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STEVEN J. ZALOGA, illustrated by JIM LAURIER
V-1 FLYING BOMB. 1942-52. HITLER'S INFAMOUS "DOODLEBUG"

FI-103 SERIES PRODUCTION

Unlike conventional aircraft, the FZG-76 was not completely assembled at the plants. Instead, the major components such as the fuselage, engine, wings, warhead and other sub-assemblies were delivered to a Luftwaffe munitions depot Four of these were assigned to the FZG-76 program, of which the most important were Pulverhof in Mecklenberg and Karlwitz near Dannenberg. There, the components were merged; the fuselage, engine, and warhead were assembled, and the rest of the components along with the completed fuselage mounted on a TW-76 trolley. This made it easier to deliver the missile to the field depots in France. At that point, the sensitive equipment such as the autopilot and compass were fitted, and from these depots the missiles were delivered to the launch sites. It was only at the launch site that the FZG-76 was completely assembled.

The FZG-76 was delivered from the manufacturing plant on its TW-76 trolley to the Luftwaffe munitions depots in the configuration shown in the lower illustration with no warhead and the tail fastened above the rudder. The depot then mated the warhead to the fuselage, added the wings and wing-spar to the trolley, and delivered the semi-complete missile to the forward supply units as shown in the upper illustration. (NARA)

When the Fi-103 finally reached quantity production in March 1944, the time to manufacture the missile had been reduced to 350 hours of which the complicated autopilot accounted for 120 hours. The unit cost was RM5,060, only four percent of the cost of a V-2 ballistic missile, and only about two percent of the cost of a twin-engine bomber.

To test whether the improvements worked, on April 14th-17th, 1944, the Luftwaffe conducted field tests of 30 Fi-103 missiles from the Heidelager test range near Blizna in Poland. Nine missiles crashed shortly after launching but the remaining missiles all struck within 30km (18 miles) of their target, and ten landed within 10km of the target One recurring problem was the fuel-pressure regulator which was supposed to alter the fuel supply automatically depending on altitude. No short-term solution to the problems could be found so in May 1944 the regulator was simplified which meant that the cruise altitude was only 4,500ft instead of the expected 9,000ft. This made the FZG-76 more vulnerable to light anti-aircraft guns such as the ubiquitous 40mm Bofors used by many British and American anti-aircraft units.

Combat deployment in France

If development and production were six months behind schedule, deployment plans at the missile bases in France were also delayed, starting only in August 1943. The initial phase was Site System 1 which contained 96 Type A sites along the Channel coast from Dieppe to Calais. Each site included a launch ramp shielded on either side by a concrete wall, a non-magnetic alignment building for final adjustment to the magnetic compass prior to launch, a launch bunker, three long missile storage buildings, and several smaller buildings for storing fuel and other supplies. The precise location of each of the buildings was dependent on the site, and some effort was made to use local terrain such as hedges and tree lines to camouflage the more conspicuous structures. The missile sites were usually located next to existing roads, which were upgraded with smooth concrete surfaces to facilitate the use of the many handling trolleys servicing the launch site. Often, the site was located near farms or other buildings which could be taken over to house the launch crews, and which also helped to camouflage the site. Site System 2 was a set of reserve sites, with the intention to complete one reserve site for each battery by December 1943. Site System 3 was a more ambitious scheme to deploy the missile bases in a wider band from Cherbourg to Flanders in Belgium which would be manned by four new battalions (V-VIII Abteilungen). Eight of these sites were begun in Normandy but since the new battalions were never raised, they were allotted to IV/FR155W.

FZG-76 production was extended to the underground Mittelwerke plant near Nordhausen after the original aviation plants were bombed. Here, some US Army officers examine some unfinished missiles after the plant was captured in April 1945. (NARA)

Wachtel's FR155W included four launch battalions (Abteilungen) each with three launch batteries and a maintenance and supply battery. Each launcher battery had three launch platoons, each with two launchers, meaning 18 launch ramps per battalion and 72 launch ramps for the regiment. Each launch ramp was manned by about 50 personnel, and the regiment as a whole totaled about 6,500 personnel. Due to the technological complexity of the new weapon, FR155W was supported by several dozen civilian engineers from the factories called the Industrie-Hilfstrupp Gehlhaar (ITG).

