German Airdromes in Western Europe, WWII Tactical and Technical Trends, No. 15, December 31, 1942 (Lone Sentry)

a. General

Since German Air Force (GAF) airdromes in the occupied countries of Western Europe have served more generally for offensive activity, they have been developed in some instances to a greater extent than those in the Fatherland. The latter are now being used principally as supply and training bases. During the past 2 years, airdromes in France and the Lowlands have undergone extensive improvements in regard to dispersal arrangements, night-landing systems, the number and length of runways, and the construction of shelters and other facilities.

Occupied France has been the theater of greatest development, with at least 500 bases now available to the GAF. Forty-seven of these are fully equipped bomber airdromes, 28 permanent fighter airdromes, and 9 bomber-reconnaissance bases. There are approximately 23 GAF airdromes and landing fields in Holland; and while Belgium has 34 German landing fields and 32 airdromes, few of these are in operational use at present. Seaplane bases are not included in these estimates.

b. Shape and Size

GAF airdromes on the Western Front are usually square in shape, and have an area of about 450 acres. Prior to 1941 few airdromes had more than one bomber runway, rarely exceeding 1,400 yards in length. Today, almost all bomber airdromes have three runways from 1,500 to 3,000 yards in length. A single instance of a bomber runway 6,000 yards long has been reported in the Morbihan area (in Brittany). The runways of bomber airdromes are flanked by specially levelled strips, probably prepared with a bituminous dressing, and providing a serviceable surface some 180 to 200 yards wide. Concrete taxi-tracks connect the runways with the dispersal areas; and there are apron assembly areas at the ends of the runways, sufficiently large for about six aircraft to assemble and take off in quick succession. Early runways on bomber airdromes were laid near and parallel to one boundary of the landing area. More recently, they were laid across the countryside, terminating at the edge of the airdrome. It is now the practice to lay additional runways across the countryside and connect them with extended dispersal areas.

Both day and night twin-engine fighters are based at airdromes similar to those used by bombers, although these airdromes are often not quite large enough, or of the proper construction, for heavily laden aircraft. The Me-110's, however, sometimes operate from airdromes which have one or two runways from 800 to 1,100 yards long. There is a specially constructed twin-engine fighter airdrome at Denain (Northern France) that has two 1,650-yard runways.

In contrast to the square-shaped bomber airdrome, a typical single-engine fighter airdrome is long and narrow, i.e., 1,400 by 700 yards, with shelters around the perimeter and near the landing surface. It has one, or sometimes two, runways averaging 850 yards in length.

Dive-bombers operate from any of the above types of airdromes, but usually from forward landing fields that have received the minimum of preparation. The use of advanced bases enables the Germans to decrease the radius of action of the bomber, thus making it possible for a larger bomb load to be carried. These fields are about 870 to 1,100 yards square. In Holland the distinction between fighter and bomber airdromes is less apparent. Here all-purpose fields, suitable for every type of aircraft, have been developed to a high degree of efficiency.

c. Dispersal of Aircraft

The normal complement of aircraft at a bomber airdrome in the occupied countries is a Gruppe of 30 to 40 planes; however, an additional bomber reconnaissance Staffel of from 9 to 12 aircraft is sometimes found at the bomber base. An airdrome built specially for bomber reconnaissance usually accommodates one or two Staffeln, and serves equally well for a Staffel of twin-engine fighters. The take-off area of such an airdrome is likely to be small and unsuitable for aircraft carrying heavy bomb loads.

The standard of dispersal of aircraft and facilities in GAF airdromes in occupied countries is thought to be superior to that in Germany. Aircraft are dispersed according to type, bomber airdromes having large areas well removed from the field, while fighter airdromes have smaller areas near the perimeter. There is usually one such area for each Staffel of 9 to 12 planes. An airdrome at which a Gruppe is stationed will normally have three to four dispersal areas. Each dispersal area has its own aircraft shelters, repair hangar, and storehouses for bombs, fuel, and ammunition.

Dispersal of aircraft has been known to cover an area of 6 square miles, and plans are said to be under way at several airdromes to accommodate two or even three Gruppen. It is believed that as many as 2,000 fighters could be stationed in the Calais-Boulogne area, distributed among at least 50 or more airdromes, and dispersed in such a way as to be almost invulnerable to attack. The existence of stop-off and alternate escape airdromes together with operational airdromes that remain unoccupied until the day of an offensive are important factors in facilitating dispersal of air units.

