COMBAT 123 AIRCRAFT Robert Forsyth HEINKEL He 177 UNITS OF WORLD WAR 2 123 HEINKEL He 177 UNITS OF WORLD WAR 2 SERIES EDITOR TONY HOLMES 123 Robert Forsyth HEINKEL He 177 UNITS OF WORLD WAR 2 C O N T E N T S CHAPTER ONE ‘BOMBER A’ 6 CHAPTER TWO TESTING TIMES 18 CHAPTER THREE SERVICE DEBUT 27 CHAPTER FOUR ANTI‑SHIPPING OPERATIONS 46 CHAPTER FIVE BOMBING BRITAIN 67 CHAPTER SIX LAST GASPS 88 APPENDICES 93 COLOUR PLATES COMMENTARY 93 BIBLIOGRAPHY AND SOURCES 94 INDEX 96 6 CHAPTER ONE ‘BomBeR A’ CHAPTeR oNe ‘BOMBER A’ In the history of aviation, many aircraft, civil and military, have been the The sleek He 119 high‑speed bomber/ reconnaissance aircraft was intended to cause or subject of tortuous development, heated debate, disagreement, incorporate advance aerodynamic uncertainty, confusion and often danger. The Heinkel He 177 was no technology in the late 1930s. It was exception and encompassed all of these factors throughout its design, powered by the DB 606 coupled engine, with early tests illustrating that motor’s evolution and operational deployment. unreliability. Seen here is the He 119 V3, The story begins at a meeting of a special commission convened in which was used as a test machine for Berlin at the Reichsluftministerium’s (RLM – German Air Ministry) planned anti‑shipping operations Technisches Amt (Technical Office) on the morning of 3 June 1936, chaired by Fliegerstabs‑Ingenieur Oberst Roluf Lucht of the department LC II, responsible for the development of aircraft, aircraft engines, equipment and weapons. The room held an impressive gathering of engineering intellect and technical acumen, including aircraft designers Ernst Zindel of Junkers, Dr‑Ing Richard Vogt and Bürkner of Blohm & Voss, Robert Lusser and gliding pioneer Fritz‑Heinrich Hentzen of Messerschmitt, Friedrich Nicolaus of Henschel and Heinkel engineers Eichler and Meschkat, along with senior specialists of LC II’s aircraft and aero‑engine development sections. The objective of the commission was to explore the feasibility of producing a strategic bomber with a range of 5000 km and the ability to carry a bomb load of 500 kg at 500 km/h for half that distance, a service ceiling of 6000 m and a maximum altitude of 10,000 m. The design was to include a crew of four, defensive armament of two machine guns or CHAPTER ONE ‘BomBeR A’ 7 cannon and it was to be powered by an unspecified number of the latest engines produced by Daimler‑Benz, Junkers, BMW or Argus. During the mid‑1930s, the Luftwaffe had been riven by conflicting views on the merits of heavy, long‑range bombers. Despite much post‑war literature stating the contrary, Germany did, in fact, remain committed to the concept of building a strategic bomber fleet from 1933 through to the mid‑war years. The fledgling Luftwaffe’s first Chief of Staff, Oberst Walther Wever, a man of charm and considerable, far‑sighted intellect, and with a reputation as a hard‑working and demanding commander, played a significant role in fostering this goal. It was his view that the Luftwaffe would need a multi‑engined bomber in order to prosecute effective strategic air warfare in the future. Wever reasoned that Germany’s main enemy would be Russia. As such, any future war would involve industrial targets deep within the Russian hinterland, possibly east of the Ural Mountains, hence the concept of a four‑engined, long‑range bomber – or ‘Ural Bomber’ – was born. Wever subsequently ordered a specification to be issued by the RLM to Junkers and Dornier for an aircraft capable of fulfilling this role. It was a specification that was well in advance of the plans of most of the world’s air forces, and it would stretch the resources of the still very young post‑World War 1 German aircraft industry to its limits – demanding the carrying of a heavy bomb load over a great distance with the benefit of speed and good defensive armament. By May 1934, the development of such a heavy bomber became the Luftwaffe’s top priority, and the resulting designs became known as the Dornier Do 19 and Junkers Ju 89. However, Oberst Wilhelm Wimmer, head of the Technisches Amt, who was considered to have the best technical mind in the Luftwaffe, became disappointed by the design of the new bombers even before they flew, and with Wever’s approval, he issued revised specifications and demanded totally new proposals: hence the Berlin commission of 3 June 1936. As a result of this meeting, another bomber specification began to take shape under the design‑concept name ‘Bomber A’, a tender for which was put out to the five aircraft manufacturers that had been in attendance. ‘Bomber A’ was to weigh 27 tonnes, have a range of 5000 km and a speed of 500 km/h at 5500 m. Like the ‘Ural Bomber’, the plan was for the aircraft to be powered by four engines, each of around 1000 hp, of either the Daimler‑Benz DB 601 or Jumo 211 12‑cylinder liquid‑cooled in‑line type, the Jumo 206 six‑cylinder diesel, the BMW 139 or Bramo 329 14‑cylinder air‑cooled radials, or the Argus As 412 14‑cylinder liquid‑cooled in‑line. The aircraft was to be able to take off, overloaded if necessary, within 1000 m. It was further decreed that the bomber should