Heinkel He 177
Encyclopedia
The Heinkel
Heinkel
Heinkel Flugzeugwerke was a German aircraft manufacturing company founded by and named after Ernst Heinkel. It is noted for producing bomber aircraft for the Luftwaffe in World War II and for important contributions to high-speed flight.-History:...
He 177 Greif (Griffin
Griffin
The griffin, griffon, or gryphon is a legendary creature with the body of a lion and the head and wings of an eagle...
) was the only operational long-range bomber to be operated by the Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
. Starting its existence as Germany
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
's first purpose-built heavy bomber
Heavy bomber
A heavy bomber is a bomber aircraft of the largest size and load carrying capacity, and usually the longest range.In New START, the term "heavy bomber" is used for two types of bombers:*one with a range greater than 8,000 kilometers...
just before the war, and built in large numbers during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, it was also mistakenly tasked, right from its beginnings, to perform a milder version of the precision dive bombing the Junkers Ju 87
Junkers Ju 87
The Junkers Ju 87 or Stuka was a two-man German ground-attack aircraft...
had pioneered during the Spanish Civil War
Spanish Civil War
The Spanish Civil WarAlso known as The Crusade among Nationalists, the Fourth Carlist War among Carlists, and The Rebellion or Uprising among Republicans. was a major conflict fought in Spain from 17 July 1936 to 1 April 1939...
. This requirement for a dive-bombing capability in such a large aircraft resulted in a design possessing considerably lower drag than any other "four-engined" heavy bomber of its time, in order to be able to perform the task in any measure, resulting in many major deficiencies being exposed in its general design, and hindering its widespread adoption for strategic bombing. Luftwaffe aircrew nicknamed it the Luftwaffenfeuerzeug (Luftwaffe's lighter
Lighter
A lighter is a portable device used to generate a flame. It consists of a metal or plastic container filled with a flammable fluid or pressurized liquid gas, a means of ignition, and some provision for extinguishing the flame.- History :...
) or the "Flaming Coffin" due to the serious engine problems on initial versions of the aircraft. When these problems were later rectified, the type was successful, but it could not be deployed in large numbers due to Germany's deteriorating situation in the war.
Design and development
In 1936 the company of Heinkel Flugzeugwerke received details of the new Bomber A specification from the Reichsluftfahrtministerium (RLM). This specification, first proposed by the RLM on June 3, 1936, called for an aircraft more advanced than the Dornier Do 19 or Junkers Ju 89Junkers Ju 89
|-See also:-External links:*...
"Ural bomber
Ural bomber
The Ural bomber was a program to develop a long-range bomber for the Luftwaffe, created and led by General Walther Wever in the early 1930s. Wever died in an air crash in 1936 and the program ended almost immediately...
" prototypes. The aircraft was to be capable of carrying a bombload of at least 1,000 kg (2,200 lb) over a range of 5,000 km (3,100 mi), and possess a maximum speed of not less than 500 km/h (311 mph) at altitude. This was a formidable specification, calling as it did for an aircraft able to outrun any modern fighter and outperform, by a considerable margin, any bomber then in service. On June 2, 1937 Heinkel Flugzeugwerke received instructions to proceed with construction of a full scale mock-up of its Projekt 1041 Bomber A. The mock-up was completed in November 1937, and on November 5, 1937 allocated the official RLM type number "8-177", the same day that the Luftwaffe High Command
Oberkommando der Luftwaffe
The Oberkommando der Luftwaffe was the air force High Command of the Third Reich.Air Force Commanders-in-Chief* Reich Marshal Hermann Göring * Field Marshal Robert Ritter von Greim -History:...
(OKL) first stipulated the requirement for the new design to possess sufficient structural strength to enable it to undertake medium degree diving attacks. Heinkel Flugzeugwerke's estimated performance figures for Projekt 1041 included a top speed of 550 km/h (342 mph) at 5,500 m (18,050 ft) and a loaded weight of 27,000 kg (59,500 lb). In order to achieve these estimates, Heinkel's chief designer, Siegfried Gunter, employed several revolutionary features.
Engines
Daimler-Benz DB 601
|-See also:-Bibliography:* Mankau, Heinz and Peter Petrick. Messerschmitt Bf 110, Me 210, Me 410. Raumfahrt, Germany: Aviatic Verlag, 2001. ISBN 3-92550-562-8.* Neil Gregor Daimler-Benz in the Third Reich. Yale University Press, 1998-External links:...
, but the four-engine layout would imply higher propeller drag for dive bombing
Dive bomber
A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target reduces the distance the bomb has to fall, which is the primary factor in determining the accuracy of the drop...
. The use of only two 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. Indeed, the initial prototypes and pre-production models of the He 177 displayed an airspeed and maneuverability comparable to many heavy fighter
Heavy fighter
A heavy fighter is a fighter aircraft designed to carry heavier weapons or operate at longer ranges. To achieve acceptable performance, most heavy fighters were twin-engined, and many had multi-place crews....
s of the time.
For the He 177, Gunter decided to employ two of the complex Daimler-Benz DB 606
Daimler-Benz DB 601
|-See also:-Bibliography:* Mankau, Heinz and Peter Petrick. Messerschmitt Bf 110, Me 210, Me 410. Raumfahrt, Germany: Aviatic Verlag, 2001. ISBN 3-92550-562-8.* Neil Gregor Daimler-Benz in the Third Reich. Yale University Press, 1998-External links:...
"power system" setups for propulsion. He had already employed these engines on the record breaking Heinkel He 119
Heinkel He 119
|-See also:-References:*Donald, David, "An Industry of Prototypes - Heinkel He 119", Wings of Fame, Volume 12. Aerospace Publishing Ltd., London, UK/AIRtime Publishing Inc., Westport, Connecticut, 1998, ISBN 1-86184-021-7 / 1-880588-23-4, pp. 30–34....
reconnaissance aircraft prototypes. They consisted of a pair of DB 601 liquid-cooled 12-cylinder inverted-vee inline engines
Inline engine (aviation)
In aviation, an inline engine means any reciprocating engine with banks rather than rows of cylinders, including straight engines, flat engines, V engines and H engines, but excluding radial engines and rotary engines....
mounted side by side in a single nacelle
Nacelle
The nacelle is a cover housing that holds engines, fuel, or equipment on an aircraft. In some cases—for instance in the typical "Farman" type "pusher" aircraft, or the World War II-era P-38 Lightning—an aircraft's cockpit may also be housed in a nacelle, which essentially fills the...
driving a single propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
. The two component engines were inclined inwards by 30° so that the inner cylinder banks were disposed almost vertically. A single gear casing connected the front ends of the two crankcases, with the two crankshaft pinions driving a single airscrew shaft gear. The starboard DB 601 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, were to power the He 177.
Surface evaporation cooling
For aerodynamic cleanliness, Gunter decided to dispense with the usual system of drag-producing engine radiatorRadiator
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...
s and to employ an evaporative cooling system. This system was also pioneered on the He 119, and was also intended for use the He 100
Heinkel He 100
The Heinkel He 100 was a German pre-World War II fighter aircraft design from Heinkel. Although it proved to be one of the fastest fighter aircraft in the world at the time of its development, the design was not ordered into series production. Approximately 19 prototypes and pre-production machines...
high-speed fighter project. In this system the coolant water is pressurized, raising the coolant's boiling point, in this case about 110°C (230°F). As the superheated water leaves the engine it enters an expansion area where the pressure drops and the water flashes to steam. The steam is then cooled by running in pipes along the outer skin of the fuselage and wings.
Before the design of the He 177 was finalized, it was clear that such a system would be incapable of dealing with the vast amount of heat generated by each of the twinned pairs of DB 601 powerplants. As a result, the evaporative cooling system had to be abandoned in favor of conventional annular radiators fitted directly behind each propeller, which resembled but were larger than those fitted to the Junkers Ju 88 A
Junkers Ju 88
The Junkers Ju 88 was a World War II German Luftwaffe twin-engine, multi-role aircraft. Designed by Hugo Junkers' company through the services of two American aviation engineers in the mid-1930s, it suffered from a number of technical problems during the later stages of its development and early...
bomber. These radiators added significantly to the He 177's weight and drag.
