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42-479: The SNECMA C.450 Coléoptère (meaning "beetle" in French, descended from Greek for "sheathed wing") was a tail-sitting vertical take-off and landing (VTOL) aircraft designed by the French company SNECMA and manufactured by Nord Aviation . While work on the aircraft proceeded to the test flying phase, the project never progressed beyond experimental purposes. The Coléoptère was one of multiple efforts to produce

84-494: A dead-stick landing or volplaning , is a type of forced landing when an aircraft loses all of its propulsive power and is forced to land. The "stick" does not refer to the flight controls, which in most aircraft are either fully or partially functional without engine power, but to the traditional wooden propeller , which without power would just be a "dead stick". When a pilot makes an emergency landing of an aircraft that has some or all of its propulsive power still available,

126-399: A duct around a conventional propeller, and in the transition from vertical to forward flight the lift would have transferred to the wing. During the 1950s, aircraft designers around the world engaged in programmes to develop fixed-wing aircraft that could not only perform both a vertical take-off and vertical landing, but transition into and out of conventional flight as well. As observed by

168-429: A fixed-wing aircraft is demonstrating the ability to fly safely without an engine until prepared to make (or actually making) a landing. Gliders, unless they have an auxiliary motor, do all their flying without power, and trained pilots can touch down on virtually any spot they pick from the air. The success of the deadstick landing largely depends on the availability of suitable landing areas. A competent pilot gliding

210-419: A flying wing aircraft and drag-reducing housing". It was theorised that such a wing could function as a ramjet engine and propel an aircraft at supersonic speeds, suitable for an interceptor aircraft . SNECMA's design team decided to integrate this radical annual wing design into their VTOL efforts. Accordingly, from this decision emerged the basic configuration of the C.450 Coléoptère . In December 1958,

252-458: A lack of visual benchmarks, the aircraft became too inclined and too slow to maintain its altitude. Morel was unable to regain control amid a series of wild oscillations, opting to activate the ejection seat to escape the descending aircraft at only 150 m (492 ft). He survived but was badly injured, while the aircraft itself was destroyed. While plans for a second prototype had been mooted at one stage, such ambitions ultimately never received

294-426: A loss of power, the pilot’s goal is to maintain a safe airspeed and fly the descending aircraft to the most suitable landing spot within gliding distance, then land with the least amount of damage possible. The area open for potential landing sites depends on the original altitude, local terrain, the engine-out gliding capabilities of the aircraft, original airspeed and winds at various altitudes. Part of learning to fly

336-618: A naval airship hangar at Moffett Field in Mountain View, California. The XFY successfully demonstrated the full transition between flight modes on 5 November 1954. A somewhat similar aircraft was the Lockheed XFV Salmon , which paired a straight wing with an X tail ; however, the XFV never achieved the crucial flight transition. However, it became evident during flight testing that such VTOL aircraft would be flown only by

378-407: A relatively light, slow plane to a flat field or runway should result in an otherwise normal landing, since the maneuver is not especially difficult, requiring only strict attention and good judgement concerning speed and height. A heavier, faster aircraft or a plane gliding into mountains or trees could result in substantial damage. With helicopters , a forced landing involves autorotation , since

420-403: A rotor on a rotating section of the fuselage, these were driven by small jet engines positioned on the wingtips to propel the aircraft via this wing rotation. For takeoff and landing, it would fly vertically (akin to a helicopter ) before tilting over horizontally to fly as a self-propelled wing generating both lift and thrust. The contemporary Heinkel Lerche project had an annular wing forming

462-479: A series of wingless test rigs called the Atar Volant . Only the first of these was unpiloted and the second flew freely, both stabilized by gas jets on outrigger pipes The third had a tilting seat to allow the pilot to sit upright when the fuselage was level and had the lateral air intakes planned for the free flying aircraft, though it always operated attached to a movable cradle. The pilot for these experiments

