Potez 42

Last updated
Potez 42
Role Air ambulance
National origin France
Manufacturer Aéroplanes Henry Potez
First flight early August 1930
Number built 1

The Potez 42 was designed and built in 1930 to meet a French government requirement for a small air ambulance capable of operating in the colonies. It did not reach production.

France Republic with mainland in Europe and numerous oversea territories

France, officially the French Republic, is a country whose territory consists of metropolitan France in Western Europe and several overseas regions and territories. The metropolitan area of France extends from the Mediterranean Sea to the English Channel and the North Sea, and from the Rhine to the Atlantic Ocean. It is bordered by Belgium, Luxembourg and Germany to the northeast, Switzerland and Italy to the east, and Andorra and Spain to the south. The overseas territories include French Guiana in South America and several islands in the Atlantic, Pacific and Indian oceans. The country's 18 integral regions span a combined area of 643,801 square kilometres (248,573 sq mi) and a total population of 67.3 million. France, a sovereign state, is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre. Other major urban areas include Lyon, Marseille, Toulouse, Bordeaux, Lille and Nice.

Contents

Design

Around 1930 there was a French interest in small aircraft capable of evacuating a single ill or wounded patient to hospital from roughly prepared sites in the colonies. The Lorraine-Hanriot LH.21S and the Guillemin JG.40 were examples of the category and the Potez 42 was another. They posed several design challenges, principally around the need for a large, clear enclosure for the patient with easy ground access from a stretcher. [1]

Lorraine-Hanriot LH.21S

The Lorraine-Hanriot LH.21S was designed and built in 1930 to meet a French government requirement for a small air ambulance capable of operating in the colonies. It did not reach production.

Guillemin JG.40

The Guillemin JG.40 was designed and built to meet a French government requirement for a small air ambulance capable of operating in the colonies. Two were completed and performed well but the JG.40 did not reach production.

Stretcher equipment for moving patients in need of medical care

A stretcher, litter, or pram is an apparatus used for moving patients who require medical care. A basic type must be carried by two or more people. A wheeled stretcher is often equipped with variable height frames, wheels, tracks, or skids. In American English, a wheeled stretcher is referred to as a gurney.

The Potez 42 differed most obviously from the Hanriot and the Guillemin in having a low wing. This assisted take-off and landing performance, important for short, rough strip operation but required the patient's compartment to be well behind the centre of gravity for easy access, making trimming more difficult. The cantilever wing was in three parts, with a short (3.0 m (120 in)) centre-section and long outer panels. Strongly straight tapered in plan, though with very little sweep on the leading edge, it had a high aspect ratio (8.2); the tips were semi-elliptical. High aspect ratio ailerons occupied about half the span. The wings were built around two spruce spars. [1]

Cantilever beam anchored at only one end

A cantilever is a rigid structural element, such as a beam or a plate, anchored at one end to a support from which it protrudes; this connection could also be perpendicular to a flat, vertical surface such as a wall. Cantilevers can also be constructed with trusses or slabs. When subjected to a structural load, the cantilever carries the load to the support where it is forced against by a moment and shear stress.

Leading edge

The leading edge is the part of the wing that first contacts the air; alternatively it is the foremost edge of an airfoil section. The first is an aerodynamic definition, the second a structural one. As an example of the distinction, during a tailslide, from an aerodynamic point of view, the trailing edge becomes the leading edge and vice versa but from a structural point of view the leading edge remains unchanged.

Aspect ratio (aeronautics) ratio of an aircrafts wing span to its mean chord

In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low aspect ratio.

The Potez 42's fuselage, like the wings built of wood, was constructed around a frame based on four longerons and was flat-sided apart from light, rounded upper decking. It was covered in plywood. The 89 kW (120 hp) Salmson 9Ac nine-cylinder radial engine appears uncowled in photographs though early diagrams include a narrow chord Townend ring. Its pilot was in an open cockpit over the wing, with a port side door. His equipment included eight weighted messages, six droppable rockets and a pistol. The patient's compartment was behind the cockpit, under a one-piece, easily removable fairing which was provided with a forward window on each side and rear air vents. The patient was lowered into the aircraft on his stretcher which was guided by rails into four elastic supports. A strap secured him and there was an electrical heater. [1]

Fuselage aircraft main body which is the primary carrier of crew, passengers, and payload

The fuselage is an aircraft's main body section. It holds crew, passengers, and cargo. In single-engine aircraft it will usually contain an engine, as well, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage, which in turn is used as a floating hull. The fuselage also serves to position control and stabilization surfaces in specific relationships to lifting surfaces, which is required for aircraft stability and maneuverability.