Defensive armament
Junkers Ju 288
|-See also:-References:NotesBibliography* Hitchcock, Thomas H. Junkers 288 . Acton, MA: Monogram Aviation Publications, 1974. ISBN 0-914144-02-2.-External links:...
program, and only a single manned position in the tail. Compared with the manned turret, the idea of remotely controlled, turreted defensive armament traded technical complexity for reduction of size, weight, and drag. Furthermore, it held the advantage that the gunner could be installed in a protected position where he would have the best possible view, and where he would be less likely to be blinded by the flash from his own guns. Although work on remotely controlled aircraft defensive systems had reached a relatively advanced stage in Germany in the late 1930s, progress in this field was to prove insufficient to keep pace with the He 177. As a result the He 177 had to be modified to accommodate larger and heavier manned positions, such as the rear dorsal turret usually fitted to almost all examples of the Greif, armed with a single 13 mm MG 131 machine gun
MG 131 machine gun
The MG 131 was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945...
, this installation requiring that the fuselage receive structural strengthing in several locations. Eventually, most of the later production aircraft did receive a single remote forward dorsal turret, the Fernbedienbare Drehlafette (abbreviated "FDL") 131Z, armed with two MG 131 machine gun
MG 131 machine gun
The MG 131 was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945...
s, located at a point on the fuselage directly above the wing root
Wing root
The wing root is the part of the wing on a fixed-wing aircraft that is closest to the fuselage. On a simple monoplane configuration, this is usually easy to identify...
's leading edge, with its rotating hemispherical sighting station's dome located slightly offset to starboard, just behind the forward cabin area.
MG 131 machine gun
The MG 131 was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945...
, but its streamlined glazing, which demanded a prone gunner accommodation, severely restricted the gunner's comfort, so a revised tail gun position with a bulged upper glazing design which permitted the gunner to sit with their upper body upright, requiring a reduction of the lower end of the rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
surface for clearance, was fitted to the He 177 A-3 and later models, the initial MG 131 being often replaced with a 20 mm MG 151 cannon
MG 151 cannon
The MG 151 was a 15 mm autocannon produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German Luftwaffe fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as...
, or in a very few instances a semi-experimental twin MG 131Z mount, with the twinned 13 mm calibre guns mounted one above the other at the rear of the standard bulged upper glazing emplacement.
Usually, a single 7.92 mm MG 81 machine gun
MG 81 machine gun
The MG 81 was a German belt fed 7.9 mm machine gun, used in flexible installations in World War II Luftwaffe aircraft, replacing the older drum magazine-fed MG 15....
in a flexible mount was mounted in the upper starboard side of the cockpit nose glazing, for defense from a direct frontal fighter attack.
The undernose, inverted-casemate
Casemate
A casemate, sometimes rendered casement, is a fortified gun emplacement or armored structure from which guns are fired. originally a vaulted chamber in a fortress.-Origin of the term:...
Bola gondola (a common fitment on many German bombers), which was the full width of the fuselage where it emerged from under the nose, and centered under the forward cabin, usually had a flexibly mounted 20 mm MG FF cannon
MG FF cannon
The MG FF was a drum-fed, 20 mm aircraft autocannon, developed in 1936 by Ikaria Werke Berlin of Germany. It was a derivative of the Swiss Oerlikon FF F cannon, itself a development of the German World War I Becker 20 mm cannon, and was designed to be used in fixed or flexible mountings, as...
at the front end, and a flexibly mounted MG 81 machine gun
MG 81 machine gun
The MG 81 was a German belt fed 7.9 mm machine gun, used in flexible installations in World War II Luftwaffe aircraft, replacing the older drum magazine-fed MG 15....
in the rear for the initial A-1 version. A MG 151 cannon
MG 151 cannon
The MG 151 was a 15 mm autocannon produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German Luftwaffe fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as...
would replace the forward MG FF cannon in later production models, with a single MG 131 replacing the MG 81 for rearwards ventral defense.
Wing
Trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. Essential control surfaces are attached here to redirect the air flow and exert a controlling force by changing its momentum...
flaps
Flap (aircraft)
Flaps are normally hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed an aircraft can be safely flown at and to increase the angle of descent for landing without increasing air speed. They shorten takeoff and landing distances as well as...
which occupied the entire wing trailing edges, including those portions covered by the aileron
Aileron
Ailerons are hinged flight control surfaces attached to the trailing edge of the wing of a fixed-wing aircraft. The ailerons are used to control the aircraft in roll, which results in a change in heading due to the tilting of the lift vector...
s. Each aileron comprised upper and lower portions, the latter arranged to slide rearwards with flap extension while the upper part retained its function of providing lateral control for takeoff and landing. The original wing design did not take into full account the stresses resulting from the operation of the fowler flaps. A Rechlin report dated October 9, 1942 stated:
"The examination has shown that the strength of the He 177's wings is one-third below that estimated by Heinkel. The reason for this is the uneven rigidity of the individual members with consequent deformation under load. This condition was not recognized by Heinkel at the proper time, the failure tests having been undertaken too late in view of the size of the structure."
Tests on the fortieth production A-1 aircraft in September 1942 revealed serious outer wing panel component damage after only some twenty flights due to the aerodynamic stress from diving attack exercises, and very costly and extensive strengthening was needed to solve the problem. This significantly increased the aircraft's weight. Starting with the later versions of the He 177 A-3, the Fowler flaps along the outboard wing sections were deactivated and removed and an additionally strengthened wing design was introduced on the He 177 A-5.
Dive bombing
Ural bomber
The Ural bomber was a program to develop a long-range bomber for the Luftwaffe, created and led by General Walther Wever in the early 1930s. Wever died in an air crash in 1936 and the program ended almost immediately...
program demonstrated the weaknesses in existing German bombsight
Bombsight
A bombsight is a device used by bomber aircraft to accurately drop bombs. In order to do this, the bombsight has to estimate the path the bomb will take after release from the aircraft. The two primary forces during its fall are gravity and air drag, which makes the path of the bomb through the air...
s. This in itself called into question the effectiveness of horizontal bombing, whether by a medium or heavy bomber force. Some in the Luftwaffe believed that dive bombing was a more effective way to destroy targets. Technical data supported the accuracy of Stuka
Junkers Ju 87
The Junkers Ju 87 or Stuka was a two-man German ground-attack aircraft...
strikes achieving greater target destruction over Dornier Do 17
Dornier Do 17
The Dornier Do 17, sometimes referred to as the Fliegender Bleistift , was a World War II German light bomber produced by Claudius Dornier's company, Dornier Flugzeugwerke...
s or Heinkel He 111
Heinkel He 111
The Heinkel He 111 was a German aircraft designed by Siegfried and Walter Günter in the early 1930s in violation of the Treaty of Versailles. Often described as a "Wolf in sheep's clothing", it masqueraded as a transport aircraft, but its purpose was to provide the Luftwaffe with a fast medium...
s. The experience of the Condor Legion
Condor Legion
The Condor Legion was a unit composed of volunteers from the German Air Force and from the German Army which served with the Nationalists during the Spanish Civil War of July 1936 to March 1939. The Condor Legion developed methods of terror bombing which were used widely in the Second World War...
in Spain supported the theories of dive bombing and led some to believe that pinpoint accuracy was possible, consequently diverting them away from the idea of horizontal bombing in favor of dive bombing.
During the final inspection of the Projekt 1041 mock-up on November 5, 1937, Ernst Udet
Ernst Udet
Colonel General Ernst Udet was the second-highest scoring German flying ace of World War I. He was one of the youngest aces and was the highest scoring German ace to survive the war . His 62 victories were second only to Manfred von Richthofen, his commander in the Flying Circus...
stated OKL's new divebombing requirement to Ernst Heinkel
Ernst Heinkel
Dr. Ernst Heinkel was a German aircraft designer, manufacturer, Wehrwirtschaftführer in the Third Reich, and member of the Nazi party. His company Heinkel Flugzeugwerke produced the Heinkel He 178, the world's first turbojet aircraft and jet plane, and the Heinkel He 176, the first rocket aircraft...
, who replied that the aircraft would never be capable of it. The He 177 had to be strengthened to support the stresses imposed by the pull-out from a dive. Unfortunately, the dive bombing requirement was later increased to 60° attacks rather than the medium angle dives originally called for, resulting in further structural strengthening and an alarming increase in weight. Nevertheless, the requirement to dive bomb up to 60° was never satisfactorily solved, due to the constant increases in loaded weight. Despite the specially strengthened airframe, it was still possible to overstress the airframe during a dive attack maneuver. While the German bombsights of the 1930s were quite lacking, the follow-on versions of the Lotfernrohr 7
Lotfernrohr 7
The Carl Zeiss Lotfernrohr 7, or Lotfe 7, was the primary bombsight used in most Luftwaffe level bombers, similar to the United States' Norden bombsight, but much simpler to operate and maintain. Several models were produced and eventually completely replaced the simpler Lotfernrohr 3 and BZG 2...
proved to be arguably as accurate as the American Norden bombsight
Norden bombsight
The Norden bombsight was a tachometric bombsight used by the United States Army Air Forces and the United States Navy during World War II, and the United States Air Force in the Korean and the Vietnam Wars to aid the crew of bomber aircraft in dropping bombs accurately...
