The V-1 was the inaugural Vergeltungswaffen (V-weapon) used for London’s terror bombing.

The Luftwaffe developed it at the Peenemünde Army Research Center in 1939 during the early stages of World War II. Initially, it had the codename “Cherry Stone.”

Due to its limited range, Launch facilities in the French (Pas-de-Calais) and Dutch coasts released thousands of V-1 missiles towards England.

The Wehrmacht first aimed the V-1s at London on 13 June 1944, a response to the successful Allied landings in France. At its peak, over one hundred V-1s targeted southeast England daily, totaling 9,521. This number diminished as the Allies overran sites.

Contents

• V-1 Flying Bomb Design and Development
• Simple Autopilot
• Walter Catapult
• Interceptors
• Assessment

By October 1944, the last V-1 site within Britain’s range fell to Allied forces.

After this fall, Germans targeted the port of Antwerp and other Belgian locations with V-1s, launching an additional 2,448 missiles.

The attacks halted a month before the war in Europe concluded. The final launch site in the Low Countries fell on 29 March 1945.

To counter the V-1, the British deployed a variety of air defenses including anti-aircraft guns, barrage balloons, and fighter aircraft to intercept the bombs.

They also targeted launch sites and storage depots for Allied attacks.

In 1944, tests of this weapon reportedly occurred in Tornio, Finland. Finnish soldiers observed the launch of what resembled a small, winged aircraft bomb by a German plane.

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They also witnessed another prototype’s abrupt engine stop, sharp descent, and impactful explosion, which left a sizable crater. The soldiers referred to these V-1s as “flying torpedoes.”

V-1 Flying Bomb Design and Development

In 1935, Paul Schmidt and Professor Georg Hans Madelung presented a Flying Bomb design to the Luftwaffe. This design was innovative, utilizing a pulse-jet engine, diverging from Sperry Gyroscope’s 1915 propeller-based work.

Meanwhile, Fritz Gosslau, working at Argus Motoren, developed the remote-controlled FZG 43 drone.

Argus, in October 1939, proposed Fernfeuer, a drone capable of returning post-bomb release, working alongside C. Lorenz AG and Arado Flugzeugwerke. Unfortunately, the Luftwaffe didn’t award them a development contract.

In 1940, cooperation between Schmidt and Argus ensued, amalgamating Schmidt’s shutter system with Argus’ fuel injection. Testing commenced in January 1941, with the first flight on 30 April 1941 using a Gotha Go 145.

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By 27 February 1942, Gosslau and Robert Lusser conceptualized a design, forming the basis for the V-1. Lusser finalized a design in April 1942, dubbed P35 Efurt, introducing gyroscopes. The Luftwaffe received this on 5 June 1942, boasting specifications like a 299 km range and 700 km/h speed.

Albert Speer, Germany’s Minister of Armaments in the Second World War, was a strong supporter of the rocket programme headed by Wernher von Braun.

Ever since the winter of 1939, I had been closely associated with the Peenemunde development centre, although at first all I was doing was meeting its construction needs. I liked mingling with the circle of non-political young scientists and inventors headed by Werner von Braun – twenty-seven years old, purposeful, a man realistically at home in the future. It was extraordinary that so young and untried a team should be allowed to pursue a project costing hundreds of millions of marks and whose realization seemed far away.

My sympathy stood them in good stead when in the late fall of 1939 Hitler crossed the rocket project off his list of urgent undertakings and thus automatically cut off its labour and materials.

By tacit agreement with the Army Ordnance Office, I continued to build the Peenemunde installations without its approval – a liberty that probably no one but myself could have taken.

Project Fieseler Fi 103 gained approval on 19 June and underwent testing at Karlshagen, Peenemünde-West. Erhard Milch assigned the respective contracts for engine, airframe, and guidance system to Argus, Fieseler, and Askania.

By 30 August, Fieseler concluded the first fuselage, and the Fi 103 V7’s initial flight occurred on 10 December 1942.

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Subsequently, the V-1 demonstrated a successful flight on Christmas Eve. By 26 May 1943, Germany greenlighted the production of both the V-1 and the V-2. In July 1943, a V-1 impacted within a kilometer of its target after flying 245 kilometers.

Finally, with Hitler’s approval in June 1944, journalist Hans Schwarz Van Berkl of Das Reich named the V-1.

Description

Lusser and Gosslau designed the V-1 under the codename Kirschkern. The fuselage was mainly welded sheet steel, and the wings were plywood.

