d. Use of Dummy Guns and Dummy Positions
In keeping with the practices of active deception mentioned in the previous paragraph, the Germans employ dummy gun positions and dummy guns. The latter are usually employed along probable lines of air approach, and it is known that dummy gun flashes have been used. Furthermore, mobile guns may rotate through the various dummy positions, thus precluding any safe conclusions, based on hostile air reconnaissance, as to the existence of a set system of dummy positions.
e. Disposition of AA Guns in Rear Areas
(1) General.—In heavily defended areas, heavy guns are disposed on the outskirts with special attention to the expected lines of approach. A certain number of positions will be in the area itself, and will be situated about 6,000 yards apart where the target is a large one. Light guns are concentrated at particularly vulnerable points, such as factories and docks. They are occasionally emplaced on lines of approach, such as canals, rivers, or arterial roads. For isolated vulnerable points, the disposition of defenses is a special problem which varies with the nature of the particular target. For example, airdromes generally have 12 or more heavy guns, none placed nearer than 2 miles, and 12 to 30 light guns, none located nearer to the perimeter than 500 yards.
(2) Heavy guns.—(a) Four-gun positions (fig. 17).—In the normal four-gun layout, the guns are sited roughly in a square of approximately 70 yards to a side. A fully equipped position has two command posts, which for convenience may be termed Command Post No. 1 and Command Post No. 2. Command Post No. 1 is usually situated about 100 yards to the side of the gun layout, and contains the Kommandogerät, which transmits data by cable to a junction box located in the center of the square, and thence to each of the four guns. Command Post No. 2 is located approximately in the center of the square, and normally contains the auxiliary predictor (director), with its separate height- and range-finder. Communication from the auxiliary predictor to each gun is by telephone. The fire is normally controlled from Command Post No. 1; in the event of destruction or failure of the Kommandogerät or the transmission system, fire is controlled from Command Post No. 2.
Depending on the terrain, 20-mm guns are normally located between the gun layout and Command Post No. 1 in order to provide protection against low-flying aircraft.
Figure 17.—4-gun layout.
In a great many cases, the normal four-gun layout has only one command post, either in the center or, more frequently, to the side. The provision of two command posts depends partly on the importance of the locality and partly on the availability of equipment.
It is interesting to observe that wherever the existence of radio-location fire control has been suspected or observed, the equipment has been found on sites with one command post to the side, and always in close proximity to the command post. Where this equipment is used, it is suspected that one set may furnish data for several nearby gun batteries.
(b) Six-gun positions.—Six-gun layouts fall into three main categories:—
(1) Those expanded from existing four-gun layouts by the addition of two emplacements, one on either side of the original square.
Figure 18. 6-gun layout for coastal defense.
(2) New layouts, consisting either of five guns sites roughly in the form of a circle, with the sixth gun in the center, or of all six guns in the form or a circle.
(3) Coastal layouts, consisting of four guns in a straight line facing the sea, with the remaining two guns in rear (fig. 18).
The command post on six-gun positions is almost invariably located outside the gun layout, except in the case of the coastal layouts, where it is usually located between the two landward emplacements.
(3) Light and medium guns.—A triangular layout of light and medium guns is common, but not invariable, with the guns anywhere from 75 to 150 yards apart. Guns are seldom deployed singly. In built-up areas, considerable use is made of light guns on specially constructed towers; they are also mounted on the roofs of buildings.
f. Fire-Control Methods
(1) With heavy guns.—The Germans use several types of fire-control methods with heavy AA guns. As has already been indicated, the data-computing director used by the Germans does not differ materially from that used by the U.S. Army, except for the fact that in the latest standard type of director the Germans incorporate the height- and range-finder and the predicting mechanism into one instrument. Since there are times when the target is not seen, or when for various reasons it may not be practicable to rely on fire directed at only one aerial target, the Germans use several methods of fire control, principally the following:
(a) With director where target is seen.—This is the normal method and is employed under suitable conditions by day, or in conjunction with searchlights by night. The use of mechanical fuze-setters permits the maintenance of a high rate of fire. Guns may fire singly, but in recent months a tendency towards salvo firing has been observed. At night, targets in searchlight "cones" are engaged by large gun densities, indicating a preference for this type of fire.
(b) With director where target is unseen.—This method may be used by day in overcast conditions, or by night in the absence of searchlight illumination. The use of this method presupposes some means, other than visual, of obtaining the basic elements of present azimuth, present angular height, and present slant range. The Germans are known to have experimented with and used searchlight sound locators for this purpose, fixing the location of the target in space by finding the intersection point of data received from two or more separate sound locators. Authentic reports indicate, however, that the Germans have not found the use of searchlight sound locators to be very satisfactory for this purpose. Since the Germans are known to have been employing radio-location instruments since 1940, it is quite certain that such instruments are now being used for obtaining the initial data.
