The Fieseler Fi-103 (V-1)
At first, it was not certain what he had found. From his sketch it was about 4 metres long, and it might have been a rather larger version of the HS 293-glider bomb that KG100 was now using against Allied warships in the Mediterranean. Indeed, it turned out that this particular bomb had been released from a Heinkel 111, but it was in fact a research model (the 'V' probably stood for 'Versuchs' i.e. research) of the flying bomb about which we were going to hear so much in the next few months.
British Military intelligence eventually discovered that the V-1 missile was being built at Peenemünde and in May 1943, Winston Churchill ordered Operation Crossbow, a plan to destroy V-1 production and launch sites. Over the next few months over 36,000 tons of bombs were dropped on these targets.
The V-1 (also known as a flying bomb, buzz bomb or doodlebug) was a pilotless monoplane that was powered by a pulse-jet motor and carried a one ton warhead. They were launched from a fixed ramp and travelled at about 497.2 mph (800 km/h) and 9,845 ft (3000 meters) and had a range of 150 miles (240km). It was 7.9 metres (26 feet) long and had a wingspan of about 5.72 metres (19 feet).
Germany launched its new weapon from Pas-de-Calais on the northern coast of France, on 13th June 1944. The first six failed to reach England but four reached the British mainland. Two landed in Kent, one in Surrey, and one crashed in London, the intended target of all of them. Over the next few months 1,435 hit south-east England. These attacks created panic in Britain and between mid June and the end of July, around one and a half million people left London.
Germany fired 9,521 V-I bombs on southern England. Of these 4,621 were destroyed by anti-aircraft fire or by RAF fighters such as the new turbojet fighter, the Gloster Meteor. An estimated 6,184 people were killed by these flying bombs. By August only 20 per cent of these bombs were reaching England.
The Fieseler Company's Rocket
It was a simple device, with an airframe designed by Robert Liisser of Gerhard Fieseler Werke GmbH in Kassel with a Siemens guidance system and known as the Fi 103 V1 / Reichenberg and could be constructed in around fifty man-hours of mainly sheet metal. It was powered by a Argus Pulse jet providing 660lb (300kg) of thrust for a top speed of 390mph (628 km/h) and a range of around 150 miles (later the range was extended to 250 miles or 402km). It was 26 feet (7.9m) long, 17 ft (5.3m) in span, it weighed 4,800lb (2180kg) and carried an 1870lb (850kg) warhead. The guidance system was very crude, a simple anemometer in the nose of the bomb span as the device flew, after a set number of revolutions the bomb was tipped into a dive and the engine cut-out.
The first test flight of a V1 was in late 1941 or early 1942 at Peenemünde. The world's first female test pilot Hanna Reitsch, flew some of the first 'flying bombs.She was the only woman ever to be awarded the Iron Cross and Luftwaffe Diamond Clasp.
The first offensive launch was on 12th June, 1944. The Allies organised a heavy series of air attacks on the launch sites and also attacked the V1s in flight - only a quarter successfully hit their target.
Once the Allies had captured the launch sites that allowed the V1s to hit England the remaining missiles strikes were against the port of Antwerp in Belgium.
Known alternatively as the FZG 76 (Flakzielgerat: anti-aircraft aiming device 76) or Vergeltungswaffe Eins (Reprisal Weapon 1), or more simply as the VI, the Fi 103 flying bomb had an airframe designed by Dipl-Ing Robert Liisser of Fieseler, and a Siemens guidance system. It could be launched from a 50m (152ft) inclined ramp by a Walter steam driven catapult, or air dropped from a carrier aircraft (usually an He 111). The weapons were launched against Britain (from l3th June 1944) and targets in continental Europe. More than 30,000 were manufactured by Henschel, Mittelwerke and Volkswagen factories. An Askania gyroscope fed signals to the elevators and rudder to control attitude and direction, and the terminal dive was initiated when a pre-set distance had been flown.
Operational air launches were mostly made from He 111 Hs of KG 3 (later KG 63); but, whatever the launch method, about a quarter of the weapons failed in use and only about a quarter of the remainder got through Allied defences. Even more of a desperation weapon was the Reichenberg' piloted series, of which there were four versions: the single seat and two-seat unpowered Fi 103R-I and fl-Il, the singleseat powered R-lll trainer, and the proposed operational RIV. About 173 were so converted, but none was used in combat.
