The SET 2 or Proto-SET 2 was a 1920s

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, and ...

n prototype

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmisher ...

and day-

bomber aircraft A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped from an airc ...

Design and development

The SET 2, Lieutenant-Colonel Stefan Protopopescu's design for a reconnaissance and bomber aircraft, owed a good deal to the Astra-Protopopescu reconnaissance machine that he designed about two years earlier. A contraction of his name to Proto often appeared in variations of the new type's name. This was more powerful, over 25% greater in span and differed in many details, but shared the same layout and some features like the tail and the wing bracing were very similar. It was a wood-framed aircraft and only used locally resourced timber. The SET 2 was a single bay biplane with fabric covered, two

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

wings of equal span and rectangular plan, though the corners were blunted. Mounted with almost no stagger (a horizontal displacement of just ), the wings were braced together by a pair of vertical

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 strut, which act in ...

s on each side, assisted by bracing wires. The lower wings, which unlike the upper one carried considerable dihedral, were attached to the lower fuselage longerons and the upper one was held high above 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 aircraf ...

by two parallel sets of transverse W-form cabane struts. Ailerons, which reached the wing tips, were placed on the upper wing alone. It had a nose-mounted, Lorraine 12E Courlis

W-12 engine A W12 engine is a twelve-cylinder piston engine where three banks of four cylinders are arranged in a W configuration around a common crankshaft. W12 engines with three banks of four cylinders were used by several aircraft engines from 1917 unt ...

water-cooled with a honeycomb radiator and a Lamblin oil cooler on the fuselage underside. The forward fuselage was

ash Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...

framed, changing to

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...

aft. In the engine area it was covered with aluminium, the central part was fabric covered and the rear plywood skinned. The upper fuselage had a light, rounded wooden decking. There were two,

tandem Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction. The original use of the term in English was in ''tandem harness'', which is used for two ...

, open cockpits close to each other, with the forward one, from which it was flown, between the trailing edges. The upper edge had a rounded, almost semicircular cut out to improve the pilot's upward view and the lower edges had quadrantal cut-outs at the roots for downward vision. The rear cockpit had provision for a

machine gun A machine gun is a fully automatic, rifled autoloading firearm designed for sustained direct fire with rifle cartridges. Other automatic firearms such as automatic shotguns and automatic rifles (including assault rifles and battle rifles) ar ...

mounting. The fuselage tapered aft to conventional, unbalanced tail surfaces with a continuously curved

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 gyropla ...

and

elevator An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They a ...

s positioned near the top of the fuselage. 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 air or water). On an aircraft the rudder is used primarily to counter adve ...

were also smoothly curved together; the latter extended to the keel and worked in a rounded elevator cut-out. The SET 2 had a conventional, fixed tailskid undercarriage. A short V-form

strut 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. Human anatomy Part of the functionality o ...

was attached to each lower fuselage longeron, joined by a cross-piece at their apexes, above which a single axle bearing the main wheels was rubber sprung. The wooden tailskid was also rubber sprung.

Operational history

The exact date of the SET 2's first flight is not known but the 2 February 1927 Les Ailes article notes that it had started tests "recently". The number built apart from the prototype is also uncertain but here is no known record of production or service. Despite promising early test results, development of the SET-2 was abandoned after an in-flight fire and forced landing during flight-testing.

Specifications

References

{{SET aircraft S02 1920s Romanian military aircraft