The Argus-built pulsejet engine pulsed 50 times per second. This created the characteristic buzzing sound, earning it nicknames like “buzz bomb” or “doodlebug.” Briefly, in Germany, it was known as Maikäfer (May bug) and Krähe (crow), per Hitler’s orders.

The main components of the Argus pulsejet included the nacelle, fuel jets, flap valve grid, and mixing chamber venturi.

Compressed air forced gasoline from the fuel tank through the fuel jets. These jets consisted of three banks of three atomizers. The nine atomizing nozzles mixed fuel with air before it entered the chamber. A throttle valve controlled the fuel flow, connected to altitude and ram pressure instruments.

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Schmidt’s flap valve system provided an efficient path for incoming air. The flaps would close after each explosion, compressing gas in the venturi chamber. This action accelerated the exhaust gases, creating thrust, operating at 42 cycles per second.

From January 1941, they tested the V-1’s pulsejet engine on different crafts, including automobiles and an experimental attack boat, the Tornado. However, the Tornado prototype was noisy and inefficient and was abandoned for more conventional craft.

The engine had its inaugural flight on a Gotha Go 145 on 30 April 1941.

Used a Simple Autopilot

The V-1 used a simple autopilot developed by Askania in Berlin. It regulated altitude and airspeed. Gyroscopes controlled yaw and pitch, and a magnetic compass maintained azimuth. A barometric device maintained altitude.

Two spherical tanks held compressed air. This air operated gyros, pneumatic servomotors, and pressurized the fuel system. The magnetic compass, located at the front, was adjusted before launch for magnetic variances.

Originally, the RLM wanted to use radio control for precision attacks. However, the government decided to deploy the missile against London.

Some V-1s had a basic radio transmitter operating between 340–450 kHz. Over the channel, the vane counter switched the radio on.

Each V-1 site had a unique Morse code. It transmitted the route and impact zone. An odometer, driven by a vane anemometer, determined when the target area had been reached. It was set before launch and counted backwards from a preset value.

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Every 30 rotations of the propeller counted down one number on the odometer. This triggered the arming of the warhead after about 60 km. When the count reached zero, it triggered a series of actions, putting the V-1 into a steep dive.

Originally, this was supposed to be a power dive. However, the dive usually cut the fuel flow, stopping the engine. The ensuing silence after the buzzing was a sign of the imminent impact.

At first, V-1s had a landing accuracy within a 31 km diameter circle. By war’s end, the accuracy improved to about 11 km, comparable to the V-2 rocket.

V-1 Flying Bomb Warhead

The warhead had 850 kg of high-grade Amatol, 52A+ explosive, with three fuses. One electrical fuse activated upon nose or belly impact.

Another was a slow-acting mechanical fuse for deeper ground penetration, regardless of altitude. The last was a delayed action fuse, set for two hours post-launch.

This third fuse aimed to prevent British examination of the secret weapon, designed to destroy it if impact fuses didn’t trigger on a soft landing. These fuses were highly reliable, leaving almost no dud V-1s recovered.

V-1 Flying Bomb Walter Catapult

The ground-launched V-1s used a “steam generator” for propulsion up an inclined launch ramp. This was designed by Hellmuth Walter Kommanditgesellschaft. Here, hydrogen peroxide mixed with sodium permanganate to create steam.

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The system, WR 2.3 Schlitzrohrschleuder, included a small gas generator trailer. In it, high-pressure steam formed and moved into a tube in the launch rail box.

A piston connected under the missile was pushed forward by this steam. Contrary to popular belief, this wasn’t for starting the engine. It was because the Argus lacked the power to propel the V1 over its high stall speed.

The launch rail measured 49 m, made up of eight 6 m modular sections and a muzzle brake. The production of this catapult system started in January 1944.

The Walter catapult propelled the V-1 to 320 km/h, surpassing the required operational speed of 240 km/h. By London, its speed increased to 640 km/h as fuel diminished.

Launch Bunkers

On 18 June 1943, Hermann Göring chose to launch V-1s using Walter catapults from Wasserwerk bunkers and lighter Stellungsystem installations. Wasserwerk bunkers were expansive, and four were planned initially. Stellungsystem-I was stationed in the Pas-de-Calais region with multiple batteries.

