Plate 039 — Battles
REF: BF-BTL-039V-1 Flying Bomb (Vergeltungswaffe 1)
End of V1 attacks
By September 1944, the V-1 threat to England was temporarily halted when the launch sites on the French coast were overrun by the advancing Allied armies. 4,261 V-1s had been destroyed by fighters, anti-aircraft fire and barrage balloons.
V1 Rocket - Flying Bomb
The Vergeltungswaffe 1 FZG-76 (V1), known as the Flying Bomb, Buzz Bomb or Doodlebug, was the first modern guided missile used in wartime and the first cruise missile. Vergeltungswaffe means "reprisal weapon", and FZG is an abbreviation of Flak Ziel Gerät ("anti-aircraft aiming device"), a misleading name.
Called the Buzz Bomb because of the of the engine it caused considerable fear in the population of London. People would listen for the sound approaching, but then be relieved when it sounded overhead as that meant the bomb had actually passed them.
Developed in Germany during WW II it was used initially against England, mainly London from "ski-jump" launch sites along the French (Pas-de-Calais) and Dutch coasts until they were over-run. It was superseded by the V2 rocket
It was a simple device, designed by Robert Liisser of the Fieseler company as the Fi 103 and could be constructed in around fifty man-hours of mainly sheet metal. It was powered by an Argus pulse jet engine providing 660lb (300kg) of thrust for a top speed of 390mph and a range of around 150 miles (later the range was extended to 250 miles). It was 26 feet (7.9m) long, 17 ft (5.3m) in span, it weighed 4,800lb (2180kg) and carried a 1870lb (850kg) warhead.
The guidance system was very crude in construction but sophisticated in conception (and had a few flaws in execution). Once clear of the launching pad, an autopilot was engaged. It regulated height and speed together, using a weighted pendulum system to get fore and aft feedback linking these and the device's attitude to control its pitch (damped by a gyromagnetic compass, which it also stabilised). There was a more sophisticated interaction between yaw, roll, and other sensors: a gyromagnetic compass (set by swinging in a hangar before launch) gave feedback to control each of pitch and roll, but it was angled away from the horizontal so that controlling these degrees of freedom interacted (the gyroscope stayed trued up by feedback from the magnetic field, and from the fore and aft pendulum mentioned before). This interaction meant that rudder control was sufficient without any separate banking mechanism. On reaching the target, the desired altitude was reset to be negative; this should have led to a power dive, but the steep descent caused the fuel to run away from the pipes and so the power cut out. As there was a belly fuse as well as a nose fuse, there was still usually an explosion although not always with the device buried deep enough to increase the effect of the blast.
The first test flight of a V1 was in late 1941 or early 1942 at Peenemünde. The first offensive launch was on June 12, 1944. The Allies organised a heavy series of air attacks on the launch sites and also attacked the V1s in flight. Due to defensive measures and guidance errors, only a quarter successfully hit their target.
Once the Allies had captured the launch sites that allowed the V1s to hit England the remaining missile strikes were against the port of Antwerp.
Almost 30,000 V1s were manufactured. about 10,000 were fired at England up to March 29, 1945. Of these, about 7000 were "hits" in the sense that they landed somewhere in England, and a little more than half of those (3876) landed in the Greater London area.
An almost equal number were shot down or intercepted by barrage balloons. When the V1 raids began, the only effective defence was interception by a handful of very high performance fighter aircraft, in particular the Hawker Tempest.
Anti-aircraft gunners found that such small, fast-moving targets were difficult to hit, and most fighter aircraft were too slow to catch a V1 unless they had a useful height advantage. Even when caught, the V1 was difficult to bring down: machine gun bullets had little effect on the sheet steel structure and 20mm cannon shells had a shorter range, which meant that setting the warhead off could all too easily destroy the fighter aircraft as well.
When the attacks began in mid-June 1944 there were less than 30 Tempests in 150 Wing to defend against them, and few other aircraft had the low altitude performance to be effective. Initial attempts to intercept V1s were often unsuccessful, but aiming techniques were rapidly developed. (Including the hair raising but effective method of simply flying so close alongside that the airflow disturbed the buzz bomb's gyros and sent it out of control.)
The Tempest wing was built up to over 100 aircraft by September; Griffin-engined Spitfire XIVs and Mustangs were polished and tuned to make them almost fast enough, and during the short summer nights the Tempests shared defensive duty with Mosquitoes. (There was no need for radar - at night the V1's engine could be seen from 10 miles or more away.)
