biplane

A biplane is a fixed-wing aircraft configuration in which two main wings are stacked one above the other. The two wings are usually connected by interplane struts and wires, forming a rigid airframe that provides substantial lift at relatively low speeds. This arrangement allows a large total wing area without requiring a very long wingspan, which was advantageous for early aircraft needing short takeoff distances and rugged ground handling.

Construction and design features vary, but most historical biplanes used wood-and-fabric structures, with wings and fuselage covered in fabric and framed by wood spars and ribs. Later models employed metal frames and metal-covered wings. Control surfaces such as ailerons and elevators are typically mounted on one or both wings; in early designs, wing warping was used instead of ailerons. Variants include the sesquiplane, where the lower wing is significantly smaller than the upper, and staggered configurations, where the wings are offset fore or aft.

Performance and role: the two-wing arrangement increases lift and wing stiffness, enabling good low-speed handling and short-field capability. However, the extra wing area creates drag and aerodynamic interference, reducing top speed and overall efficiency at higher speeds. As speeds and aerodynamics advanced, monoplanes generally offered better performance, leading to a decline of the biplane in most military and commercial roles by the mid-20th century. Nevertheless, biplanes remain common in training, aerobatics, vintage aircraft, and some light sport or agricultural applications.

History and examples: biplanes dominated early aviation and were especially prominent in World War I for fighters and reconnaissance aircraft. Notable types include the Sopwith Camel and the Fokker D.VII; the Wright Flyer was an early successful biplane.