Longeron

In engineering, a longeron is a load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural frameworks.

Plywood manufactured wood panel made from thin sheets of wood veneer

Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured boards which includes medium-density fibreboard (MDF) and particle board (chipboard).

The fin had a cropped triangular profile and the tailplane was mounted well forward on it, just above the fuselage to which it was braced from below on each side with a single strut. Its balanced rudder was full, prominent and extended down to the keel and the inset, unbalanced elevators were on forward swept hinges so that the overall horizontal tail was strongly tapered in plan. [1]

Fin flight control surface

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. Fins are also used to increase surface areas for heat transfer purposes, or simply as ornamentation.

Tailplane 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 gyroplanes

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 gyroplanes. Not all fixed-wing aircraft have tailplanes. Canards, tailless and flying wing aircraft have no separate tailplane, while in V-tail aircraft the vertical stabiliser, rudder, and the tail-plane and elevator are combined to form two diagonal surfaces in a V layout.

Strut structural component designed to resist longitudinal compression

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.

The Potez 42 had fixed, tailwheel landing gear with a track of 2.86 m (113 in). Each mainwheel was on a bent axle and a drag strut, both hinged on the lower fuselage longeron and with a vertical, stacked rubber ring shock absorber strut of Potez design to the centre-section forward spar. The wheels had differential brakes for steering, aided by a small, elastically mounted castoring tailwheel. [1]

Landing gear aircraft part which supports the aircraft while not in the air

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

Shock absorber mechanical or hydraulic device designed to absorb, smooth out or damp any sudden shock impulse and dissipate kinetic energy (typically heat); usually consists of a combination of a spring and a dashpot; most shock absorbers are a form of dashpot

A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy which is then dissipated. Most shock absorbers are a form of dashpot.

Caster type of wheel mounted on the bottom of an object

A caster is a wheeled device typically mounted to a larger object that enables relatively easy rolling movement of the object. Casters are essentially housings, that include a wheel and a mounting to install the caster to objects. Casters are found virtually everywhere, from office desk chairs to shipyards, and from hospital beds to automotive factories. They range in size from the very small furniture casters to massive industrial casters, and individual load capacities span 100 pounds (45 kg) or less to 100,000 pounds (45 t). Wheel materials include cast iron, plastic, rubber, polyurethane, polyolefin, nylon, thermoplastic rubber, forged steel, stainless steel, aluminum, and more.

Development

The Potez 42's first flights were made in the first week of August 1930. Potez's chief test pilot Labouchière found its initial handling satisfactory. [2] Like the Guillemin JG.40, it was on display at the 12th Paris Salon in December 1930. [3]

By late January 1931 the Potez 42 had already made several evaluation flights at Villacoublay. [1] In July 1931 Les Amis de l'aviation sanitaire (Friends of Medical Aviation) organised a large meeting on the subject spread over several days, one of which was used for demonstration flights undertaken by nine different types of aircraft. The Potez 42, a Guillemin JG.40 and a Lorraine-Hanriot LH.21S formed the single patient group. [4] By September it was back at Villacoublay, undergoing extensive static tests. [5]

The Potez 42 did not receive a government order so only one example was built. [6] The small air-ambulance role was filled by the later and more powerful Bloch MB.81. [7]


Specifications

Data from Les Ailes January 1931 [1]

General characteristics

Performance

  • Maximum speed: 185 km/h (115 mph; 100 kn)
  • Service ceiling: 5,000 m (16,000 ft) absolute

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References

  1. 1 2 3 4 5 6 7 Frachet, André (22 January 1931). "Le monoplan Henry Potez, type 42". Les Ailes (501): 3.
  2. "D'aérodrome en aérodrome - à Meaulte". Les Ailes (477): 13. 7 August 1930.
  3. "Le Salon de l'aéronautique". Les Ailes (493): 11. 27 November 1930.
  4. "Les Onze Voeux de l'Aviation Sanitaire". Les Ailes (535): 7. 17 September 1931.
  5. "D'aérodrome en aérodrome - à Meaulte". Les Ailes (541): 12. 29 October 1931.
  6. Bruno Parmentier (17 November 2005). "Potez 42" . Retrieved 8 October 2016.
  7. Bruno Parmentier. "Bloch MB-81" . Retrieved 3 October 2016.