A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilever can be formed as a beam , plate, truss , or slab .
46-571: The Fairey Hendon was a British monoplane , heavy bomber of the Royal Air Force , designed by Fairey Aviation , and first flown in 1930. The aircraft served in small numbers with one squadron of the RAF between 1936 and 1939. It was the first all-metal construction low-wing monoplane to enter service with the RAF. The Hendon was built to meet the Air Ministry Specification B.19/27 for
92-538: A cantilever, but the completed structure does not act as a cantilever. This is very helpful when temporary supports, or falsework , cannot be used to support the structure while it is being built (e.g., over a busy roadway or river, or in a deep valley). Therefore, some truss arch bridges (see Navajo Bridge ) are built from each side as cantilevers until the spans reach each other and are then jacked apart to stress them in compression before finally joining. Nearly all cable-stayed bridges are built using cantilevers as this
138-496: A cantilever-winged sesquiplane built instead with wooden materials, the Fokker V.1 . In the cantilever wing, one or more strong beams, called spars , run along the span of the wing. The end fixed rigidly to the central fuselage is known as the root and the far end as the tip. In flight, the wings generate lift and the spars carry this load through to the fuselage. To resist horizontal shear stress from either drag or engine thrust,
184-611: A dozen years after the Wright Brothers ' initial flights, Junkers endeavored to eliminate virtually all major external bracing members in order to decrease airframe drag in flight. The result of this endeavor was the Junkers J 1 pioneering all-metal monoplane of late 1915, designed from the start with all-metal cantilever wing panels. About a year after the initial success of the Junkers J 1, Reinhold Platz of Fokker also achieved success with
230-570: A few specialist types. Jet and rocket engines have even more power and all modern high-speed aircraft, especially supersonic types, have been monoplanes. Cantilever When subjected to a structural load at its far, unsupported end, the cantilever carries the load to the support where it applies a shear stress and a bending moment . Cantilever construction allows overhanging structures without additional support. Cantilevers are widely found in construction, notably in cantilever bridges and balconies (see corbel ). In cantilever bridges,
276-472: A further sixty Hendons were cancelled in 1936, as the prototype of the first of the next generation of British heavy bombers—the Armstrong Whitworth Whitley —had flown and showed much higher performance. The Hendon Mk.II was powered by two Rolls-Royce Kestrel VI engines. The production Hendon Mk.II included an enclosed cockpit for the pilot and navigator. The type was delayed by the crash and
322-608: A light aircraft, the configuration is significant because it offers superior visibility to the pilot. On light aircraft, shoulder-wings tend to be mounted further aft than a high wing, and so may need to be swept forward to maintain correct center of gravity . Examples of light aircraft with shoulder wings include the ARV Super2 , the Bölkow Junior , Saab Safari and the Barber Snark . A high wing has its upper surface on or above
368-407: A pendulous fuselage which requires no wing dihedral for stability; and, by comparison with a low-wing, a shoulder-wing's limited ground effect reduces float on landing. Compared to a low-wing, shoulder-wing and high-wing configurations give increased propeller clearance on multi-engined aircraft. On a large aircraft, there is little practical difference between a shoulder wing and a high wing; but on
414-464: A popular configuration for amphibians and small homebuilt and ultralight aircraft . Although the first successful aircraft were biplanes, the first attempts at heavier-than-air flying machines were monoplanes, and many pioneers continued to develop monoplane designs. For example, the first aeroplane to be put into production was the 1907 Santos-Dumont Demoiselle , while the Blériot XI flew across
460-616: A rebuild of the prototype and the Heyford received the majority of the orders to replace RAF heavy bombers, the Hendon coming into service three years later. The only Hendon-equipped unit, 38 Squadron , began operational service at RAF Mildenhall in November 1936, replacing Heyfords, later moving to RAF Marham , Norfolk . Later, the Hendons went to 115 Squadron , which was formed from 38 Squadron. The type
506-632: A steel tube structure with fabric covering with a pilot, a radio operator/navigator and three gunners, in open nose, dorsal and tail positions. Bombs were carried in ten large and six smaller bomb cells in the fuselage and wing centre section between the engines. Variants powered by either radial engines or liquid-cooled V12 engines were proposed. The prototype K1695 (which was known as the Fairey Night Bomber until 1934) first flew on 25 November 1930, from Fairey's Great West Aerodrome in Heathrow and
