With the end of World War 2 (1939-1945), French aero-industry began the painful process of rebuilding to which many initiatives ultimately emerged. By the time of the 1950s, the Soviet Union was the primary enemy of the West and its force of nuclear-capable bombers was of high concern. This led to projects undertaken in Europe and elsewhere centered on the prospect of high-speed, high-flying interceptors intended to meet these threats head-on and at-range by direction of radar and attacking with missiles. Nord Aviation eventually attempted to deliver such an aircraft to the French Air Force - the Armee de l'Air - through its Nord 5000 "Harpon" proposal.
The Harpon was the evolution of several earlier attempts by the company to produce a lightweight interceptor. As early as 1953, the company undertook design studies on a canard-centric form featuring a rocket-only propulsion scheme - the "Nord Intercepteur Leger" or "NIL". While this design was eventually rejected by French authorities, the company followed up with a Rolls-Royce "Nene" turbojet-powered version but this, too, was passed on by the service for various design and operating reasons. Through additional testing of rocket-powered subscale models from the period of mid-1954 to early-1955, the company persevered to deliver a more acceptable interceptor form, resulting in the "NIL-6", also known as the "Nord 5000".
The new aircraft held a sleek design featuring a tubular fuselage form void of any major obstructions for excellent aerodynamic efficiency at high-speeds. The nose was extremely pointed for this same reason and all wing surfaces were finished with extensive sweepback of the leading edges (60-degree sweepback). The aircraft was given a "canard" configuration, smaller triangular wings mounted ahead of the cranked-delta mainplanes, and the mainplanes were set well-aft (at the tail section) in the overall arrangement for balance. The tail was dominated by a single, large-area triangular vertical fin. The cockpit was seated aft of the nose cone but ahead of midships with only light framing used at the canopy. However, views to the rear were obstructed by a section of raised dorsal spine.
The mainplanes were of particular note for their tips were designed to rotate to aid in maneuvering of this vehicle at high-speed. Similarly, the canards were also being designed as all-moving surfaces to help with agility.
Propulsion would stem from a "combination" arrangement involving 2 x Turbomeca "Gabizo" afterburning turbojet engines of 3,375lb thrust each at the tail and 1 x SEPR-66 auxiliary rocket booster fired through two combustion exhaust chutes under the tail. Engineers estimated the aircraft could have a straight-line speed approaching Mach 2.0 and reach altitudes beyond 80,000 feet.
As an interceptor, and going along with the aircraft's estimated inherent speed and altitude capabilities, the product would carry a single Nord 5103 series air-to-air missile under the fuselage to meet the Soviet bomber threat in short order.
However, despite its promising aspects, the Harpon was simply too great a financial and developmental risk for the French Air Force to fund development of. As such, the rocket-assisted interceptor proposal fell by the wayside and ultimately into military aviation history concerning the Cold War as more modest solutions were ultimately sought and had.