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Tiltrotor
A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called ''proprotors'') mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a transverse rotor design, with a few exceptions that use other multirotor layouts. Tiltrotor design combines the VTOL capability of a helicopter with the speed and range of a conventional fixed-wing aircraft. For vertical flight, the rotors are angled so the plane of rotation is horizontal, generating lift the way a normal helicopter rotor does. As the aircraft gains speed, the rotors are progressively tilted forward, with the plane of rotation eventually becoming vertical. In this mode the rotors provide thrust as a propeller, and the airfoil of the fixed wings takes over providing the lift via the forward motion of the entire aircraft. Since the rotors can be configured to be more efficient for propulsion (e.g. with root-tip twist) and it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VTOL
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. Some VTOL aircraft can operate in other modes as well, such as CTOL (conventional take-off & landing), STOL (short take-off & landing), or STOVL (short take-off & vertical landing). Others, such as some helicopters, can only operate as VTOL, due to the aircraft lacking landing gear that can handle taxiing. VTOL is a subset of V/STOL (vertical or short take-off & landing). Some lighter-than-air aircraft also qualify as VTOL aircraft, as they can hover, takeoff and land with vertical approach/departure profiles. Electric vertical takeoff and landing aircraft, or eVTOLs, are being developed along with more autonomous flight control tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiltwing
A tiltwing aircraft features a wing that is horizontal for conventional forward flight and rotates up for vertical takeoff and landing. It is similar to the tiltrotor design where only the propeller and engine rotate. Tiltwing aircraft are typically fully capable of VTOL operations.Markman, Steve and Bill Holder. "Tilt-Wing VTOL Systems". ''Straight Up: A History of Vertical Flight''. Schiffer Publishing, 2000. . The tiltwing design offers certain advantages in vertical flight relative to a tiltrotor. Because the slipstream from the rotor strikes the wing on its smallest dimension, the tiltwing is able to apply more of its engine power to lifting the aircraft. For comparison, the V-22 Osprey tiltrotor loses about 10% of its thrust to interference from the wings. Another advantage of tiltwing aircraft is the ease of transition between VTOL and horizontal flight modes. A tiltrotor must first fly forwards like a helicopter, building airspeed until wing lift is sufficient to allow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XV-15 N703NA USCG
The Bell XV-15 is an American tiltrotor VTOL aircraft. It was the second successful experimental tiltrotor aircraft and the first to demonstrate the concept's high speed performance relative to conventional helicopters. Development Early VTOL rotor aircraft The idea of building VTOL aircraft using helicopter-like rotors at the wingtips originated in the 1930s. The first design resembling modern tiltrotors was patented by George Lehberger in May 1930, but he did not develop the concept further. In World War II, a German prototype called the Focke-Achgelis Fa 269 was developed starting in 1942, but it never flew. Two prototypes that made it to flight were the one-seat Transcendental Model 1-G and two-seat Transcendental Model 2, both powered by single reciprocating engines. Development started on the Model 1-G in 1947, and it flew in 1954. The Model 1-G flew until a crash in Chesapeake Bay on 20 July 1955, destroying the prototype aircraft but not seriously injuring the pilot. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focke-Achgelis Fa 269
The Focke-Achgelis Fa 269 was a tiltrotor VTOL aircraft project designed by Henrich Focke. Development Conceived as a single-seat fighter, the Fa 269 project resulted from a design study order issued by the Reich Air Ministry to Focke-Achgelis in 1941. The order called for a local defence fighter which would combine the VTOL capabilities of a helicopter with the speed and economy of a conventional fixed-wing aircraft. A large amount of wind tunnel testing was undertaken, along with work on gearboxes, drives and power-pivoting mechanisms, and a full-scale mock-up of the aircraft was built to demonstrate the VTOL concept, but much of this was destroyed by Allied bombing raids and all work was shelved in 1944, when Focke-Achgelis estimated that there was little likelihood of a practical prototype being available before 1947. Design A mid-wing monoplane, the Fa 269 was to have been powered by a single BMW 801 air-cooled radial engine buried in the fuselage behind the cockpit, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transverse Rotor