Stellungsystem-II acted as a reserve unit, with Stellungsystem-III organized between Rouen and Caen in spring 1944. Each Stellungsystem location had distinctive features pointing toward London. Oberst Schmalschläger introduced simpler launching sites, called Einsatz Stellungen, in spring 1944.

These sites were less conspicuous, quickly constructed, and strategically located. They utilized the Walter catapult, which was erected in 7–8 days when ready. Once close to the launch ramp, the missile was assembled and shifted to the launch ramp.

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The ramp catapult was powered by the Dampferzeuger trolley. The pulse-jet engine started with the help of the Anlassgerät, energizing the engine and autopilot. The Bosch spark plug ignited the engine, reaching full power in 7 seconds, and the catapult accelerated the bomb above its stall speed.

The Beginning – Operation Eisbär

Mass production of the FZG-76 began in spring 1944, and FR 155(W) received equipment in late May 1944. Operation Eisbär, targeting London, started on 12 June.

Yet, only four launch battalions could operate, having only 72 launchers in the Pas-de-Calais area. Since D-Day, they had received missiles, Walter catapults, and other essentials. On 12th, none of the launched missiles reached England; only four did on the 13th.

On the night of 15/16 June, 144 missiles targeted England, causing significant damage in various locations. This led to Eisenhower prioritizing attacks on V-1 sites.

By August, Operation Cobra had forced a retreat from French launch sites, concluding with the last battalion leaving on 29 August. Finally, Operation Donnerschlag was initiated from Germany on 21 October 1944.

Were They Effective?

The first complete V-1 airframe arrived on 30 August 1942, and the first glide test was on 28 October 1942 at Peenemünde. It was launched from under a Focke-Wulf Fw 200. The first powered trial happened on 10 December from beneath an He 111.

The LXV Armeekorps z.b.V. formed in November 1943 in France. General Erich Heinemann commanded it, overseeing operational use of V-1. Conventional launch sites theoretically could launch about 15 V-1s per day. Achieving this rate consistently was difficult; the maximum was 18.

Overall, only about 25% of the V-1s hit targets, most lost due to defensive measures, mechanical failures, or guidance errors. After losing launch facilities attacking England, V-1s targeted strategic points in Belgium, like the port of Antwerp.

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Countermeasures against the V-1 included barrage balloons and aircraft like the Hawker Tempest and the Gloster Meteor. By August 1944, about 80% of V-1s were being destroyed. In total, aircraft destroyed about 1,000 V-1s.

Launch Sites

Initially, the operational altitude was 2,750 m (9,000 ft), but failures led to a change in May 1944, halving the operational height. This brought V-1s into the range of 40mm Bofors light anti-aircraft guns.

Trial versions of the V-1 were air-launched, but most operational ones were launched from static sites. From July 1944 to January 1945, the Luftwaffe launched about 1,176 V-1s from modified Heinkel He 111 H-22s over the North Sea.

This tactic allowed the Luftwaffe to bypass British defences against the missile. To minimize risks, aircrews developed a tactic called “lo-hi-lo,” altering altitude to avoid radar detection. Research estimated a 40% failure rate for air-launched V-1s, and launch made He 111s vulnerable to attack.

The combat potential of air-launched V-1s dwindled during 1944, as British defence tactics became increasingly effective against the weapon.

Experimenting With the V-1 Flying Bomb

Towards the end of the war, several piloted V-1s, called Reichenbergs, were developed but never saw combat use. Hanna Reitsch flew the modified V-1 Fieseler Reichenberg to investigate why test pilots couldn’t land it and had fatally crashed.

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Through high-altitude simulated landings, she found the craft had an extremely high stall speed. Previous pilots, inexperienced with high speeds, had approached too slowly.

Hanna then recommended higher landing speeds in training for Reichenberg volunteer pilots. Contrary to portrayals in the film Operation Crossbow, Reichenbergs were air-launched, not catapulted.

V-1 Flying Bomb, Arado Ar 234 Jet Bomber

Plans existed to launch V-1s from the Arado Ar 234 jet bomber, but they weren’t realized. The idea was to tow them or launch them from a “piggy back” position on top of the aircraft.

The Ar 234 would use a pilot-controlled, hydraulic mechanism to lift the missile clear of the fuselage.

This prevented damage when the pulsejet ignited and ensured clean airflow for the Argus motor.

Another concept involved adapting the missile as a “flying fuel tank” for the Messerschmitt Me 262 jet fighter. Initial tests towed it behind an He 177A Greif bomber.

