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Type: heavy bomber and missile carrier;
Powerplant: 2 x 2,950hp Daimler-Benz DB 610A/B engines, each comprising two DB 605 12-cyclinder inverted-vee engines close-coupled;
Performance: 304mph / 490kph at 19,685ft / 6,000m (maximum speed), 258mph / 415kph (cruising speed), 26,245 ft / 8,000m (service ceiling), 3,417 miles / 5,500 km with two HS293 missiles (maximum range),
Weight: 37,038lbs / 16,800kg (empty), 68,343lbs / 31,000kg (maximum take-off);
Dimensions: 103ft 1.75in / 31.44m (wing span), 66ft 11.25in / 20.4m (length), 20ft 11.75in / 6.39m (height), 1,097.95sq.ft / 102m.sq (wing area);
Armament: 3 x 7.92mm (0.31in) MG81 machineguns, 3 x 13mm (0.51in) MG131 machineguns and 2 x 20mm MG151/20 cannon, plus 2,205lbs (1,000kg) of bombs internally and two Henschel HS293 missiles under the wings;
The idea of constructing a long-range four-engine strategic bomber had been mooted as early as 1934 by General Walter Wever, the Luftwaffe's first Chief of Staff and two aircraft were built to that specification, the Dornier Do19 and Junkers Ju89. Neither aircraft was adopted, the programme being abandoned after the death of General Wevel in an air accident on 3 June 1936. The design of the Ju89 eventually evolved into the Junkers Ju290, but in the spring of 1938, Heinkel received a development contract from the Reichsluftfahrtministerium (RLM) for its P.1041 project, which gradually evolved into a specification for a long-range bomber, capable of carrying a 4,410lbs (2,000kg) bombload over a radius of 1,000 miles (1,600km) at a speed of 310mph (500kph). Although almost 1,200 examples of the resulting He177 Greif (Griffon) were built, the type never really fulfilled its potential and even earned the nickname the 'flaming coffin'. This was somewhat unfair, although the Daimler-Benz DB 606 engines were prone to overheat and a few in-flight engine fires occurred. Heinkel's designer, Siegfried Günter, required two 2,000hp engines to power his design but a suitable power unit in that class was not then available and indeed the German aviation industry never managed to produce an engine of this power in large quantities before the end of the war, one of the major reasons being the lack of sufficient high-octane fuel. So two Daimler-Benz DB 601 engines were coupled together to form the 2,600hp DB 606 engine, but was it was never particularly reliable. Another novel feature of the He177 was the landing gear, comprising twin main legs on each side, which retracted sideways into the wing, one inboard and one outboard from each engine nacelle. Trouble is, even if this aircraft had proven an unqualified success, there is reason to believe that the Luftwaffe would have had trouble in mounting a sustained strategic bombing offensive as the Germans would have had difficulty in replacing the crews lost to the RAF and ground defences of the British Isles (look at the losses incurred by RAF Bomber Command) and there were problems in the provision of effective radio aids in order to guide the bombers to their target. The Luftwaffe pioneered the use of such technology but the British eventually found ways to jam it and the Germans gradually fell behind the Allies. Lastly, Germany suffered from an increasingly problematic fuel supply situation, especially after 1942, despite pioneering the use of synthetic fuels. Assuming that each bomber required six tons of fuel for an operation and 500 bombers would be used, that equates to 3,000 tons of fuel per mission. Allowing a maximum of six operations per month plus an extra third for training, this comes to 24,000 tons of fuel per month, or about one sixth of Germany's entire fuel production in 1943. To have been of real benefit, such a force would have had to have been formed at the start of the war to have had an impact in the Battle of Britain or in the early stages of the campaign against the Soviet Union.
The He177 was an attractive mid-wing monoplane, with a semi-circular-section fuselage (reminiscent of the later American B-29 Superfortress) and square tail surfaces. The high aspect ratio wing was built in three sections with the centre section having parallel chord. The coupled engines were mounted on the outer areas of the centre sections and large Fowler-type flaps dominated the trailing edges of the wings. The original design had a system of evaporation cooling, similar to that used on the He100 and He119 which dispensed with the need for radiators and reduced drag but by the spring of 1939, Günter had been forced to admit that while this system had worked well on smaller aircraft, they were impractical on this size of operational aircraft and so had to install radiators which increased drag. This led to the aircraft having to carry more fuel and therefore a strengthening of the wings was required as well. What made things worse was the requirement from the RLM that the aircraft be capable of dropping its bombs in a dive, something that has to be seriously questioned given the size of the aircraft. The first prototype flew on 19 November 1939 at Rostock-Marienehe at the hands of Dipl. Ing. Francke of Erprobungsstelle E-2, based at Rechlin. This initial flight was cut short when engine temperatures rose rapidly and although Francke was generally complimentary about the aircraft; he reported some tail flutter, a vibration in the airscrew shafts and inadequate tail surfaces. These were increased in area after the second prototype experienced similar problems and crashed due to flutter incurred during diving trials, which also claimed the fourth prototype. The fifth prototype was the first that was armed, with four 7.92mm (0.31in) MG15 machineguns in the nose, dorsal, ventral and tail positions as well as bomb bays but was also the first to suffer an engine fire and was subsequently lost. Three more prototypes were built (V6, V7 and V8), the first two with modified nose sections that mounted two MGFF cannon and an MG131 machinegun and after further testing, thirty-five He177A-0 preproduction aircraft were ordered, fifteen at Rostock, fifteen and Oranienburg and five at Warnemünde by Arado. They were used for a variety of development trials and for the conversion of crews onto the production He177A-1 aircraft which was introduced in March 1942. Arado built a total of 130 aircraft in four major sub-variants, each with minor armament variations, designated He177A-1/R1 to He177A-1/R4.