Key fighter airdromes are protected by satellite or auxiliary airfields located in the same vicinity, which also function as extended dispersal areas but sometimes serve as decoys. It is believed that most of the permanent GAF fields along the French coast have satellites, over 20,000 acres of land having been estimated as lost to cultivation because of this program. This is in marked contrast to the policy in Germany of confining shelters within small compact areas to save agricultural acreage.

d. Protection for Aircraft

The system of wide dispersal of aircraft has replaced to a certain extent the use of hangars. Hangars are now employed chiefly as repair shops, the old V-shaped and Z types, and the typical French domed structures being the most common. Medium-sized fields generally have from two to six hangars which average about 180 by 105 feet. Larger fields, like the one at Evre, in Brussels, have 40 hangars, 30 feet high in front and 15 feet high in the rear, with walls about 2 feet thick. Each is large enough to hold a bomber with three fighters under its wings, and is camouflaged as a store, cafe, etc.

Well-dispersed revetments apparently afford the most satisfactory protection for aircraft. They are of a more permanent nature than those built in 1939, which consisted of two parallel sandbag walls and were roofless. The new shelters are built beyond the periphery of the take-off runway, in woods, villages or on farms, and are usually of U-shaped concrete construction with camouflage-net roofs into which foliage has been woven.

The concrete shelters are often built underground and have electric installations. They slope into the earth on all sides except the south, this side being left vertical since it casts no shadow. When two or more planes are stored in a shelter, they are partitioned off by blast walls erected all the way to the roof. T-shaped tunnels about 9 feet deep, into which planes are placed tail-first, are among the underground shelters, and are particularly in evidence at single-engine fighter fields. Underground and semi-underground shelters are used principally as quarters for personnel, protection for individual aircraft, and supply depots; however, entire underground airdromes are known to exist at vital points, and unconfirmed information indicates that the number of airdromes constructed in this way is rapidly increasing.

In addition to concrete shelters, there are shelters of metal construction. It has been estimated that 25 tons of iron were used in the construction of each of 35 shelters at the Vannes airdrome. There are also the "villa" type shelters with red roofs, dummy chimneys, etc., these often being grouped to give the impression of a village. Some of them, e.g., those at the Deelen airdrome in Holland, are large enough for two bomber or several fighter aircraft. Similar shelters in Belgium are made of stone blocks, with roofs of wire netting thatched with heather; one at Liege has a dummy church spire erected over it.

e. Camouflage and Deception

GAF airdromes are camouflaged by the usual methods, some of which have been already mentioned in connection with shelter and hangar construction. Simulated farms, factories, villages, etc., are common; artificial trees, shrubbery, nets to break shadows, and disruptive painting are among the usual methods of disguise and concealment. In some cases, actual villages are taken over, their principal buildings being used for air shelters, repair shops, hangars, administrative offices, etc. The framework of these buildings is left intact, i.e., a church may serve as a hangar, or a school as barracks. Camouflage is also effected by building airdromes astride important highways, by diverting or covering streams, and by the frequent use of unmarked landing take-off zones in open country (see Tactical and Technical Trends, No. 7, p. 16).

Dummy and decoy airdromes continue to be employed extensively. A dummy airdrome, usually a replica of a real airdrome in its vicinity, is simply a fraud and is never used for landings, while a decoy airdrome, used solely for the purpose of diverting air attacks from a more important target, has been used in the past and will undoubtedly be used again. It has been reported that complete lighting systems have been set up after the pattern of installation used at a real airdrome. The use of dummy installations on active fields, or near any permanent airdrome buildings, has recently been banned since they invite fire from the enemy. Such installations, when employed, were placed one and one-half or two miles from the real airdromes.

f. Refuelling

The old "ladder" type servicing apron, which is still employed, has been the most general refuelling system until recently. Aircraft serviced by this method stood on the concrete rungs of the ladder while motor transport and bomb trolleys circulated freely on the apron on either side of the rungs. Three rungs were normally served by a fuel line, with refuelling points beside each rung. The present trend is for the aircraft to be refuelled from tanks in dispersal areas. At the Morlaix airdrome in France there is an underground concrete reservoir system for gasoline storage. The reservoirs are close to the perimeter and about 8 feet underground; they measure approximately 1,000 cubic feet and are made of concrete about 3 feet thick. They are connected to each other by central tube, and the complete system is connected to the highway by a hose. Fuel and munitions are also stored in small camouflaged trenches scattered on, or at varying distances from, the periphery.