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#1733085803961552-547: A twin-engine night bomber to replace the Vickers Virginia , competing against the Handley Page Heyford and Vickers Type 150 . The specification required a range of 920 mi (1,480 km) at a speed of 115 mph (185 km/h), with a bomb load of 1,500 lb (680 kg). To meet this requirement, Fairey designed a low-winged cantilever monoplane with a fixed tailwheel undercarriage . The fuselage had
598-503: A variation in this parameter indicates the concentration of the analyte . Recently, microcantilevers have been fabricated that are porous, allowing for a much larger surface area for analyte to bind to, increasing sensitivity by raising the ratio of the analyte mass to the device mass. Surface stress on microcantilever, due to receptor-target binding, which produces cantilever deflection can be analyzed using optical methods like laser interferometry. Zhao et al., also showed that by changing
644-489: A wing of a given size, the weight reduction allows it to fly slower and with a lower-powered and more economical engine. For this reason, all monoplane wings in the pioneer era were braced and most were up until the early 1930s. However, the exposed struts or wires create additional drag, lowering aerodynamic efficiency and reducing the maximum speed. High-speed and long-range designs tend to be pure cantilevers, while low-speed short-range types are often given bracing. Besides
690-458: A wire-braced design. However, as the speed of the aircraft increases, the drag of the bracing increases sharply, while the wing structure must be strengthened, typically by increasing the strength of the spars and the thickness of the skinning. At speeds of around 200 miles per hour (320 km/h) the drag of the bracing becomes excessive and the wing strong enough to be made a cantilever without excess weight penalty. Increases in engine power through
736-432: 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 configuration and is the simplest to build. However, during the early years of flight, these advantages were offset by its greater weight and lower manoeuvrability, making it relatively rare until
782-455: Is force and w {\displaystyle w} is the cantilever width. The spring constant is related to the cantilever resonance frequency ω 0 {\displaystyle \omega _{0}} by the usual harmonic oscillator formula ω 0 = k / m equivalent {\displaystyle \omega _{0}={\sqrt {k/m_{\text{equivalent}}}}} . A change in
828-578: Is one of their chief advantages. Many box girder bridges are built segmentally , or in short pieces. This type of construction lends itself well to balanced cantilever construction where the bridge is built in both directions from a single support. These structures rely heavily on torque and rotational equilibrium for their stability. In an architectural application, Frank Lloyd Wright 's Fallingwater used cantilevers to project large balconies. The East Stand at Elland Road Stadium in Leeds was, when completed,
874-410: Is that the fuselage is closer to the ground which eases cargo loading, especially for aircraft with a rear-fuselage cargo door. Military cargo aircraft are predominantly high-wing designs with a rear cargo door. A parasol wing is not directly attached to the fuselage but held above it, supported by either cabane struts or a pylon. Additional bracing may be provided by struts or wires extending from
920-401: Is the cantilever thickness. Very sensitive optical and capacitive methods have been developed to measure changes in the static deflection of cantilever beams used in dc-coupled sensors. The second is the formula relating the cantilever spring constant k {\displaystyle k} to the cantilever dimensions and material constants: where F {\displaystyle F}
966-422: Is the immunosensor based on an antibody layer that interacts selectively with a particular immunogen and reports about its content in a specimen. In the static mode of operation, the sensor response is represented by the beam bending with respect to a reference microcantilever. Alternatively, microcantilever sensors can be operated in the dynamic mode. In this case, the beam vibrates at its resonance frequency and
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#17330858039611012-564: The English Channel in 1909. Throughout 1909–1910, Hubert Latham set multiple altitude records in his Antoinette IV monoplane, eventually reaching 1,384 m (4,541 ft). The equivalent German language term is Eindecker , as in the mid-wing Fokker Eindecker fighter of 1915 which for a time dominated the skies in what became known as the " Fokker scourge ". The German military Idflieg aircraft designation system prior to 1918 prefixed monoplane type designations with an E , until
1058-617: The Fokker D.VIII and Morane-Saulnier AI in the later part of the First World War. A parasol wing also provides a high mounting point for engines and during the interwar period was popular on flying boats, which need to lift the propellers clear of spray. Examples include the Martin M-130 , Dornier Do 18 and the Consolidated PBY Catalina . Compared to a biplane , a parasol wing has less bracing and lower drag. It remains