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504-623: A tail-sitting aircraft can be attributed to originate with the inventor Nikola Tesla , who filed for an associated patent during 1928. However, no immediate attempt to implement this concept into a functional aircraft would emerge for almost two decades. During the Second World War , Nazi Germany worked on the Focke-Wulf Triebflügel (wing-driven) fighter that incorporated the tail-sitter concept into its design. It featured three wings that were mounted radially as

546-659: A test UAV flew successfully in hover mode in 1972, before development was discontinued. Another contemporary UAV project was the NSRDC BQM-108 that was developed by the United States Navy ; although work was discontinued almost immediately after its single successful test flight. During the 1970s, several studies and wind tunnel models were made of a tail-sitting version of the General Dynamics F-16 Fighting Falcon that

588-543: A viable VTOL aircraft being conducted around the world throughout the 1950s. SNECMA had previously experimented with several wingless test rigs, known as the Atar Volant , which influenced the design. In terms of its general configuration, the Coléoptère was a single-person aircraft with an unusual annular wing ; the aircraft was designed to take-off and land vertically, therefore requiring no runway and very little space. Performing its maiden flight during December 1958,

630-411: The Atar Volant . Only the first of these was unpiloted and the second flew freely, both stabilized by gas jets on outrigger pipes. The third had a tilting seat to allow the pilot to sit upright when the fuselage was level and had the lateral air intakes planned for the free flying aircraft, though it always operated attached to a movable cradle. The pilot for these experiments was Auguste Morel. However,

672-612: The United States Navy to contract American helicopter manufacturer Kaman Aircraft to design its own annular-wing vehicle, nicknamed the Flying Barrel. Accordingly, the United States experimented with its own tail-sitters, typically involving propeller -driven design configurations with relatively conventional fixed wings. The Convair XFY Pogo was one such aircraft, featuring a delta wing with cruciform tail configuration; initial test flights were conducted inside of

714-678: The 1920s with the inventor Nikola Tesla , the first aircraft to adopt a tail-sitter configuration were developed by Nazi Germany during the Second World War . Development of such aircraft spiked during the late 1940s and 1950s, as aircraft designers and defence planners alike recognised the potential value of fixed-wing aircraft that could perform both a vertical take-off and vertical landing while also transitioning into and out of conventional flight. Inherent problems with tail-sitter aircraft were poor pilot visibility and control difficulties, especially during vertical descent and landing. Programmes to develop manned tail-sitters were typically terminated in

756-558: The Atar Volant was not an end onto itself; its long term purpose was to serve as precursors to a larger fixed-wing aircraft. Separately to the internal work, substantial influence on the direction of development came from the Austrian design engineer Helmut von Zborowski , who had designed an innovative doughnut-shaped annular wing that could function "as power plant, airframe of a flying wing aircraft and drag-reducing housing". It

798-408: The Coléoptère first left the ground under its own power, albeit while attached to a gantry. Several challenging flight characteristics were observed, such as the tendency for the aircraft to slowly spin on its axis while in a vertical hover; its pilot also noted that the vertical speed indicator was unrealistic and that the controls were incapable of steering the aircraft with precision while performing

840-401: The Coléoptère rapidly made waves in the public consciousness, even internationally; author Jeremy Davis observed that the aircraft had even influenced international efforts, having allegedly motivated the United States Navy to contract American helicopter manufacturer Kaman Aircraft to design its own annular-wing vehicle, nicknamed the Flying Barrel. In December 1958, the Coléoptère first left

882-547: The United States commenced flight testing of a jet-powered design, the Ryan X-13 Vertijet . Two prototypes were constructed, both of which flew, made successful transitions to and from horizontal flight, and landed . The X-13's final test flight was conducted near Washington DC during 1957. An inherent problem with all these tail-sitter designs was poor pilot visibility, especially of the ground, during vertical descent and landing. Ultimately, most work on applying