. With the introduction of the Lotfe 7, which offered an average error of 20 m to 30 m (65 ft to 98 ft) from a release altitude of 3,000 m to 4,000 m (9,842 ft to 13,123 ft), and Hermann Göring
Hermann Göring
Hermann Wilhelm Göring, was a German politician, military leader, and a leading member of the Nazi Party. He was a veteran of World War I as an ace fighter pilot, and a recipient of the coveted Pour le Mérite, also known as "The Blue Max"...
's rescindment of the dive attack requirement in September 1942, the barred-gate type dive brakes, on the wing's lower surfaces and placed just forward of each of the outboard ends of the Fowler flap panels, were omitted from all He 177 built after the initial pre production batch.
Undercarriage
Undercarriage
The undercarriage or landing gear in aviation, is the structure that supports an aircraft on the ground and allows it to taxi, takeoff and land...
of sufficient strength began to pose a major problem. Neither the engine nacelles or the wings provided much stowage space for the main undercarriage members, which needed to be of a longer-than-usual design to allow ground clearance for the large diameter four blade propellers of the aircraft's powerplants, and after several extremely complex arrangements had been considered during the aircraft's initial design stages, a rather novel, but still quite complex, system was adopted. Instead of the originally projected single wheel leg under each engine nacelle, two massive single wheel legs were attached to the main spar at each engine nacelle, the outboard legs retracting upward and outward into shallow wing wells, the inboard legs swinging upward and inward into similar wells in the wing roots, all units being completely enclosed by flush fitting doors, and almost "meeting" under each engine nacelle when fully extended. The lever-action lower gear strut sections, on which the wheels were mounted onto their axles, also had to pivot to a 90º angle (from their 120º angle while fully extended) to the main gear leg during the retraction cycle, just to fit into their wheel wells. A more conventional single-leg twin wheel arrangement for each main gear was actually used on the two examples (one during the war, one post-war) of the He 274 in France, and a few developments that only existed as drawings actually had tricycle gear
Tricycle gear
Tricycle gear describes an aircraft undercarriage, or landing gear, arranged in a tricycle fashion. The tricycle arrangement has one wheel in the front, called the nose wheel, and two or more main wheels slightly aft of the center of gravity...
setups being fitted to the Amerika Bomber
Amerika Bomber
The Amerika-Bomber project was an initiative of the Reichsluftfahrtministerium, the Nazi Germany Air Ministry, to obtain a long-range strategic bomber for the Luftwaffe that would be capable of striking the continental United States from Germany, a range of about 5,800 km...
entry version of the paper-only He 277, which were also depicted as using single main gear struts with twin wheels. The two hour time that it could take to change just one damaged main gear tire, using special Heinkel-provided 12-tonne capacity main gear jackstand blocks, which were in short supply, was just one of the myriad of problems that the He 177 A's complex main gear format brought about.
Prototypes
On November 9, 1939, the first prototype, the He 177 V1 was flown for the first time with Leutnant Carl Francke, Dipl. Ing., chief of the Rechlin flight test center, at the controls. The initial flight terminated abruptly after only twelve minutes as a result of overheating engines. Francke referred favorably to the general handling and landing characteristics of the prototype but complained of some vibration in the airscrew shafts, the inadequacy of the tail surfaces under certain conditions, and some flutter which accompanied any vigorous movement of the elevatorsElevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...
. The He 177 V2 made its first flight soon afterwards. Following Francke's initial flight, the He 177 V1 received several modifications suggested by the initial trials, including a 20% increase in the tail surface area. These modifications were not applied to the He 177 V2 when another test pilot undertook the first diving trials. During the diving trials, the V2 developed severe control flutter and broke-up in the air. Following this incident, the tail surfaces of the V3, V4, and V5 prototypes were modified in a similar fashion to those of the He 177 V1. The He 177 V3 was allocated the task of power plant development. The V1 through V3 prototype airframes were all equipped with two counterclockwise rotating DB 606 A powerplants, while the V4 prototype and all later aircraft, throughout the production run of the A-series, used a DB 606 A or DB 610 A engine on the starboard wing and one clockwise rotating B-version of the same powerplant on the port wing, so that the propellers rotated "away" from each other at the tops of the propeller arcs. The He 177 V4 was retained at Heinkel's test field where it undertook diving trials. While flying over the Baltic
Baltic region
The terms Baltic region, Baltic Rim countries, and Baltic Rim refer to slightly different combinations of countries in the general area surrounding the Baltic Sea.- Etymology :...
, the He 177 V4 failed to recover from a moderate dive, crashing into the sea near Ribnitz
Ribnitz-Damgarten
Ribnitz-Damgarten is a town in Mecklenburg-Vorpommern, Germany. It is situated at the Ribnitzer See . Ribnitz-Damgarten is the largest town of the district Vorpommern-Rügen, but not its capital.-Geography:...
. It was later discovered that the accident had resulted from the malfunctioning of an airscrew pitch control
Controllable pitch propeller
A controllable pitch propeller or variable pitch propeller is a type of propeller with blades that can be rotated around their long axis to change their pitch...
mechanism.
The He 177 V5 incorporated a number of changes which were principally concerned with defensive armament installations. Early in 1941, during a simulated low-level attack, both DB 606 engines burst into flames, the V5 hitting the ground and exploding. The He 177 V6 was the first aircraft equipped with main production type DB 606 A/B engines instead of the pre-production units which offered a slight increase in takeoff power by 100 PS to 2700 PS (2,663 hp, 1,986 kW). The He 177 V7 featured a revised nose section which, while generally following the contours of the nose sections employed by the previous prototypes, was considerably reinforced and embodied fewer glazed panels. In September 1941, the He 177 V8, the last of the aircraft to be built as prototypes from the outset with a different, almost "bulletlike" cockpit construction from the production He 177A series aircraft, was made available for engine tests, but owing to the urgency of other development work it was returned to Heinkel after only forty days, and it was not possible to resume engine tests in the air until February 1942. The He 177 V1 to V8 and the A-0 production prototypes are notable for having a broad-bladed set of four-bladed propellers, with blade shapes and profiles similar to those used on the Junkers Ju 88
Junkers Ju 88
The Junkers Ju 88 was a World War II German Luftwaffe twin-engine, multi-role aircraft. Designed by Hugo Junkers' company through the services of two American aviation engineers in the mid-1930s, it suffered from a number of technical problems during the later stages of its development and early...
medium bomber
Medium bomber
A medium bomber is a bomber aircraft designed to operate with medium bombloads over medium distances; the name serves to distinguish them from the larger heavy bombers and smaller light bombers...
, which were not used on the production He 177A series aircraft.
Circle of latitude
A circle of latitude, on the Earth, is an imaginary east-west circle connecting all locations that share a given latitude...
s and meridian
Meridian (geography)
A meridian is an imaginary line on the Earth's surface from the North Pole to the South Pole that connects all locations along it with a given longitude. The position of a point along the meridian is given by its latitude. Each meridian is perpendicular to all circles of latitude...
s on a globe
Globe
A globe is a three-dimensional scale model of Earth or other spheroid celestial body such as a planet, star, or moon...
would. Two sets of four roughly square windows, themselves arranged in a square of four windows each, on each side of the upper cockpit, just behind the "fishbowl's" rear edge, provided sideways vision from the cockpit for the pilot and crew. Often, the two lower rows of the "fishbowl's" windows in the lower nose were made opaque, with the exception of the bombardier's projecting bombsight window, either by painting them over or replacement with metal panels that performed the same function.
Production
Eight prototypes were completed, followed by 35 pre-production He 177 A-0s (built by AradoArado Flugzeugwerke
Arado Flugzeugwerke was a German aircraft manufacturer, originally established as the Warnemünde factory of the Flugzeugbau Friedrichshafen firm, that produced military hydroplanes during the First World War.-History:...
and Heinkel
Heinkel
Heinkel Flugzeugwerke was a German aircraft manufacturing company founded by and named after Ernst Heinkel. It is noted for producing bomber aircraft for the Luftwaffe in World War II and for important contributions to high-speed flight.-History:...
