When the Heinkel He 49a single seat biplane made its first flight in November 1932 it was ostensibly a civilian advanced trainer. However, its BMW VI engine gave it a top speed of almost 199 mph (320 km/h), which was in keeping with its true role as the forerunner of the first fighter to serve with the Luftwaffe upon its official formation in April 1935. Two more prototypes were built, the He 49b flown in February 1933 with a fuselage lengthened by 1 ft 3 3/4 in (0.40 m), and the He 49e with faired landing gear. The type was ordered as the He 51, the initial He 51A-O pre-production example being flown for the first time in May 1933; eight more were built to this standard and were unarmed. Of all-metal construction, with fabric covering, the He 51 was a single-bay biplane, armed with two 7.92 mm (0.31 in) MG 17 machine guns mounted above the engine. Deliveries of the initial He 51A-1 production version began in July 1934, and in April 1935 some of them equipped the Luftwaffe's first fighter unit, the Jagdgeschwader 'Richthofen'.

In January 1936 the He 51B was introduced on the production line, a structurally strengthened version, of which 12 pre-production aircraft were built initially under the designation He 51B-0, then being followed by 12 generally similar He 51B-1 aircraft. An He 51A-1 converted to have float landing gear was the forerunner of 38 He 5IB-2 floatplane fighters with twin aluminium floats and equipped for catapult launching from Kriegsmarine cruisers and other large warships; racks were sometimes fitted to carry up to six 22 lbs (10 kg) bombs. An experimental high-altitude version of basic He 51B, with increased-span two-bay wings, was completed under the designation He 51B-3. Following testing of this aircraft two additional prototypes were built for high-altitude tests under the designations He 52B and He 52D, but no production resulted. Final version was the C-series, the He 51C-1 intended primarily for export to the Spanish Nationalists being equipped as standard with racks for six 22 lbs (10 kg) bombs. A total of 79 were shipped to Spain, 51 being used by the Nationalist air force and the balance going to the Legion Condor. Subsequently, a small number of the generally similar He 51C-2, which differed by having improved radio equipment, was supplied to the Luftwaffe.

Total production of all versions reached 700, built by Heinkel, and by Arado, Erla Maschinen-werk and Fieseler. Some He 51s remained in first-line service with the Luftwaffe untfl 1938, then being relegated to the training role, in which capacity they were used for much of World War II.

Variants

He 49a/He 49b/He 49c/He 51A-0/A-1

Forerunner of the Luftwaffe's first fighter, the Heinkel He 49a single-seat biplane flown in November 1932 was ostensibly a civilian advanced trainer. Two more prototypes, the He 49b with a lengthened fuselage and He 49c with faired landing gear, led to the first He 51A-0 pre-production aircraft flown in May 1933; eight more unarmed aircraft were built to this standard. Deliveries of the initial armed production version began in July 1934. In April 1935 some equipped the Luftwaffe's first squadron, Jagdgeschwader 'Richthofen'; He 51s flew with the legion Condor during the Spanish Civil War, and were used also by the Nationalist forces. The type was later relegated to a training role, remaining in service until 1942-43. The He 51A-1 was the production version, of which, 75 built in 1935.

He 51B/He 51B-0/He 51B-2/B-3

The He 51B was structurally strengthened. He 51B-0 landplanes (12 built) replaced He 51As on the production line in January 1936. The He 51B-2 (38 built) was a float-plane fighter version equipped for catapult launching, but sometimes had racks for up to six 10 kg (22 lbs) bombs. A long-span high-altitude version was designated He 51B-3.

He 51C/C-1/C-2

The He 51C was the designation for aircraft modified to carry four 50 kg (110 lbs) of bombs. He 51C-1 version was the designation used by Legion Condor and Spanish Nationalist units in the Civil War. The He 51C-2 had improved radio equipment and was supplied to the Luftwaffe.

Specifications (Heinkel He 51B-1)

Type: Single Seat Biplane Fighter

Design: Ernst Heinkel AG

Manufacturer: Ernst Heinkel AG, Arado, Erla Maschinen-Werke and Fieseler

Powerplant: one 750 hp (559 kW) BMW VI 7-3Z 12-cylinder inverted Vee piston engine.

Performance: Maximum speed 205 mph (330 km/h) at sea level; cruising speed 174 mph (280 km/h) at sea level; service ceiling 25,260 ft (7700 m).

Range: 354 miles (570 km) on internal fuel.

Weight:  Empty equipped 3,219 lbs (1460 kg) with a maximum take-off weight of 4,178 lbs (1895 kg).

Dimensions: Span 36 ft 1 in (11.00 m); length 27 ft 6 3/4 in (8.40 m); height 10 ft 6 in (3.20 m); wing area 292.79 sq ft (27.20 sq m).

Armament: (Standard) Two forward firing 7.92 mm (0.31 in) Rheinmtall MG 17 synchronised machine guns above the fuselage. (B-2) Same as above plus underwing racks for up six 22 lbs (10 kg) bombs. (C-1) Standard armament plus underwing racks for four 110 lbs ( 50 kg) bombs.

Variants: He 49a (initial prototype), He 49b (second prototype with a lengthened fuselage), He 49c (third prototype with faired landing gear), He 51A (production prototype), He 51A-1 (75 production aircraft), He 51B-0 (12 land based aircraft), He 51B-2 (38 floatplane conversions), He 51B-3 (high altitude), He 51C/C-1/C-2 (ground attack).

History: First flight (He 49a) November 1932, pre-production (He 51A-0) May 1933, deliveries of the armed production version in July 1934, equipped the first Luftwaffe squadron 'Richthofen' in April 1935.

Avionics: None.