1104-451: The braced parasol wing became popular on fighter aircraft, although few arrived in time to see combat. It remained popular throughout the 1920s. On flying boats with a shallow hull, a parasol wing allows the engines to be mounted above the spray from the water when taking off and landing. This arrangement was popular on flying boats during the 1930s; a late example being the Consolidated PBY Catalina . It died out when taller hulls became
1150-695: The 1930s, the cantilever monoplane was fast becoming the standard configuration for a fixed-wing aircraft. Advanced monoplane fighter-aircraft designs were mass-produced for military services around the world in both the Soviet Union and the United States in the early–mid 1930s, with the Polikarpov I-16 and the Boeing P-26 Peashooter respectively. Most military aircraft of WWII were monoplanes, as have been virtually all aircraft since, except for
1196-457: The 1930s. Since then, the monoplane has been the most common form for a fixed-wing aircraft. The inherent efficiency of the monoplane is best achieved in the cantilever wing, which carries all structural forces internally. However, to fly at practical speeds the wing must be made thin, which requires a heavy structure to make it strong and stiff enough. External bracing can be used to improve structural efficiency, reducing weight and cost. For
1242-476: The aircraft more manoeuvrable, as on the Spitfire ; but aircraft that value stability over manoeuvrability may then need some dihedral . A feature of the low-wing position is its significant ground effect , giving the plane a tendency to float farther before landing. Conversely, this ground effect permits shorter takeoffs. A mid wing is mounted midway up the fuselage. The carry-through spar structure can reduce
1288-521: The approval of the Fokker D.VIII fighter from its former "E.V" designation. However, the success of the Fokker was short-lived, and World War I was dominated by biplanes. Towards the end of the war, the parasol monoplane became popular and successful designs were produced into the 1920s. Nonetheless, relatively few monoplane types were built between 1914 and the late 1920s, compared with the number of biplanes. The reasons for this were primarily practical. With
1334-395: The behavior of MEMS cantilevers. The first is Stoney's formula , which relates cantilever end deflection δ to applied stress σ: where ν {\displaystyle \nu } is Poisson's ratio , E {\displaystyle E} is Young's modulus , L {\displaystyle L} is the beam length and t {\displaystyle t}
1380-518: The cantilever structure to release it, often with an anisotropic wet or dry etching technique. Without cantilever transducers, atomic force microscopy would not be possible. A large number of research groups are attempting to develop cantilever arrays as biosensors for medical diagnostic applications. MEMS cantilevers are also finding application as radio frequency filters and resonators . The MEMS cantilevers are commonly made as unimorphs or bimorphs . Two equations are key to understanding
1426-528: The cantilevers are usually built as pairs, with each cantilever used to support one end of a central section. The Forth Bridge in Scotland is an example of a cantilever truss bridge . A cantilever in a traditionally timber framed building is called a jetty or forebay . In the southern United States, a historic barn type is the cantilever barn of log construction . Temporary cantilevers are often used in construction. The partially constructed structure creates
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1472-581: The force applied to a cantilever can shift the resonance frequency. The frequency shift can be measured with exquisite accuracy using heterodyne techniques and is the basis of ac-coupled cantilever sensors. The principal advantage of MEMS cantilevers is their cheapness and ease of fabrication in large arrays. The challenge for their practical application lies in the square and cubic dependences of cantilever performance specifications on dimensions. These superlinear dependences mean that cantilevers are quite sensitive to variation in process parameters, particularly
1518-402: The fuselage sides. The first parasol monoplanes were adaptations of shoulder wing monoplanes, since raising a shoulder mounted wing above the fuselage greatly improved visibility downwards, which was useful for reconnaissance roles, as with the widely used Morane-Saulnier L . The parasol wing allows for an efficient design with good pilot visibility, and was adopted for some fighters such as
1564-433: The general variations in wing configuration such as tail position and use of bracing, the main distinction between types of monoplane is where the wing is mounted vertically on the fuselage . A low wing is one which is located on or near the bottom of the fuselage. Placing the wing low allows good visibility upwards and frees the central fuselage from the wing spar carry-through. By reducing pendulum stability, it makes
1610-680: The largest cantilever stand in the world holding 17,000 spectators. The roof built over the stands at Old Trafford uses a cantilever so that no supports will block views of the field. The old (now demolished) Miami Stadium had a similar roof over the spectator area. The largest cantilevered roof in Europe is located at St James' Park in Newcastle-Upon-Tyne , the home stadium of Newcastle United F.C. Less obvious examples of cantilevers are free-standing (vertical) radio towers without guy-wires , and chimneys , which resist being blown over by