In daylight, V1 chases were chaotic and often unsuccessful until a special defence zone between London and the coast was declared in which only the fastest fighters were permitted. Between June and mid-August 1944, the handful of Tempests shot down 638 flying bombs. (One Tempest pilot, Joseph Berry, downed fifty-nine V1s, another 44, and Wing Commander Beaumont himself destroyed 31.) Next most successful was the Mosquito (428), Spitfire XIV (303), and Mustang, (232). All other types combined added 158. The still-experimental jet-powered Gloster Meteor, which was rushed half-ready into service to fight the V1s, had ample speed but suffered from jamming cannon and accounted for only 13.
In mid-August 1944, the threat was all but overcome - not by aircraft, but by the sudden arrival of two enormously effective electronic aids for anti-aircraft guns, both developed in the USA by the Rad Lab: radar-based automatic gunlaying, and above all, the proximity fuse. Within weeks, the vast majority of V1s launched were shot down by anti-aircraft guns as they crossed the coast.
V1 Experimental and long-range variants
Late in the ww2r, several air-launched piloted V-1s, known as Reichenbergs, were built, but never used in combat. Hanna Reitsch made some flights in the modified V-1 Fieseler Reichenberg when she was asked to find out why test pilots were unable to land it and had died as a result. She discovered, after simulated landing attempts at high altitude where there was air space to recover, that the craft had an extremely high stall speed and the previous pilots with little high speed experience had attempted their approaches much too slowly. Her recommendation of much higher landing speeds was then introduced in training new Reichenberg volunteer pilots. The Reichenbergs were air-launched rather than fired from a catapult ramp as erroneously portrayed in Operation Crossbow.
There were plans, not put into practice, to use the Arado Ar 234 jet bomber to launch V-1s either by towing them aloft or by launching them from a "piggy back" position (in the manner of the Mistel, but in reverse) atop the aircraft. In the latter configuration, a pilot-operated hydraulic arrangement would lift the missile on its launch cradle some eight feet clear of the 234's dorsal fuselage. This was necessary to avoid damaging the mother craft when the pulse jet ignited, as well as to ensure a 'clean' airflow for the Argus motor's intake. A somewhat less ambitious project undertaken was the adaptation of the missile as a 'flying fuel tank' for the Messerschmitt Me 262 jet fighter. The pulse-jet, internal systems and warhead of the missile were removed, leaving only the wings and basic fuselage, now containing a single large fuel tank. A small cylindrical module, similar in shape to a finless dart, was placed atop the vertical stabilizer at the rear of the tank, acting as a centre of gravity balance and attachment point for a variety of equipment sets. A rigid tow-bar with a pitch pivot at the forward end connected the flying tank to the Me 262. The operational procedure for this unusual configuration saw the tank resting on a wheeled trolley for take-off. The trolley was dropped once the combination was airborne, and explosive bolts separated the towbar from the fighter upon exhaustion of the tank's fuel supply. A number of test flights were conducted in 1944 with this set-up, but inflight "porpoising" of the tank, with the instability transferred to the fighter, meant the system was too unreliable to be used. An identical utilisation of the V-1 flying tank for the Ar 234 bomber was also investigated, with the same conclusions reached. Some of the "flying fuel tanks" used in trials utilised a cumbersome fixed and spatted undercarriage arrangement, which (along with being pointless) merely increased the drag and stability problems already inherent in the design.
One variant of the basic Fi 103 design did see operational use. The progressive loss of French launch sites as 1944 proceeded and the area of territory under German control shrank meant that soon the V-1 would lack the range to hit targets in England. Air-launching was one alternative utilised, but the most obvious solution was to extend the missile's range. Thus the F-1 version developed. The weapon's fuel tank was increased in size, with a corresponding reduction in the capacity of the warhead. Additionally, the nose-cones of the F-1 models were made of wood, affording a considerable weight saving. With these modifications, the V-1 could be fired at London and nearby urban centres from prospective ground sites in the Netherlands. Frantic efforts were made to construct sufficient F-1s so that a large-scale bombardment campaign could coincide with the Ardennes Offensive, but numerous factors (bombing of the factories producing the missiles, shortages of steel and rail transport, the chaotic tactical situation Germany was facing at this point in the war etc) delayed the delivery of these long-range V-1s until February/March 1945. Before the V-1 campaign ended for good at the end of the latter month, several hundred F-1s were launched at Britain from Dutch sites.
