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A variable-incidence wing has an adjustable angle of incidence relative to its fuselage. This allows the wing to operate at a high angle of attack for take-off and landing while allowing the fuselage to remain close to horizontal. [1]
The pivot mechanism adds extra weight over a conventional wing and increases costs, but in some applications the benefits can outweigh the costs.
Several examples have flown, with one, the F-8 Crusader carrier-borne jet fighter, entering production.
Some early aeroplanes had wings which could be varied in incidence for control and trim, in place of conventional elevator control surfaces. Wing warping varied the incidence of the outer wing and was used by several pioneers, including initially the Wright brothers.
Early examples of rigid variable-incidence wings were not particularly successful. They include the Mulliner Knyplane in 1911, the Ratmanoff monoplane in 1913 and the Pasul Schmidt biplane, also in 1913. [2] A patent for a rigid variable-incidence wing was lodged in France on 20 May 1912 by Bulgarian inventor George Boginoff. [3] It is believed that four unsuccessful Russian types were built between 1916 and 1917. [4] The Zerbe Air Sedan was a tandem quadruplane which flew only once, in 1921.
The first example to be made in any quantity was the French tandem-wing Mignet Pou du Ciel (Flying Flea), which became briefly popular during the 1930s. It had a variable-incidence forewing which proved unsafe, and sales were discontinued following a series of fatal crashes.
During World War II, the German company Blohm & Voss developed the variable-incidence monoplane to provide increased lift at takeoff, where the rear fuselage was too close to the ground to allow rotation of the whole aircraft. [5] The fuselage of the BV 144 prototype transport sat low on a short undercarriage, allowing passengers to go on and off without the need for additional steps. Another proposal by B&V, the P 193 attack aircraft, was of pusher configuration and could not rotate its fuselage for takeoff without the propeller fouling the ground, so it was given a variable-incidence wing. [6] Russian designer S. G. Kozlov designed the E1 variable-incidence fighter, but the unfinished prototype was destroyed when the factory was overrun by Germany in 1941. [4]
Carrier-borne aircraft must have good forward visibility during the descent and approach for a deck landing. Without a variable-incidence wing (or other high-lift device), the pilot must pitch up the entire aircraft to maintain lift at the slow approach speed required, and this can restrict forward vision. By increasing the incidence of the wing but not the fuselage, both high lift and good forward vision can be maintained. The device also avoids the need for a long, bulky and heavy nose undercarriage to raise the angle of attack at takeoff. The Supermarine Type 322 prototype flew in 1943, and the Seagull ASR.1 amphibian flying boat in 1948. [2]
After the war the USA revisited the idea for the jet age. The Martin XB-51 bomber and the Republic XF-91 interceptor adopted variable incidence for much the same reason as B&V. Both first flew in 1949, but only a handful of prototypes of either was built. They were followed in 1955 by the Vought F-8 Crusader carrier-borne jet fighter, the only variable-incidence type to go into production and enjoy a successful service career.
A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-wing aircraft and other hybrid aircraft with powered rotors such as cyclogyros/cyclocopters and gyrodynes.
The Blohm & Voss BV 155 is a German high-altitude interceptor aircraft intended to be used by the Luftwaffe against raids by USAAF Boeing B-29 Superfortresses. Work started on the design as the Messerschmitt Me 155 in 1942, but the project went through a protracted development period and change of ownership, and prototypes were still under test and development when World War II ended.
Hamburger Flugzeugbau (HFB) was an aircraft manufacturer, located primarily in the Finkenwerder quarter of Hamburg, Germany. Established in 1933 as an offshoot of Blohm & Voss shipbuilders, it later became an operating division within its parent company and was known as Abteilung Flugzeugbau der Schiffswerft Blohm & Voss from 1937 until it ceased operation at the end of World War II. In the postwar period it was revived as an independent company under its original name and subsequently joined several consortia before being merged to form Messerschmitt-Bölkow-Blohm (MBB). It participates in the present day Airbus and European aerospace programs.
The Blohm & Voss BV 40 was a prototype armoured German glider initially designed in mid-1943 by Blohm & Voss to attack Allied bomber formations during World War II. The BV 40 would be towed to high altitude by single-engined fighters and then ram the bombers while in a dive, but this concept was rejected before its first flight in May 1944 in favour of using its guns. The Luftwaffe had lost interest in the BV 40's original mission the month prior; development continued as its mission changed to attacking ships with specialized bombs. Blohm & Voss discovered that the prototypes were significantly overweight, and some of the armour and one gun had to be removed to conduct flight testing. The BV 40 was cancelled in August with only 6 gliders completed out of the 21 ordered. All of the aircraft were destroyed in an air raid in October.
A tandem wing is a wing configuration in which a flying craft or animal has two or more sets of wings set one behind another. All the wings contribute to lift.
The Blohm & Voss Ha 142 was a four-engined long-distance monoplane designed and built by the German aircraft manufacturer Blohm & Voss.
The Blohm & Voss BV 144 was an advanced twin-engined commercial airliner developed by Germany during World War II but intended for post-war service. It was unusual in having a variable-incidence wing. Two prototypes were built by Breguet in France.
The Supermarine Type 322 was a prototype British carrier-borne torpedo, dive bomber and reconnaissance aircraft of the Second World War. A single-engined monoplane, it was unsuccessful, with only two examples being built. The Fairey Barracuda, built to the same specification, would fill this role.
In aeronautics, a tailless aircraft is a fixed-wing aircraft with no other horizontal aerodynamic surface besides its main wing. It may still have a fuselage, vertical tail fin, and/or vertical rudder.
Richard Vogt was a military German aircraft designer who was known for his original airframes, including the asymmetrical BV 141 during World War II. After the war, he moved to the United States as part of Operation Paperclip, where he worked on American military aircraft design.
The wing configuration or planform of a fixed-wing aircraft is its arrangement of lifting and related surfaces.
A composite aircraft is made up of multiple component craft. It takes off and flies initially as a single aircraft, with the components able to separate in flight and continue as independent aircraft. Typically the larger aircraft acts as a carrier aircraft or mother ship, with the smaller sometimes called a parasite or jockey craft.
Asymmetrical aircraft have left- and right-hand sides which are not exact mirror images of each other. Although most aircraft are symmetrical, there is no fundamental reason why they must be, and design goals can sometimes be best achieved with an asymmetrical aircraft.
The Supermarine Type 525 was a British prototype naval jet fighter aircraft of the 1950s.
The Hamburger Flugzeugbau Ha 136 was an all-metal, single-seat training monoplane. It was the first design for the company by Dr. Richard Vogt and the first to feature his trademark tubular steel wing spar which doubled as the main fuel tank. Two prototypes were built but it was not ordered into production.
The Blohm & Voss Bv P 188 was a long-range, heavy jet bomber design project by the Blohm & Voss aircraft manufacturing division during the last years of the Third Reich. It featured a novel W-wing planform with variable incidence.
The Blohm & Voss P215 was an advanced jet night fighter project by Blohm & Voss during the Second World War. With a crew of three and twin jet engines, it featured a tailless swept-wing layout and heavy armament. An order for three prototypes was received just weeks before the war ended.
The Blohm & Voss P.202 was an unusual design study for a variable-geometry jet fighter during World War II. It was the first design to incorporate a slewed wing in which one side swept forward and the other back. The P.202 was never built or flown.
The Blohm & Voss P 193 was a design study for a dive bomber/ground attack aircraft intended to replace the Junkers Ju 87.