) and 130 Arado-built He 177 A-1s. The early aircraft in this batch were used for further trials, and after a brief and unhappy operational debut the remainder were also withdrawn from service. From late 1942 they were replaced by 170 He 177 A-3s and 826 A-5s, which had longer rear fuselages and slightly lengthened engine nacelles.
| Version | EHF | HWO | ArB | Total | Production period |
|---|---|---|---|---|---|
| Prototypes | 8 | 8 | |||
| He 177 A-0 | 15 | 15 | 5 | 35 | |
| He 177 A-1 | 88 | 42 | 130 | January 1942 - January 1943 | |
| He 177 A-3 | 217 | 398 | 615 | November 1942 - June 1944 | |
| He 177 A-5 | 71 | 278 | 349 | December 1943 - August 1944 | |
| Total | 23 | 391 | 723 | 1,137 |
Note - One A-0, one A-3, and two A-5 rebuilt as He 177B prototypes from before December 1943 to July 1944.
Engine difficulties
Heinkel He 119
|-See also:-References:*Donald, David, "An Industry of Prototypes - Heinkel He 119", Wings of Fame, Volume 12. Aerospace Publishing Ltd., London, UK/AIRtime Publishing Inc., Westport, Connecticut, 1998, ISBN 1-86184-021-7 / 1-880588-23-4, pp. 30–34....
and later used on other aircraft such as the Messerschmitt Me 261
Messerschmitt Me 261
-References:NotesBibliography* Donald, David, ed. Warplanes of the Luftwaffe. London: Aerospace Publishing, 1994. ISBN 1-874023-56-5.* Green, William. Warplanes of the Third Reich. New York: Galahad Books, 1986. ISBN 0-88365-666-3...
where they functioned as intended, but the extremely tight cowling
Cowling
A cowling is the covering of a vehicle's engine, most often found on automobiles and aircraft.A cowling may be used:* for drag reduction* for engine cooling by directing airflow* as an air intake for jet engines* for decorative purposes...
s on the He 177 led to considerable problems, the most common being in-flight engine fires and engine overheating. There were several reasons for the flammability of the DB 606 engine, one of which was the common "central" exhaust manifold, serving a total of twelve cylinders, on the two inner cylinder banks of the engines, which became excessively hot and caused the usual accumulation of oil
Motor oil
Motor oil or engine oil is an oil used for lubrication of various internal combustion engines. The main function is to lubricate moving parts; it also cleans, inhibits corrosion, improves sealing, and cools the engine by carrying heat away from moving parts.Motor oils are derived from...
and grease
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
in the bottom of the engine cowling to catch fire. When the pilot throttled back there was a tendency for the injection pump
Fuel pump
A fuel pump is a frequently essential component on a car or other internal combustion engined device. Many engines do not require any fuel pump at all, requiring only gravity to feed fuel from the fuel tank through a line or hose to the engine...
to deliver more fuel than was required by the engine, in addition to which the injection pump connections leaked. In order to restrict the aircraft's weight, no firewall had been provided, and the DB 606 was fitted so close to the main spar
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings whilst on the ground...
that there was insufficient space for the fuel/oil pipelines and electrical leads. The engine was frequently saturated by fuel and oil from leaking connections. At high altitude, the oil tended to foam due to a badly designed oil pump
Oil pump
Oil pump may refer to:*A hydraulic pump, which pressurizes hydraulic fluid in a hydraulic system*An oil pump , a part of the lubrication system that pressurizes motor oil for distribution around the engine...
, and in this condition it circulated in the engines, its lubricating qualities being severely reduced. Insufficient lubrication resulted in the disintegration of the connecting rod bearings which burst through the engine crankcase, puncturing the oil tanks which poured their contents on to the hot exhaust pipe collector. The tightly packed nature of the engine installations also led to very poor access to the engines as well as very poor ventilation. As a result of these factors, as well as a lack of routine maintenance in the field, the DB 606 easily caught fire in flight. The effort to create an adequately powerful engine for the He 177 by mechanically coupling pairs of lower-power engines, while theoretically sound, proved to be difficult and time consuming to perfect, leading to numerous engine complications especially on the initial production models.
Reichsmarschall Hermann Göring
Hermann Göring
Hermann Wilhelm Göring, was a German politician, military leader, and a leading member of the Nazi Party. He was a veteran of World War I as an ace fighter pilot, and a recipient of the coveted Pour le Mérite, also known as "The Blue Max"...
, angered at the apparent slowness with which the He 177 was having its powerplant problems researched and solved late in August 1942, responded thus to one Oberst
Oberst
Oberst is a military rank in several German-speaking and Scandinavian countries, equivalent to Colonel. It is currently used by both the ground and air forces of Austria, Germany, Switzerland, Denmark and Norway. The Swedish rank överste is a direct translation, as are the Finnish rank eversti...
Edgar Petersen
Edgar Petersen
Edgar Petersen was a German Luftwaffe bomber pilot and recipient of the Knight's Cross of the Iron Cross during World War II. The Knight's Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership...
s report (the Kommandeur der Erprobungstellen) on the He 177's powerplant troubles, remarking on the unusual engine configuration, and the difficulty of maintenance access, of the DB 606"s:
Starting with the He 177 A-3/R2, a modified engine nacelle with a new engine, the Daimler-Benz DB 610
Daimler-Benz DB 605
|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7...
which consisted of a pair of Daimler-Benz DB 605
Daimler-Benz DB 605
|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7...
's, was used to eliminate the tendency for engine fires. With the introduction of the DB 610 came several improvements including the relocation of the engine oil tank, the lengthening of the engine mountings by 20 cm (8 in), the complete redesign of the exhaust system which also facilitated the installation of exhaust dampers for night missions, and the setting of a power limitation on the engines which resulted in greater reliability. These modifications, supposedly numbering 56 of both major and minor varieties, were successful as far as eliminating engine fires were concerned, but other minor problems with the transfer gearbox between the two engines and their shared propeller remained.
Experimental weapon loads
In addition to carrying a variety of bombs, torpedoes, and guided weapons the He 177 was tested with a number of unorthodox armaments. The first of these experimental weapon schemes known to have been tested were the twelve examples of the He 177 A-1/U2 Zerstörer variant, which was armed with a pair of limited-traverse 30 mm MK 101 cannonMK 101 cannon
The MK 101 is the designation of a 30 mm autocannon used in German combat aircraft during World War II. Although accurate and powerful, with a high muzzle velocity, it was very heavy, with a low rate of fire, which limited its production....
s in the extreme front of a dramatically enlarged Bola ventral gondola, and intended for ground attack, train busting, and possibly long-range anti-ship raids. Later, when assigned to flak-suppression sorties in the area of Stalingrad during the winter of 1942, Luftwaffe forward maintenance units modified a small number of He 177s, fitting a 50 mm Bordkanone BK 5
BK-5 cannon
The Bordkanone 5, or BK 5 for short, was a 50 mm autocannon intended primarily for use against Allied heavy bombers, especially the USAAF's combat box heavy bomber flight formations, so that defending Luftwaffe fighter aircraft could fire from a great enough distance to make the USAAF bomber's...
cannon within the aircraft's undernose Bola gondola, with the long barrel protruding well forward, beyond the glazed "fishbowl" nose. This variant was unofficially dubbed the Stalingradtyp. Although a small number of He 177 A-3/R5 models were to be built from scratch, with the larger PaK-40-based, autoloading 75 mm Bordkanone BK 7,5 ventral cannon, structural problems caused by the weapon's recoil meant that the Stalingradtyp did not see combat use outside of the original, BK 5-armed improvised handful. Five He 177 A-5s were experimentally equipped in January 1944 with batteries of thirty-three obliquely mounted 21 cm (8-1/4 in) calibre rocket mortar tubes, likely derived from components of the Nebelwerfer
21 cm Nebelwerfer 42
The 21 cm Nebelwerfer 42 was a German multiple rocket launcher used in the Second World War. It served with units of the Nebeltruppen, the German equivalent of the American Chemical Corps...
infantry barrage rocket system, to create the Grosszerstörer ("Big Destroyer") flying battleship, meant to break up and destroy the tight combat box
Combat box
The Combat box was a tactical formation used by heavy bombers of the U.S. Army Air Forces during World War II. The combat box was also referred to as a "staggered formation"...
defensive formations used by USAAF daylight bombers over Germany. The bomb bays and fuselage-housed auxiliary fuel tanks were removed on these aircraft in order to provide space for the spin-stabilized 21 cm (8 in) rockets and their firing tubes. The tubes were inclined to fire upward at an angle of 60° to the horizontal axis of the aircraft and slightly to starboard. The tubes could be fired individually, simultaneously, or in two salvoes of fifteen and eighteen. Tests with fixed balloon targets showed the potential of this system, and limited operational trials against US Eighth Air Force bomber streams were authorized. The aircraft were operated by Erprobungskommando 25, flying out of Tarnewitz. The intended mode of operation called for the He 177s to follow the enemy bomber formations, passing below (as with a Schräge Musik
Schräge Musik
Schräge Musik, derived from the German colloquialism for "Jazz Music" was the name given to installations of upward-firing autocannon mounted in night fighters by the Luftwaffe and Imperial Japanese Navy Air Service during World War II, with the first victories for each occurring in May 1943...
cannon fitment) and to port of the target, maintaining a difference of altitude of 2,000 m (6,560 ft) at the time of the attack from below. A few trial daylight operations were flown but no contact was made with Allied bomber formations, and as the escort fighters were becoming ever more numerous the entire scheme was abandoned.
