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80-558: The Armstrong Whitworth Atlas was a British single-engine biplane designed and built by Armstrong Whitworth Aircraft . It served as an army co-operation aircraft for the Royal Air Force (RAF) in the 1920s and 1930s. It was the first purpose-designed aircraft of the army co-operation type to serve with the RAF. The Armstrong Whitworth Atlas was designed by a team led by John Lloyd, chief designer of Armstrong Whitworth Aircraft , as

160-426: A hawk will use powered flight to rise, then soar on thermals, then descend via free-fall to catch its prey. While gliding occurs independently from powered flight, it has some ecological advantages of its own as it is the simplest form of flight. Gliding is a very energy -efficient way of travelling from tree to tree. Although moving through the canopy running along the branches may be less energetically demanding,

240-653: A W shape cabane, however as it does not connect the wings to each other, it does not add to the number of bays. Large transport and bombing biplanes often needed still more bays to provide sufficient strength. These are often referred to as multi-bay biplanes . A small number of biplanes, such as the Zeppelin-Lindau D.I have no interplane struts and are referred to as being strutless . Because most biplanes do not have cantilever structures, they require rigging wires to maintain their rigidity. Early aircraft used simple wire (either braided or plain), however during

320-412: A biplane aircraft, two wings are placed one above the other. Each provides part of the lift, although they are not able to produce twice as much lift as a single wing of similar size and shape because the upper and the lower are working on nearly the same portion of the atmosphere and thus interfere with each other's behaviour. In a biplane configuration with no stagger from the upper wing to the lower wing,

400-560: A documented jet-kill, as one Lockheed F-94 Starfire was lost while slowing down to 161 km/h (100 mph) – below its stall speed – during an intercept in order to engage the low flying Po-2. Later biplane trainers included the de Havilland Tiger Moth in the Royal Air Force (RAF), Royal Canadian Air Force (RCAF) and others and the Stampe SV.4 , which saw service postwar in the French and Belgian Air Forces. The Stearman PT-13

480-428: A drag force that is proportion to surface area and to velocity squared, and this force will partially counter the force of gravity, slowing the animal's descent to a safer speed. If this drag is oriented at an angle to the vertical, the animal's trajectory will gradually become more horizontal, and it will cover horizontal as well as vertical distance. Smaller adjustments can allow turning or other maneuvers. This can allow

560-562: A factor. In Australia, many mammals (and all mammalian gliders) possess, to some extent, prehensile tails. Globally, smaller gliding species tend to have feather-like tails and larger species have fur covered round bushy tails, but smaller animals tend to rely on parachuting rather than developing gliding membranes. The gliding membranes, patagium , are classified in the 4 groups of propatagium, digipatagium, plagiopatagium and uropatagium. These membranes consist of two tightly bounded layers of skin connected by muscles and connective tissue between

640-513: A faster and more comfortable successor to the Dragon. As the available engine power and speed increased, the drag penalty of external bracing increasingly limited aircraft performance. To fly faster, it would be necessary to reduce external bracing to create an aerodynamically clean design; however, early cantilever designs were either too weak or too heavy. The 1917 Junkers J.I sesquiplane utilized corrugated aluminum for all flying surfaces, with

720-415: A generally poor fossil record, and a particular lack of transitional forms. Furthermore, as fossils do not preserve behavior or muscle, it can be difficult to discriminate between a poor flyer and a good glider. Insects were the first to evolve flight , approximately 350 million years ago. The developmental origin of the insect wing remains in dispute, as does the purpose prior to true flight. One suggestion

800-422: A given wing area. However, interference between the airflow over each wing increases drag substantially, and biplanes generally need extensive bracing, which causes additional drag. Biplanes are distinguished from tandem wing arrangements, where the wings are placed forward and aft, instead of above and below. The term is also occasionally used in biology , to describe the wings of some flying animals . In

880-427: A low wing loading, that is a large wing area relative to their weight, which maximizes lift. Soaring is very energetically efficient. During a free-fall with no aerodynamic forces, the object accelerates due to gravity, resulting in increasing velocity as the object descends. During parachuting, animals use the aerodynamic forces on their body to counteract the force or gravity. Any object moving through air experiences