A number of the early production aircraft were delivered to I / Kampfgeschwader 40 at Bordeaux-Mérignac for operational trials in July 1942. It was one of these aircraft that dropped a single 250kg bomb on the Broad Wier district of Bristol on 28 August 1942, killing forty-five people and injuring another sixty-six. Structural weaknesses in the wing necessitated a major redesign and so the first of the modified He177A-3s (as they were now designated) saw service with the Luftwaffe towards the end of 1942. A total of 170 A-3 aircraft were built at Oranienburg, the first fifteen being the R1 sub-variant and retaining the DB 606 engines. The remaining aircraft were powered by DB 610 engines, as tested by the He177 V11 and which also served as the test bed for the Ju288 programme at Dessau. They included the He177A-3/R2 which featured an improved armament line-up, the He177A-3/R3 which carried three Henschel Hs293 missiles and the He177A-3/R4 that had a gondola containing FuG203 missile-control equipment. The He177A-3/R5 carried a 75mm cannon in the ventral gondola while three He177A-3/R7 aircraft were built and equipped with two torpedoes. The first He177A-3s were delivered to the training unit I / KG50 based at Brandenburg-Briest but which was undergoing winter trials at Zaporozh'ye and quickly transferred to the Stalingrad front to assist in the supply operation to the beleaguered 6th Army. The He177A-4 was a high altitude programme that evolved into the He274. The final production aircraft was the He177A-5 and featured a strengthened wing to allow for heavier under-wing loads, deletion of the Fowler flaps and shortened main landing gear legs. The variant was produced initially as sub-variants R1 to R4 with minor changes in armament but was then followed by the He177A-5/R5 that mounted a remotely controlled barbette to the rear of the bomb bay and the similar R6 which had two forward bomb bays deleted. The He177A-5/R7 introduced a pressurised cockpit, while the R8 was equipped with barbettes in the chin and tail positions. Five A-5 series aircraft were modified to carry an increased offensive armament, the bomb bay being used to mount an array of thirty-three rocket tubes that fired upwards at a forward angle of 60 degrees. There aircraft were delivered in June 1944 and were known as the He177 Zerstörer (destroyer) and were flown by Erprobungskommando 25 at Tarnewitz. The first operational use of the He177A-5 occurred on the 21 November 1943 when II / KG40, commanded by Major Mons, attacked a convoy with Hs293 missiles.
Six He177A-6/R1 were built as development aircraft for the proposed A-6 production aircraft which included additional armour protection for the crew compartment and fuel tanks, as well as extra armament. The He177 V22 served as a prototype for the He177A-6/R2 which had a new forward fuselage and defensive armament of two 20mm MG151/20 cannon, four MG81 and two MG131 machineguns. The He177A-6 was abandoned in favour of the He277. The final variant consisted of the conversion of six He177A-5 airframes to incorporate a 118ft 1.5in (36m) wing span which was designed for the He177A-7 high altitude bomber, but were flown with four DB 610 engines instead of the intended 3,600hp DB 613 engines produced by coupling two DB 603G engines together. During the first half of 1944, French and German-based He177s took part in Operation 'Steinbock', an air offensive against British targets, making their attacks in high-speed shallow dives from altitude. This enabled them to penetrate air defences much more effectively but hindered bombing accuracy. The Imperial Japanese Navy, which never had an efficient heavy bomber, showed quite an interest in the He177 and especially the A-7 variant, resulting in the Hitachi company proposing that they build the machine under license. To this end, Heinkel sent sample tools to Japan via U-Boat and readied the third He177A-7 (available in May 1944) to make a non-stop flight from Germany to Japan. Much of the armour protection and defensive armament was taken out to make room for additional fuel and the aircraft was planned to make the trip at extreme high-altitude across Soviet territory. The Japanese were not happy about the aircraft crossing Soviet territory (although one must wonder how else it could get to Japan) and the plan was eventually abandoned.