A V-1 flying bomb resembled a small aircraft with a stovepipe mounted over its tail and no cockpit. Its overall length was just over 26 feet (7.9m), with a wingspan of 17ft (5.3m). Standard 80-octane petrol (gasoline) kept its jet engine running, which was housed in the stovepipe assembly; this was the same fuel used by trucks. The flying bomb was easy and cheap ($500 in 1942) to build and carried a 1,870-pound (816 kilo) warhead. But while the flying bomb may have been cheap and simple, it was not very accurate-it could not hit small targets, or even moderate-sized villages. It was accurate enough to hit a target the size of Greater London, however, and that was all that was expected-a way to hit back at the Allies without risking the depleted reserves of the Luftwaffe's bomber fleet.
During the early months of 1943, extensive tests were carried out involving the FZG-76. Only nine months had passed between the beginning of work on the project in March 1942 and the first successful launch, which took place on Christmas Eve, although the flying bomb still had its share of teething problems. One question involved the proper type of launching site for the flying bombs. Some favoured large concrete emplacements; others proposed small, portable sites. As head of the Luftwaffe, Reichsmarschall Hermann Göring compromised, ordering four concrete bunkers and 96 smaller sites begun immediately.
Next, men had to be trained to handle and fire the flying bomb. A new Luftwaffe unit was formed in August 1943, called Flakregiment 155 ('N). The anti-aircraft designation was, once again, aimed at deceiving Allied intelligence.
Preparing & Launching the Rocket
The new unit was placed under the command of Luftwaffe Colonel Max Wachtel, who had been in charge of all the experimental flying bomb launches. Wachtel was instructed to get his men ready for firing the bomb under actual combat conditions, and he took his orders to heart; his Flakregiment began exercises within days of the unit's creation. From the western side of Peenemünde, on Usedom Island in the Baltic Sea, the launching crews began readying the small, jet-propelled planes and firing them downrange over the Baltic.
Under Wachtel, Flakregiment 155 ('N) continued its training through the winter of 1943 and into 1944. By June 1944, Wachtel and his unit were in France, ready to begin operations. But few others connected with the flying bomb project were as efficient as Wachtel.
One of the main problems was with the production of the flying bombs themselves. Because of the many defects that plagued the bomb, it did not go into production until March 1944. Engineers at the Volkswagen plant at Fallersleben, near Hamburg, did their best to work out the problems, but the pilotless planes kept crashing immediately after launching. Full production did not begin until April 1944, when 1,000 flying bombs rolled off the Volkswagen assembly line.
Wachtel had been ordered to begin launching the pilotless bombs against England by June, but his unit had no equipment, no launching rails and no supplies. It had been decided that lightweight launching ramps, called modified sites, would be used in place of larger ramps that had proved too vulnerable to Allied bombing attacks.
The supplies and equipment that Wachtel needed to begin operations did not arrive until 12th June, 1944, only a few hours before he was to begin launching V-1's against southern England. Only 10 ramps were ready for launching; 55 were supposed to have been prepared, but not enough spare parts and equipment had been sent for all of them.
By 3:30 on the morning of 13th June the 10 firing ramps were ready. The Luftwaffe high command decided to go ahead despite the fact that so few ramps were operational.
Months of practice made the pre-launch procedure a set routine for the crews. First, the flying bomb's fuel tank was checked, to make certain that it had been topped off. Following this, the wooden wings were attached-these had been folded over the fuselage to make storing and moving the aircraft easier. After assembly, the plane was aligned precisely with its firing ramp-which was pointed directly at London-and its gyrocompass was set at zero to ensure it flew the straight course on which it had been aimed.
The flying bomb, now ready for launching, was moved onto its firing ramp. After it was loaded onto its catapult, a lug on the underside of the fuselage was attached to the catapult's firing piston. When the piston was released, it accelerated the V-1 off the launch rails in the same way that a jet plane is catapulted off the flight deck of an aircraft carrier.
With the stubby-winged flying bomb poised for takeoff, the launching crew took cover inside the "control bunker," a heavily armoured trailer that housed the catapult's firing controls, or lumped into a nearby slit trench. The firing officer gave an order, a technician pulled a lever, and the flying bomb's pulse-jet engine came to life with a throbbing, ear-numbing roar.