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960-399: A means of evading predators. Animal aerial locomotion can be divided into two categories: powered and unpowered. In unpowered modes of locomotion, the animal uses aerodynamic forces exerted on the body due to wind or falling through the air. In powered flight, the animal uses muscular power to generate aerodynamic forces to climb or to maintain steady, level flight. Those who can find air that

1040-507: A minimum of struts; however, it was relatively easy to damage the thin metal skin and required careful handling by ground crews. The 1918 Zeppelin-Lindau D.I fighter was an all-metal stressed-skin monocoque fully cantilevered biplane, but its arrival had come too late to see combat use in the conflict. By the 1930s, biplanes had reached their performance limits, and monoplanes become increasingly predominant, particularly in continental Europe where monoplanes had been increasingly common from

1120-448: A parachuting animal to move from a high location on one tree to a lower location on another tree nearby. Specifically in gliding mammals, there are 3 types of gliding paths respectively being S glide, J glide, and "straight-shaped" glides where species either gain altitude post launch then descend, rapidly decrease height before gliding, and maintaining a constant angled descent. During gliding, lift plays an increased role. Like drag, lift

1200-524: A private venture, first flying on 10 May 1925. It was delivered to the Aeroplane and Armament Experimental Establishment (A & AEE), Martlesham Heath , where it was evaluated against the Bristol Boarhound , de Havilland Hyena , Vickers Vespa , and Short Chamois . It proved superior in performance and handling and was recommended for production. While the performance was generally good,

1280-524: A private venture, to replace the DH.9A and Bristol Fighter as an army co-operation aircraft for the RAF, in parallel with a very closely related design, the Armstrong Whitworth Ajax, intended for more general purpose roles. While the two types were private ventures, relevant Air Ministry requirements included Specification 8/24 , 30/24 and 20/25. The prototype Atlas ( G-EBLK ) was built as

1360-463: A small degree, but more often was used to improve access to the cockpit. Many biplanes have staggered wings. Common examples include the de Havilland Tiger Moth , Bücker Bü 131 Jungmann and Travel Air 2000 . Alternatively, the lower wing can instead be moved ahead of the upper wing, giving negative stagger, and similar benefits. This is usually done in a given design for structural reasons, or to improve visibility. Examples of negative stagger include

1440-473: A somewhat unusual sesquiplane arrangement, possessing a more substantial lower wing with two spars that eliminated the flutter problems encountered by single-spar sesquiplanes. The stacking of wing planes was suggested by Sir George Cayley in 1843. Hiram Maxim adopted the idea for his steam-powered test rig, which lifted off but was held down by safety rails, in 1894. Otto Lilienthal designed and flew two different biplane hang gliders in 1895, though he

1520-465: Is a very successful strategy once evolved. Bats , after rodents , have the most species of any mammalian order, about 20% of all mammalian species . Birds have the most species of any class of terrestrial vertebrates . Finally, insects (most of which fly at some point in their life cycle) have more species than all other animal groups combined. The evolution of flight is one of the most striking and demanding in animal evolution, and has attracted

1600-560: Is better known for his monoplanes. By 1896 a group of young men in the United States, led by Octave Chanute , were flying hang gliders including biplanes and concluded that the externally braced biplane offered better prospects for powered flight than the monoplane. In 1903, the Wright Flyer biplane became the first successful powered aeroplane. Throughout the pioneer years, both biplanes and monoplanes were common, but by

1680-430: Is considerably more contentious, with various scientists supporting either a "trees down" origin (in which an arboreal ancestor evolved gliding, then flight) or a " ground up " origin (in which a fast-running terrestrial ancestor used wings for a speed boost and to help catch prey). It may also have been a non-linear process, as several non-avian dinosaurs seem to have independently acquired powered flight. Bats are

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1760-493: Is harder to obtain as animal size increases. Larger animals need to glide from much higher heights and longer distances to make it energetically beneficial. Gliding is also very suitable for predator avoidance, allowing for controlled targeted landings to safer areas. In contrast to flight, gliding has evolved independently many times (more than a dozen times among extant vertebrates); however these groups have not radiated nearly as much as have groups of flying animals. Worldwide,

