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39-511: The X-55 is a one-off aircraft intended to demonstrate the use of advanced composite materials in the fuselage of an otherwise conventional high-wing transport aircraft. There are no plans to place the X-55 into production. Lockheed Martin's design for Advanced Composite Cargo Aircraft (ACCA) was chosen over Aurora Flight Sciences ' design based on the Antonov An-72 in 2007. The aircraft

78-465: A cranked or polyhedral wing the dihedral angle varies along the span. (Note that the description "cranked" varies in usage. See also Cranked arrow planform.) Some designs have no clear join between wing and fuselage, or body. This may be because one or other of these is missing, or because they merge into each other: Some designs may fall into multiple categories depending on interpretation, for example many UAVs or drones can be seen either as

117-429: A few specialist types. Jet and rocket engines have even more power and all modern high-speed aircraft, especially supersonic types, have been monoplanes. Wing configuration The wing configuration of a fixed-wing aircraft (including both gliders and powered aeroplanes ) is its arrangement of lifting and related surfaces. Aircraft designs are often classified by their wing configuration. For example,

156-627: 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

195-407: 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

234-470: 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

273-462: A side effect. The wing chord may be varied along the span of the wing, for both structural and aerodynamic reasons. Wings may be swept back, or occasionally forwards, for a variety of reasons. A small degree of sweep is sometimes used to adjust the centre of lift when the wing cannot be attached in the ideal position for some reason, such as a pilot's visibility from the cockpit. Other uses are described below. Some types of variable geometry vary

312-538: A tailless blended wing-body or as a flying wing with a deep centre chord. A variable geometry aircraft is able to change its physical configuration during flight. Some types of variable geometry craft transition between fixed wing and rotary wing configurations. For more about these hybrids, see powered lift . A polymorphic wing is able to change the number of planes in flight. The Nikitin-Shevchenko IS "folding fighter" prototypes were able to morph between biplane and monoplane configurations after takeoff by folding

351-489: 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

390-432: 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

429-484: Is common to refer to a plane as a wing, as in "a biplane has two wings", or alternatively to refer to the whole thing as a wing, as in "a biplane wing has two planes". Where the meaning is clear, this article follows common usage, only being more precise where needed to avoid real ambiguity or incorrectness. Fixed-wing aircraft can have different numbers of wings: A fixed-wing aircraft may have more than one wing plane, stacked one above another: A staggered design has

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468-438: Is particularly so for variable geometry and combined (closed) wing types. Most of the configurations described here have flown (if only very briefly) on full-size aircraft. A few theoretical designs are also notable. Note on terminology: Most fixed-wing aircraft have left hand and right hand wings in a symmetrical arrangement. Strictly, such a pair of wings is called a wing plane or just plane. However, in certain situations it

507-500: Is powered by two Pratt & Whitney Canada PW306B turbofans . The X-55 design is based on the existing Fairchild Dornier 328JET . The fuselage of that aircraft, which is constructed of aluminium alloys , was replaced aft of the entrance door with a newly designed fuselage. The new design makes extensive use of advanced composite materials, selected to allow out-of- autoclave (industrial) curing at lower temperatures and pressures than previous materials. The new widened fuselage allows

546-410: 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

585-408: Is the silhouette of the wing when viewed from above or below. See also variable geometry types which vary the wing planform during flight. The aspect ratio is the span divided by the mean or average chord. It is a measure of how long and slender the wing appears when seen from above or below. Most variable geometry configurations vary the aspect ratio in some way, either deliberately or as

624-488: The Beechcraft Staggerwing . To support itself a wing has to be rigid and strong and consequently may be heavy. By adding external bracing, the weight can be greatly reduced. Originally such bracing was always present, but it causes a large amount of drag at higher speeds and has not been used for faster designs since the early 1930s. The types are: Wings can also be characterised as: The wing planform