FLAK REGIMENT 155 (WERFER)

As the battalions from FR155W completed their training at Zempin, they were transferred to France in late October 1943 to assist in preparing the missile bases. To coordinate the bombardment of London by the Luftwaffe Fi-103 and the Army A-4 ballistic missile, on December 1st, 1943, the Wehrmacht created a hybrid organization, the 65. Armee Korps zur besonderen Venwendung (65th Army Corps for Special Employment), staffed by Army and Air Force officers. Command of the 65th Corps was given to Generalleutnant Erich Heinemann, previous commander of the Army artillery school, and the chief of staff was Luftwaffe Colonel Eugen Walter. After inspecting the missile sites, the corps staff was dismayed by the poor planning and unrealistic expectations of the high command which seemed to be completely unaware of the problems. The high command insisted that the missile attack on London begin in January 1944, ignoring the fact that the bases were not complete, training had not been concluded, and there were no stores of missiles.

This shows an Fi-103 on its TW-76 trolley in shipping configuration at the Luftwaffe's Karlwitz munitions depot near Dannenberg in 1945. The warhead is not fitted yet, and the standard blue protective cover is fitted to the nose which served to protect the delicate auto-log propeller as well as contain the fuzes for the warhead which were not fitted until at the launch site. (NARA)

This map illustrates a typical "ski site," No. 13 built near a farm along the Chemin du Moulin á Vent outside Le Rocher near Hardinvast in Normandy. The launcher (1) and launch bunker (2) are aligned with the non-magnetic guidance building (3). To the east are three of the distinctive "ski" buildings (4) used to store V-1 missiles. The support buildings are to the west and include the fuel bunkers (5, 7); blockhouse (6); assembly building (6); pump building (9); and preparation garage (10). (Author)

The Crossbow campaign

In late August 1943 a FZG-76 crashed on the island of Bornholm and Danish resistance workers spirited out photos of the wreckage to Britain. British technical intelligence was on the lookout for missile sites due to intercepted signals and other evidence. By October 1943 British intelligence had also learned from the French resistance of a flurry of unusual construction in Normandy and the Fas de Calais. One of the first sites to be completed was located in a wooded area near Abbeville called Bois Carré and, after receipt of a detailed French report on the site, it was photographed by RAF reconnaissance aircraft in late October. The most distinctive features of the sites were three long storage buildings which an RAF photo interpreter thought resembled skis turned on their side, so the missile bases were called "ski sites" or "Bois Carré" sites. Ominously, the ramp structure at the site was aimed at London. Photos taken over Peenemünde in November revealed a small winged aircraft and another reconnaissance run over Zempin on November 28th actually showed one of the missiles on a launch ramp like those in France, along with several of the characteristic buildings. Intelligence analysts estimated that each site could store 20 missiles, suggesting that the missile bases could launch up to 2,000 missiles per day against England.

The original launch sites had large walls to protect the launch ramp. This is one of the eight sites constructed on the Cotentin peninsula in Normandy which were never used due to the Allied Crossbow air attacks. (NARA)

By this time, Allied work to identify German missiles and missile sites had come under the heading of "Crossbow", named after the investigative committee set up by Churchill in the summer of 1943 to coordinate all of the reports emerging from occupied Europe about secret missile programs. RAF photo interpreters quickly identified new sites because of their use of standardized buildings. A German Air Force officer assigned to the missile units later described efforts to camouflage the sites as a farce. By December 1943, more than half the sites were complete, and by late January, Allied intelligence had identified all 96 launch sites of Site System 1.