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924-405: The aviation author Francis K. Mason, a combat aircraft that possessed such qualities would have effectively eliminate the traditional reliance on relatively vulnerable runways by taking off and landing vertically as opposed to the conventional horizontal approach. Accordingly, the development of viable vertical take-off and landing (VTOL) aircraft was particularly attractive to military planners of

966-404: The aviation author Francis K. Mason, a combat aircraft that possessed such qualities would have effectively eliminate the traditional reliance on relatively vulnerable runways by taking off and landing vertically as opposed to the conventional horizontal approach. Accordingly, the development of viable vertical take-off and landing (VTOL) aircraft was particularly attractive to military planners of

1008-457: The back of the aircraft to the ground (...a vertical orientation), and then reorient to a horizontal orientation in flight. Some tail-sitters then landed conventionally in horizontally-oriented configuration, while others had a much more ambitious goal of landing vertically with the aircraft's back to the ground, a highly hazardous procedure for many reasons, prime of which was increased fuel consumption and limited pilot visibility. The concept of

1050-479: The concept towards manned aircraft were abandoned upon the arrival of more practical form of VTOL appeared, in the form of thrust vectoring , as used by production aircraft such as the Hawker Siddeley Harrier and Yakovlev Yak-38 . An unmanned aerial vehicle (UAV) does not suffer the problem of pilot attitude. The Dornier Aerodyne is of ducted-fan configuration similar to a coleopter , and

1092-481: The critical landing phase. Dead-stick landings were deemed to be an impossibility. Morel conducted a total of eight successful flights, attaining a recorded maximum altitude of 800 m (2,625 ft). One of these flights involved a display of the aircraft's hover performance before an assembled public audience. The ninth flight, on 25 July 1959, was planned to make limited moves towards entering horizontal flight; however, hindered by insufficient instrumentation and

1134-417: The critical landing phase. Dead-stick landings were deemed to be an impossibility. One of aircraft's flights involved a public display of its hover performance before an assembled audience. The eye-catching design of the Coléoptère rapidly made waves in the public conscious, even internationally; author Jeremy Davis observed that the aircraft had even influenced international efforts, having allegedly motivated

1176-502: The early postwar era. As the thrust-to-weight ratio of turbojet engines increased sufficiently for a single engine be able to lift an aircraft, designers began to investigate ways of maintaining stability while an aircraft was flying in the VTOL stage of flight. One company that opted to engage in VTOL research was the French engine manufacturer SNECMA who, beginning in 1956, built

1218-435: The early postwar era. As the thrust-to-weight ratio of turbojet engines increased sufficiently for a single engine be able to lift an aircraft, designers began to investigate ways of maintaining stability while an aircraft was flying in the VTOL stage of flight. One company that opted to engage in VTOL research was the French engine manufacturer SNECMA who, beginning in 1956, built a series of wingless test rigs called

1260-563: The flight mode of the aircraft, moving so that they would be seated nearly-upwards during the vertical phase of flight, such as landing and taking-off. The intakes for the powerplant, a single SNECMA Atar axial-flow turbojet engine were positioned on either side of the cockpit. While the aircraft had been designed by SNECMA, the majority of the manufacturing process was performed by another French aircraft company, Nord Aviation . Data from Les Avions Francais de 1944 à 1964 General characteristics Tail-sitter Originating in

1302-466: The form of the more practical thrust vectoring approach, as used by aircraft such as the Hawker Siddeley Harrier and Yakovlev Yak-38 . A tail-sitter sits vertically on its tail for takeoff and landing, then tilts the whole aircraft forward for horizontal flight. This is very different from the many other kinds of VTOL technologies, which have horizontally-oriented fuselages. Tail-sitters change fuselage orientation after take-off. They start off with