(c) Predicted concentrations.—In this method a number of gun positions operate under a central control or "master station"; gun densities may include as many as 32 guns. Predicted salvos from individual positions have also been encountered. Unless irregular evasive action is taken by the hostile aircraft, both types of fire can be fairly accurately produced by taking a mean of plots of the plane's course.
(d) Fixed barrages.—This method was particularly used in the early part of the war. Controlled by a central operations room, the fire can be laid in almost any shape; screen, box, cylindrical, or in depth. This type of barrage is usually put up over a vulnerable point or just outside the bomb release line. At the present time it is used mostly at night or under conditions of bad visibility. Furthermore, the development of up-to-date instruments has made its use secondary.
(2) With light and medium guns.—(a) At visible targets.—By use of the several course and speed sights, AA fire from light and medium guns is opened With reasonable accuracy, and corrections are made by observation of tracers. The light or medium AA guns are highly maneuverable and can engage a target almost immediately as it comes in view and in range. These guns rely for effect on the high rate and volume of fire. For altitudes below 1,500 feet, they are exceedingly accurate. At very low levels, particularly from 0 to 50 feet, accuracy is considerably reduced, owing partly to the limitation of field of view with a consequent restricted time of engagement, and partly to the high angular velocity of the target in relation to the guns. By night the method of engagement of an illuminated target is similar to that used by day, with greater reliance placed on observation of tracer.
(b) At unseen targets.—Against unseen targets, light AA fire is nothing more than a deterrent, as the Germans have no instruments for "unseen" firing with light and medium guns. These guns are sometimes sited close to a heavy searchlight, probably for the purpose of obtaining early approximate data, as well as for the protection of the searchlight.
(c) Fixed or curtain barrages.—Fixed or curtain barrages are occasionally fired by the weapons by day or by night over small vulnerable points, at targets or along likely lines of approach.
21. Employment of Searchlights
a. General
The Germans use a large number of searchlights in connection with the AA defense of Germany and important installations of occupied countries. The searchlights have not been particularly successful in illuminating high-flying hostile bombardment planes at night for the sole benefit of gun units. The Germans have learned, however, to use their searchlights for other purposes. Searchlight crews are known to have been dipping their light beams to indicate to their fighter planes the direction in which hostile bombers are flying. Searchlights have also been used successfully to produce "dazzle" and "glare" in efforts to blind and confuse hostile pilots, bombardiers, and gunners. There is now no doubt that all these uses are proving a big help to the Germans in protecting their cities and strategic centers.
b. Equipment
As has already been indicated, the main searchlight equipment used by the Germans consists of the 150-cm (heavy) and the 60-cm (light) searchlights. The latter type is primarily for mobile employment with light Flak batteries. In addition to these two main items of equipment, the Germans also have a limited number of 200-cm and a few French 230-cm lights which are used to supplement the main equipment. Except for mass employment, initial data for the heavy searchlights are usually obtained through the use of sound-locators. With the development of radio-location equipment, there may now be a special set for use with searchlights, but no exact data is available on the extent of development in this field. It should be noted that the light searchlights use no sound locators, picking up their targets by definite searching patterns.
c. Location of Searchlights
Searchlights may be laid out in belts or in concentrations on likely lines of approach to important targets, and around or near gun-defended areas. German searchlights are used to aid night-fighter interception, and those at or near gun target areas are also used to cooperate with Flak. In gun-defended areas, searchlights are used to illuminate aircraft for Flak and for dazzle effect. The spacing of searchlights is as follows:
(1) In belts.—A belt usually consists of 10 to 15 or 20 to 30 searchlights, 1,000 to 2,000 yards apart along the course of the belt. The remainder of the lights are 5,000 to 6,000 yards apart.
(2) In concentrations.—When used in this manner, searchlights are usually spaced 2,000 to 3,000 yards apart in the shape of a triangle, a circle, or two concentric circles.
(3) In gun-defended areas.—Normal disposition is an even spacing approximately 3,000 to 4,000 yards apart. In some special areas, there are small groups with searchlights not more than 1,500 yards apart.
d. Searchlight Tactics
(1) On cloudy nights.—Unless a hostile airplane breaks through low-hanging clouds, only a limited number of searchlights, in belt or otherwise, go into action. They attempt to follow the course of the aircraft along the base of the clouds in order to indicate its course to fighters or in order to produce an illuminated cloud effect against which the aircraft might be silhouetted for the benefit of fighters or the AA artillery.
(2) On nights with considerable ground or industrial haze.—When the searchlight beams are unable to penetrate the haze, searchlights occasionally go into action at a low angle of elevation on to the haze. They thus diffuse and produce over the target area a pool of light through which the crews of attacking aircraft find identification and orientation extremely difficult.