Almost 30,000 V-1s were made; by March 1944, they were produced in 350 hours (including 120 for the autopilot), at a cost of just 4% of a V-2, which delivered a comparable payload. Approximately 10,000 were fired at England; 2,419 reached London, killing about 6,184 people and injuring 17,981.[11] The greatest density of hits were received by Croydon, on the southeast fringe of London. Antwerp, Belgium was hit by 2,448 V-1s from October 1944 to March 1945
To adjust and correct settings in the V-1 guidance system, the Germans needed to know where the V-1s were landing. Therefore, German intelligence was requested to obtain this impact data from their agents in Britain. However, all German agents in Britain had been turned, and were double agents under British control (the Double Cross System).
On 16 June 1944, British double agent Garbo (Juan Pujol) was requested by his German controllers to give information on the sites and times of V-1 impacts, with similar requests made to the other German agents in Britain, Brutus (Roman Czerniawski) and Tate. If given this data, the Germans would be able to adjust their aim and correct any shortfall. However, there was no plausible reason why the double agents could not supply accurate data; the impacts would be common knowledge amongst Londoners and very likely reported in the press, which the Germans had ready access to through the neutral nations. In addition, as John Cecil Masterman, chairman of the Twenty Committee, commented, "if St Paul's Cathedral were hit, 'it would be useless and harmful to report that the bombs had descended upon a cinema in Islington.
While the British decided how to react, Pujol played for time. On 18 June it was decided that the double agents would report the damage caused by V-1s fairly accurately and minimise the effect they had on civilian morale. It was also decided that Pujol should avoid giving the times of impacts, and should mostly report on those which occurred in the north west of London, to give the impression to the Germans that they were overshooting the target area.
While Pujol had been downplaying the extent of V-1 damage, an uncontrolled agent in Lisbon codenamed Ostro had exaggerated in the other direction, reporting to the Germans that London had been turned into a wasteland and had been mostly evacuated due to enormous numbers of casualties. Due to an inability to perform aerial reconnaissance of London, the Germans believed Ostro's reports in preference to those of Pujol, and believed that the Allies would make every effort to destroy the V-1 launch sites in France. Due to Ultra however, the Allies read his messages and were able to adjust for them.
A certain number of the V-1s fired had been fitted with radio transmitters, which had clearly demonstrated a tendency for the V-1 to fall short. Max Wachtel, commander of Flak Regiment 155(W), which was responsible for the V-1 offensive, compared the data gathered by the transmitters with the reports obtained through the double agents. He concluded, when faced with the discrepancy between the two sets of data, that there must be a fault with the radio transmitters, as he had been assured that the agents were completely reliable. It was later calculated that if Wachtel had disregarded the agents' reports and relied on the radio data, he would have made the correct adjustments to the V-1's guidance, and casualties might have increased by 50% or more.
The policy of diverting V-1 impacts away from central London was initially controversial. The War Cabinet refused to authorise a measure which would increase casualties in any area, even if it reduced casualties elsewhere by greater amounts. It was thought that Churchill would reverse this decision later (he was then away at a conference); but the delay in starting the reports to Germans might be fatal to the deception. So Sir Findlater Stewart of Home Defence Executive took responsibility for starting the deception programme immediately. His action was approved by Churchill when he returned
Japanese V1
In 1943, an Argus pulse jet engine was shipped to Japan by German submarine. The Aeronautical Institute of Tokyo Imperial University and the Kawanishi Aircraft Company conducted a joint study of the feasibility of mounting a similar engine on a piloted plane. The resulting design was based on the Fieseler Fi-103 Reichenberg (Fi 103R, a piloted V1), and was named Baika ("ume blossom").
Baika never left the design stage but technical drawings and notes suggest that two versions were under consideration: an air-launch version with the engine mounted under the fuselage, and a ground-launch version that could take off without a ramp.
Intelligence reports of the new Baika weapon are rumored to be the source of the name given to the Yokosuka MXY-7, a rocket-propelled suicide plane better known as the "Baka Bomb". However, as baka means "fool" or "idiot" in Japanese, and the MXY-7 was officially designated the "Ohka", the true origin is unknown.[citation needed] The MXY-7 was usually carried by the G4M2e version of the Mitsubishi G4M "Betty" naval bomber, then the pilot lit the solid-fuel rockets and guided his flying bomb into a ship.
Another Japanese Fi 103 version was the Mizuno Shinryu, a proposed rocket-powered kamikaze aircraft design which was not built.