Transverse rotor aircraft have two large horizontal rotor assemblies mounted side by side. Single-rotor helicopters (unicopters) need an additional tail rotor or tail exhaust to neutralize the reactional angular momentum produced by the main rotor. Transverse rotor helicopters, however, use counter-rotating rotors, with each cancelling out the other's torque. Counter-rotating rotor blades also won't collide with and destroy each other if they flex into the other rotor's pathway. In addition, transverse rotor configuration has the advantage of higher payload with shorter blades, since there are two sets working to provide lift. Also, all of the power from the engines can be used for lift, whereas a single-rotor helicopter must divert part of its engine power to generate tail thrust. Transverse rotor design with rotatable nacelles are known as tiltrotors while designs where the whole wing rotates are known as tiltwings. List of transverse rotor aircraft Transverse-mounted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, helicopters, airships (including blimps), gliders, paramotors, and hot air balloons. The human activity that surrounds aircraft is called ''aviation''. The science of aviation, including designing and building aircraft, is called '' aeronautics.'' Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others. History Flying model craft and stories of manned flight go back many centuries; however, the first manned ascent — and safe descent — in modern times took place by larger hot-air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trascendental Model 1-G
Transcendence, transcendent, or transcendental may refer to: Mathematics * Transcendental number, a number that is not the root of any polynomial with rational coefficients * Algebraic element or transcendental element, an element of a field extension that is not the root of any polynomial with coefficients from the base field * Transcendental function, a function which does not satisfy a polynomial equation whose coefficients are themselves polynomials * Transcendental number theory, the branch of mathematics dealing with transcendental numbers and algebraic independence Music * ''Transcendence'' (Adil Omar album), a 2018 hip hop album * ''Transcendence'' (Alice Coltrane album), a 1977 jazz album * ''Transcendence'' (Crimson Glory album), a 1988 heavy metal album * ''Transcendence'' (Devin Townsend Project album), a 2016 heavy metal album * "Transcendence" (Lindsey Stirling instrumental), a 2012 instrumental piece * " Transcendence (Segue)", a 2000 progressive metal instrumen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retreating Blade Stall
Retreating blade stall is a hazardous flight condition in helicopters and other rotary wing aircraft, where the retreating rotor blade has a lower relative blade speed, combined with an increased angle of attack, causing a stall and loss of lift. Retreating blade stall is the primary limiting factor of a helicopter's never exceed speed, VNE. Retreating blade stall occurs at high forward speeds, and should not be confused with rotor stall, which is caused by low rotor RPM and can occur at any forward speed. Advancing vs. retreating blades A rotor blade that is moving in the same direction as the aircraft is called the ''advancing blade'' and the blade moving in the opposite direction is called the ''retreating blade.'' Balancing lift across the rotor disc is important to a helicopter's stability. The amount of lift generated by an airfoil is proportional to the square of its airspeed (velocity). In a zero airspeed hover the rotor blades, regardless of their position in rotati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Original Tiltrotor Patent
Originality is the aspect of created or invented works that distinguish them from reproductions, clones, forgeries, or substantially derivative works. The modern idea of originality is according to some scholars tied to Romanticism, by a notion that is often called romantic originality.Smith (1924)Waterhouse (1926)Macfarlane (2007) The validity of "originality" as an operational concept has been questioned. For example, there is no clear boundary between "derivative" and "inspired by" or "in the tradition of." The concept of originality is both culturally and historically contingent. For example, unattributed reiteration of a published text in one culture might be considered plagiarism but in another culture might be regarded as a convention of veneration. At the time of Shakespeare, it was more common to appreciate the similarity with an admired classical work, and Shakespeare himself avoided "unnecessary invention".Royal Shakespeare Company (2007) ''The RSC Shakespeare - Wil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south; it covers an area of , with a population of almost 84 million within its 16 constituent states. Germany borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The nation's capital and most populous city is Berlin and its financial centre is Frankfurt; the largest urban area is the Ruhr. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
