Heinkel He 50

Heinkel
Industry	Aerospace, Defence
Founded	1922
Founder	Ernst Heinkel
Headquarters	Germany
Products	Aircraft, including the Heinkel He 50 dive bomber

Template:Infobox aircraft

The Heinkel He 50 was a German-made biplane designed as a dive bomber and manufactured by Heinkel. Despite limited production numbers, it saw service during the Second World War.

Initially developed in the early 1930s for the Imperial Japanese Navy, the He 50 effectively served as the foundation for the Aichi D1A. The first prototype, known as the Heinkel He 50aW, suffered from insufficient engine power. Subsequent prototypes addressed this issue through engine upgrades, resulting in an aircraft recognized for its excellent handling and brief takeoff runs. The design quickly attracted interest from German authorities, leading to its adoption by the newly established Luftwaffe.

By 1935, the He 50 was delivered to the Luftwaffe's inaugural dive-bombing unit and eventually equipped ten such units. However, at the outbreak of World War II, it was gradually replaced by more advanced models like the Henschel Hs 123 and Junkers Ju 87. Nevertheless, it continued to serve in secondary roles, primarily as a trainer. Midway through the conflict, most remaining airframes were reassigned to front-line duties as night harassment bombers on the Eastern Front, where they remained active until nearly the war's conclusion.

Development

In 1931, the Imperial Japanese Navy commissioned Heinkel to design a two-seat dive bomber capable of carrying a 250 kg (550 lb) bomb load, structurally reinforced for catapult launches, and adaptable to both wheeled and float undercarriage configurations. The aircraft that emerged was an evolution of Heinkel’s earlier combat planes dating back to the First World War, integrating contemporary aerodynamic improvements and technological advancements.

The initial prototype, designated Heinkel He 50aW, was completed during summer 1931. This mixed-construction biplane featured twin floats and was powered by a single Junkers L5 inline engine. Flight trials revealed that this powerplant lacked sufficient thrust. Subsequently, a second prototype called He 50aL was developed; it employed a Siemens Jupiter VI radial engine and utilized conventional wheeled landing gear. A further He 50aL was produced and later redesignated as He 50b. From this variant arose the Heinkel He 66, crafted specifically for the Japanese Navy and serving as the precursor to the Aichi D1A.

Design

File:He 50 46168922.jpg

A prototype He 50, circa 1932

The He 50 was designed as a biplane with equal wingspan for both upper and lower wings. It was recognized for its robustness and stability, capable of reaching relatively high speeds while maintaining a notably low landing velocity. The aircraft exhibited excellent flight characteristics, an extended operational range, and required minimal runway length for takeoff.^[1] Its notably smooth and brief takeoff run is partly attributed to the aircraft’s comparatively low wing loading. Additionally, the He 50 was known for its well-balanced flight dynamics.^[2]

The fuselage featured a rectangular cross-section topped with a sturdy, curved upper surface.^[1] Toward the tail section, the fuselage inclined upward to raise the tail above water level consistently. The main framework consisted of welded steel tubes shaped into an oval form by wooden formers and stringers.^[1]^[3] This framework included four tubular longerons connected by welded tubular bulkheads, internally reinforced with a combination of steel cables and tubular struts where necessary. The exterior was covered with doped fabric except for the very front, which was clad in lightweight alloy.^[3]^[1]

The wings incorporated a slight stagger and minimal sweepback; ailerons were installed on all four wing panels.^[4] The arched wing profile was created using two robust box girders designed to withstand aerobatic maneuvers. Wing ribs were constructed with spruce flanges and plywood webs, while internal bracing utilized steel tubing. Both wing halves were fastened to the fuselage by hook fittings.^[5] Bracing against the floats was provided by N-shaped struts, with approximately two-thirds of the wing extending beyond this support. The leading edges were plywood-covered, while the entire wing surface was finished with doped fabric.^[5]

The He 50 could accommodate various engines within the 350 to 500 hp range, including several imported models.^[6] Engine mounting involved steel tubing structures attached to the four main longerons via four conical bolts, facilitating straightforward engine replacement.^[5] A steel bulkhead separated the engine compartment from the pilot’s cockpit, where fuel flow could be rapidly shut off through a conveniently located stopcock on the fuel line. Fuel tanks were housed within the wings and supplied to the engine by pumps.^[5]

Positioned immediately behind the engine, the pilot’s cockpit offered a forward placement that allowed clear visibility of the float fronts during takeoff and landing operations. Two additional seats were situated behind the pilot, featuring good downward visibility achieved partly through cut-outs in the trailing edge of the wing.^[7] The fuselage interior provided ample space for installing radio equipment and advanced cameras alongside storage for baggage.^[5]

