The Caudron C.860 was a single engine, single seat

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 ...

ordered by the French government as a long distance communications aircraft. First flown in 1938, it was also expected to set speed and altitude records but the outbreak of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

ended developments.

Design

The C.860 was ordered by the French Air Ministry who planned to use it, piloted by André Japy, for rapid long distance communications. Powered by a

Renault 6Q-03 The Renault 6Q, also called the Renault Bengali 6, is an air-cooled six-cylinder, inverted piston engine, producing about continuous power. It was designed and built in France and produced for more than ten years after its homologation in 19 ...

engine, it had a range of up to when cruising at . It was also expected to set distance and altitude records in Category 1 with a Renault engine and in Category 2 with a Renault, but war intervened. Its wing and

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...

were aerodynamically similar to those of the

Caudron Simoun The Caudron Simoun was a 1930s French four-seat touring monoplane. It was used as a mail plane by Air Bleu, flew record-setting long-range flights, and was also used as a liaison aircraft by the ''Armée de l'Air'' during World War II. The airc ...

, though the single-piece wing was structurally closer to that of the record-setting

Rafale The Dassault Rafale (, literally meaning "gust of wind", and "burst of fire" in a more military sense) is a French twin-engine, canard delta wing, multirole fighter aircraft designed and built by Dassault Aviation. Equipped with a wide ran ...

racer. The wing was

tetragonal In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square ...

in plan, with more sweep on 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, 1997. ...

than on the

leading edge The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...

, though the tips were semi-elliptical. It had an all-wood structure with a single box spar which incorporated an upper flange of

gumbo-limbo ''Bursera simaruba'', commonly known as gumbo-limbo, copperwood, chaca, West Indian birch, naked Indian, and turpentine tree, is a tree species in the family Burseraceae, native to the Neotropics, from South Florida to Mexico and the Caribbean t ...

, a

Central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

and

South American South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

wood of particularly high

bulk modulus The bulk modulus (K or B) of a substance is a measure of how resistant to compression the substance is. It is defined as the ratio of the infinitesimal pressure increase to the resulting ''relative'' decrease of the volume. Other moduli describe ...

, together with

spruce A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

and

plywood 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 ...

rib In vertebrate anatomy, ribs ( la, costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the ches ...

s. The ply skin was finished with a fabric overlay. Its

aileron 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 ...

s were carried on auxiliary spars. The C.860's

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 ...

was slender, with a maximum width of only and about one third of it ahead of the wing

. Its air-cooled six-cylinder

inverted in-line engine,

supercharged In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a supercharger is a form of forced induct ...

to , was in the nose with its main and collector fuel tanks behind it over the

centre of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...

. Together with four smaller wing tanks, these gave a fuel capacity of . The pilot had an enclosed

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

with his head raised only slightly above the fuselage under a shallow

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 ...

with a horizontal strip of

plexiglas Poly(methyl methacrylate) (PMMA) belongs to a group of materials called engineering plastics. It is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Plexiglas, Acrylite, ...

for forwards and sideways vision, a solid top and an extended fairing aft. There were also windows in the fuselage sides for downward views. The fuselage had a wooden frame with canvas covered sides and curved magnesium sheet top and bottom. The

of the C.860 was conventional, with a straight-tapered, blunt-tipped horizontal tail carrying separate

elevator An elevator or lift is a wire rope, cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or deck (building), decks of a building, watercraft, ...

s. The tall vertical tail had a similar shape though, unlike the elevators, the

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 ...

was

balanced In telecommunications and professional audio, a balanced line or balanced signal pair is a circuit consisting of two conductors of the same type, both of which have equal impedances along their lengths and equal impedances to ground and to other ...

. The aircraft had a fixed, tailwheel

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

with a track. Messier

oleo strut An oleo strut is a pneumatic air–oil hydraulic shock absorber used on the landing gear of most large aircraft and many smaller ones. This design cushions the impacts of landing and damps out vertical oscillations. It is undesirable for an airp ...

landing legs were mounted on the wing spar. Legs, mainwheels and the steerable tailwheel, also on an oleo strut, were enclosed in fairings.

Development

By 5 September 1938 the C.860 had been brought, still not quite complete, from the Caudron factory at

Issy-les-Moulineaux Issy-les-Moulineaux () is a commune in the southwestern suburban area of Paris, France, lying on the left bank of the river Seine. Its citizens are called ''Isséens'' in French. It is one of Paris' entrances and is located from Notre-Dame Cath ...

to the airfield at

Guyancourt Guyancourt () is a commune in the Yvelines department in the Île-de-France region in north-central France. It is located in the south-western suburbs of Paris, from the center of Paris, in the "new town" of Saint-Quentin-en-Yvelines. Geography ...

. The first flight had been made, piloted by Delmotte, by 10 September. Its initial tests had been completed by the end of September, when the C.860 entered the Centre d'Essais de Matériels Aériens (CEMA), the French official testing centre at Villacoublay. These tests temporarily finished at the beginning of January 1939 but the C.860 returned to CEMA at the end of the month. With certification complete, the Air Ministry took the C.860 to

Istres Istres (; Occitan: Istre) is a commune in southern France, some 60 km (38 mi) northwest of Marseille. It is in the Provence-Alpes-Côte d'Azur region, in the Bouches-du-Rhône department, of which it is a subprefecture. Location Istr ...

to determine the take-off run required with the heavy fuel load needed to achieve the desired long range. A 24.5 hour flight at , covering , consumed of petrol and of oil. The resulting take-off weight of , required a take-off run of , well within the Air Ministry's specification limit.

Specifications

References

{{Caudron aircraft 1930s French civil aircraft C. Aircraft first flown in 1938