The Heinkel HD 55 was a biplane flying boat produced in Germany in the early 1930s for use as a reconnaissance aircraft aboard Soviet warships. The design was based on the HD 15 mail plane of 1927 and was a conventional design for its time, with equal span, unstaggered wings, and an engine mounted tractor-wise on struts above the pilot's open cockpit. A second open cockpit was added on the rear fuselage to provide a position for a tail gunner.

General characteristics

Crew: Two, pilot and gunner
Length: 10.35 m (34 ft 0 in)
Wingspan: 14.00 m (45 ft 11 in)
Height: 4.28 m (14 ft 1 in)
Wing area: 56.9 m2 (612 sq ft)
Empty weight: 1,520 kg (3,350 lb)
Gross weight: 2,270 kg (5,000 lb)
Powerplant: 1 × Siemens-Halske Sh 20 , 360 kW (480 hp)
Performance

Maximum speed: 194 km/h (120 mph, 100 kn)
Range: 800 km (500 mi, 430 nmi)
Service ceiling: 4,800 m (15,800 ft)
Armament

1 × fixed, forward-firing 7.62 mm (.30 in) PV-1 machine gun
2 × trainable, rearward-firing 7.62 mm DA machine guns