1656-473: The late 1920s and early 1930s raised speeds through this zone and by the late 1930s cantilever wings had almost wholly superseded braced ones. Other changes such as enclosed cockpits, retractable undercarriage, landing flaps and stressed-skin construction furthered the design revolution, with the pivotal moment widely acknowledged to be the MacRobertson England-Australia air race of 1934, which
1702-415: The low engine powers and airspeeds available, the wings of a monoplane needed to be large in order to create enough lift while a biplane could have two smaller wings and so be made smaller and lighter. Towards the end of the First World War, the inherent high drag of the biplane was beginning to restrict performance. Engines were not yet powerful enough to make the heavy cantilever-wing monoplane viable, and
1748-410: The norm during World War II, allowing a high wing to be attached directly to the hull. As ever-increasing engine powers made the weight of all-metal construction and the cantilever wing more practical — first pioneered together by the revolutionary German Junkers J 1 factory demonstrator in 1915–16 — they became common during the post–World War I period, the day of the braced wing passed, and by
1794-399: The thickness as this is generally difficult to accurately measure. However, it has been shown that microcantilever thicknesses can be precisely measured and that this variation can be quantified. Controlling residual stress can also be difficult. A chemical sensor can be obtained by coating a recognition receptor layer over the upper side of a microcantilever beam. A typical application
1840-449: The top of the fuselage. It shares many advantages and disadvantages with the shoulder wing, but on a light aircraft, the high wing has poorer upwards visibility. On light aircraft such as the Cessna 152 , the wing is usually located above the cabin, so that the wing spar passes over the occupants' heads, leaving the wing in the ideal fore-aft position. An advantage of the high-wing configuration
1886-439: The useful fuselage volume near its centre of gravity, where space is often in most demand. A shoulder wing (a category between high-wing and mid-wing) is a configuration whereby the wing is mounted near the top of the fuselage but not on the very top. It is so called because it sits on the "shoulder" of the fuselage, rather than on the pilot's shoulder. Shoulder-wings and high-wings share some characteristics, namely: they support
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1932-424: The wind through cantilever action at their base. The cantilever is commonly used in the wings of fixed-wing aircraft . Early aircraft had light structures which were braced with wires and struts . However, these introduced aerodynamic drag which limited performance. While it is heavier, the cantilever avoids this issue and allows the plane to fly faster. Hugo Junkers pioneered the cantilever wing in 1915. Only
1978-453: The wing must also form a stiff cantilever in the horizontal plane. A single-spar design will usually be fitted with a second smaller drag-spar nearer the trailing edge , braced to the main spar via additional internal members or a stressed skin. The wing must also resist twisting forces, achieved by cross-bracing or otherwise stiffening the main structure. Cantilever wings require much stronger and heavier spars than would otherwise be needed in
2024-511: Was powered by two 460 hp (340 kW) Bristol Jupiter VIII radial engines. The prototype crashed and was severely damaged in March 1931 and was rebuilt with two Rolls-Royce Kestrel VI engines. After trials, 14 production examples named the Hendon Mk.II were ordered. These were built by Fairey's Stockport factory in late 1936 and early 1937 and flown from Barton Aerodrome , Manchester. Orders for
2070-583: Was soon obsolete and replaced from late 1938 by the Vickers Wellington . By January 1939, the Hendons had been retired and were then used for ground instruction work, including the radio school at RAF Cranwell . Of the 14 Hendon IIs only two were lost in accidents: Data from The British Bomber since 1914 ; Fairey Aircraft since 1915 General characteristics Performance Armament Aircraft of comparable role, configuration, and era Related lists Monoplane A monoplane
2116-671: Was won by a de Havilland DH.88 Comet . Currently, cantilever wings are almost universal with bracing only being used for some slower aircraft where a lighter weight is prioritized over speed, such as in the ultralight class. Cantilevered beams are the most ubiquitous structures in the field of microelectromechanical systems (MEMS). An early example of a MEMS cantilever is the Resonistor, an electromechanical monolithic resonator. MEMS cantilevers are commonly fabricated from silicon (Si), silicon nitride (Si 3 N 4 ), or polymers . The fabrication process typically involves undercutting
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