He 50 / He 66
Wishing to contend in early 1931 for an Imperial Japanese navy requirement for a two-seat carrier-based dive bomber, Aichi requested Heinkel to design and build an aircraft to meet the navy's specification.
Required for operation with float or wheel landing gear, the resulting Heinkel He 50 prototype He 50aW flew for the first time in mid-1931, powered by a 390-hp Junkers L-5 engine. It had a twin-float undercarriage and was designed to meet the naval requirement for a marine aircraft with a 250-500kg (550-1100 lb) bombload capacity. A second version was built with wheel landing gear.
The Japanese requirement was pursued through the modified He 50b prototype. This went to Japan in early 1933 (with the 'export' designation He 66), where it entered production as the Aichi D1A, of which 590 were built between 1936-40.
The He 50 was a two-seat biplane of sturdy construction, but the Junkers engine was not nearly powerful enough, and the second prototype was fitted with a Siemens Bramo 322B (Bristol Jupiter VI) 490-hp powerplant. This aircraft had a wheeled undercarriage which could, however, readily be replaced by floats. Designated He 50aL, it was delivered to the military aircraft test centre at Rechlin, where it was considered to be underpowered, and three more He 50aL prototypes, fitted with uncowled 600-hp BMW SAM 22B nine-cylinder radial engines, were completed in mid-1932.
After demonstration to the RVM (predecessor to the RLM, or German aviation ministry) a production order for 25 He 50As was placed for the Luftwafre. This total was later increased to 60, the second batch of 35 being built by Bayerische Flugzeugwerke (BFW). They were armed with a single, fixed 7.9-mm (0. 311 -in) MG 17 machine-gun operated by the pilot, with a movable MG 15 gun on a ring in the rear cockpit. The Luftwaffe aircraft were employed as trainers, although during 1935-36 they were flown as single seater dive-bombers.
Two batches of He 66s were ordered from Heinkel by China: 12 similar to the He 50b, and 12 patterned on the He 50A. Only the former batch were delivered, the latter being requisitioned and put into Luftwaffe service as He 50Bs.
Luftwaffe He 50A remained operational on the Eastern Front until 1944. Maximum level speed was 235km/h and armament comprised one forward-firing 7.9mm MG 17 or one rear-mounted MG 15 machine-gun (dive-bomber and reconnaissance types respectively), plus up to 500kg of bombs.
Engine: 1 x Bramo SAM 322, 440kW
Max take-off weight: 2620 kg / 5776 lb
Empty weight: 1756 kg / 3871 lb
Wingspan: 11.5 m / 37 ft 9 in
Length: 9.6 m / 31 ft 6 in
Height: 4.4 m / 14 ft 5 in
Wing area: 34.8 sq.m / 374.58 sq ft
Max. speed: 235 km/h / 146 mph
Cruise speed: 190 km/h / 118 mph
Range w/max.fuel: 600 km / 373 miles
Armament: 1 machine-gun
He 50A-2 landplane
Span: 11.5 m (37 ft 8.75 in)
Length: 9.6 m (31 ft 6 in)
Gross weight: 2620 k (5775 lb)
Maximum speed: 235 km/h (146 mph).