The Dewoitine D.15 was a single-engine, single-seat

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 ...

fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

built in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

in the 1920s. Intended to offer structural simplifications when compared with

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 ...

s, it had a disappointing performance and was soon abandoned.

Design and development

In a long series of single-engine fighters built by Dewoitine from the D.1 of 1922 to the 1940 D.521, the Dewoitine D.15 was the only biplane. An attempt to design a competitive but structurally less complicated machine, it was a

single bay 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 ...

biplane with wings of unequal span mounted without stagger, braced by pairs of outward sloping parallel interplane struts, cross wire bracing and N form

cabane 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 strut, which act in ...

s. Ailerons were fitted only on the longer, upper wing. In plan the unswept wings had constant

chord Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...

and straight edges, ending in angled tips. They were metal structures, entirely fabric covered. The D.15's

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 gyroplane ...

, mounted on top of the

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 similar in plan and structure to the wing. 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. Fin ...

and

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 ...

were triangular; the latter, mounted on a rudder post only just ahead of the tailplane trailing edge, extended down to the keel. The D.15's flat-sided fuselage had steel

longeron In engineering, a longeron and stringer is the 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 ...

s and Duralumin tube cross members; the sides were fabric covered but the curved ventral and dorsal decking was metal. The front of its single seat open cockpit was at the wing trailing edge, though there was a small wing cut-out to assist his forward and upper vision. The fighter was powered by an upright

Hispano-Suiza 12H Hispano-Suiza () is a Spanish automotive–engineering company. It was founded in 1904 by Marc Birkigt and Damian Mateu as an automobile manufacturer and eventually had several factories in Spain and France that produced luxury cars, aircraft en ...

a liquid-cooled

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 fir ...

, driving a two-blade

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 ...

. It had a fixed

conventional undercarriage Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Term ...

with a single axle enclosed within a wing-like fairing which was mounted on to the fuselage with forward, near vertical shock absorbing legs, torsionally strengthened by sloping, rearward struts. There was a tailskid. Two synchronised

Vickers machine gun The Vickers machine gun or Vickers gun is a Water cooling, water-cooled .303 British (7.7 mm) machine gun produced by Vickers Limited, originally for the British Army. The gun was operated by a three-man crew but typically required more me ...

s mounted on the fuselage fired through the propeller arc and two Darne machine guns were placed on the upper wing centre-section, firing over the propeller. The D.15 first flew on 13 August 1924 and demonstrated a lack of both lateral ( yaw) and longitudinal ( pitch) stability. After modification it went for tests at Villacoublay with the Commission des Essais Pratiques de l'Aviation (Commission for Trials of Aircraft Practices) for tests. These showed that the D.15 had a poorer performance than the Dewoitine D.19, a

parasol-wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplane (aeronautics), multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowe ...

aircraft, despite the latter's lower power. Accordingly, the D.19 was not submitted to the Service Technique de l'Aéronautique (Technical Section of Aeronautics) 1923 fighter programme's tests, held in 1925–26.

Specifications

References

{{Dewoitine aircraft Single-engined tractor aircraft Biplanes 1920s French fighter aircraft D.15 Aircraft first flown in 1924