The Payen Arbalète ( en, Crossbow) was a small,

pusher configuration In an aircraft with a pusher configuration (as opposed to a tractor configuration), the propeller(s) are mounted behind their respective engine(s). Since a pusher propeller is mounted behind the engine, the drive shaft is in compression in nor ...

experimental An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when ...

French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

tailless aircraft In aeronautics, a tailless aircraft is an aircraft with no other horizontal aerodynamic surface besides its main wing. It may still have a fuselage, vertical tail fin (vertical stabilizer), and/or vertical rudder. Theoretical advantages of the ...

, designed by

Nicolas Roland Payen Nicolas Roland Payen (2 February 1914 in Athis-Mons, France – 8 December 2004) was a French aeronautical engineer Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two ...

, and first flown in 1965.

Design and development

Though there were significant changes during its development, the Arbalète's basic, unusual configuration remained unaltered. It was a

low 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 ...

cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...

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 confi ...

resembling a cropped double delta in plan, with a short

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 ...

ending at the pusher engine and

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

. The centre section of the wing was strongly swept and of very broad chord, extending from the engine to the cockpit. Swept

fins 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 ...

were placed at the outer end of the centre section and beyond them the wings were much less strongly swept, with blunt tips. The Arbalète had a fixed

tricycle undercarriage Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', arranged in a tricycle fashion. The tricycle arrangement has a single nose wheel in the front, and two or more main wheels slightly aft of the center of gravity. Tricycle ge ...

. The first version of the Arbalète was the Pa.60 which made its first flight on 5 June 1965. It was powered by a

Hirth HM 504 The Hirth HM 504 is a four-cylinder air-cooled inverted inline engine. The HM 504 was a popular engine for light aircraft of the 1930s-1940s, and it was used to power a number of Germany's trainer aircraft of World War II. The engine featured a ...

air-cooled, four cylinder, inverted inline engine, which was totally enclosed within the flat sided fuselage with no side-scoops for cooling air, an arrangement which led to overheating. Its swept, straight edged fins were placed with their leading edges on the wing leading edges; they extended beyond the wing

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, 1997. ...

via rounded tips to

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

s with swept, curved trailing edges and

trim tabs Trim tabs are small surfaces connected to the trailing edge of a larger control surface on a boat or aircraft, used to control the trim of the controls, i.e. to counteract hydro- or aerodynamic forces and stabilise the boat or aircraft in a pa ...

. The two side-by-side seats were enclosed by a long, wide two piece

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

. The main undercarriage legs of the Pa.60 Arbalète were located near the wing leading edge, immediately under the fins. After the cooling problems and some issues concerning the undercarriage had been resolved, the same aircraft flew as the Pa.61B Arbalète but proved to be underpowered with the Hirth engine. As a result, a new machine, the Pa.61F Arbalète II, was built, powered by a

Lycoming O-360 The Lycoming O-360 is a family of four-cylinder, direct-drive, horizontally opposed, air-cooled, piston aircraft engines. Engines in the O-360 series produce between 145 and 225 horsepower (109 to 168 kW), with the basic O-360 produc ...

air-cooled

flat-four engine A flat-four engine, also known as a horizontally opposed-four engine, is a four-cylinder piston engine with two banks of cylinders lying on opposite sides of a common crankshaft. The most common type of flat-four engine is the boxer-four engine, ...

with side air intakes on the

semi-monocoque The term semi-monocoque or semimonocoque refers to a stressed shell structure that is similar to a true monocoque, but which derives at least some of its strength from conventional reinforcement. Semi-monocoque construction is used for, among ot ...

, circular cross-section fuselage. The Arbalète II's cockpit was large enough to hold three. The mid-span fins were different, slightly straight tapered, mounted on the trailing edge and extending below it. Below the rudders they carried airbrakes. The slight sweep on the centre wing section trailing edge has led to a description of the wing plan as "

crescent A crescent shape (, ) is a symbol or emblem used to represent the lunar phase in the first quarter (the "sickle moon"), or by extension a symbol representing the Moon itself. In Hinduism, Lord Shiva is often shown wearing a crescent moon on his ...

" rather than delta. A narrow continuation of the leading edge of the wing to the nose formed strakes on each side. There were control surfaces on the trailing edges both within and beyond the fins. The Arbalète II's main undercarriage legs were moved inboard, mounted on the wing but close to the fuselage. The Arbalète II flew for the first time on 5 August 1970. The flight was satisfactory up to an over fast landing, when it was damaged. It was rebuilt but its subsequent history is obscure. Several proposed developments were abandoned.

Variants

;Pa.60 Arbalète:

engine. ;Pa.61B Arbalète: Improved engine cooling and landing gear. ;Pa.61F Arbalète II:

engine. Other changes described above. ;Pa.61G Arbalète II: Proposed version, similar to Pa.61F but with retractable foreplanes instead of rudder airbrakes and forward fuselage strakes. ;Pa.61H Arbalète II: Proposed twin

Turbomeca Palas The Turbomeca Palas is a diminutive centrifugal flow turbojet engine used to power light aircraft. An enlargement of the Turbomeca Piméné, the Palas was designed in 1950 by the French manufacturer Société Turbomeca,Gunston 1989, p. 169. a ...

turbojet version, otherwise like Pa.61F but without strakes. ;Pa.610 Arbalète III: Proposed four seat version with retractable gear and engine.

Specifications (Pa.61F Arbalète II)

References

Bibliography

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External links

Photo of the Payen PA-61 Arbalète
{{DEFAULTSORT:Payen Arbalete Payen aircraft 1960s French experimental aircraft Tailless aircraft Single-engined pusher aircraft Aircraft first flown in 1965