Airworthiness and handling
Trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. Essential control surfaces are attached here to redirect the air flow and exert a controlling force by changing its momentum...
of the wing, and tests of the modified aircraft, from the longer distance of the "tail moment" that resulted, gave a marked degree of improvement in the yaw and pitch axis stability, enough to mandate the construction of the He 177 A-3 and all later models of the He 177 with the lengthened fuselage.
In early September 1944, the Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
was ordered to supply an aircrew for a He 177 that the French Maquis
Maquis (World War II)
The Maquis were the predominantly rural guerrilla bands of the French Resistance. Initially they were composed of men who had escaped into the mountains to avoid conscription into Vichy France's Service du travail obligatoire to provide forced labour for Germany...
and Allied units in Vichy France
Vichy France
Vichy France, Vichy Regime, or Vichy Government, are common terms used to describe the government of France that collaborated with the Axis powers from July 1940 to August 1944. This government succeeded the Third Republic and preceded the Provisional Government of the French Republic...
would take control of at the airfield at Blagnac
Blagnac
Blagnac is a commune in the Haute-Garonne department in southwestern France.It is the third-largest suburb of the city of Toulouse, although governed by a separate council, and is adjacent to it on the northwest side. It is a member of the Urban community of Greater Toulouse...
near Toulouse. A transport and two escort fighters from the RAE flew to the area to leave the Chief Test Pilot and a flight engineer with the commando group. On 10 September, the aircraft was seized and flown back to the UK. Soon afterwards, Eric Brown, a RN pilot currently posted to the RAE as a test pilot flew the He 177. He wrote about the in-flight handling characteristics of the He 177 A-5:.
"...positive about all axes, but the controls were all remarkably light for such a large aircraft. Indeed I had the feeling that the elevator was dangerously light and I was all too aware of the intelligence reports of He 177s breaking up in the air so I decided to treat this control very gently... The aircraft had an automatic pull-out device and an acceleration warning apparatus fitted, but it really was nailbiting to have to treat a giant like this immense Heinkel bomber as if it was made of glass. The stalling characteristics with flaps and undercarriage lowered the aircraft buffeted violently at 140 km/h (87 mph) before the nose dropped at 135 km/h (84 mph). The buffet experienced was so violent that I had some concerns over structural damage. Somehow the He 177 always conveyed an impression of fragility despite its size."
He said it was "one of the very few German aircraft of the period that I tested that I did not enjoy flying".
Further development-The Heinkel He 177B
Due to continuing problems with the DB 606's configuration, much development work was being done in order to rectify engine complications, including a complete redesign of the original He 177, primarily through newer wing designs and layouts to accommodate them, intended towards the creation of a four-engined version of the Greifs airframe. The first occurrence of such concerns over the coupled-engine vs. four separate engine issue for the He 177 emerged in mid-November 1938, as Ernst Heinkel had requested that he wished for two of the requested eight He 177 prototypes to be fitted out with four individual engines in place of the coupled-engine arrangements, eventually specifying that the V3 and V4 airframes get four individual engines each in a November 17 in-plant corporate meeting. Ernst UdetErnst Udet
Colonel General Ernst Udet was the second-highest scoring German flying ace of World War I. He was one of the youngest aces and was the highest scoring German ace to survive the war . His 62 victories were second only to Manfred von Richthofen, his commander in the Flying Circus...
was also critical of the coupled DB 606 powerplant choice for the He 177 from before the war's start, with Göring adding his input from his own frustrations with the seemingly interminable engine problems delaying the introduction of the He 177A into service. Göring was reported as stating in August 1942:
Nearly four years after Herr Heinkel had unsuccessfully requested two of the prototype He 177 V-series airframes to be built with four individual powerplants, the RLM's requirement for the He 177 to perform diving attacks was finally rescinded in September 1942 by Göring himself, and with that decision finally rendered, Heinkel's design work on the pair of "separately" four-engined versions of the He 177A, the A-8 and A-10, collectively re-named the He 177B in August 1943, were then able to progress, meant to be powered with four individual Daimler-Benz DB 603
Daimler-Benz DB 603
|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7...
engines, with each liquid-cooled DB 603 fitted with a Heinkel He 219
Heinkel He 219
The Heinkel He 219 Uhu was a night fighter that served with the German Luftwaffe in the later stages of World War II. A relatively sophisticated design, the He 219 possessed a variety of innovations, including an advanced VHF-band intercept radar...
-style annular radiator right behind the propeller for engine cooling. This task was accomplished in a considerably later timeframe than British aircraft designer Roy Chadwick
Roy Chadwick
Roy Chadwick, CBE, FRAeS was an aircraft designer for Avro. Born at Marsh Hall Farm, Farnworth in Widnes, son of the mechanical engineer Charles Chadwick, he was the Chief Designer for the Avro Company and was responsible for practically all of their aeroplane designs...
had done in similarly converting the Avro Manchester
Avro Manchester
|-See also:-References:NotesCitationsBibliography* Buttler, Tony. British Secret Projects: Fighters and Bombers 1935–1950. Hickley, UK: Midland Publishing, 2004. ISBN 978-1857801798....
. The Manchester, like the A-series Greif (with its coupled DB 606s and 610s) had depended on two very powerful and quite troublesome 24-cylinder powerplants, the British Rolls-Royce Vulture
Rolls-Royce Vulture
|-See also:-Bibliography:* Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9...
, but by 1941 had been redesigned with four Rolls-Royce Merlin
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...
s, as the Avro Lancaster
Avro Lancaster
The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other...
.
By August 1943 much of the detail work for the He 177B series aircraft was well on its way to completion, and Erhard Milch
Erhard Milch
Erhard Milch was a German Field Marshal who oversaw the development of the Luftwaffe as part of the re-armament of Germany following World War I, and served as founding Director of Deutsche Luft Hansa...
eagerly approved the creation of three He 177B prototypes, designated He 177 V101 to V103, from his statement on August 10:
The B-5's first-built prototype, the He 177 V101, was converted from a mid-production He 177 A-3 airframe (number 535550, with Stammkennzeichen of NN + QQ), the V102 being converted from the eighth He 177 A-0 production prototype aircraft (which required lengthening to the He 177A-3 and later fuselage specification), and the V103 being converted from an existing, early production He 177 A-5 airframe, and all three of which initially retained the production 177A-style tail surfaces. The V101 was uniquely fitted with a small-area matching pair, one per side, of so-called pivoting "drag rudders" mounted a short distance in from the horizontal stabilizers' tips, directly inline with the inner engine nacelles, to simulate "engine-out" conditions. Each of the pivoted "drag rudders" had their area divided equally above and below the plane of the stabilizer. Because of the 177A-style single-tailed V101 prototype having increasingly serious stability problems with higher airspeeds in its flight testing, the second prototype, the V102, was both the first He 177B example to fly on December 20, 1943, and the first to be fitted with an empennage
Empennage
The empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...
of twin tail
Twin tail
A twin tail is a specific type of vertical stabilizer arrangement found on the empennage of some aircraft. Two vertical stabilizers — often smaller on their own than a single conventional tail would be — are mounted at the outside of the aircraft's horizontal stabilizer...
configuration that, when tested, gave the V102 significantly better in-flight handling when compared to the original He 177A's single tail design, except during the landing approach when the Fowler flaps were extended, when flown in November 1943, while still flying with its A-series wing and powerplants before its own pair of B-series "four engine" wing units were ready. By late February 1944, as the USAAF's Big Week
Big Week
Between February 20–25, 1944, as part of the European strategic bombing campaign, the United States Strategic Air Forces launched Operation Argument, a series of missions against the Third Reich that became known as Big Week. The planners intended to lure the Luftwaffe into a decisive battle by...
strategic bombing campaign against Nazi Germany was initiated, at a meeting held at the Wiener Neustadt
Wiener Neustadt
-Main sights:* The Late-Romanesque Dom, consecrated in 1279 and cathedral from 1469 to 1785. The choir and transept, in Gothic style, are from the 14th century. In the late 15th century 12 statues of the Apostles were added in the apse, while the bust of Cardinal Melchior Klesl is attributed to...
military airfield, visited by Erhard Milch
Erhard Milch
Erhard Milch was a German Field Marshal who oversaw the development of the Luftwaffe as part of the re-armament of Germany following World War I, and served as founding Director of Deutsche Luft Hansa...