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1344-474: The funding to proceed. The Coléoptère featured a central core akin to the Atar Volant, but differed in that the fuselage was surrounded by an annular wing greatly resembling the proposals made by von Zborowski. Aerodynamic control and stability was regulated by a series of four triangular winglets , which were installed upon the outwards side of the annual wing; however, these were only effective during conventional horizontal flight. Instead, control while hovering

1386-415: The ground under its own power, albeit while attached to a gantry; Morel was at the aircraft's controls. Several challenging flight characteristics were observed, such as the tendency for the aircraft to slowly spin on its axis while in a vertical hover; Morel also noted that the vertical speed indicator was unrealistic and that the controls were incapable of steering the aircraft with precision while performing

1428-419: The helicopter glides by allowing its rotor to spin freely during the descent thus generating lift. When a single engine aircraft suffers an engine failure , it must do a dead-stick landing. A danger comes from the pilot subsequently allowing a critical loss of airspeed, which will result in excessively fast loss of altitude and, when poorly handled, loss of control. The instinct to "stretch the glide" by pulling

1470-460: The most experienced pilots, even if all technical problems were disregarded; thus, it was not feasible to place VTOL fighters—as previously hoped for—on every ship. Also, whereas jet-engined fighters had top speeds that approached Mach 2, the turboprop VTOL fighter was at a disadvantage due to its maximum speed being below Mach 1. As a result of these circumstances, work on the XFY was halted. During 1955,

1512-402: The nose up beyond its optimum point will simply make the aircraft sink faster. Should the engine power be lost shortly after takeoff, the pilot(s) must evaluate their options: attempting a low-altitude turn back to the airport might be dangerous. This "impossible turn" has killed many pilots because it very likely will result in a crash whereas a landing straight ahead (or within a few degrees of

1554-434: The procedure is known as a precautionary landing . All fixed-wing aircraft have some capability to glide with no engine power; that is, they do not fall straight down like a stone, but rather continue to move horizontally while descending. For example, with a glide ratio of 15:1, a Boeing 747-200 can glide for 150 kilometres (93 mi; 81 nmi) from a cruising altitude of 10,000 metres (33,000 ft). After

1596-437: The sole prototype was destroyed on its ninth flight on 25 July 1959. While there were intentions at one stage for a second prototype to be produced, financing was never sourced. During the 1950s, aircraft designers around the world engaged in programmes to develop fixed-wing aircraft that could not only perform both a vertical take-off and landing ( VTOL ), but transition into and out of conventional flight as well. As observed by

1638-410: Was Auguste Morel. However, the Atar Volant was not an end onto itself; its long term purpose was to serve as precursors to a larger fixed-wing aircraft. Independently of this work, substantial influence on the direction of development came from the Austrian design engineer Helmut von Zborowski , who had designed an innovative doughnut-shaped annular wing that could function "as power plant, airframe of

1680-448: Was intended for use on board ships; however, it was decided not to pursue further development of the concept due to the large thrust requirement involved, as well as the need for extensive apparatus to handle take-off and landing. At present, most of the tail sitter projects or proposals fall under the category of unmanned aircraft such as Bell Apt or Northrop Grumman Tern . Deadstick landing A deadstick landing , also called

1722-465: Was provided by a series of deflecting vanes within the engine exhaust. The undercarriage of the Coléoptère consisted of four relatively compact castored wheels. The pilot controlled the aircraft from within an enclosed cockpit ; however, the pilot's position was somewhat unorthodox. To accommodate the changing orientation of the aircraft between vertical and horizon flight, the pilot was seated upon an ejector seat that would tilt appropriately to match

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1764-477: Was theorised that such a wing could function as a ramjet engine and propel an aircraft at supersonic speeds, suitable for an interceptor aircraft . SNECMA's design team decided to integrate this radical annual wing design into their VTOL efforts. Accordingly, from this decision emerged the basic configuration of the C.450 Coléoptère. During early 1958, the completed first prototype arrived at Melun Villaroche Aerodrome ahead of testing. The eye-catching design of

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