The Argus Pulse Jet Engine
This simple jet engine was the flying bomb's most unique feature. Housed outside the fuselage, above the tail, the jet is usually described as looking like either a stovepipe or a giant blowtorch. At the front end of the engine housing was a set of intake flaps that resembled a Venetian blind. These flaps opened at the beginning of the engine's cycle, allowing air to be drawn into the combustion chamber, where it was mixed with 80-octane fuel. In the second stage of the combustion cycle, the flaps closed and the fuel-oxygen mixture was ignited. With a tremendous flash, a burst of hot exhaust shot out from the rear of the engine to provide forward thrust. Immediately following the exhaust stage, the intake flaps opened again, allowing air into the combustion chamber and repeating the cycle.
This simple jet engine could complete up to 500 combustion cycles every minute, giving the flying bomb a maximum speed of about 497.2 mph (800 km/h). The engine's pulsing combustion process also gave the flying bomb its distinctive duv-duv-duv sound in flight, a sound that Londoners would soon come to recognise.
Launching Attacks against Britain
After listening for a moment to ensure that the engine was firing properly, the firing officer gave the order to launch. A second lever was pulled, releasing the catapult's piston. The flying bomb lurched forward, shot along the length of steel rail, and lumped uncertainly into the night sky. During the next half-hour, between about 3:30 and 4 a.m., nine more of the bombs bolted from their catapults. The launching crews watched as the small aircraft left their ramps, brilliant flashes of fire trailing from their exhausts.
Four of the shots failed, the flying bombs crashing just after takeoff, with explosions loud enough to hurt the eardrums of the catapult crews. Two of the successfully launched flying bombs crashed into the English Channel. The other four reached England, two landed in Kent, one in Surrey, and one crashed in London, the intended target of all of them. The London bomb came down in Bethnal Green, East London (which coincidentally had a large Jewish population), about three miles away from its Tower Bridge target point. The explosion killed three people and knocked out a railway bridge.
Although only four flying bombs reached England during this first launch, hundreds more would be launched during the next several weeks. An inexpensive, and not very accurate, mechanism sent the flying bomb diving into its target upon arrival. Each bomb had a small, propeller like anemometer device on its nose that was connected to the bomb's autopilot. As the flying bomb flew through the air, its forward motion turned the propeller like a pinwheel in the wind. After a pre-set number of revolutions, the propeller tripped the diving controls, pointing the bomb earthward at a steep angle. The mechanism was set by the catapult crew before launching; the setting of how many revolutions were needed to trip the diving controls was based upon calculations involving the flying bomb's speed and the distance to target.
Any number of factors could undo this inherently imprecise system. Headwinds or tailwinds could alter the machine's ground speed, undermining carefully worked-out calculations that were usually a lot more accurate than the mechanism itself. The autopilot might go haywire and send the bomb plunging into the Channel or it might not work at all, causing the bomb to overfly London and keep going until it ran out of fuel. When the windmill device tilted the bomb toward the earth, all the fuel ran to one end of the tank away from the fuel pump. The pump began drawing air, and the engine, cut off from its fuel supply, stopped running.
People in London and southern England very quickly learned to use this "cutting out" of the engine to their advantage. Between the time the pulsing duv-duv-duv ended and the bomb hit the ground, an average of between five and 15 seconds would pass-enough time for people to dive under a table or some sort of cover. This characteristic undoubtedly saved many lives.
In spite of the machine's defects, Wachtel's Flakregiment 155 ('N) kept launching the bombs at a steady rate. On Saturday, 18th of June 1944, his unit launched its 500th flying bomb. One of them landed on Hungerford Bridge, the railway bridge across the River Thames to Charing Cross Station in London. The explosion blew a gaping hole in the middle of the bridge, forcing one of London's major rail terminals to shut down. Later in the day, an American intelligence officer saw the damage done to the bridge. It had been blown almost in half by the explosion. He also noticed that several large buildings on the Thames embankment had all the windows facing the river blown out.
Each flying bomb had an efficient system of sensitive fuses and pressure switches that detonated the warhead on first contact, before the machine could bury its nose (and warhead) in the earth. When the 1,900 pounds (862 kg) of high explosives went off on the surface of a roadway, the blast cut down everything within reach. Solid walls crumbled-often, even individual bricks in a wall would be reduced to pebble-sized bits. Windows a quarter of a mile away cracked from the force of the explosion.