be capable of carrying the heaviest types of ordnance. ‘Bomber A’ would be operated by a crew of three, made up of two pilots, one of whom would command the aircraft and operate one of its defensive guns, while the third man would act as radio operator and gunner. In an ominous portent, however, the same day that the Berlin meeting took place, Oberst Wever was killed in a flying accident, forcing a rethink of the entire ‘Ural Bomber’ concept. Meanwhile, at his works at Rostock‑Marienehe, the creative, ambitious and industrious Ernst Heinkel went to work on a design to conform to 8 CHAPTER ONE ‘BomBeR A’ the ‘Bomber A’ requirement, and it was his offering that was accepted by the RLM. As Heinkel recorded in his memoirs; ‘I got that contract for various reasons. Firstly, on account of the Air Ministry’s decision to turn me into a bomber designer after the success with the He 111, and secondly from considerations of a quite different nature.’ These ‘considerations’ centred upon engines, an area in which Germany was faltering in terms of performance for heavier aircraft. Indeed, BMW, Daimler‑Benz and Junkers were working The Daimler‑Benz DB 606 engine, with its twin 12‑cylinder DB 601 liquid‑cooled units on engines of 2000 hp, but none had so far actually powered an aircraft mounted either side of the gearing system in the air. A solution lay in the idea of coupling two engines to effectively from which extends the shaft. Note how the double power in one unit while also maintaining drag levels to that of DB 601s have been set so that the inner cylinder banks were disposed almost one engine. vertically. Intended to produce 2350 hp, the In 1936, Heinkel approached Daimler‑Benz with this idea in respect to engine suffered a troublesome history the He 119 experimental high‑speed bomber/reconnaissance aircraft. The He 119 was, to all intents and purposes, a private venture on the part of Heinkel, with the aim of incorporating the most advanced aerodynamic technology. A radical design featuring a ‘pencil’ fuselage, fitted with low elliptical wings and tail, the aircraft would be powered by the new DB 606 that comprised two 1100 hp DB 601 engines mounted adjacent to each other and inclined so that the inner cylinder banks were disposed almost vertically. The two crankcases were connected by a single gearing system and clutch arrangement. The two crankshaft pinions drove a single propeller via a long shaft, with two of the crew accommodated either side of it within a forward glazed section, while a third crewmember sat aft of the wings. Initially, Ernst Heinkel admitted to being ‘rather doubtful’ about the concept, but four landplane prototypes of the He 119 – presented to the world for security reasons as the ‘He 606’ – had been completed by the end of 1937, and a seaplane variant followed. The V4 went on to claim a world speed record when, in November 1937, it achieved 504.59 km/h at a height of 4500 m while carrying loads of 500 and 1000 kg over 1000 km from Hamburg to Stolp and back. This gave credence to the concept of the coupled engine. It would be another four months before the RLM issued its specification for the ‘Bomber A’, but the only company considered capable of seriously developing the aircraft was Heinkel on account of its work with the He 119. On 16 October 1936, Heinkel allocated the ‘Bomber A’ assignment the project reference ‘P 1041’. Work on the P 1041 proceeded slowly under the overall direction of Prof Dr‑Ing Heinrich Hertel. He had worked at the Deutsches Versuchsanstalt für CHAPTER ONE ‘BomBeR A’ 9 Luftfahrt (DVL) at Berlin‑Adlershof as a test engineer, and in 1930 received his doctorate from the Technisches Hochschule in Berlin‑Charlottenberg, his thesis centring on ‘torsional rigidity and torsional strength in aircraft components’. Hertel joined Heinkel at Rostock in 1933, being appointed Technical Director a year later. Reporting to Hertel specifically to undertake design projects were the Günter twins, Siegfried and Walter. Born on 8 December 1899, the brothers had joined the same artillery regiment in 1917 and were subsequently captured by the British on the same day! Both spent time in England as PoWs. Following World War 1, they enrolled at the Technical University in Hannover to study aircraft design. Siegfried was the mathematician of the pair, while Walter was more artistic, with a true flare for design. In their spare time, the twins built gliders, and one of their efforts, built with their friends Walter Mertens and Werner Meyer‑Cassel, caught the attention of businessman Paul Bäumer, who witnessed the craft flying over the famous Wasserkuppe plateau in the Rhön Mountains where so much advancement in German sailplane development took place during the inter‑war years. Bäumer immediately offered the twins jobs with his Bäumer Aero company in Berlin. There, they began designing motor gliders and, increasingly, fast sports machines, including one in which Bäumer was killed in a crash in 1928. In 1931, the twins applied for positions with the Ernst Heinkel Flugzeugwerke at Warnemünde. The eye of Ernst Heinkel had also been caught by one of the twins’ designs, and he later recorded his first impressions of Siegfried Günther; ‘A 30‑year‑old man stood in my office. He was extraordinarily solemn and in suitably old‑fashioned clothes. He wore a stiff collar and a dickey. His jacket was carefully buttoned, his cuffs protruded well out of the sleeves and on his nose was perched a pair of rimless glasses. The young man looked sober, not to say shy. One could easily have imagined him to be a parson or school‑teacher, but under no circumstances an aeroplane designer and one who had succumbed to the intoxication of speed into the bargain.’ A little later, after Heinkel had met Walter, he recorded; ‘They were both bachelors, took rooms with a widow and hardly ever went out in society. If they had a passion, it was for good food and fast cars. With their small, pretty little Fiat, they drove at speed, which in their case was as incongruous as seeing a country parson in a racing car. This very strange pair represented what unconsciously I had been seeking. The brothers could complete and co‑ordinate what I saw roughly in my mind. They combined technical efficiency with a feeling for artistic beauty. They could design the aerodynamic shape I was looking for.’ Heinkel’s quest for ‘aerodynamic shape’ was very much ahead of what were actually being built as ‘strategic’ bomber aircraft in Germany in October 1936. The emerging Do 19 was a box‑like, mid‑wing monoplane with twin tail fins, powered by four 715 hp Bramo 322 H‑2 radial engines and fitted with a retractable undercarriage. The crew of nine comprised pilot, co‑pilot/navigator, bomb‑aimer, radio operator and five gunners. It was fitted with a nose turret housing a 7.9 mm MG 15 machine gun, with another such weapon in the tail and a pair of two‑man dorsal and 10 CHAPTER ONE ‘BomBeR A’ ventral turrets each armed with a 20 mm cannon. The prototype flew for the first time on 28 October 1936 without armament, but it was quickly realised that the aircraft was underpowered and that the two‑man turrets simply added more weight. The second and third prototypes featured more powerful 810 hp Bramo 132 F engines. By comparison, the Ju 89 was a better performing machine, with the V1 fitted with four 1075 hp Jumo 211 engines. The aircraft made its first flight in December 1936 and was followed early the next year by a second prototype powered by four Daimler‑Benz DB 600 engines. Similar to the Dornier, the Ju 89 was to have been armed with a 7.9 mm machine gun in the nose and tail positions and with 20 mm cannon in dorsal and ventral turrets. Soon after, Generaloberst Hermann Göring gave an order for all further development work on the ‘Ural Bomber’ types to cease and the project was officially shelved on 29 April 1937, despite protests from the Technisches Amt. ‘The Führer will never ask me how big our bombers are’, Göring commented, ‘but how many we have’. At this, the Do 19 was abandoned and all prototypes scrapped, while the Ju 89 V1 was converted to become the Ju 90 transport. Meanwhile, at Heinkel, the Günter twins had been continuing work on enhancing the cooling system of the DB 606 engine with which it was planned to power the P 1041. By employing evaporative cooling, a method pioneered by Heinkel and used in the smaller, single‑engined He 100 and He 119, the need for drag‑inducing radiators in a larger aircraft could be eliminated. Coolant water and anti‑freeze would be pressurised, meaning that it could be heated to 100 degrees centigrade – boiling point – before steam began to form in the engine. The heated water would then be ducted away and depressurised, at which point steam formed. The water which then formed was returned to the engine. Simultaneously, the residual steam was channelled through pipes built into the wing, cooled by the airflow. Once condensation had followed, water from the pipes in the wing would be returned to the engine. The overall design of the P 1041 was clean and simple, if unremarkable – a mid‑wing monoplane incorporating a semi‑circular section, all‑metal, fuselage with a stressed duralumin skin, at the forward end of which was a glazed nose section. The high‑aspect ratio wing was built in three sections around a single spar, the centre portion having a parallel chord. A large single vertical tail was set above square‑section horizontal stabilisers and elevators. The DB 606 coupled engines were located in the centre of the wings, beneath each of which was a pair of oleo legs holding two large mainwheels. The two legs would retract inwards and outwards respectively in opposite directions and would lock up into the wing. The entire length of the wing trailing edges were taken up with Fowler‑type flaps, the outer sections forming the lower part of the ailerons. For armament, it was Siegfried Günter’s initial intention to fit the aircraft with three advanced, aerodynamically clean, remotely‑controlled gun barbettes plus a manned tail turret. Although requiring more complex engineering, gun barbettes were smaller and thus reduced drag, and allowed a gunner to be located at the best possible position for observation and the avoidance of gun flash. However, in the mid‑ to late‑1930s, barbette design