This is how the "ski" buildings appeared from the ground. These long storage bunkers could contain 20 missiles on their shipping trolleys. This particular site is one of those on the Cotentin peninsula in Normandy captured by the US Army in June 1944. (NARA)

Besides the dispersed ramp sites, four Wasserwerk ("Waterworks") heavy sites were begun in September 1943, Siracourt and Lottinghen in the Pas de Calais and Nardouet and Brecourt on the Cotentin peninsula. The massive missile bunkers were 212m (232 yards) long and 36m (39 yards) wide and could house up to 150 missiles. A single ramp exited the middle of the structure, aimed at London. The first of these to enter construction, Wasserwerk St. Pol near Siracourt, was identified almost immediately by Allied reconnaissance aircraft. Due to their complexity, the heavy sites were not expected to be ready until August 1944. The sites would require another regiment to operate them and the planned ten sites would have a rate of fire of 480 missiles daily and 1,680 weekly.

The first Allied air attacks on the Grossbow sites began on December 5th, 1943, when B-26 aircraft of the US Ninth Air Force attacked three sites near Ligescourt. Due to weather conditions the results were poor, and the RAF became convinced that heavy bombers would be needed. The first Bomber Command attack took place on the night of December 16th/17th, 1943, on sites near Abbeville. The results were poor due to the difficulties of conducting precision bombing against such small and bomb-resistant targets at night. On December 15th, the Joint Chiefs of Staff (JCS) decided to begin employing US heavy bombers in daylight, and when clear weather arrived on Christmas Eve, 672 B-17 and B-24 bombers delivered 1.472 tons of bombs on 24 sites. By the end of the year, 52 sites had been attacked and nine were believed to have been seriously damaged. Actually, seven sites had been put out of action of which three had been completely obliterated.

This is an illustration from the wartime Sanders' report showing how the Wasserwerk St. Pol missile bunker near Siracourt might have looked had it been completed. The launch ramp was oriented towards London but was never finished. (NARA)

The December attacks were only the beginning of a long air campaign against the Crossbow sites which added to the problems FR155W had in preparing for combat. The relentless Allied air attacks systematically pulverized Site System 1. According to the regimental diary, by the end of March 1944, nine sites had been destroyed, 35 seriously damaged and 29 had suffered medium damage, By the end of April, 18 sites had been destroyed and 48 suffered heavy damage, and by mid-May, 24 had been destroyed and 58 had suffered serious damage. The large bunker sites received special attention. Siracourt was bombed 27 times with a total of 5,070 tons of bombs including an 11-ton Aphrodite guided-aircraft bomb and several Tallboy 6-ton bombs, making it the most heavily attacked of all Crossbow sites.

The Crossbow campaign absorbed about 14 percent of all Allied heavy bomber missions from August 1943 to August 1944, and about 15 percent of the medium bomber missions. The diversion of reconnaissance aircraft was greater, absorbing about 40 percent of the missions from May 1943 to May 1944. The figures below summarize the scale of Crossbow missions, though it should be kept in mind that these included attacks on V-2 sites as well as V-1 sites, and also raids on Peenemünde, production plants, storage areas, and fuel depots.

CROSSBOW BOMBING CAMPAIGN AUGUST 1943-MARCH 1945

Although the Crossbow campaign was costly in terms of aircrew losses and the diversion of bomber missions, the initial attacks proved very effective in delaying the start of the missile campaign against London. In early December 1943, before the attacks, Wachtel reported that he expected to be ready to start the campaign later in the month, and even the more skeptical General Heinemann thought it might be possible in January. In fact, the bombing so disrupted the creation of launch sites, and so badly interfered with training and deployment, that the missile campaign started six months late. General Eisenhower later wrote that if the missile campaign had started on time at the end of 1943, it might have disrupted the D-Day plans. This is a misunderstanding of the role of the missiles, as neither Hitler nor any of the other senior leaders had the sense to use the missiles against the invasion fleet, so obsessed were they with their revenge mission against London. The Crossbow campaign also lessened the volume of the summer missile attacks since it reduced the production rate of the missiles through attacks on the factories, and forced the Germans to adopt less efficient launch bases, with a lower rate of fire than the original configuration.