A central London fire station got a firsthand look at the effects from the blast of a flying bomb. The firemen had opened the station's big front doors, trying to enjoy a sunny but not very warm June day, when a buzz bomb landed less than a block away. The blast waves first slammed the heavy wooden doors shut; then, a second later, the vacuum created by the explosion wrenched them open again. When the bomb's warhead detonated, shock waves flew out in concentric circles, like gigantic ripples. As the blast waves pulsed outward, they created a vacuum behind them. The vacuum was capable of creating as much damage as the blast itself.
Defence of the Realm
In an effort to stop the flying bomb attacks, anti-aircraft defences and more than 1,000 barrage balloons were sent to Kent, southeast of London. Bombs launched from the Pas de Calais would have to fly over this "gun belt" on their way to London. Also, eight fighter squadrons, equipped with Hawker Typhoons, Supermarine Spitfire IXs and XIVs, and Hawker Tempest Vs, flew standing patrols.
Fighters assigned to combat the flying bombs underwent modifications to squeeze every last bit of power from their engines to help them chase the speedy flying bombs. All armour and excess weight were removed. The leading edges of wings and stabilisers were polished to a high gloss. The engines themselves received particular care, with meticulous tuning and overhauling at frequent intervals. After all the cutting and streamlining, the flying bomb interceptors consisted of little more than machine guns and cannons, a fuel tank, and a finely tuned engine. Because the buzz bombs travelled at more than 400 miles per hour (644 km/h), the piston-engine fighters needed all the speed they could muster.
Pilots of the modified Spitfires and Tempests could now close with the flying bombs more easily. Some could even fly right alongside the bombs, close enough to read the German writing on the fuselages. A few enterprising pilots discovered that they could slide a wing under the wingtip of the "flying blowlamp" and lift it, tipping the flying bomb out of control. That quickly became a standard method of destroying the bombs.
"Tipping the doodlebugs" nearly always worked. The flying bombs had a very delicate gyro mechanism, any sudden, violent movement-such as wing lifting would cause it to malfunction. With the gyroscope out of order, the machine would spiral earthward and crash. From the air, the concentric shock wave of the crashed bomb was said to look like "a single ripple on a lake."
But this manoeuvre was not without its risks. The flying bomb was made of rolled sheet steel, while the RAF fighters had a skin of light aluminium alloy. Many a Spitfire and Tempest hobbled back to base with one of its highly polished wings bent and twisted out of shape from the "wing wrestling."
Bringing down a buzz bomb with gunfire also presented problems for Allied pilots. The most frequent method of attack was the deflection shot, approaching from the side and opening fire when the bomb crossed the pilot's line of sight. "It's like firing at a large flame with wings sprouting out of it," the pilot of a Tempest V said. "Your cannon scores hits, and suddenly there is a big red flash."
The top "doodlebug ace" was Squadron Leader Joseph Berry, who flew Tempest Vs with the Fighter Interception Unit, and then No. 501 Squadron. Berry's final score was 59½ V-1s, including a one-night record of seven on July 23. During a low-level chase four days later, he closed to 100 feet (30.4 meters) before downing the doodlebug, and his plane was damaged in the ensuing explosion. To his chagrin, he had to share the credit with a de Havilland Mosquito that had fired at the V-1 from 1,000 yards (914.4 meters) and, in the opinion of his unit, had "missed hopelessly."
Another noted V-1 specialist was Flying Officer R.F. Burgwal, a Dutch pilot who flew Rolls-Royce Grifon-engined Spitfire XIVs with No. 322 Squadron, a Dutch unit based in southeast England. Burgwal was credited with 21 V-1s, while a squadron mate and fellow Hollander, Flight Lt. J.L. Plesman, accounted for 12.
Number 616 Squadron could combat the pilotless planes on an equal footing. In July 1944, the unit received seven Gloster Meteors, the RAF's first jet fighter. The Meteor had a maximum speed in excess of 400 miles per hour (644 km/h), and could easily overtake the missiles. But the Meteor suffered from constant gun trouble-its 20mm cannons had a habit of jamming.
In spite of the balky cannons, however, the Meteors accounted for 13 flying bombs. When the guns failed, pilots could always rely upon the tipping techniques.