, fellow guests Oberst Edgar Petersen and Oberstleutnant
Oberstleutnant
Oberstleutnant is a German Army and Air Force rank equal to Lieutenant Colonel, above Major, and below Oberst.There are two paygrade associated to the rank of Oberstleutnant...
Siegfried Knemeyer
Siegfried Knemeyer
Siegfried Knemeyer was a German Aeronautical engineer and Aviator. He invented an early flight computer, was the Head of Technical Development for the Ministry of Aviation during World War II, and invented numerous aviation technologies for the United States Air Force during the Cold War. In the...
each had a chance to fly the now four-engined V102 prototype after the B-series set of wings had been fitted, with Knemeyer stating that he could not believe a four-engined heavy bomber could possess the "excellent handling qualities" the V102 machine displayed. The only verifiable photograph that exists today of any of these He 177B prototypes is one of the V101, parked outdoors on a foggy German airfield, most likely the Heinkel-Sud factory airfield at Schwechat
Schwechat
Schwechat is a city south-east of Vienna known for the Vienna International Airport and Schwechater beer. It is also home to the refineries belonging to the Austrian national oil company OMV.- Geography :...
.http://i61.photobucket.com/albums/h79/janswede/He277-3s.jpg One additional surviving photo that is known to exist, showing what looks like an He 177B-series prototype from the right side with a production-style A-series single vertical tail surface set, and bearing the Stammkennzeichen code of NE+OD, does not match any item of the surviving documentation for the four known 177B-series prototypes ordered, built or flown before the end of the war.
The He 177B was also intended to introduce a slightly enlarged, somewhat more aerodynamic fully glazed nose, first meant for use on the production A-7 version, that could incorporate a remotely controlled power chin turret at the front of its Bola for forward ventral defense, mounting either a pair of MG 131 machine gun
MG 131 machine gun
The MG 131 was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945...
s or MG 151 cannon
MG 151 cannon
The MG 151 was a 15 mm autocannon produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German Luftwaffe fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as...
, but the new nose design was only tested on the fifteenth He 177 A-0 production prototype, without the chin turret, and was never fitted on any of the He 177B prototypes, which used the standard "Cabin 3" He 177A's well-framed nose. No photographs of this new nose design are known to have survived the war and only drawings exist of it in modern archives. The remaining defensive armament generally remained similar to the He 177A, particularly the twin dorsal gun turrets for the He 177 B-5, with the aft manned dorsal turret being deleted on the planned He 177 B-7 (as on the He 177 A-7) to reduce weight, and a fully powered manned Hecklafette HL 131V tail turret, carrying a quartet of MG 131 machine gun
MG 131 machine gun
The MG 131 was a German 13 mm caliber machine gun developed in 1938 by Rheinmetall-Borsig and produced from 1940 to 1945...
s, was intended for installation on the prototypes and would have been standardized on the production aircraft, but never went beyond the mockup and working prototype stage. The cumbersome four-strut main landing gear of the A-series was retained intact for the B-series prototypes, even though their height, meant to allow clearance for the A-series' pair of large four-blade propellers, was not changed - the outer edge of the DB 603's inner engine nacelle/wing surface juncture was located right at the "centreline" of each of the twin pairs of A-series main gear strut locations, on all four of the B-series prototypes.
The first flights of the He 177B prototypes occurred between late December 1943 and early January 1944 in the vicinity of the Vienna-Schwechat
Vienna International Airport
Vienna International Airport , located in Schwechat and southeast of central Vienna, is the busiest and biggest airport in Austria. It is often referred to as Schwechat, the name of the county it is in. The airport is capable of handling wide-body aircraft such as the Boeing 747 and Airbus A340...
airfield, at the firm's Heinkel-Süd southern production facility, where an additional prototype, the V104, whose purpose was to be the "finalized" production prototype for the He 177B-5, and also meant to be a twin tailed prototype like the earlier V102, was being completed by order from the RLM, converted from an early production He 177 A-5.
However, from April 23 through July 1944, repeated Fifteenth Air Force bombing raids on German aircraft production facilities in Vienna destroyed the airworthy V103 and the incomplete V104 at the Floridsdorf
Floridsdorf
Floridsdorf is the 21st district of Vienna, Austria .Floridsdorf is located in the northern part of Vienna.The District Office and the centre of Floridsdorf are located round Am Spitz, at the junction of Prager Straße and Brünner Straße .Since 2004, Floridsdorf has had its own tower: the...
and Zwölfaxing
Zwölfaxing
Zwölfaxing is a municipality in the district of Wien-Umgebung in Lower Austria, Austria....
satellite plants of the Heinkel-Süd complex, setting back plans of producing any series examples of the B-5 version. Arado Flugzeugwerke
Arado Flugzeugwerke
Arado Flugzeugwerke was a German aircraft manufacturer, originally established as the Warnemünde factory of the Flugzeugbau Friedrichshafen firm, that produced military hydroplanes during the First World War.-History:...
, which had been the major subcontractor for the A-series Greif airframes, at that time was itself fully involved with the production of its own, much more advanced Arado Ar 234
Arado Ar 234
The Arado Ar 234 was the world's first operational jet-powered bomber, built by the German Arado company in the closing stages of World War II. Produced in very limited numbers, it was used almost entirely in the reconnaissance role, but in its few uses as a bomber it proved to be nearly impossible...
B turbojet-powered reconnaissance-bomber, and was not able to handle the anticipated demand from Heinkel to produce the B-5 by October 1944, and would have not started the He 177B-5's production for another month, from its own focus on the Ar 234B. The last known official accounts of the whereabouts of the two He 177B prototypes that escaped heavy bombing had the V101 still at the Heinkel-Süd plant's airfield at Schwechat near Vienna, and the V102 also there at Schwechat as late as February 1945, after damage sustained from a bad landing in April 1944 while evading one of the initial USAAF 15th Air Force raids on the area, which had kept it from being flown north to the Luftwaffe's well-known, central Erprobungstelle test facility
Rechlin-Lärz Airfield
Rechlin-Lärz Airfield is an airfield in the village of Rechlin, Mecklenburg-Western Pomerania, Germany, which is certified for aviation equipment up to 14 tons weight...
at Rechlin
Rechlin
Rechlin is a municipality in Mecklenburg-Western Pomerania, Germany. The town's airport has a long history and was the Luftwaffe's main testing ground for new aircraft designs during the Third Reich....
for safety. It is possible, from some accounts, that the V101 prototype might have survived until at least February 1945 (as the V102 had) before it was scrapped, as some photos of what is stated as the damaged V101 place it at Cheb
Cheb Airport
Cheb Airport is the oldest airport on area of the Czech Republic. It is located 4,5 km from city of Cheb ....
in May 1945, and showing that the V101 had even been test-fitted with a quartet of Junkers Jumo 222 engines, if verified, would conflict with Heinkel records as to the V101 having been scrapped.
The adoption of the Emergency Fighter Program in early July 1944 dealt the final blow to the entire He 177B development program, with the Heinkel He 162
Heinkel He 162
The Heinkel He 162 Volksjäger was a German single-engine, jet-powered fighter aircraft fielded by the Luftwaffe in World War II. Designed and built quickly, and made primarily of wood as metals were in very short supply and prioritised for other aircraft, the He 162 was nevertheless the fastest of...
jet fighter being the only new Heinkel aircraft design that would be allowed into production.
Operational history
Dive bomber
A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target reduces the distance the bomb has to fall, which is the primary factor in determining the accuracy of the drop...
. Although the He 177 entered service in 1942 it was still far from operational. In an assessment of the aircraft on April 9, 1942 the newly activated Erprobungsstaffel 177 reported that the Greif had good flying characteristics, but had unacceptable engine troubles and deficits with the airframe strength. As an emergency measure it was used to supply the encircled 6th Armee at Stalingrad where it was determined that it was totally unsuited for the transport role, carrying a little more cargo than the smaller and more reliable Heinkel He 111
Heinkel He 111
The Heinkel He 111 was a German aircraft designed by Siegfried and Walter Günter in the early 1930s in violation of the Treaty of Versailles. Often described as a "Wolf in sheep's clothing", it masqueraded as a transport aircraft, but its purpose was to provide the Luftwaffe with a fast medium...