1840-430: Is proportional to velocity squared. Gliding animals will typically leap or drop from high locations such as trees, just as in parachuting, and as gravitational acceleration increases their speed, the aerodynamic forces also increase. Because the animal can utilize lift and drag to generate greater aerodynamic force, it can glide at a shallower angle than parachuting animals, allowing it to cover greater horizontal distance in

1920-472: Is rising faster than they are falling can gain altitude by soaring . These modes of locomotion typically require an animal start from a raised location, converting that potential energy into kinetic energy and using aerodynamic forces to control trajectory and angle of descent. Energy is continually lost to drag without being replaced, thus these methods of locomotion have limited range and duration. Powered flight has evolved at least four times: first in

2000-446: Is that wings initially evolved from tracheal gill structures and were used to catch the wind for small insects that live on the surface of the water, while another is that they evolved from paranotal lobes or leg structures and gradually progressed from parachuting, to gliding, to flight for originally arboreal insects. Pterosaurs were the next to evolve flight, approximately 228 million years ago. These reptiles were close relatives of

2080-536: The Bristol M.1 , that caused even those with relatively high performance attributes to be overlooked in favour of 'orthodox' biplanes, and there was an allegedly widespread belief held at that time that monoplane aircraft were inherently unsafe during combat. Between the years of 1914 and 1925, a clear majority of new aircraft introduced were biplanes; however, during the latter years of the First World War,

2160-653: The First World War -era Fokker D.VII fighter and the Second World War de Havilland Tiger Moth basic trainer. The larger two-seat Curtiss JN-4 Jenny is a two bay biplane , the extra bay being necessary as overlong bays are prone to flexing and can fail. The SPAD S.XIII fighter, while appearing to be a two bay biplane, has only one bay, but has the midpoints of the rigging braced with additional struts; however, these are not structurally contiguous from top to bottom wing. The Sopwith 1½ Strutter has

2240-703: The Grumman Ag Cat are available in upgraded versions with turboprop engines. The two most produced biplane designs were the 1913 British Avro 504 of which 11,303 were built, and the 1928 Soviet Polikarpov Po-2 of which over 20,000 were built, with the Po-2 being the direct replacement for the Soviet copy of the Avro 504. Both were widely used as trainers. The Antonov An-2 was very successful too, with more than 18,000 built. Although most ultralights are monoplanes,

2320-844: The Hawker Audax , a variant of the Hawker Hart , with the last operational squadron, 208, re-equipping in 1935. It was also replaced in the advanced trainer role in 1935 by the Hawker Hart Trainer. Four civil registered Atlas trainers were used by Air Service Training Ltd for advanced and reserve flying training. They were scrapped in 1938. Data from The British Bomber since 1914. General characteristics Performance Armament Related lists Biplane Biplanes offer several advantages over conventional cantilever monoplane designs: they permit lighter wing structures, low wing loading and smaller span for

2400-617: The Lite Flyer Biplane, the Sherwood Ranger , and the Murphy Renegade . The feathered dinosaur Microraptor gui glided, and perhaps even flew, on four wings, which may have been configured in a staggered sesquiplane arrangement. This was made possible by the presence of flight feathers on both forelimbs and hindlimbs, with the feathers on the forelimbs opening to a greater span. It has been suggested that

2480-556: The Nieuport-Delage NiD 42 / 52 / 62 series, Fokker C.Vd & e, and Potez 25 , all serving across a large number of air forces. In the general aviation sector, aircraft such as the Waco Custom Cabin series proved to be relatively popular. The Saro Windhover was a sesquiplane with the upper wing smaller than the lower, which was a much rarer configuration than the reverse. The Pfalz D.III also featured

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2560-501: The Sopwith Dolphin , Breguet 14 and Beechcraft Staggerwing . However, positive (forward) stagger is much more common. The space enclosed by a set of interplane struts is called a bay (much as the architectural form is used), hence a biplane or triplane with one set of such struts connecting the wings on each side of the aircraft is a single-bay biplane . This provided sufficient strength for smaller aircraft such as

2640-430: The insects , then in pterosaurs , next in birds , and last in bats . Studies on theropod dinosaurs do suggest multiple (at least 3) independent acquisitions of powered flight however, and a recent study proposes independent acquisitions amidst the different bat clades as well. Powered flight uses muscles to generate aerodynamic force , which allows the animal to produce lift and thrust. The animal may ascend without