Meteor pilot T.D. Dean had a problem with his Meteor's cannons on 4th of August; he attacked a flying bomb, but his guns jammed. Undeterred, Dean manoeuvred his aircraft alongside the bomb, slid a wingtip under the missiles, and executed a sharp bank, using the tipping manoeuvre. The V-1's gyro mechanism was thrown out of balance, and the flying bomb crashed. This was the first combat victory for an Allied jet fighter.
When a flying bomb was disabled by gunfire, it behaved in the same way as any conventional aeroplane-it went out of control sometimes trailing smoke, and smashed into the earth. But the V-1s presented some problems that fighter pilots had not encountered before. One of the main problems was with the sheet steel skin. It deflected .303 calibre machine-gun bullets like armour plate.
Cannon fire was most effective against the V-1; a shell from a 20mm cannon would blow a hole right through the steel outer covering. But a 20mm cannon had a much shorter range than a .303 calibre machine gun, forcing the attacking pilot to move in at close range before pressing the firing button. And if a cannon shell should hit the flying bomb's 2,000-pound (907.2 kg) warhead, the result could be disastrous for the attacker. When a buzz bomb exploded in mid-air, great chunks of metal sprayed in all directions. The result could be the same as having a huge anti-aircraft shell explode nearby.
Jagged shrapnel holes and blasted-away control surfaces were the reward of a careless or overeager pilot who attacked a flying bomb. At least five aircraft were destroyed by mid-air flying bomb explosions. One such aircraft, a Spitfire, was flown by a Free French pilot, Jean-Marie Maridor, who attacked a flying bomb at point-blank range near the south coast. The bomb's ton of Trialen exploded, blasting the Spitfire apart and killing Maridor instantly.
The flying bomb offensive-air launched V-1's
The flying bomb offensive against London and southern England continued throughout the summer of 1944. In late summer, the launch sites on the Normandy coast were captured by the Allied armies as they moved inland from the D-Day beaches. By the first week of September, the flying bomb attacks had all but ended. More than 2,000 of them had hit London, with many others coming down on the surrounding suburbs.
In mid-September, the bombs began to be fired at England by a new method-launched in mid-air from twin-engine Heinkel He-111 bombers. The V-1 was slung under the Heinkel's port wing, inboard of the engine.
The Heinkels approached England at low altitudes to avoid radar detection. The pilot climbed to about 20,000 feet (6,096 m) when the bomber neared the flying bomb's launching point, and he instructed the crew to start the bomb's engine and gyroscope. When everything was ready and the bomber had reached its required altitude, the V-1 was released. The pilotless plane dropped for several hundred feet before it levelled out and headed toward its target. Some never pulled out, and crashed into the North Sea. But most levelled off and continued along their pre-set course toward the eastern coastline of England.
Only one or two of these air-launched bombs was aimed at London; some shots were aimed at the port of Southampton. Apart from putting an added strain on Britain's defences, as well as on already taut British nerves, this new attack had little effect. It was proposed to tow V-1s on platforms behind submarines for lauch against the United States but with the technology of the time this was easier said than done. The last flying bomb was launched at London on 29th March 1945, only six weeks before Germany surrendered.
Post War Development
Both the United States and the Soviet Union "exported/stole" Fi 103 missiles for duplication and further development. The US Navy developed a version called the JB-2 Loon, which was designed to be launched from submarines. In Russia, Vladimir Chelomei, who experimented with pulsating engines himself, later developed a Soviet version of the Fi 103 missile, known as 10 KhN.
Footnote: One of the few photographs on this site not taken at the Planes of Fame Museum is the second photo in the slideshow of the V-1 Rocket which was taken at Eden Camp, Malton, North Yorkshire, which I learned about by chance on a visit back to Britain from Germany where I was living at the time, while on motorcycling holiday across the North of England in June of 1995.
Eden Camp as it is known locally was one of 1,500 camps built under a Government expansion plan to accommodate Italian & German prisoners captured on the war-torn battlefields of Africa & Europe who were then transported back to Britain for internment. From as early as October 1939 to July 1948 Britain hosted some 402,200 prisoners.
For more detailed information on Eden Camp log on to http://www.edencamp.co.uk/.
The rocket base at Peenemünde from where research in
rocketry was extensivly carried out in Germany during WWII & from
where V-1s & V-2s were launched is now a museum.
For the official site of the museum which is in German log on to Peenemünde.
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