This map illustrates a typical "modified" V-1 launch site, No. 240 at the entrance to La Maison de Bricqueboscq in Normandy. A stretch of Route D204 was reinforced with concrete where It met the chateau's entrance road. A pad for the launcher (1) has been created, along with an aligned pad for the non-magnetic guidance platform (2). A launch control bunker has been built near the launch pad (4) and a small "garage" bunker (3) for preparing the V-1 was built near the road access point. (Author)

In late December 1943, General Heinemann held a conference for all leaders of the FZG-76 program, in order to determine how to get the program back on track. The conference concluded that neither missile production nor manufacture of the Walter launcher were going to be ready until late February 1944. Heinemann therefore concluded that the existing Site System 1 and the four heavy bases were such obvious targets for attack that they could not be used in the forthcoming missile campaign. Instead, the French work crews would complete them, and even effect modest repairs after Allied air raids, in order to distract attention from a new series of bases. The new Operational Site System would be constructed by German engineer battalions with no participation by French construction firms, and security around the sites would be draconian. The new sites would have as little construction as possible to prevent their detection by Allied intelligence. The only concrete fixtures at the sites would be a basic concrete platform for the launch ramp, a concrete floor for the non-magnetic alignment building, a small garage for preparing the missile, and a modest amount of concrete road improvements. None of the distinctive "ski" buildings or other facilities would be used, and no distinctive missile equipment would be allowed near the sites until six days before the start of the missile campaign. Storage of missiles and their equipment would be moved to local caves and tunnels and not specialized bunkers. The simplified sites were also much easier to construct, taking only eight days compared to eight weeks for the "ski-sites." These new bases, called "modified sites" or "Belhamelin" sites by Allied intelligence, proved much more difficult to locate, and the first Was not identified until April 26th, 1944. After the meeting, the Germans referred to the Type A ski sites as Stellungen alter Bauart ("Old pattern sites") and the new types as Einsatz Stellungen ("Special sites").

Deployment of Flak Regiment 155 (W) in northern France in June 1944 for Operation Eisbär. (Author)

Heinemann realized that photographic reconnaissance coverage over London was unlikely when the missile attacks began, so novel methods were concocted to determine whether the missiles had hit their target. Fieseler equipped about seven percent of the FZG-76 missiles with radio transmitters which would permit tracking where they landed. This was supplemented by a special SS observation battalion using sound location and seismographic instruments. Heinemann planned to start the campaign on March 1st, 1944, but by the spring of 1944 the Crossbow campaign had effectively delayed construction of the launch sites and Allied air attacks against the railroad network in France to support ihe D-Day invasion further undermined the missile program.

A supply battery of Flak Regiment 155 (W) prepares missiles for launch. The missile on the left is mounted on the Zubringerwagen loading trolley which was mated to the launch ramp, and the missile slid into place. (NARA)

Besides the ground-launched missile program, the Luftwaffe began an air-launched missile program in early 1944. Aircraft had already been used in the test program, but had been ignored as possible combat launchers since, unlike fixed land bases, there was no existing navigation system accurate enough to determine the precise launch point. Tests of various navigation systems began in November 1943, and a conference was held at the Rechlin test base on March 18th, 1944, to examine some of the options including the Egon, Y-Gerät and Zyklop, and Knickebein navigation systems. The only practical way to perform this mission was to pre-set the guidance on the Fi-103 for launch from a single predetermined location along a predetermined bearing. Needless to say, this offered a much lower level of accuracy than the ground launchers. On April 6th, 1944, tests began of various bombers, and the Heinkel He-111 was selected. A program began to convert old subtypes into the He-111H-22 configuration with a launch station under the light wing. General Milch was not very keen on this program but acquiesced, feeling that the bomber launches would help confuse the British. In early May 1944, III/Kampfgeschwader 3 was assigned the missile mission and sent to Karlshagen for training.

The last launcher option examined before the start of the campaign was a local initiative by FR155W to develop a mobile, vehicle-mounted launch system, but this did not progress very far.

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