g. Night Approach Systems

Most GAF bomber and fighter bases are now approached at night by means of the visual Lorenz blind-flying systems. Installations are still in the process of completion, and it is believed that all bases will soon be equipped with this system. Previously, a GAF bomber homing at night would locate its airdrome by means of the direction-finder station. The aircraft would then elect a landing principally by the use of non-visual procedure such as Lorenz, Z.A., etc.

Visual aids at airdromes used for night operations have been developed increasingly during the past 2 years. They include flashing and rotation light beacons, star-shell cannon, searchlights, flare-paths, and obstruction lights. The visual Lorenz is perhaps the most common of a dozen or more lighting systems; however, a newer method about which little is known is believed to be in effect now.

A Lorenz system consists of a straight line of lights, one and one half to three miles in length, which aligns the axis of each runway of an airdrome, and is crossed at right angles by short lines of lights 500 to 1,400 yards long. The short lines indicate the exact distance from the airdrome boundary, and the height at which the aircraft should be flying. Several systems of four to six main lines of lights usually approach the airdrome from different directions to line up each runway and to allow for variation in wind direction. Each set of lights is so arranged that it can be switched on independently of the others. Systems have now been completed to provide four to six separate cross lines instead of the two or three formerly used.

In the current visual Lorenz system there is apparently no fixed length for either the main or cross lines of lights. Both the length of the main line, and the distances of the cross lines from the airdrome boundary vary among the several sets of lights at one airdrome; thus pilots must be familiar with each set of lights employed at the airdromes which they use.

h. Protection of Airdromes

All airdromes are well protected with antiaircraft guns. The normal distribution consists of one battery of heavy guns to four or more batteries of light weapons, emplaced from one to several hundred feet from the landing ground, and a varying allotment of small-caliber machine guns, usually 20-mm and 37-mm, emplaced near the immediate approaches of the runways, or even in the midst of the installations. Antiaircraft protection is increased at the more vital bases, especially those equipped with visual Lorenz, to two heavy and eight or nine light batteries.

Heavy 88-mm guns are generally located in a four-pointed star pattern, the gun positions constituting the points, with the predictor unit in the center. Protection of guns and men often appears to be subordinated to better visibility and firing conditions. Wherever obstacles interfere with the field of fire, towers about 30 feet high and 12 feet wide are erected, on which medium and light guns are mounted. Flak towers at Diest-Schaffen in Belgium are 50 feet high, and are mounted with 40-mm guns.

The usual barbed-wire entanglements surround all airdromes; and movable objects such as metal beams are placed on the fields to prevent enemy landings. These obstructions are removed 2 hours before the arrival of friendly aircraft, and are immediately replaced after their departure. Forty cistern trucks were said to have been employed to remove these obstacles from one particular field.

i. Communications

As has been previously reported, GAF airdromes are sited near a main railroad, usually on the outskirts of villages or small towns, or about 3 miles from cities. There is a notable increase in the number of branch lines being built, and airdromes are frequently encircled by spur tracks with underground discharging points. Motor units are employed for transporting supplies from these points, and from specially built sidings on the fields. Ju-52's continue to be used for air transport throughout the entire GAF.

j. Conclusion

From an analysis of these improvements and changes in GAF policy, we may conclude that the Germans consider the following as the chief elements of airdrome security: means of quick dispersal, adequate antiaircraft defense against low-flying attacks, effective camouflage, and (obviously) the alertness of combat crews. We have only to recall that the typical French airfield in 1940 consisted of about 250 acres and had no special runways and few other facilities, to realize the tremendous undertaking of the Germans. Their achievements represent the solution of serious drainage problems and runway construction difficulties, as well as the immediate replacement of methods, both offensive and defensive, that have proved ineffective. It is needless to say that this program has required a vast airdrome construction and maintenance crew, from one to two thousand civilian and military personnel generally being employed for one airdrome area.