The undercarriage consisted of cold-drawn tubular steel struts streamlined with balsa wood.^[5] The design effectively transmitted landing shocks directly to the aircraft’s main structure rather than to the floats, enhancing seaworthiness significantly. Floats were mounted via clamps at the ends of transverse undercarriage struts, enabling rapid removal if necessary.^[8] Structural rigidity of the landing gear was maintained through longitudinal tubes connecting each junction pair. Each float featured a continuous plywood top surface and a duralumin bottom; internal compartments were separated by watertight bulkheads constructed from wooden ribs and plywood walls.^[2] The displacement volume of each float exceeded the aircraft’s flying weight individually, allowing either float alone to support it on water. Each float had a single step with a keel-shaped bottom located aft of this step.^[2]

Operational history

The He 50aL was redesignated as the He 50 V1 and showcased to the German Defence Ministry in 1932. This presentation led to a contract for three development models, followed by a production run of 60 He 50A-1 aircraft completed during the summer of 1933. The Republic of China ordered 12 He 50As, modified with the addition of an engine cowling and identified as the He 66b. These planes were later requisitioned by the Luftwaffe and reclassified as He 50B. By 1935, the He 50 was assigned to the Luftwaffe's inaugural dive bomber squadron and subsequently equipped parts of nine additional dive bomber groups. Over time, the He 50 was progressively replaced by the Henschel Hs 123 and Junkers Ju 87, with remaining aircraft being reassigned to dive bomber training units.

In early 1943, after the Soviet VVS's Night Witches successfully conducted nocturnal harassment missions against Wehrmacht Heer frontline positions flying Polikarpov Po-2 biplanes, surviving He 50s were retrieved from training schools and allocated to night ground attack units on the Eastern Front. The He 50 continued to perform night harassment missions until October 1944, when these units were disbanded.

Author Lennart Andersson notes that although twelve He 66 aircraft were reportedly ordered by China in 1934, they were never delivered. Furthermore, claims that twelve former Luftwaffe He 50Bs were sent to China in 1936 have been debunked, lacking any archival evidence.

Variants

Information sourced from Eden and Moeng

He 50aW: Initial prototype configured as a floatplane, equipped with a 291 kW (390 hp) Junkers L5 inline engine; suffered severe damage during a forced landing.
He 50aL: Second prototype designed as a landplane, powered by a 365 kW (490 hp) Siemens Jupiter VI radial engine.
He 50b: Third prototype labeled He 66 for export to Japan; three additional units built for German testing, featuring a 373 kW (600 hp) Bramo 322B radial engine.
He 50A: Dive bomber and reconnaissance model produced for the Luftwaffe, with a total of 60 aircraft manufactured.
He 50L: Production variant of the He 50A; Heinkel constructed 25 units while Bayerische Flugzeugwerke built 35, all powered by a 373 kW (600 hp) Bramo 322B radial engine.
He 66aCh: Exported batch of twelve aircraft to China, powered by a 358 kW (480 hp) Siemens Jupiter VIIF radial engine.Template:Fix/category^{[citation needed]}
He 66bCh: Powered by the Bramo 322B engine; twelve units produced for China but seized for Luftwaffe use as He 50B. These were later sent to Hong Kong, stored from January 1936 until July 1937, then transferred to Peking where they saw limited action during the 2nd Sino-Japanese War.
Aichi D1A1

Some reconnaissance variants of the He 66 were manufactured under license by Aichi in Japan.
Aichi D1A2

A refined version of the Aichi D1A1 model.

Operators

Template:JPN

Imperial Japanese Navy – operated a single He 50b prototype

Template:China as ROC: Acquired 12 He 66aCh and 12 He 66bCh aircraftTemplate:Fix/category^{[citation needed]}
File:Flag of Germany (1935–1945).svg Germany: Utilized 60 He 50A models within the Luftwaffe
Template:ESP

Spanish Air Force

Specifications (He 50A)

File:Heinkel He 50.jpg

Profile view of a He 50

Template:Aircraft specs

External links

WRG - Luftwaffe Resource Group - Heinkel He 50

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[naca_3-2] 2.0 ^2.1 ^2.2 NACA 1926, p. 3.

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[naca_2-5] 5.0 ^5.1 ^5.2 ^5.3 ^5.4 ^5.5 NACA 1926, p. 2.

[naca_34-6] NACA 1926, pp. 3-4.

[naca_12-7] NACA 1926, pp. 1-2.

[naca_23-8] NACA 1926, pp. 2-3.

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