The aircraft also saw service on the Eastern Front, with the whole of KG 1 converting to the He177. It was a powerful striking force and the unit hit Soviet troop concentrations, supply sources, depots and headquarters in support of the Army, attacking in daylight at about 20,000ft (6,000m). Losses were very light as few Soviet fighters could intercept at that height and those that made it rarely pressed their attacks home due to the heavy defensive armament. The unit even undertook several pattern bombing runs, the only time this tactic was used by the Luftwaffe with one attack of ninety aircraft in three waves being led by Oberstleutnant Horst von Riesen on the railway centre of Velikye Luki. One of the last operations undertaken by KG 1 was on 20 July 1944 when the first of about eighty He177s took off and orbited around the Masurian Lakes. Two aircraft developed engine troubles and were ordered to jettison their bombs and head for home. When von Riesen returned, he was arrested and told he would be court martialled for bombs to be dropped on Hitler's nearby headquarters at Rastenburg! After some very anxious hours, von Riesen was told that the explosion was in fact a deliberate attempt on Hitler's life (the July bomb plot) and cleared of all charges. But Germany's critical fuel situation as well as its concentration on fighter production and operations led to the virtual grounding of the He177 by the end of 1944. One interesting example of the He177 was He177 V38 which was flown to the Letov factory near Prague during 1942, having its wings removed and modifications made to its bomb bay between 1943 and 1944 to provide enough space in order to hold the planned German atomic bomb, when and if that terrifying weapon ever became available. As one German engineer put it, 'if we succeed in this, we shall rule the world'. In August 1944, work stopped on the He177 V38 and other aircraft that were being modified and they were all were badly damaged in an American air raid on 25 March 1945.
Finally, mention must be made of the two direct off-shoots of the He177 programme, the He274 and He277. In November 1941, Heinkel proposed a high-altitude version of the He177, the A-4 variant. The aircraft was to be powered by two coupled Daimler-Benz DB 610 engines, have a pressurised cabin and remote controlled defensive armament. The design was gradually refined, with a high-aspect ratio wing and Hirth 2291 turbochargers being added, the He177A-4 being re-designated the He274. Because Heinkel was busy with the He177, the detailed design work was transferred to the Société Anonyme des Usines Farman at Suresnes near Paris. The He274 was a mid-wing monoplane powered by four separate 1,750hp Daimler-Benz DB 603A-2 engines in annular cowlings. The wing had a high-aspect ratio and the twin main wheels retracted back into the engine cowlings. The fuselage was similar to the He177A-3 variant apart from the pressurised cabin, but during the early production process was lengthened to 78ft 1.75in (23.8m). A new tail assembly was developed for the design with twin fins and rudders. In May 1943, an order was placed for two prototypes and four preproduction aircraft, the latter being powered by four 1,900hp DB 603G engines. Construction of the two prototypes began during the summer of 1943 but later in the year, the four preproduction aircraft were abandoned. By July 1944 the He274 V1 was nearing completion but the Allied advance forced the Germans to withdraw from Paris and despite attempting to destroy the airframe, the aircraft fell into Allied hands and the He274 V1 was eventually completed and flown under the designation AAS 01A in December 1945 from Orléans-Bricy. It was used to test fly scale-models of the French SO4000 and NC270 but was scrapped at Marseilles in 1953. Meanwhile, back in 1940 when the Germans were having a great deal of trouble from the coupled engines on the He177, Heinkel proposed a new version, powered by four separate DB 603 engines. The proposal failed to find favour with the RLM however, as it was assumed that too many delays would result in replacing the He177 on the production lines. Eventually, because of continued demands from Ernst Heinkel that production should be switched to the He277, Göring forbade any further mention of the new bomber. Fortunately, due to the wording of his order, this did not prevent work continuing under the cover designation He177B. Finally, during a conference of aircraft manufacturers at Obersalzberg on 23 May 1943, Hitler demanded the immediate production of a heavy bomber that could carry out round-the-clock attacks on London and attacks on Allied shipping far out in the Atlantic. Heinkel immediately suggested the He177B and was awarded a development contract for the aircraft. The He277 V1 (also known as the He177B-0) was a conversion of a He177A-3/R2 and fitted with four separate DB 603A engines with the first flight taking place at Vienna-Schwechat late in 1943 while the He277 V2 followed on 28 February 1944 and was a conversion of an A-5/R1. Both prototypes suffered from some directional instability, a problem that wasn't cured until the modified He277 V3 came out with twin fins and rudders, similar to those used on the He274. The first production model was the He277B-5/R2 which was equipped with four 1,750hp DB 603A engines but only four aircraft were completed before all heavy bomber production was cancelled in favour of the emergency fighter production programme launched on 3 July 1944. A number of other variants were proposed, including the He277B-6/R1 that had an increased span, four 2,060hp Junkers Jumo 213F engines, enlarged tail surfaces, the nose of a He177A-6/R2 and an HL/131V tail turret containing four MG131 machineguns. The He277B-6/R2 had a lengthening of the fuselage and a modified nose that was more streamlined, while the B-6/R3 had a deeper fuselage, additional glazing and manually-operated gun positions. The He277B-7 was a long-range reconnaissance variant based on the He177A-7 but would have been powered by four Jumo 213 or 222 engines.
Gunston, Bill. The Illustrated Encyclopedia of Combat Aircraft of World War II, Salamander Books, London, 1978.
Kay, A L & Smith, J R. German Aircraft of the Second World War, Putnam Aeronautical Books, London, 2002.
Mondey, David. The Hamlyn Concise Guide to Axis Aircraft of World War II, Bounty Books, London, 2006.
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