The Caudron C.91 was a French single engine

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

with an enclosed passenger cabin seating four. It first flew in 1923.

Design and development

The C.91 was a conventional single engine two bay biplane with a wooden structure and fabric covering. The bays were defined by pairs of parallel

interplane strut In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of struts, which act in ...

s; similar but shorter pairs of

cabane struts In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of struts, which act in ...

ran from the upper

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

to the upper wing centre section. In plan its wings were rectangular, with

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 aroun ...

s only on the upper wing. For its first flights, made in late 1923, the C.91 was powered by a

Renault 12Fe The Renault 12Fe, or 300 CV, is a water-cooled V12 aero engine. The 12Fe was the most produced Renault aircraft engine and powered many French aircraft during World War I and the 1920s. The 12Fe engines were the result of incremental improvemen ...

water-cooled upright

V-12 engine A V12 engine is a twelve-cylinder piston engine where two banks of six cylinders are arranged in a V configuration around a common crankshaft. V12 engines are more common than V10 engines. However, they are less common than V8 engines. The f ...

with a rectangular

radiator A radiator is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

in the extreme nose behind the

propeller A propeller (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 a working flu ...

, enclosed in a flat sided, slotted

cowling A cowling (or cowl) 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 ...

. The rest of the fuselage was also flat sided. The pilot had an open

cockpit A cockpit or flight deck is the area, on the front part of an aircraft, spacecraft, or submersible, from which a pilot controls the vehicle. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls th ...

under the wing and behind him the four passengers sat in an enclosed cabin with four windows. Passenger comfort was a priority and up to of baggage could be placed in the hold. At the rear the

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. F ...

was triangular and broad, carrying a

balanced rudder Balanced rudders are used by both ships and aircraft. Both may indicate a portion of the rudder surface ahead of the hinge, placed to lower the control loads needed to turn the rudder. For aircraft the method can also be applied to elevator (air ...

which extended down to the keel.

Tailplane A tailplane, also known as a horizontal stabilizer, is a small lift (force), 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

elevator An elevator (American English) or lift (Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems suc ...

s were mounted on top of the fuselage. The C.91 had a

tailwheel undercarriage Conventional landing gear, or tailwheel-type landing gear, is an aircraft Landing gear, undercarriage consisting of two main wheels forward of the Center of gravity of an aircraft, center of gravity and a small wheel or skid to support the tail ...

with its mainwheels on a single axle longer than the fuselage width, sprung to a pair of V-struts to the lower fuselage longerons. Rather little is known about the C.91's activities but it did compete in the 1925 Coupe d'Aviation Zenith (Zenith Aviation Cup), awarded for fuel-economical load carrying. It was held in early July 1925, by which time the Renault engine had been replaced with a more powerful

Lorraine 12D The Lorraine 12D, also referred to as Lorraine-Dietrich 12D, was a series of water-cooled V12 engines produced by the French company Lorraine-Dietrich. The first variant began production in 1917, and the engines were used to power bombers for the ...

water-cooled V-12. Bad weather kept most of the competitors, including Bechelet's C.91, grounded and the event was rerun in 1926.

Specifications

References

{{Caudron aircraft C.091 1920s French airliners Biplanes Single-engined tractor aircraft