, and was useless for the evacuation of wounded troops. As a result the He 177s reverted to bombing and flak-suppression missions in support of the German Army
Heer
Heer is German for "army". Generally, its use as "army" is not restricted to any particular country, so "das britische Heer" would mean "the British army".However, more specifically it can refer to:*An army of Germany:...
in the vicinity of Stalingrad. Only thirteen missions were flown and seven of the He 177s crashed in flames without any action attributable to the enemy.
As the war progressed, He 177 operations became increasingly desultory. Fuel and personnel shortages presented insurmountable difficulties, and He 177s were sitting on airfields all over Europe awaiting the replacement of engines or engine related modifications. Serviceability also was invariably low as a result of last-minute mishaps before operations. On the night of February 13, 1944 as part of Operation Steinbock
Operation Steinbock
Operation Steinbock was the nocturnal Second World War Luftwaffe offensive operation to destroy British military and civilian targets in southern England, between January and May 1944. The attacks were mainly in and around the Greater London area...
, fourteen He 177 taxied
Taxiing
Taxiing refers to the movement of an aircraft on the ground, under its own power, in contrast to towing or push-back where the aircraft is moved by a tug...
out on a bombing mission, thirteen took off, one suffering a burst tire, eight promptly returned to base with overheating or burning engines. Of the four He 177s which did reach London one was shot down by night fighters. It is not always clarified that these aircraft were brand new, delivered about a week before the operation and not properly flown-in, as the air unit had moved to a new airfield the day before and lacked sufficient maintenance personnel and material. The constant attacks of Allied bombers against the Luftwaffe's long range combat units in France made continuous operations on these airfields quite difficult. Many aircraft could not be maintained properly due to destroyed hangars or were simply unserviceable due to damages caused by Allied strafing attacks.
During operations on the Eastern Front in early 1944, often carried out in daylight at about 6,000 m (19,690 ft) or higher, losses were relatively light. The Soviet Air Force, equipped mainly for low-level interception and ground-attack roles, was able to do little to hinder the high-flying bombers. Individual pilots did make interceptions but, unaccustomed to engaging such comparatively large targets and disconcerted by the effective defensive armament, they rarely pressed home their attacks.
In common with most German bombers, the He 177 was grounded from the summer of 1944 as the Allied bombing campaign began to seriously affect German fuel production. By this time the He 177 had proved itself to be the most technically advanced bomber of the Luftwaffe. This was confirmed by postwar tests on the He 177 A-5 and the single long-range He 177 A-7, which the Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
found impressive. The He 177 can be compared with the Boeing B-29 Superfortress which also took about two years to have its problems ironed out, after which it became one of the most successful bombers of aviation history. However, due to the Emergency Fighter Program, fuel shortages, and the deteriorating war situation in Germany the He 177 was never able to achieve its full potential.
Variants
He 177 V1 to V8- 8 prototypes built in total. He 177 V4 and subsequent aircraft powered by DB 606 A/B engines.
He 177 A-0
- Pre-production series, 35 built.
He 177 A-1
- First production series, 130 built. Armed with a single MG 81 in the nose, a single MG FF cannon in the forward end of the Bola ventral gondola, a remote controlled dorsal turret with a single (later twinned) MG 131, and a single tail mounted MG 131.
- He 177 A-1/R1
- :Equipped with a supplementary pair of aft firing MG 81 in the rear of the ventral gondola
- He 177 A-1/R2
- :Equipped with a sighting station in the rear of the ventral gondola for a remotely controlled ventral turret housing a single MG 131
- He 177 A-1/R4
- :Equipped with a supplementary aft firing MG 131 in the rear of the ventral gondola and a manned aft dorsal turret containing an MG 131
- He 177 A-1/U2
- :Zerstörer heavy fighter with a pair of limited-traverse 30 mm MK 101 cannon in enlarged Bola lower nose mount, twelve conversions
He 177 A-2
- Proposed four-man pressurized variant with reduced defensive armament of six MG 81 and a single MG 131, never built.
He 177 A-3
- Second production series, 170 built, with 1.6 meter-longer lengthened rear fuselage. Sixteenth and subsequent aircraft powered by DB 610 A/B engines.
- He 177 A-3/R1
- :Powered by two Daimler-Benz DB 606 A/B engines, fifteen built
- He 177 A-3/R2
- :Improved electrical system. MG FF cannon replaced by an MG 151 cannonMG 151 cannonThe MG 151 was a 15 mm autocannon produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German Luftwaffe fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as...
in the ventral gondola. Larger redesigned tail position, MG 131 replaced by MG 151 cannon in the tail position - He 177 A-3/R3
- :Anti-shipping version capable of using the Henschel Hs 293Henschel Hs 293The Henschel Hs 293 was a World War II German anti-ship guided missile: a radio-controlled glide bomb with a rocket engine slung underneath it. It was designed by Herbert A. Wagner.- History :...
- He 177 A-3/R4
- :Ventral gondola lengthened by 1.2 m (3 ft 11 in) to provide room for the FuG 203b Kehl III missile-control equipment
- He 177 A-3/R5
- :Planned, never-built Stalingradtyp version armed with a 75 mm Bordkanone BK 7,5 cannon based on the 7.5 cm PaK 40 installed in the ventral Bola gondola, also used on the Junkers Ju 88 P-1Junkers Ju 88The Junkers Ju 88 was a World War II German Luftwaffe twin-engine, multi-role aircraft. Designed by Hugo Junkers' company through the services of two American aviation engineers in the mid-1930s, it suffered from a number of technical problems during the later stages of its development and early...
, based on a small number of 177As actually field-equipped as A-3/Rüstsatz 5 machines, with the KwK 395 cm KwK 39The 5 cm KwK 39 L/60 was a German 50 mm caliber gun used during Second World War, primarily as the main armament of later variants of the German Panzerkampfwagen III tank between 1941-1942. It was developed as a variant of the towed gun 5 cm PaK 38...
-based Bordkanone BK 5BK-5 cannonThe Bordkanone 5, or BK 5 for short, was a 50 mm autocannon intended primarily for use against Allied heavy bombers, especially the USAAF's combat box heavy bomber flight formations, so that defending Luftwaffe fighter aircraft could fire from a great enough distance to make the USAAF bomber's...
cannon - He 177 A-3/R7
- :Torpedo bomber version abandoned in favor of the He 177 A-5, only three built
He 177 A-4
- Proposed high altitude pressurised version, never built under the designation, and later developed into the Heinkel He 274Heinkel He 274The Heinkel He 274 was a German Luftwaffe heavy bomber developed during World War II, purpose-designed for high-altitude bombing with pressurized crew accommodation.- He 177 ancestry :...
.
He 177 A-5
- Main production series, 826 built. Standardized the A-3's longer rear fuselage, atrengthened wing, shortened undercarriage oleo legs, increase in maximum external bombload.
- He 177 A-5/R1
- :Version optimized for Fritz X and Hs 293 guided bombs, equipped with Kehl control gear
- He 177 A-5/R2
- :Armed with a single MG 81 in the nose, a single MG 151 cannon in the forward end of the ventral gondola, a pair of MG 81 in the rear end of the ventral gondola, a pair of MG 131 in an FDL 131Z remotely controlled forward dorsal turret, a single MG 131 in a manned aft dorsal turret, and a single tail mounted MG 151 cannon
- He 177 A-5/R4
- :Simplified bomb rack installation, equipped with Kehl control gear
- He 177 A-5/R5
- :Tested with a supplementary pair of MG 131 in an FDL 131Z aft ventral remote turret aft of the rear bomb-bay, only one built
- He 177 A-5/R6
- :Replacement of the forward and central bomb-bays with enlarged, full-fuselage-depth fuel tanks
- He 177 A-5/R7
- :Pressurised cockpit study with a projected ceiling of 15,200 m (49,869 ft) and similar reduced armament to the He 177 A-2
- He 177 A-5/R8
- :Armed with FDL-series remote gun turrets. Abandoned as a result of difficulties with the turrets, only one built
- He 177 A-5 Grosszerstörer
- :Anti-bomber variant based on the He 177 A-5, armed with up to 33 spin-stabilised 21 cm calibre rockets obliquely mounted in fuselage, supplanting bomb bays and auxiliary fuel tanks, and most likely based on components of the 21 cm Nebelwerfer 4221 cm Nebelwerfer 42The 21 cm Nebelwerfer 42 was a German multiple rocket launcher used in the Second World War. It served with units of the Nebeltruppen, the German equivalent of the American Chemical Corps...
infantry barrage rocket system. Five examples delivered in January 1944 for operational trials. Abandoned due to increasing numbers of Allied escort fighters
He 177 A-6
- Meant to be a "32 metric-ton" loaded-weight long-range bomber, as a planned improvement over the A-5 version, the A-6 dispensed with the rear manned dorsal turret, and retained the A-5/R2's single MG 151 flexible cannon at the front of the Bola, the flexible ball-mount MG 81 in the "fishbowl" nose glazing, along with the regular A-series FDL 131Z remote forward dorsal turret, and standardized the rear armament with the planned Hecklafette manned HL 131V quadmount MG 131 machine gun turret for the first time. Not produced, due to building volume of design work on the He 177B-series four-engined aircraft.