2720-419: The lift coefficient is reduced by 10 to 15 percent compared to that of a monoplane using the same airfoil and aspect ratio . The lower wing is usually attached to the fuselage , while the upper wing is raised above the fuselage with an arrangement of cabane struts , although other arrangements have been used. Either or both of the main wings can support ailerons , while flaps are more usually positioned on

2800-514: The CR.42 was able to achieve success in the defensive night fighter role against RAF bombers that were striking industrial targets throughout northern Italy. The British Fleet Air Arm operated the Fairey Swordfish torpedo bomber from its aircraft carriers, and used the type in the anti-submarine warfare role until the end of the conflict, largely due to their ability to operate from

2880-528: The Caribou , performed the first non-stop flight between the Canadian mainland and Britain in 30 hours 55 minutes, although the intended target for this long distance flight had originally been Baghdad , Iraq . Despite its relative success, British production of the Dragon was quickly ended when in favour of the more powerful and elegant de Havilland Dragon Rapide , which had been specifically designed to be

2960-515: The First World War, the British Royal Aircraft Factory developed airfoil section wire named RAFwire in an effort to both increase the strength and reduce the drag. Four types of wires are used in the biplane wing structure. Drag wires inside the wings prevent the wings from being folded back against the fuselage, running inside a wing bay from the forward inboard corner to the rear outboard corner. Anti-drag wires prevent

3040-577: The French Nieuport 17 and German Albatros D.III , offered lower drag than a conventional biplane while being stronger than a monoplane. During the Interwar period , numerous biplane airliners were introduced. The British de Havilland Dragon was a particularly successful aircraft, using straightforward design to could carry six passengers on busy routes, such as London-Paris services. During early August 1934, one such aircraft, named Trail of

3120-661: The Germans had been experimenting with a new generation of monoplanes, such as the Fokker D.VIII , that might have ended the biplane's advantages earlier had the conflict not ended when it had. The French were also introducing the Morane-Saulnier AI , a strut-braced parasol monoplane , although the type was quickly relegated to the advanced trainer role following the resolution of structural issues. Sesquiplane types, which were biplanes with abbreviated lower wings such as

3200-417: The aid of rising air. Ballooning and soaring are not powered by muscle, but rather by external aerodynamic sources of energy: the wind and rising thermals , respectively. Both can continue as long as the source of external power is present. Soaring is typically only seen in species capable of powered flight, as it requires extremely large wings. Many species will use multiple of these modes at various times;

3280-459: The air at a constant speed moves its wings up and down (usually with some fore-aft movement as well). Because the animal is in motion, there is some airflow relative to its body which, combined with the velocity of its wings, generates a faster airflow moving over the wing. This will generate lift force vector pointing forwards and upwards, and a drag force vector pointing rearwards and upwards. The upwards components of these counteract gravity, keeping

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3360-466: The attention of many prominent scientists and generated many theories. Additionally, because flying animals tend to be small and have a low mass (both of which increase the surface-area-to-mass ratio), they tend to fossilize infrequently and poorly compared to the larger, heavier-boned terrestrial species they share habitat with. Fossils of flying animals tend to be confined to exceptional fossil deposits formed under highly specific circumstances, resulting in

3440-407: The biplane naturally has a deep structure and is therefore easier to make both light and strong. Rigging wires on non-cantilevered monoplanes are at a much sharper angle, thus providing less tension to ensure stiffness of the outer wing. On a biplane, since the angles are closer to the ideal of being in direct line with the forces being opposed, the overall structure can then be made stiffer. Because of

3520-475: The body in the air, while the forward component provides thrust to counteract both the drag from the wing and from the body as a whole. Pterosaur flight likely worked in a similar manner, though no living pterosaurs remain for study. Insect flight is considerably different, due to their small size, rigid wings, and other anatomical differences. Turbulence and vortices play a much larger role in insect flight, making it even more complex and difficult to study than

3600-608: The competition aerobatics role and format for such a biplane well-defined by the mid-1930s by the Udet U 12 Flamingo and Waco Taperwing . The Pitts Special dominated aerobatics for many years after World War II and is still in production. The vast majority of biplane designs have been fitted with reciprocating engines . 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

