Secret Weapons (7 page)

Submarine commanders, however, knew that some means of carrying out reconnaissance was imperative. Current limitations were imposing severe restraints upon the U-boat campaigns. The distance of vision is severely restricted through a periscope, and some means of gaining height – as in the abandoned Ar-231 – conferred a considerable advantage. Accordingly, focus was directed instead to the notion of having an observer towed along underneath some kind of kite. This would not be just a conventional kite, either, but a superbly thought-out and well-designed kite with rotary wings.

The project was put to the designers at the Focke-Achgelis Flugzeugbau (a division of Weser Flugzeugwerke) of Hoykenkamp in Lower Saxony, who were experienced in helicopter production. Since helicopters had emerged in their present-day form in 1936, their production had become routine and companies like Focke-Achgelis Flugzeugbau were well equipped to tackle the problem. The Weser Flugzeugwerke were based at the Lloyd Building in Bremen, and they acted as the government contractors for the project; all development and manufacture, however, was carried out at Hoykenkamp. The result was the Focke-Achgelis Fa-330 gyroglider, an autogyro that could be tethered to the deck of a submarine at the end of a wire cable 500ft (150m) long. A minimum airflow of 20mph (32km/h) from the movement of the submarine caused the rotors to turn at about 200rpm, lifting the glider 400ft (120m) above the sea. The observer could spy out features up to 25 miles (40km) away, rather than being able to see just 5.5 nautical miles (10km) from the top of the submarine’s conning tower, and he could send back real-time reports by telephone. When observations were over, the Fa-330 was hauled down, the rotors stopped by means of a hub brake, and the craft stowed away in watertight compartments aft of the conning tower. This was not a simple task and could take 20–25 minutes in rough seas.

The Fa-330 was nicknamed the
Bachstelge
(Sandpiper) and 200 were built. These little gliders were successful in use, but were disappointing as agents of warfare. There was only one instance when a sinking resulted from their use – a Greek steamer in 1943. They also posed a problem for the submarines, for they could be detected by British radar and thus inadvertently reveal the location of the submarine. Pilots of the Fa-330 were sometimes forgotten about by the captain of the submarine, which suddenly dived leaving the pilot and his craft doused in the sea. It soon became routine for the pilot to call down the line ‘Haul me in!’
before
announcing that an enemy ship had been sighted. In May 1944 one of these gyrogliders was captured and examined by the Allies. Experiments were carried out by the British, but the helicopter was seen as a higher priority and the little rotary glider was never used again. Design of the Rotachute, a British single-seat gyroglider, was undertaken by an expatriate Austrian designer, Raoul Hafner. The design was modified by Dr Igor Bensen after he had seen one of the German Fa-330 gliders, and the Benson design became popular. This original Rotachute was intended to be towed behind an aircraft, and was not ready until 1946; but Benson’s B-7 gyroglider was a success and later re-emerged as a sports craft. It is still popular with enthusiasts today.

The gyroglider was a form of aircraft similar to an autogyro – the essential difference being that the forward motion of an autogyro was provided by its own onboard propulsion system, whereas the gyroglider was towed by a moving vehicle. Autogyros were the invention of Juan de la Cierva, a Spanish engineer and flight enthusiast. His first successful design, the fourth with which he experimented (the C-4), flew in 1923. The aircraft had a forward propeller and engine with a rotor on a vertical mast. The C-19 was licensed to several overseas manufacturers, including Harold Pitcairn in the United States and Focke-Achgelis in Germany. Amelia Earhart flew a Pitcairn PCA-2 to a world-record altitude of 18,415ft (5,613m) in 1931.

During the war, Germany also employed the Focke-Wulf Fw-186 and experimented with the Focke-Achgelis Fa-225 and the two-seater Flettner Fl-184. But it was the Spanish design of the La Cierva C.30A that was most successful. The United States used a version which they named the Kellet KD-1A; Britain and Canada produced their own models as the Avro 671 Rota Mark.1 and the French called theirs the Lioré-et-Olivier LeO C.30/31. The Soviets had their own design, the TsAGI (Kamov) A-7 observation autogyro. In the Pacific arena, the Japanese produced their Kayaba Ka-1 Autogyro for reconnaissance and for use as an anti-submarine observation aircraft. Although the war brought helicopters visibly into use as a crucial means of transporting men and materiel, we should also remember the small, secret ‘spy in the sky’ that was the autogyro. Autogyros remain popular to the present day, mostly as the aircraft of hobbyists, yet they flourished only because of the pressures of secret weapons development in the war.

