Biplane

A biplane is a fixed-wing aircraft with two main wings of similar spans, normally one mounted above, and the other level with, the underside of the fuselage. The upper wing normally overlaps the lower wing, and vertical or slightly raked slender struts are often positioned symmetrically on either side of the fuselage (connecting the rigid sections of the upper and lower wings into a stong box structure). When the upper and lower wing overlap only partially, this is known as stagger; it is designed to minimise aerodynamic interference between the two wings. Forward stagger (where the upper wing is further forward) is most common, but backward stagger has also been used, notably in Beechcraft Staggerwing.

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Aircraft built with two main wings (or three in a triplane) can usually lift more than can a similarly sized monoplane of similar wing-span, but most biplanes also have a third horizontal surface, either a tailplane or a foreplane, to control the pitch, or angle of attack of the aircraft. Either or both of the main wings can support flaps or ailerons to assist lateral and speed control.

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Biplanes were most successfully marketed in the early days of aviation when the wing sections used were very thin and consequently the wing structure needed to be strengthened by external bracing wires. The biplane configuration allowed the two wings to be braced against one another, increasing the structural strength. Another advantage was the more compact layout with a shorter wing span, which led to greater maneuverability. The big disadvantage of the biplane layout was that the two wings interfered with one another aerodynamically, each reducing the lift produced by the other. This meant that for a given wing area the biplane produced more drag and less lift than a monoplane. Once thicker wing sections and improved structural materials were introduced, removing the need for external bracing, monoplanes quickly superceded biplanes in aviation. Modern biplane designs now exist only in specialist niche roles and markets such as aerobatics and agricultural aircraft.

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A variation on the biplane was the sesquiplane, where the (usually) lower wing was significantly smaller than the other, either in span, chord, or both. On occasion, the lower wing was only large enough to support the bracing struts for the upper wing. The name means "one-and-a-half wings".

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Famous biplanes include the Avro Tutor, Antonov An-2, Beechcraft Staggerwing, Boeing Stearman, Bristol Bulldog, de Havilland Tiger Moth, Fairey Swordfish, Hawker Hart, Pitts Special and the Wright Flyer. The Stearman is particularly associated with stunt flying with wing-walkers. Famous sesquiplanes include the Nieuport 17 and Albatros D.III. The vast majority of biplane designs have been fitted with reciprocating engines of comparatively low power; exceptions include the Antonov An-3 and WSK-Mielec M-15 Belphegor, fitted with turboprop and turbofan engines, respectively. Some older biplane designs, such as the Grumman Ag Cat and the aforementioned An-2(in the form of the An-3) are available in upgraded versions with turboprop engines.

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Fixed-wing aircraft: Fixed-wing aircraft is a term used to refer to what are more commonly known as aeroplanes in Commonwealth English (excluding Canada) or airplanes in North American English. This term can refer to a large range of craft designed for many purposes, ranging from large commercial aircraft, known as airl...

Beechcraft Staggerwing: The Beechcraft Staggerwing is a biplane with, unusually, a backward stagger (the lower wing is further forward than the upper wing). It was the first aircraft built by the newly-formed Beech Aircraft Corporation. The company was founded in 1932, and the original Staggerwing Model 17R first flew on...

Triplane: A triplane is a fixed-wing aircraft equipped with three sets of wings, each roughly the same size and mounted one above the other. Typically, the lower set of wings would be level with the underside of the aircraft's fuselage, the middle set level with the top of the fuselage, and the top set suppor...

Biplane related Images and Photos (experimental)

Bi-Plane	Biplane Detail	Biplane Over the Coastline	Biplane Over the Coastline
The Wright Biplane 1903	Unidentified German Biplane Two-Seater with "Pusher" Engine	German Ago Biplane Over the Coast	Royal Air Force Biplane Climbing as It Takes Off
Wilbur Wright Aviation Biplane	King Kong: Kong Attacks a Biplane from the WB Photo Collection	"Good Visibility!" an American Two-Seater Biplane Flies Over a Town	French Aviator Lieutenant Collot Successfully Flies His Biplane Beneath the Tour Eiffel