The missile’s pulsejet, internal systems, and warhead were removed, leaving only the wings and fuselage as a fuel tank. A small module was added at the rear for balance and equipment attachment.

A rigid towbar connected the flying tank to the Me 262. During operations, the tank sat on a wheeled trolley for take-off, dropped once airborne. Explosive bolts separated the towbar from the fighter when the tank was empty.

Several test flights occurred in 1944, but instability made the system unreliable. Using the V-1 as a flying fuel tank for the Ar 234 was also considered but deemed impractical. Some trials used a fixed undercarriage arrangement, increasing drag and stability problems already present in the design.

Fi 103 design

One variant of the Fi 103 design saw operational use due to the loss of French launch sites in 1944. As German-controlled territory shrunk, the V-1’s ability to hit English targets diminished.

Air launching was a used alternative, but extending the missile’s range was crucial, leading to the F-1 version. This model had a larger fuel tank and smaller warhead capacity.

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The F-1’s nose cones and wings were made of wood, saving considerable weight. These modifications allowed the V-1 to target London from the Netherlands.

Efforts to construct enough F-1s for a large-scale bombardment during the Ardennes Offensive were frantic.

However, several delays, including factory bombings and steel shortages, pushed back the delivery of these V-1s until February/March 1945.

From 2 March 1945, hundreds of F-1s were launched at Britain under Operation “Zeppelin”. Germany, frustrated by Allied air dominance, also used V-1s to attack forward RAF airfields in the Netherlands.

V-1 Flying Bomb Countermeasures

British defenses against German weapons were under codename Crossbow, and Operation Diver handled V-1 countermeasures.

Royal Artillery and RAF Regiment guns first moved in mid-June 1944 to the south coast. In September, defenses repositioned on East Anglia’s coast. Finally, in December, a layout was established along the Lincolnshire–Yorkshire coast.

These shifts followed the changing approach tracks of V-1 as Allies captured launch sites. Initial engagements saw jubilant anti-aircraft crews around Croydon.

They believed they were downing German bombers, realizing later they were V-1s. Gunners found the small, fast-moving targets challenging.

The V-1’s altitude between 600 and 900 meters rendered many anti-aircraft guns ineffective. Standard British QF 3.7-inch mobile guns struggled, while their static counterparts had a faster traverse.

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Temporary platforms by the Royal Electrical and Mechanical Engineers proved effective, facilitating easier redeployment. The development of the proximity fuze and advanced radars helped in countering the V-1’s speed and size.

Bell Labs introduced an anti-aircraft predictor fire-control system in 1944, arriving in June as guns were positioned on the coast.

Success rates increased significantly, with 74% of V-1s being destroyed by the end of August. This nearly concluded the V-1 threat.

As General Frederick Pile put it in an April 5, 1946 article in the London Times: “It was the proximity fuse which made possible the 100 per cent successes that A.A. Command was obtaining regularly in the early months of last year…American scientists…gave us the final answer to the flying bomb.”

V-1 Flying Bomb Interceptors

The Defence Committee doubted the Royal Observer Corps’ (ROC) ability to counter the new threat. However, Commandant Air Commodore Finlay Crerar reassured them, citing the ROC’s flexibility and alertness. He orchestrated plans, dubbed “Operation Totter,” to counter the new threat.

Dymchurch coast post observers identified the first of these weapons swiftly, and anti-aircraft defenses reacted instantly. The introduction of this new weapon increased the workload for the ROC.

Eventually, RAF controllers used radio equipment in ROC operation rooms, directing fighters using ROC information. This silenced critics who doubted the Corps’ capability to handle fast-flying jet aircraft.

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V-1s had an average speed of 550 km/h and flew at altitudes between 1,000 m to 1,200 m. Interception required aircraft to have low-altitude speed and considerable firepower.

Most aircraft were too slow to intercept a V-1 without a height advantage, allowing them to dive onto their targets.

Initially, only the Hawker Tempest had the required speed to counter V-1s when attacks started in mid-June 1944.

Despite early failures, refined techniques enabled successful interceptions and the destruction of V-1s by utilizing airflow over the interceptor’s wing.

By September, over 100 Tempest aircraft were operational, and various aircraft models were modified for effectiveness against V-1s.