3680-475: The development is to aid canopy animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among rainforest animals, especially in the rainforests in Asia (most especially Borneo ) where the trees are tall and widely spaced. Several species of aquatic animals , and a few amphibians and reptiles have also evolved this gliding flight ability, typically as

3760-539: The dinosaurs, and reached enormous sizes, with some of the last forms being the largest flying animals ever to inhabit the Earth, having wingspans of over 9.1 m (30 ft). However, they spanned a large range of sizes, down to a 250 mm (10 in) wingspan in Nemicolopterus . Birds have an extensive fossil record, along with many forms documenting both their evolution from small theropod dinosaurs and

3840-691: The distribution of gliding animals is uneven, as most inhabit rain forests in Southeast Asia . (Despite seemingly suitable rain forest habitats, few gliders are found in India or New Guinea and none in Madagascar.) Additionally, a variety of gliding vertebrates are found in Africa , a family of hylids ( flying frogs ) lives in South America and several species of gliding squirrels are found in

3920-470: The drag from the number of struts used. The structural forces acting on the spars of a biplane wing tend to be lower as they are divided between four spars rather than two, so the wing can use less material to obtain the same overall strength and is therefore lighter. A given area of wing also tends to be shorter, reducing bending moments on the spars, which then allow them to be more lightly built as well. The biplane does however need extra struts to maintain

4000-549: The end of World War I . At the start of World War II , several air forces still had biplane combat aircraft in front line service but they were no longer competitive, and most were used in niche roles, such as training or shipboard operation, until shortly after the end of the war. The British Gloster Gladiator biplane, the Italian Fiat CR.42 Falco and Soviet I-153 sesquiplane fighters were all still operational after 1939. According to aviation author Gianni Cattaneo,

4080-399: The faster transition between trees allows for greater foraging rates in a particular patch. Glide ratios can be dependent on size and current behavior. Higher foraging rates are supported by low glide ratios as smaller foraging patches require less gliding time over shorter distances and greater amounts of food can be acquired in a shorter time period. Low ratios are not as energy efficient as

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4160-494: The fitting of slats, the Atlas proved well suited for army co-operation, in use at home and overseas, with 208 squadron , being the first squadron to operate Atlases outside Britain, replacing Bristol fighters at Heliopolis , Egypt in 1930. Atlases were also used for communications duties and as advanced trainers , with 175 dual-control models built. The Atlas continued in service in the army co-operations role until replaced with

4240-432: The flight of vertebrates. There are two basic aerodynamic models of insect flight. Most insects use a method that creates a spiralling leading edge vortex . Some very small insects use the fling-and-clap or Weis-Fogh mechanism in which the wings clap together above the insect's body and then fling apart. As they fling open, the air gets sucked in and creates a vortex over each wing. This bound vortex then moves across

4320-423: The fore and hind limbs. Powered flight has evolved unambiguously only four times— birds , bats , pterosaurs , and insects (though see above for possible independent acquisitions within bird and bat groups). In contrast to gliding, which has evolved more frequently but typically gives rise to only a handful of species, all three extant groups of powered flyers have a huge number of species, suggesting that flight

4400-662: The forests of northern Asia and North America. Various factors produce these disparities. In the forests of Southeast Asia, the dominant canopy trees (usually dipterocarps ) are taller than the canopy trees of the other forests. Forest structure and distance between trees are influential in the development of gliding within varying species. A higher start provides a competitive advantage of further glides and farther travel. Gliding predators may more efficiently search for prey. The lower abundance of insect and small vertebrate prey for carnivorous animals (such as lizards) in Asian forests may be

4480-416: The gap between the wings, which add both weight and drag. The low power supplied by the engines available in the first years of aviation limited aeroplanes to fairly low speeds. This required an even lower stalling speed, which in turn required a low wing loading , combining both large wing area with light weight. Obtaining a large enough wing area without the wings being long, and thus dangerously flexible

4560-420: The higher ratios, but an argument made is that many gliding animals eat low energy foods such as leaves and are restricted to gliding because of this, whereas flying animals eat more high energy foods such as fruits , nectar , and insects. Mammals tend to rely on lower glide ratios to increase the amount of time foraging for lower energy food. An equilibrium glide, achieving a constant airspeed and glide angle,