The flowering of innovation in the development of German secret weapons during the war years was especially pronounced in the field of revolutionary aeronautics. Britain was consumed with finding responses to the German onslaught, but the German High Command became fanatical about the domination of the Western world. The engineers and visionaries came up with startling, stunning concepts, and the rate at which they progressed was astonishing. Some of the ideas could never reach fulfilment. One was for the 3 x 1,000 project, intended to bomb English cities. This was the aim of Reichsmarschall Hermann Göring, and would have involved a bomber carrying 1,000kg of explosives for 1,000km at 1,000km/h, equivalent to 2,200lb of bombs for 625 miles at 625mph.

The birth of the ‘flying wing’ had been in the USA where Jack Northrop had experimented with delta-wing designs in the late 1920s. Little came of it, however, until the pressures of World War II led to new calls for revolutionary aircraft designs. Both the United States and Germany began development, but research took longer than expected. In Germany, two brilliant brothers, Walter and Reimar Horten, revived the concept during war and planned to take it to unprecedented heights. Both were members of the Hitler Youth and later of the Nazi Party. They first designed an unpowered delta-wing glider, the Ho-229, for flight testing, and its initial flight was in March 1944. After this successful test, the development was taken over by the Gothaer Waggonfabrik Company. They installed an ejector seat for the pilot, and added systems to carry air to the jet engine with which it was proposed to power the plane. Even before the aircraft had flown under jet power, Göring had an order placed for 40 of these aircraft with the designation Ho-229. Further test flights showed that the plane had superb handling qualities, though there were some tragic accidents during the test flights of prototypes. The Germans were building a twin-engined Ho-229 V3 when the Americans arrived during the liberation of Europe at the end of the war.

During the final stages of the conflict, the United States military initiated Operation
Paperclip
, a top-secret initiative by the United States intelligence agencies to capture advanced German weapons research, and keep it out of the hands of advancing Soviet troops. A Horten test glider, and the partly built Ho-229 V3, were packed up and shipped to the United States, and the Hortens – for all their active Nazi participation – were secretly taken to America and given sanctuary. Their hardware was sent to Jack Northrop.

The first of Jack Northrop’s new generation of planes, the N-1M, had taken to the air in July 1941 at Baker Dry Lake, California. These pioneering test flights showed that the design clearly had a future, though the plane’s twin 65hp (48kW) Lycoming 0-145 four-cylinder engines left it low on power and the construction was too heavy. The power-plants were replaced with 120hp (88kW) six-cylinder air-cooled Franklin engines and the design was modified though, in spite of it all, the plane never went into production.

Engineering design of the first American delta-winged planes started in 1942. The aircraft would be constructed of the latest light-alloy sheet. There would be a cabin embedded in the delta wing with bunk beds for crew to sleep on during prolonged flights. Bomb bays would be fitted in each wing with seven gun turrets carrying machine guns. Yet progress was slow and the XB-35 did not make her first successful flight until June 1946 when she flew from Hawthorne, California, to Muroc Dry Lake. By May 1948 the plane was ready to start production, but the planes – powered by propeller engines – were rendered obsolete by the advent of the jet bomber. Jet engines were fitted to a few but they were not successful, though one plane, designated the YRB-49A, was tested as a reconnaissance aircraft. Although the United States Air Force had originally ordered 200 of the original B-35 planes, they proved unsatisfactory and not worth converting to jet propulsion so the entire project was peremptorily cancelled. It was a controversial decision, and Jack Northrop later stated that it was due to his refusal to accede to the wishes of Secretary of the Air Force Stuart Symington, who wanted Northrop to merge with the Convair Company. Jack Northrop insisted that unfair terms were being imposed on him, and that it was Symington who suddenly cancelled the flying wing. Northrop may have been right; Symington subsequently became President of the Convair Company when he resigned from government service shortly afterwards.