“Diver Patrols”

Nighttime interventions didn’t require radar as V-1 engines were audible and visible from a distance. Adjustments were made to aircraft weapons, increasing the chances of successful interceptions. These interventions, called “Diver patrols”, were dangerous due to the V-1’s resilient structure and the risk of detonating its warhead.

Daylight pursuits of V-1s were often chaotic and typically failed until a specialized defense zone was established.

Here, only the fastest fighters operated. F/L J. G. Musgrave, with a No. 605 Squadron RAF Mosquito, achieved the first V-1 interception on the night of 14/15 June 1944.

As daylight increased, a Spitfire was observed closely following a V-1 over Chislehurst and Lewisham. Between June and 5 September 1944, 150 Wing Tempests shot down 638 flying bombs, with No. 3 Squadron RAF claiming 305 alone. Joseph Berry of 501 Squadron claimed 59 V-1s, and Remy Van Lierde of 164 Squadron destroyed 44.

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The Mosquito, Spitfire XIV, and Mustang were also successful interceptors, with 623, 303, and 232 victories respectively.

All other types combined totaled 158 victories. The jet-powered Gloster Meteor was also deployed against V-1s but had limited success due to technical issues.

In late 1944, a radar-equipped Vickers Wellington bomber was modified for use as an airborne early warning and control aircraft. Flying at low altitudes over the North Sea, it directed interceptors to He 111s launching V-1s from the air.

German Agents, The V-1 Flying Bomb Spies

To fine-tune the V-1 guidance system, Germans needed impact locations. Thus, they relied on agents in Britain for this information. However, all German agents in Britain were double agents under British control.

British double agent Garbo, real name Juan Pujol, received requests for impact sites and times on 16 June 1944. German agents Brutus and Tate received similar requests.

Accurate data from double agents would have helped Germans correct their aim. However, providing inaccurate information was harmful as well, as the truth would inevitably reach Germany.

While deciding on a response, Pujol stalled for time. On 18 June, it was decided that double agents would report V-1 damages but would avoid giving exact times of impacts. They would also report impacts mostly in northwest London to give the impression of overshooting.

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Ostro, another agent, falsely informed Germans about devastating damage in London. The Germans believed him over Pujol due to the lack of aerial reconnaissance of London. Allies, aware of his messages, made necessary adjustments.

Some V-1s had radio transmitters showing a tendency to fall short. Max Wachtel, compared transmitter data with double agent reports. He erroneously trusted the agents over the transmitters, leading to miscalculations in V-1 guidance. If he had trusted the transmitter data, casualties might have been 50% higher.

Diverting V-1 impacts away from central London sparked controversy. The War Cabinet initially refused to authorize such a strategy. Findlater Stewart started the deception program immediately, which Churchill later approved upon his return.

The Numbers

By September 1944, advancing Allied armies overran V-1 launch sites on the French coast, temporarily halting the threat to England.

In all, attackers launched 10,492 V1s at Britain, aiming nominally for Tower Bridge. Defenses destroyed 4,261 V-1s through fighters, anti-aircraft fire, and barrage balloons.

Around 2,400 V-1s landed within Greater London, causing 6,000 deaths and 18,000 severe injuries. The last strike on British soil was a V-1 hitting Datchworth in Hertfordshire on 29 March 1945.

Assessment, Was V-1 Flying Bomb Effective?

The V-1 was cost-effective for the Germans, unlike the V-2. It forced the Allies to allocate substantial resources to defensive measures.

The Allies had to divert bombers to target V-weapon sites. Over 25% of the Combined Bomber Offensive’s bombs in July and August 1944 targeted these sites, often without success.

In December 1944, American General Clayton Bissell advocated for the V-1, comparing it favorably to conventional bombers.

However, the validity of his report’s statistics sparked debates. V-1 missiles, launched from bombers, had a tendency to explode prematurely. This flaw sometimes led to the loss of the carrier aircraft. The Luftwaffe lost 77 aircraft in 1,200 of these missions.

Technical personnel at Wright Field reverse-engineered the V-1 from remains found in Britain, resulting in the Republic-Ford JB-2 by early 1945.

After the war in Europe, officials considered using it against Japan. General Hap Arnold noted the weapon’s cost-effectiveness, highlighting its construction from steel and wood, requiring 2,000 man-hours and costing around US$600 in 1943.

For comparison, a Boeing B-29 Superfortress cost about 126 times more per ton of explosive delivered, excluding additional operational costs. Despite being reusable, these aircraft rarely accomplished enough missions to cover their production costs.

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