4640-508: The hind limbs could not have opened out sideways but in flight would have hung below and slightly behind the fore limbs. Flying and gliding animals A number of animals are capable of aerial locomotion, either by powered flight or by gliding . This trait has appeared by evolution many times, without any single common ancestor. Flight has evolved at least four times in separate animals: insects , pterosaurs , birds , and bats . Gliding has evolved on many more occasions. Usually

4720-639: The low speeds and simple construction involved have inspired a small number of biplane ultralights, such as Larry Mauro's Easy Riser (1975–). Mauro also made a version powered with solar cells driving an electric motor called the Solar Riser . Mauro's Easy Riser was used by "Father Goose", Bill Lishman . Other biplane ultralights include the Belgian-designed Aviasud Mistral , the German FK12 Comet (1997–),

4800-519: The lower wing. Bracing is nearly always added between the upper and lower wings, in the form of interplane struts positioned symmetrically on either side of the fuselage and bracing wires to keep the structure from flexing, where the wings are not themselves cantilever structures. The primary advantage of the biplane over a monoplane is its ability to combine greater stiffness with lower weight. Stiffness requires structural depth and where early monoplanes had to have this provided with external bracing,

4880-573: The most famed copies was the Siemens-Schuckert D.I . The Albatros D.III and D.V , which had also copied the general layout from Nieuport, similarly provided the backbone of the German forces during the First World War. The Albatros sesquiplanes were widely acclaimed by their aircrews for their maneuverability and high rate of climb. During interwar period , the sesquiplane configuration continued to be popular, with numerous types such as

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4960-417: The most recent to evolve (about 60 million years ago), most likely from a fluttering ancestor, though their poor fossil record has hindered more detailed study. Only a few animals are known to have specialised in soaring : the larger of the extinct pterosaurs , and some large birds. Powered flight is very energetically expensive for large animals, but for soaring their size is an advantage, as it allows them

5040-609: The night ground attack role throughout the Second World War. In the case of the Po-2, production of the aircraft continued even after the end of the conflict, not ending until around 1952. A significant number of Po-2s were fielded by the Korean People's Air Force during the Korean War , inflicting serious damage during night raids on United Nations bases. The Po-2 is also the only biplane to be credited with

5120-511: The numerous bird-like forms of theropod which did not survive the mass extinction at the end of the Cretaceous. Indeed, Archaeopteryx is arguably the most famous transitional fossil in the world, both due to its mix of reptilian and avian anatomy and the luck of being discovered only two years after Darwin's publication of On the Origin of Species . However, the ecology of this transition

5200-437: The objects that generate lift (wings) and thrust (engine or propeller) are separate and the wings remain fixed, flying animals use their wings to generate both lift and thrust by moving them relative to the body. This has made the flight of organisms considerably harder to understand than that of vehicles, as it involves varying speeds, angles, orientations, areas, and flow patterns over the wings. A bird or bat flying through

5280-486: The outbreak of the First World War biplanes had gained favour after several monoplane structural failures resulted in the RFC's "Monoplane Ban" when all monoplanes in military service were grounded, while the French also withdrew most monoplanes from combat roles and relegated them to training. Figures such as aviation author Bruce observed that there was an apparent prejudice held even against newly-designed monoplanes, such as

5360-444: The poor handling. The production Atlas had a steel tube fuselage with fabric covering with single-bay swept metal wings. It could be fitted with a hook under the fuselage to pick up messages and could carry a 460 lb (210 kg) bombload under the wings. The first batch of 37 aircraft were ordered in 1927, entering service with 13 Squadron RAF and 26 Squadron in that year. Once the initial handling problems had been solved by

5440-493: The prototype could not be sideslipped steeply, and this resulted in a redesign where sweptback metal wings, with differing wing section, were fitted. When tested again, the Atlas was found to have lost its good handling, having dangerous stall characteristics. The Atlas had already been ordered for service, however, and suffered a number of accidents during takeoff and landing in the first few months of operation until modified with automatic slats and increased sweepback. This cured

5520-424: The reduced stiffness, wire braced monoplanes often had multiple sets of flying and landing wires where a biplane could easily be built with one bay, with one set of landing and flying wires. The extra drag from the wires was not enough to offset the aerodynamic disadvantages from having two airfoils interfering with each other however. Strut braced monoplanes were tried but none of them were successful, not least due to