The final legacy of the Horten brothers’ original design lives on, however. Their aircraft were intended not only to be aerodynamically efficient, but also to reduce the radar signature. As the British began to develop and improve radar technology, the Germans were increasingly aware of the need to defeat its penetrating gaze. The Hortens used a unique glue in their planes, rather than metal nails or rivets; the glue – a carbon composite – and the low profile meant that the aircraft were far harder to see on radar. In 2009, a full-size reproduction of the Ho-229 V3 was constructed for a television documentary. It cost $250,000 (£160,000) and took 2,500 hours to build, but its radar profile was found to be less than 40 per cent of a World War II fighter (such as the Messerschmitt Bf-109). Not only was this a revolution in design, but the plane, had it gone into production, would have been the world’s first stealth bomber.

An Olympic vision – the Adolphine

An aircraft with a greatly extended range had begun as an idea before the war and by the war’s end it was envisaged as a plane that could span the world from high altitude. It is a remarkable story of both brilliance and foolhardy adventurism that far out-reached itself.

This story had its roots in 1936 in Berlin, site of the XI Olympiad. The city selected to host the next Olympics was Tokyo, Japan, and Hitler had a vision that the German team would fly direct from Germany to Japan in a record-breaking non-stop flight aboard a futuristic aircraft designed especially for the event. As it happens, plans for the Olympics were agreed at the Cairo Conference of the International Olympic Committee held in 1938 but Japan renounced the conference because of the Second Sino-Japanese War. Japan was thus stripped of her right to hold the games, which were rescheduled to be held in Helsinki, Finland. By this time, the Germans were already developing the super-plane Hitler had envisaged: work had started in 1937, when the Messerschmitt Company launched Projekt
P-1064
. It was viewed as a development of the Messerschmitt Bf-110 twin-engined heavy fighter into a reconnaissance plane that had unprecedented range. Conceived with a slender fuselage and with two engines, this was the Messerschmitt Me-261 and it was seen as spearheading German superiority in long-range flight. The Luftwaffe designated it the 8-261. Since it had the backing of the Führer, the projected aircraft was named Adolphine.

For its time, the plane was remarkably futuristic. The all-metal wings were deep and served as fuel tanks, and were fixed to a fuselage with a rectangular cross-section which had room for five crew, with pilot and co-pilot seated in the cockpit alongside the radio operator, and a navigational officer and engineer at the rear. The four Daimler-Benz DB-601 engines were coupled in pairs through a shared gearbox. Work was under way in 1939 and was supported from the highest levels of the Nazi power structure – but with the outbreak of World War II the 1940 Olympics were cancelled, and the project lost both urgency and direction. By August 1939, work had come to a standstill. Within a year, however, it was plain that the war would be no walkover for Germany, and the Luftwaffe began once again to involve long-distance bombers in their strategy. The Adolphine suddenly had a part in these plans, so work was resumed under conditions of urgency and the first prototype flew in December 1940.

It seemed highly promising and, with the DB-606 engines, the range was predicted to be as much as 12,000 miles (20,000km) for the production aircraft. The engines were in short supply, however. They were being produced as fast as possible, but all were needed for established, successful planes like the Heinkel He-177. The second version was flown in 1941, but Messerschmitt realized that the fuel-carrying wings posed a radical problem: there was no room in the wing structure for weapons. There was a plan for the aircraft to fly over New York, dropping propaganda leaflets, but this public relations scheme was abandoned when Allied bombing destroyed both prototypes. There was a third prototype, fitted with two DB-610 engines and with space for two further crew members. It first flew in early 1943 and in April 1943, the Me-261 V3 flew for 10 hours over 2,790 miles (4,500km), the distance from Europe to America across the Atlantic. It was an unprecedented achievement. Three months later the prototype crash-landed, damaging the undercarriage. The plane was used for several long-distance reconnaissance missions but the need for an aircraft to catch the public attention no longer existed, and the project was finally scrapped in 1944.

The idea of a plane that could cross the Atlantic had remained a continuing preoccupation of the German High Command throughout the war. The Commander-in-Chief of the Luftwaffe, Hermann Göring, often spoke of his wish to have a bomber that could curtail the ‘arrogance of the Americans’. One scheme had been to use the mid-Atlantic Portuguese islands of the Azores as a stop for fuel. The Portuguese dictator António de Oliveira Salazar had allowed the Germans to obtain fuel for their U-boats and Navy vessels from São Miguel in the Azores, but in 1943 he signed leases with the British, allowing them to use the islands as a base from which to patrol the North Atlantic by air.