The Potez 51 was a 1930s French intermediate trainer, intended to replace the ageing Potez 25 which had sold worldwide. It did not go into production.

Design

Although the main rôle of the Potez 51 was as an intermediate trainer Potez, with their very successful Potez 25 in mind, hoped that it would also serve as a photographic reconnaissance aircraft, an air-ambulance and, in the civil sphere, a grand tourer. It was a

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

with a constant chord

parasol wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

with about 2.5° of sweep. The tips were semi-circular and there was a deep, rounded cut-out in the

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 199 ...

over the cockpits. High aspect ratio

ailerons An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...

occupied the whole trailing edge. The wing was built around wooden box-spars and was fabric covered. It was braced to the lower

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 aircraf ...

by parallel

strut A strut is a structural component commonly found in engineering, aeronautics, architecture and anatomy. Struts generally work by resisting longitudinal compression, but they may also serve in tension. Human anatomy Part of the functionality o ...

s to the wing beyond mid-span. Four cabane struts from the upper fuselage on each side braced the wing centre section. Its fuselage was largely wooden, with spruce longerons and ply skin, though the forward section, which contained the Potez 9A

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...

, had metal bearers and removable metal sheet covering. The engine was enclosed by a

NACA The National Advisory Committee for Aeronautics (NACA) was a United States federal agency founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its assets ...

long chord

engine cowling A cowling is the removable covering of a vehicle's engine, most often found on automobiles, motorcycles, airplanes, and on outboard boat motors. On airplanes, cowlings are used to reduce drag and to cool the engine. On boats, cowlings are a cove ...

. Behind the engine the fuselage was flat sided, though with rounded decking both forward and aft of the two open cockpits, the forward one under the

cut-out and the other close behind. Fairings ahead of each gave protection from the slipstream and dual controls were fitted. Both

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...

and

tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyropla ...

were essentially triangular and carried balanced control surfaces. The tailplane was mounted on top of the fuselage and its angle of incidence could be adjusted in flight; it was braced on each side at the apex of a V-strut from the lower fuselage. The Potez 51 had fixed

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...

, with mainwheels on cranked axles and drag struts from the lower fuselage; near vertical shock absorbing legs were attached to the forward wing struts, reinforced at their tops by struts inwards to the upper fuselage. The wheels were enclosed in semi-circular fairings. There was a short tailskid.

Development

The trainer was on display, unflown, at the 1932 Paris Salon. Its first flight was made towards the end of January 1933. Trials continued into 1934, though by August 1933 the aircraft was well harmonized. In November the propeller had to be modified to meet homologation requirements, as Potez had initially underestimated the full power of their new engine, at 2,100 rpm. Finally in March 1934 the factory testing was done and the Potez 51 went to Villacoublay for official evaluation. Its fate is not recorded in the contemporary French aviation journals, but it seems no more were built.

Specifications

References

{{Potez aircraft Parasol-wing aircraft 1930s French military trainer aircraft 051 Single-engined tractor aircraft Aircraft first flown in 1933