page_title: Heinkel He 177
section_title: Engines
hierarchical_section_title: Heinkel He 177 / Design and development / Engines
caption_attribution_description: Daimler Benz DB 610 Aircraft Engine, Deutsches Museum, Munich
context_page_description: The Heinkel He 177 Greif was a long-range heavy bomber flown by the Luftwaffe during World War II. The introduction of the He 177 to combat operations was significantly delayed, by both problems with the development of its engines, and frequent changes to its intended role. Nevertheless, it was the only long-range, heavy bomber to become operational with the Luftwaffe during the war. The He 177 had a payload/range capability similar to that of four-engined heavy bombers used by the Allies in the European theatre; it also had higher cruising and maximum speeds than its Allied counterparts.
  Work on the design began in response to a 1936 requirement, known as Bomber A, issued by the RLM for a purely strategic bomber. Thus the He 177 was intended originally to be capable of a sustained bombing campaign against Soviet manufacturing capacity, deep inside Russia.
  In contrast to its heavy payload and very wide, 30 metres planform, the specifications called for the design to have only two, very powerful engines. To deliver the power required, the He 177 needed engines of at least 2,000 horsepower. Engines of this type were new and unproven at the time.
context_section_description: The He 177 required at least a pair of 2,000 PS (1,973 hp, 1,471 kW) engines to meet performance requirements. No engine in the German aviation power-plant industry at that time developed such power. A four-engine version would have been possible with engines like the Daimler-Benz DB 601 but the four-engine layout would impose higher propeller drag to the detriment of performance in dive bombing. The use of only two counter-rotating propellers on a heavy bomber offered many advantages, such as a substantial reduction in drag, reduction of dive instability and a marked improvement in maneuverability. The eight initial V-series prototypes, and the larger number of A-0 pre-production models of the He 177, displayed an airspeed and maneuverability comparable to many heavy fighters of the time.
  For the He 177, Günter decided to employ two of the complex Daimler-Benz DB 606 "power system" setups for propulsion. He had already employed these engines on the record-breaking Heinkel He 119 reconnaissance aircraft prototypes. They consisted of a pair of DB 601 liquid-cooled 12-cylinder inverted-vee inline engines mounted side by side in a nacelle – for the He 119, centrally within the fuselage, just behind its heavily glazed cockpit enclosure – driving one propeller. The two engines were inclined inwards by 30° when mounted onto either side of their common, vertical-plane space-frame primary engine mount so that the inner cylinder banks were disposed almost vertically. A common gear-housing connected the front ends of the two crankcases, with the two crankshaft pinions driving a single airscrew shaft gear. The outer sides of each of the component engines' crankcases were connected to the nacelle firewall through forged mountings similar to what would be used for either a single DB 601 or DB 605 engine-powered aircraft installation. When combined with the central space-frame mount designed especially for the "power system" format, this resulted in a Daimler-Benz "coupled" twin-crankcase "power system" having a trio of engine mount structures within its nacelle accommodation. The starboard DB 601 component engine had to be fitted with a mirror-image version of its mechanically driven centrifugal supercharger, drawing air from the starboard side of the engine. Two of the DB 606s, each of which initially developed 2,600 PS (2,564 hp, 1,912 kW) for take-off and weighing some 1,515 kg (3,340 lb) apiece, were to power the He 177. The DB 606 — and its eventual replacement, the Daimler-Benz DB 605-based "DB 610" — were to be the only two production German aviation powerplants designed to surpass 2,040 PS (2,010 hp, 1,500 kW) of power, something that the Germans had considerable challenges in developing during the war into production-ready, combat-reliable aviation engines.
caption: A later DB 610 "power system" which equipped the He 177 A-5. The DB 606A/B powerplants were similar in configuration, with outermost "pair" of engine mount forgings not shown.
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