The following intelligence report on gyroscopic compasses used in German tanks was originally published in Tactical and Technical Trends, No. 7, Sept. 10, 1942. [DISCLAIMER: The following text is taken from the U.S. War Department publication Tactical and Technical Trends. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]

GYROSCOPIC COMPASSES IN GERMAN TANKS A German Mark II tank with an electric gyroscopic compass has made its appearance in Libya. It is possible that all commander's tanks may be equipped with this particular device. The whole equipment is first-class in quality and workmanship. It is not likely that breakdowns will occur to any great extent, and the equipment should give long service without overhaul. The main components of this instrument are the generator and the gyro, connected to each other by a flexible multicore cable. Switches for operation and lighting are fixed to the casing. The motor generator is housed in a separate casing which may be placed in a convenient location in the vehicle. A 12-volt motor drives a three-phase alternator supply to the gyro. The whole arrangement is compact, and appears fully suppressed and screened to avoid radio interference. Fitted to the dashboard in front and to the left of the driver, the gyroscopic instrument consists of a small box with a panel showing two cards rotating in a horizontal plane. A switch and two control knobs, one for each dial, are added features of this equipment (see accompanying sketch). German Electric Directional Gyroscope To march on a certain point, a celluloid disk, marked around the circumference in clock-rays, is centered on the position of the tank on the map with 12 pointing due north. A thread leading from the center of the disk is joined to the point on the map which is the objective, and thus shows, in terms of clock-rays, the bearing of the objective from the tank. This is termed the "march number." The indicator must be set before using. This is done by finding the course of the tank, setting the gyro, and starting the gyro and allowing it to gain speed. The course is set on the course-setting dial and the tank steered until the dial markings on both dials coincide. A special compass is provided to find the tank's course. It has a glass marked with clock-ray divisions. The compass user must not stand nearer than 15 yards from the tank when finding its heading. Setting of the gyro is done by turning the gyro dial with the setting knob until it is the same as the tank's course previously found with hand compass. After setting, the gyro must be started and allowed 3 or 4 minutes to gain speed; it then must be set free by pressing the release button. The course-setting dial is to assist the driver in keeping to his course without constantly remembering what the actual bearing is. Therefore, the dial is set to the desired course (or march number) and the tank then steered to make the top dial figures keep opposite the lower (gyro) dial. Resetting of the indicator may be necessary, either periodically because of deviation, or because exceptional tilt temporarily interferes with the internal mechanism. When this occurs a red warning-light is shown.

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