663-571: 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

702-693: 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

741-621: The Supermarine Spitfire is a conventional low wing cantilever monoplane of straight elliptical planform with moderate aspect ratio and slight dihedral. Many variations have been tried. Sometimes the distinction between them is blurred, for example the wings of many modern combat aircraft may be described either as cropped compound deltas with (forwards or backwards) swept trailing edge, or as sharply tapered swept wings with large leading edge root extensions (or LERX). Some are therefore duplicated here under more than one heading. This

780-451: 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

819-725: 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

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858-457: 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

897-481: 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

936-525: 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

975-425: The entrance door consists of the existing (metal) 328J component, with fasteners used to bring the forward and new aft sections together. As of April 2008, the fuselage was being fabricated. The first flight of the modified aircraft was expected during the winter of 2008/2009. However, due to a "glitch" during fabricating the composite fuselage, that schedule slipped. The delay was caused by an unsatisfactory bond of

1014-402: 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

1053-433: 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

1092-465: The horizontal stabilizer. Angling the wings up or down spanwise from root to tip can help to resolve various design issues, such as stability and control in flight. Some biplanes have different degrees of dihedral/anhedral on different wings. The Sopwith Camel had a flat upper wing and dihedral on the lower wing, while the Hanriot HD-1 had dihedral on the upper wing but none on the lower. In

1131-425: The loading of cargo through a rear ramp. The new fuselage section is constructed as a single large component, including the vertical stabilizer . When attached to the existing nose section, the fuselage is 55 feet (16.8 m) long and 9 feet (2.74 m) diameter. The fuselage has upper and lower halves, each with a roughly-oval shape similar to a canoe. The halves are bonded to circular frames. The fuselage section ahead of

1170-415: 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

1209-453: The lower wing up into a cavity in the underside of the upper wing. The slip wing is a variation on the polymorphic idea, in which a low-wing monoplane is fitted with a second detachable "slip" wing above it to assist takeoff. The upper wing is then released and discarded once in the air. The idea was first flown on the experimental Hillson Bi-mono . Aircraft may have additional minor aerodynamic surfaces. Some of these are treated as part of

Lockheed Martin X-55 - Misplaced Pages Continue

1248-410: 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

1287-429: The overall wing configuration: Additional minor features may be applied to an existing aerodynamic surface such as the main wing: High-lift devices maintain lift at low speeds and delay the stall to allow slower takeoff and landing speeds: On a swept wing, air tends to flow sideways as well as backwards and reducing this can improve the efficiency of the wing: Vortex devices maintain airflow at low speeds and delay

1326-573: The program, 15 to 20 flights were expected. Furthermore, it was estimated that the vehicle was built for half the cost of a conventional design for a similar aircraft. As of September 12, 2014, the X-55 aircraft is on display at the Joe Davies Heritage Airpark in Palmdale, California. Related development [REDACTED] Media related to Lockheed Martin X-55 at Wikimedia Commons High-wing A monoplane

1365-591: The skin on the lower fuselage, which required a second fuselage to be fabricated. The first flight was completed at Lockheed Martin's Advanced Development Programs facility (Air Force Plant 42) in Palmdale, California on June 2, 2009 by the Air Force Research Laboratory in conjunction with Lockheed Martin. In October 2009, the ACCA demonstrator was designated X-55A by the USAF. Over the course of

1404-453: 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

1443-402: The upper wing slightly forward of the lower. Long thought to reduce the interference caused by the low pressure air over the lower wing mixing with the high pressure air under the upper wing; however the improvement is minimal and its primary benefit is to improve access to the fuselage. It is common on many successful biplanes and triplanes. Backwards stagger is also seen in a few examples such as

1482-439: 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

1521-458: The wing sweep during flight: The angle of a swept wing may also be varied, or cranked, along the span: On a few asymmetrical aircraft the left and right hand sides are not mirror-images of each other: The classic aerofoil section wing is unstable in pitch, and requires some form of horizontal stabilizing surface. Also it cannot provide any significant pitch control, requiring a separate control surface (elevator) mounted elsewhere - usually on

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