The Kommandogerät 40 was a German analog fire control computer used during World War Two for directing anti-aircraft artillery, particularly the 88 mm FlaK 36 and 37 guns and 105 mm Flak 38 and 39 guns. It was a mechanical predictor system that calculated the target’s speed, altitude, and trajectory to provide accurate firing solutions. The device required input from rangefinders and spotters to adjust for wind, lead angle, and shell flight time. Typically deployed alongside a (mobile) Würzburg radar, it significantly improved the effectiveness of German flak batteries against enemy aircraft. Its advanced computing capabilities made it one of the most effective gun-laying systems of the era.
The Kdo-Gerät 40 in these pictures is combined with the Raumbildentfernungsmesser (Eng: rangefinder) 4 RL designated Em4mRL. This 4-meter stereoscopic rangefinder was a crucial instrument for precise distance measurement in anti-aircraft artillery to base its fire control calculations on.
Operation
The Kommandogerät 40 was the successor to the Kommandogerät 36. The device was developed at Zeiss Ikon in Dresden, Germany, and introduced in 1937. From 1941 it was used on a larger scale in defense of the growing number of Allied bombing raids.
With the permanently mounted rangefinder of 4 m base length, the distance to the target is measured and mechanically fed into the calculation process. Two sight-adjusted angle measuring devices are mounted parallel to the sight line on the rangefinder. The elevation finder determines the target’s elevation angle and inputs it into the calculation. The azimuth finder keeps the target aligned in the horizontal direction, thereby feeding the azimuth changes into the calculation. These three measured values serve as input parameters and form the basis for fire control calculations.
Compared to the Kdo-Gerät 36, the Kdo-Gerät 40 can account for deviations from a straight-line course.
The Kommandogerät was transported on a special trailer 52.
Rangefinder 4 RL
The stereoscopic rangefinder was used to determine the distance to a target for the heavy weapons of anti-aircraft artillery. It was used on the Kommandogerät 40 or mounted on a stand in combination with the command auxiliary device. The measuring device does not require a special correction device.
The device includes two aiming telescopes (12×60) for azimuth and elevation and one double observation telescope (12×60).
Specifications
- Measuring principle: Stereoscopic illuminated mark
- Measuring range: 1.2 to 100 km
- Measuring base (baseline): 4 m
- Magnification: 32x
- Entrance pupil: 50 mm
- Exit pupil: 1.6 mm
- Field of view: 33 m at 1000 m
- Eyepiece adjustment range: ±6 diopters
- Interpupillary distance adjustment range: 56 to 74 mm
- Year of introduction: After 1940
- Year of manufacture: Around 1942
- Weight: 220 kg
- Manufacturer: Carl Zeiss, Jena
Special Features
- Viewing angle for aiming direction is inclined by 80°
- Electric illuminated measuring marks
- Unlike the 4m R40, the magnification is not adjustable
Operating Ranges
- Azimuth angle at measuring point: 0 – 360°
- Elevation angle at measuring point: 0 – 90°
- Target distance at measuring point: 1200 m – 18,000 m
- Target distance at impact point: 600 m – 17,000 m
- Target distance at hit point: 800 m – 14,500 m
- Measuring height: 0 – 11,800 m
- Hit height: 0 – 11,800 m
- Horizontal target speed: 0 – 300 m/s
- Vertical target speed: 0 – 200 m/s
- Horizontal deviation distance: 0 – 6,000 m
- Azimuth retention: ± 60°
- Elevation retention: ± 90°
- Horizontal position difference: 0 – 500 m
- Vertical position difference: ± 210 m
- Shell flight time: 0 – 30 s
- Operational steps: ± 22 levels
- Weight in firing position: 1595 kg
- Year of introduction: 1940
The Kdo-Gerät 40 with Entfernungsmesser 4 RL combination is on display at the Wehrtechnische Studiensammlung in Koblenz, Germany.
