conjunction with a scientific evaluation of the film reel, the entire battle situation can be reconstructed after the flight. It is possible to identify which shots would have hit the target and to determine the aiming mistakes of the gunner. The predicted fire can be analyzed without any conversion.
The MBK 1000 is mounted in the airplane in the same way as the standard light machine gun model MG 15. It can be separated into two pieces for installation on mounts with a cupola. Its appearance, handling, sighting device and wind vane are just like those of the real thing. The drive of the camera is powered by a spring mechanism, which is housed in a special “spring drum” (Federtrommel). Its housing resembles the standard double-drum for the MG 15, and both drums insert into their devices in the same way. The drum contains two springs and one regulator to slow down the movement of the springs. Using a pluggable wrench, the springs can be wound up. The strength of the springs is exactly adjusted to move 75 photos (corresponding to the real drum that contains 75 rounds of 7.92x57 ammunition). The spring drum can be stored in all drum racks and holders in aircraft that were suitable for the MG 15 double drums.
The film images show the points of aim, the exact time when the trigger was pressed and a writing tablet on which the combat training, the fights and the aircraft types are listed. An additional picture section shows the position of the wind vane. For each training film, a cassette with 22 meters of standard film was used. This length corresponds to 1125 movie picture frames. Fourteen pictures are taken per second, corresponding to a rate of 840 images per minute. Analysis allows the hits on the target, and hence the winner of the fight, to be determined.
The housing of the MBK 1000 is tubular, with a lid on the right side to get access to the film cassette. The front end holds a cast-iron head that carries the wind vane or a spider sight (Kreiskorn) on top and the clock on its underside. Additionally, the front side of the housing is covered with a plate of glass to protect the sensitive camera lenses. On the rear end of the housing, four control devices can be found: top right—a counter that shows the 75 shots; top left—a control for the barrel; below—a selector switch for the yellow filters; and bottom right—the switch for the lens apertures. Three yellow filters can be swiveled in front of the main lens. The different filters are marked with colors that can be seen in a small cut-out (white, yellow, red and blue). An additional glass plate with etched concentric circles is pictured on every photo. This allows distances to be calculated. The housing is painted black with white inscriptions.
The complete stock with grip-piece can be detached from the camera. Both are held together by a bayonet joint with a safety bolt. A pivot serves to fix the camera-gun in the mount. One pull of the cocking handle is used to tension the recoil spring before a new 75-round series begins. The grip-piece and trigger mechanism are the same as those of the MG 15. At its handle end is a drill hole that can be latched to immobilize the device when it is not in use.
The same leather spent brass catcher bag as used with the MG 15 could be fixed to the MBK 1000. It serves no other purpose than to make the handling of the camera-gun more realistic.
The sights are the same as on the standard light machine gun model MG 15 and are used in the same way. The optical device is made of the main lens and two smaller lenses. The main lens with a light intensity of 1:1.5 and a focal length of 25 millimeters is used to film the shots. Another lens films the clock and the writing tablet. The third lens films the wind vane. The clock face is divided into 300 parts. The second marks are printed in bold and every second is subdivided into five parts. Above the clock is fixed an exchangeable label. It is used to note the name of the gunner and information about the exercise. It is filmed together with the clock.
The counter on the rear of the housing counts the photo-series, each consisting of 75 photos. A 22-meter film is good for 15 series of 75 photos. After inserting a new film cassette, the counter has to be set back to zero by turning a knurled knob. The gripper inside the housing for moving the film reel is powered by the spring drum.
By pulling the cocking handle back, the firing pin is cocked in the same way as on the standard MG 15. After pulling the trigger, the firing pin is pushed forward. This connects the clockwork of the spring drum with the drive of the camera. When the trigger is pulled again, a little nib is retracted, and the drive begins to run for as long as the trigger is pulled. A complicated assembly of gearwheels and couplings puts the other devices (the clock, counter and so on) into motion.
Once the films were developed, the moment of truth came for the prospective gunners. Two stands, slightly offset from one another, would be placed in front of a white screen. One would hold the MBK 1000 and the other one a special film projector. Additionally, there were educational charts for determining the angle of flight and a transparent template with circular speed markings that could be placed in front of the projector. A probable hit was assumed if the enemy’s speed and angles of flight were correctly estimated, the sight followed the trajectory of the target and the distance was not more than 400 meters. The film in the projector was moved by hand and could at any time be stopped for more precise evaluation and discussion of an image. The results were written down in a notebook.
According to the instructions, after about 200 meters of film (nine cassettes) the camera had to be partially disassembled and cleaned, because dust and abrasion of the films could make the lenses cloudy. The cleaning was carried out only with brushes and soft cloths. From time to time, the plush seals around the entry and exit openings for the film had to be exchanged. When not in use, the camera-gun could be stowed together with its accessories in the “Storage box for MBK 1000” (with a total weight 42kg).
Today, the MBK 1000 is a very rare and highly desirable collectors’ item. The device pictured here (serial number 12067) is the later “B” variant with some minor changes in design. For example, it features two image lens systems that simultaneously record the aim on the target and the internal clock for each “shot.” It came from the collection of Dr. Sturgess and will be auctioned off by James D. Julia.
Thanks to James D. Julia Auctioneers, Fairfield, Maine, USA (www.jamesdjulia.com) for the photos.
This article first appeared in Small Arms Review V22N3 (March 2018) |
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