The Heinkel HD 55 was a

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a ...

flying boat A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fuselag ...

produced in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...

in the early 1930s for use as a

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops ( skirmishe ...

aircraft aboard

Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

warship A warship or combatant ship is a naval ship that is built and primarily intended for naval warfare. Usually they belong to the armed forces of a state. As well as being armed, warships are designed to withstand damage and are usually faster ...

s. The design was based on the HD 15

mail plane A mail plane is an aircraft used for carrying mail. Aircraft that were purely mail planes existed almost exclusively prior to World War II. Because early aircraft were too underpowered to carry cargoes, and too costly to run any "economy class" ...

of 1927 and was a conventional design for its time, with equal

span Span may refer to: Science, technology and engineering * Span (unit), the width of a human hand * Span (engineering), a section between two intermediate supports * Wingspan, the distance between the wingtips of a bird or aircraft * Sorbitan ester ...

, unstaggered wings, and an engine mounted tractor-wise on struts above the pilot's open

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls that e ...

. A second open cockpit was added on the rear

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

to provide a position for a tail gunner. The HD 55 came about as a result of a meeting between Heinkel and Soviet officials in May 1929, leading to a contract for 15 such aircraft, and two pneumatic

catapult A catapult is a ballistic device used to launch a projectile a great distance without the aid of gunpowder or other propellants – particularly various types of ancient and medieval siege engines. A catapult uses the sudden release of stor ...

s similar to the type Heinkel had developed to launch the HE 12 mail plane from the , although this order was substantially increased as time went by. In Soviet service, the designation KR-1 was used (корабельный разведчик - ''Korabelniy Razvedchik'' - "Shipboard Reconnaissance"). The first catapult was installed on the battleship '' Parizhskaya Kommuna'' in October 1930, and trials commenced immediately, revealing problems with both the catapult and the aircraft. These difficulties were never fully resolved, and the KR-1 was plagued through its career by various structural defects. Nevertheless, the type was deployed into service, with catapults and aircraft installed at various times aboard the cruisers , , , and ''

Profintern The Red International of Labor Unions (russian: Красный интернационал профсоюзов, translit=Krasnyi internatsional profsoyuzov, RILU), commonly known as the Profintern, was an international body established by the Comm ...

''. The type lingered on in service well into obsolescence in the mid-1930s, mostly due to the failure of its intended replacement, the

Beriev Be-2 The Beriev Be-2 (originally designated KOR-1) was a two-seat reconnaissance seaplane built for the Soviet Navy shortly before World War II. It was designed to replace the Navy's obsolete license-produced Heinkel He 55 aircraft operating from wa ...

. The final operational use of the KR-1 was around 1938, and by 1941 all had been either scrapped or placed in indefinite storage.

Operators

; *

Soviet Naval Aviation Soviet Naval Aviation (AV-MF, for ''Авиация военно-морского флота'' in Russian, or ''Aviatsiya voyenno-morskogo flota'', literally "aviation of the military maritime fleet") was the naval aviation arm of the Soviet Na ...

Specifications

References

* {{Soviet scout designations 1920s German military reconnaissance aircraft Flying boats HD 55 Biplanes Single-engined tractor aircraft Aircraft first flown in 1929