(3) On clear dark nights.—When in belts to aid fighter interception, the most usual functions are: to illuminate the target; to permit a limited degree of searching in "cone" formation; and, by exposing vertically, to produce ahead of the hostile bomber a wall of light against which it may at some time be visible to fighters attacking from the rear, or to compel the hostile bomber, as it runs the gantlet of lights, to fly so close to one of the beams or group of beams that it becomes visible from the ground, thus enabling other lights to engage. In the parts of belts where the lights are more openly spaced, some beams act as pointers for the benefit of night fighters.
In gun-defended areas, some groups of searchlights produce the maximum degree of dazzle, by exposing (almost vertically) and dousing at fairly regular intervals, and even by waving about in the sky.
Other groups of searchlights possessing a "master" light cooperate with Flak. If illumination is obtained, the guns engage; if not, fire is sometimes directed at the point of intersection of the beam over the target area or just outside the bomb-release line, beams being held stationary until a suitable target presents itself.
(4) On clear moonlight nights.—This condition greatly reduces the efficiency of the searchlights. In target areas, tactics are adopted similar to those employed on a clear dark night, except that less attention is paid to dazzle. When attempted, this method has not been able to prevent crews from bombing accurately. In belts, tactics are similar to those employed on a clear dark night, except that a larger number of lights are detailed to indicate the course of hostile aircraft.
e. Dazzle and Glare
"Dazzle" is the blinding of persons in a plane caught in the direct light rays of one or more searchlights. "Glare" means obscuring the target from the plane crew by a light beam played between the plane and the target.
The extent of dazzle is dependent on the height of the plane, the number of searchlights concentrated on it, weather conditions, the direction of the light beams, and to some degree on the reactions of persons in the plane.
Dazzle or glare created by AA searchlights greatly lowers the ability of an aviator to adapt his eyes to seeing at night. Either dazzle or glare makes the location of targets difficult and lessens the accuracy of bombing. Also, keeping beams directly on a plane helps defending fighter-craft to approach the plane unobserved and to attack it more effectively.
22. Employment of Barrage Balloons
Although extensive use of barrage balloons was not planned by the Germans prior to commencement of World War II, very early in the war they made their appearance in certain industrial and strategic towns in western Germany.
The number of balloons in use varies with the considered needs of the area to be defended. For example, they are used in such large numbers over one of the important industrial regions of Germany that a recent observer reported that they were so thick that he "could see several hundred of them at one glance." Although the statement is undoubtedly far-fetched, it well illustrates the psychological value, aside from the practical value, that balloon barrages have.
According to reports, the German balloon barrage usually forms an irregular belt about five-eighths of a mile wide and about 1 3/4 miles from the outer edge of the target area. There is reputedly anywhere from 200 to 800 yards between the balloons. The balloons are flown at varying heights at different times, the exact height and numbers of balloons flown depending on the time of day, the weather, and the threat of aerial attack.
The purpose of the balloon barrage is to form an irregular pattern of perpendicular steel cables in the vicinity of the defended area, presenting a real as well as a mental hazard to any hostile aviator attempting to fly below the level of the balloons. The net result is to discourage hostile flyers from entering the region of the barrage for dive-bombing tactics against the defended area, and to force the hostile planes to an altitude less favorable for precision bombing. The plan for a barrage is coordinated with light-, medium-, and heavy-caliber gun defense, any gaps in the barrage being covered by light and medium Flak. It should also be noted that in defended areas which include harbors and docks, the balloon barrage may extend out over the water, balloons being suspended from stationary or movable barges.
23. Aircraft-Warning System
a. Responsibility
The aircraft-warning service for Germany and for the important occupied areas is the responsibility of the German Air Force, and is a definite integral part of the organization of defense against hostile aircraft. Although a part of the Air Signal Service, for all practical purposes the aircraft-warning service is a separate org
anization created for the sole purpose of constant observation of the air space over Germany, and for the prompt recognition and reporting of airplanes flying over Germany and other defended zones of the interior. This service is operated through the air district headquarters commanders, to whom the aircraft-warning service is subordinated.
b. Operation
In the operation of this system, there is a fixed "German territorial aircraft-warning service," as well as a mobile aircraft-warning service which is carried out by "aircraft-warning-service companies."
The fixed "aircraft-warning-service net" is mesh-like in character. The distances of individual air guard lines from one another vary between 20 and 45 miles, these distances and lines being established in accordance with tactical considerations. "Air guard stations" comprising observation and reporting stations are generally 6 to 8 miles apart. "Air guard headquarters," comprising plotting and relaying stations, are agencies of the aircraft-warning service. As with our system, the function of the air guard stations is to report the number, type, height, flying direction, identity, etc., of any planes flying over the sector. These reports find their way to a center where they are filtered and evaluated, with subsequent disposition of appropriate information to military authorities as well as to civil protection authorities.
German Artillery in Combat Page 9