- He 177 A-6/R1
- :Replacement of the forward and central bomb bays with full-fuselage-depth fuel tanks (as on the A-5/Rüstsätz 6 modification) and the addition of external bomb rack under the new fuel tank bays, capable of carrying a single 2,500 kg (5,511 lb) bomb or Fritz X/Hs 293 in addition to the rear bomb-bay loadout. Range of 5,800 km (3,604 mi), only six test conversions built, from A-5 versions
- He 177 A-6/R2
- :Equipped with a redesigned fuselage nose of improved aerodynamic form, abandoning the earlier "Cabin 3" A-series cockpit, with the new nose being generally the same as intended for He 177A-7 and all He 177B development versions. Retained the FDL 131 remotely controlled forward dorsal turret, a single flexible-mount MG 131 in the rear of the Bola, a pair of MG 151 cannon in a remotely controlled FDL 151Z "chin" turret (to be standardized on the B-version) at the front of the Bola, and a manned HL 131V MG 131 "quadmount" tail turret. Similar bombload and range to He 177 A-6/R1, only one test conversion built, as the He 177 V15, of which no photos are known to survive
He 177 A-7
- High altitude bomber with an extended wing spanning 36 m (118 ft 1⅓ in) and with DB 610 A/B engines instead of the intended 3,800 PS (3,748 hp, 2,795 kW) DB 613 engines. Six examples, for wing tests, converted from He 177 A-5 airframes, but never fitted with the intended He 177 B-series advanced cockpit. One captured by American forces, scrapped postwar and believed buried under the grounds of Chicago's O'Hare International AirportO'Hare International AirportChicago O'Hare International Airport , also known as O'Hare Airport, O'Hare Field, Chicago Airport, Chicago International Airport, or simply O'Hare, is a major airport located in the northwestern-most corner of Chicago, Illinois, United States, northwest of the Chicago Loop...
.
He 177 A-8
- First proposed He 177 design to feature four individual engines, using the A-3 or A-5 fuselage with a new wing design, and either Daimler-Benz DB 603Daimler-Benz DB 603|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7...
or Junkers Jumo 213Junkers Jumo 213|-See also:-Bibliography:* Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7-External links:*...
engines with Heinkel He 219Heinkel He 219The Heinkel He 219 Uhu was a night fighter that served with the German Luftwaffe in the later stages of World War II. A relatively sophisticated design, the He 219 possessed a variety of innovations, including an advanced VHF-band intercept radar...
style annular radiators. Remained a paper project only, before re-designation as the "He 177B-5" by August 1943.
He 177 A-10
- Proposed four-engined He 177 design, similar to the He 177 A-8, but based instead on the He 177 A-7 definitive production fuselage, with manned rear dorsal gun turret omitted, and re-designated as the "He 177 B-7" in August 1943.
He 177 B
- Developed as the direct, "separate four-engined" development of the "coupled engine" powered He 177A-series, four prototypes ordered (He 177 V101 to V104) with three built and flown under DB 603 power. Originally postulated in postwar aviation books to have been a "cover designation" for the never-produced, paper-only He 277 Amerika BomberAmerika BomberThe Amerika-Bomber project was an initiative of the Reichsluftfahrtministerium, the Nazi Germany Air Ministry, to obtain a long-range strategic bomber for the Luftwaffe that would be capable of striking the continental United States from Germany, a range of about 5,800 km...
design competitor.
He 177 H
- Initial project designation for the Heinkel He 274Heinkel He 274The Heinkel He 274 was a German Luftwaffe heavy bomber developed during World War II, purpose-designed for high-altitude bombing with pressurized crew accommodation.- He 177 ancestry :...
.
Special variants
- He 177 V38
- An A-5 (Werknummer 550 002, beaing Stammkennzeichen of KM+TB) - documented use was as testbed for FuG 200 Hohentwiel ASV maritime patrol radar with flexible MG 131Z nose gun installation, speculated to have been intended for the installation of an enlarged bombbay to be used in the Junkers Ju 287Junkers Ju 287-Bibliography:* Hitchcock, Thomas H. Junkers 287 . Acton, MA: Monogram Aviation Publications, 1974. ISBN 0-914144-01-4.-External links:*...
. A common myth claims V38 was the prototype for a German "atomic bomber" (purportedly capable of carrying a fisson device as a droppable weapon). Remains found at Prague's Rusiye field on V-E Day.
- An A-5 (Werknummer 550 002, beaing Stammkennzeichen of KM+TB) - documented use was as testbed for FuG 200 Hohentwiel ASV maritime patrol radar with flexible MG 131Z nose gun installation, speculated to have been intended for the installation of an enlarged bombbay to be used in the Junkers Ju 287
Operators
Germany:
- LuftwaffeLuftwaffeLuftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
- Fernkampfgeschwader 50
- Kampfgeschwader 1Kampfgeschwader 1Kampfgeschwader 1 was a Luftwaffe bomber unit during the Second World War. Heinkel He 111 and later Heinkel He 177 bombers.-History:...
- Kampfgeschwader 4Kampfgeschwader 4Kampfgeschwader 4 "General Wever" was a Luftwaffe bomber unit during World War II. The unit was formed in May 1939. The unit operated the Dornier Do 17, Junkers Ju 88 and Heinkel He 111 medium bombers, with later service on the Heinkel He 177 heavy bomber...
- Kampfgeschwader 10
- Kampfgeschwader 40
- Kampfgeschwader 100
- Kampfgeschwader 200
- Flugzeugführerschule (B) 15
- Flugzeugführerschule (B) 16
- Flugzeugführerschule (B) 31
- Wekusta/OBdLOberkommando der LuftwaffeThe Oberkommando der Luftwaffe was the air force High Command of the Third Reich.Air Force Commanders-in-Chief* Reich Marshal Hermann Göring * Field Marshal Robert Ritter von Greim -History:...
:
- French Air ForceFrench Air ForceThe French Air Force , literally Army of the Air) is the air force of the French Armed Forces. It was formed in 1909 as the Service Aéronautique, a service arm of the French Army, then was made an independent military arm in 1933...
operated at least two He 177 A-3s left behind by the Germans and rebuilt by SNCASE at BlagnacBlagnacBlagnac is a commune in the Haute-Garonne department in southwestern France.It is the third-largest suburb of the city of Toulouse, although governed by a separate council, and is adjacent to it on the northwest side. It is a member of the Urban community of Greater Toulouse...
.
:
- Royal Aircraft EstablishmentRoyal Aircraft EstablishmentThe Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
- the He 177 A-5 (Geschwaderkennung code of F8 + AP from 6./KG 40) that had been taken from Toulouse-Blagnac airfieldToulouse Blagnac International AirportToulouse Blagnac Airport or Aéroport de Toulouse - Blagnac is an airport located west northwest of Toulouse, just south of Blagnac, both communes of the Haute-Garonne département in the Midi-Pyrénées région of France....
in September 1944. Repainted with British markings and given the serialUnited Kingdom military aircraft serialsIn the United Kingdom to identify individual aircraft, all military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry , and its successor the Ministry of Defence , is used for aircraft operated by the Royal Air Force , Fleet...
TS439.
Specifications (He 177 A-5/R2)
See also
External links
- He 177's FDL 131 remote dorsal turret manual-single gun version
- Description of He 177 A-3
- He 177 A-3 manual
- YouTube German wartime footage of He 177 prototypes
- YouTube German wartime footage of He 177 V6 landing
- YouTube still photo montage of He 177s in service, with some color photos
- Photo of HL 131V tail turret exterior shell relic