5600-657: The relatively compact decks of escort carriers . Its low stall speed and inherently tough design made it ideal for operations even in the often severe mid-Atlantic weather conditions. By the end of the conflict, the Swordfish held the distinction of having caused the destruction of a greater tonnage of Axis shipping than any other Allied aircraft. Both the German Heinkel He 50 and the Soviet Polikarpov Po-2 were used with relative success in

5680-572: The same loss of altitude, and reach trees further away. Successful flights for gliding animals are achieved through 5 steps: preparation, launch, glide, braking, and landing. Gliding species are better able to control themselves mid-air, with the tail acting as a rudder, making it capable to pull off banking movements or U-turns during flight. During landing, arboreal mammals will extend their fore and hind limbs in front of itself to brace for landing and to trap air in order to maximize air resistance and lower impact speed. Unlike most air vehicles, in which

5760-728: The series of Nieuport military aircraft—from the Nieuport 10 through to the Nieuport 27 which formed the backbone of the Allied air forces between 1915 and 1917. The performance of the Nieuport sesquiplanes was so impressive that the Idflieg (the German Inspectorate of flying troops) requested their aircraft manufacturers to produce copies, an effort which was aided by several captured aircraft and detailed drawings; one of

5840-415: The structural problems associated with monoplanes, but offered little improvement for biplanes. The default design for a biplane has the wings positioned directly one above the other. Moving the upper wing forward relative to the lower one is called positive stagger or, more often, simply stagger. It can increase lift and reduce drag by reducing the aerodynamic interference effects between the two wings by

5920-670: The two planes when the high pressure air under the top wing and the low pressure air above the lower wing cancel each other out. This means that a biplane does not in practice obtain twice the lift of the similarly-sized monoplane. The farther apart the wings are spaced the less the interference, but the spacing struts must be longer, and the gap must be extremely large to reduce it appreciably. As engine power and speeds rose late in World War I , thick cantilever wings with inherently lower drag and higher wing loading became practical, which in turn made monoplanes more attractive as it helped solve

6000-400: The upper and lower wings together. The sesquiplane is a type of biplane where one wing (usually the lower) is significantly smaller than the other. The word, from Latin, means "one-and-a-half wings". The arrangement can reduce drag and weight while retaining the biplane's structural advantages. The lower wing may have a significantly shorter span, or a reduced chord . Examples include

6080-600: The wing and, in the clap, acts as the starting vortex for the other wing. Circulation and lift are increased, at the price of wear and tear on the wings. Gliding has evolved independently in two families of tree frogs, the Old World Rhacophoridae and the New World Hylidae. Within each lineage there are a range of gliding abilities from non-gliding, to parachuting, to full gliding. Several lizards and snakes are capable of gliding: Bats are

6160-434: The wings from folding up, and run from the underside of the outer wing to the lower wing root. Conversely, landing wires prevent the wings from sagging, and resist the forces when an aircraft is landing, and run from the upper wing centre section to outboard on the lower wings. Additional drag and anti-drag wires may be used to brace the cabane struts which connect the fuselage to the wings, and interplane struts, which connect

6240-421: The wings from moving forward when the aircraft stops and run the opposite direction to the drag wires. Both of these are usually hidden within the wings, and if the structure is sufficiently stiff otherwise, may be omitted in some designs. Indeed many early aircraft relied on the fabric covering of the wing to provide this rigidity, until higher speeds and forces made this inadequate. Externally, lift wires prevent

6320-404: Was more readily accomplished with a biplane. The smaller biplane wing allows greater maneuverability . Following World War I, this helped extend the era of the biplane and, despite the performance disadvantages, most fighter aircraft were biplanes as late as the mid-1930s. Specialist sports aerobatic biplanes are still made in small numbers. Biplanes suffer aerodynamic interference between

6400-777: Was widely used by the United States Army Air Force (USAAF) while the US Navy operated the Naval Aircraft Factory N3N . In later civilian use in the US, the Stearman became particularly associated with stunt flying such as wing-walking , and with crop dusting, where its compactness worked well at low levels, where it had to dodge obstacles. Modern biplane designs still exist in specialist roles such as aerobatics and agricultural aircraft with

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