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McDonnell XV-1
par Orst Mer 21 Juil 2010, 17:29
Le XV-1 sur Wikipedia en anglais :
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The McDonnell XV-1 was an experimental [Vous devez être inscrit et connecté pour voir ce lien], designated as a convertiplane, developed for a joint research program between the [Vous devez être inscrit et connecté pour voir ce lien] and the [Vous devez être inscrit et connecté pour voir ce lien] to explore technologies to develop an [Vous devez être inscrit et connecté pour voir ce lien] that could take off and land like a [Vous devez être inscrit et connecté pour voir ce lien] but fly at faster airspeeds, similar to a conventional [Vous devez être inscrit et connecté pour voir ce lien].
The XV-1 would reach a speed of 200 mph (322 km/h), faster than any previous rotorcraft, but the program was terminated due to the complexity of the technology which gave only a modest gain in performance.
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The McDonnell XV-1 was an experimental [Vous devez être inscrit et connecté pour voir ce lien], designated as a convertiplane, developed for a joint research program between the [Vous devez être inscrit et connecté pour voir ce lien] and the [Vous devez être inscrit et connecté pour voir ce lien] to explore technologies to develop an [Vous devez être inscrit et connecté pour voir ce lien] that could take off and land like a [Vous devez être inscrit et connecté pour voir ce lien] but fly at faster airspeeds, similar to a conventional [Vous devez être inscrit et connecté pour voir ce lien].
The XV-1 would reach a speed of 200 mph (322 km/h), faster than any previous rotorcraft, but the program was terminated due to the complexity of the technology which gave only a modest gain in performance.
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 17:32
Development
In 1951, the Air Force announced a competition to develop a compound helicopter, an aircraft that could take off and land vertically, like a helicopter, but could cruise at higher airspeeds than conventional helicopters.
The joint research program was being conducted by the Air Force's [Vous devez être inscrit et connecté pour voir ce lien] and the Army's [Vous devez être inscrit et connecté pour voir ce lien].
[Vous devez être inscrit et connecté pour voir ce lien] submitted the design for the [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] submitted the [Vous devez être inscrit et connecté pour voir ce lien], a retracting rotor design, and McDonnell submitted a design modified from its Model M-28 design.
In 1951, the Air Force announced a competition to develop a compound helicopter, an aircraft that could take off and land vertically, like a helicopter, but could cruise at higher airspeeds than conventional helicopters.
The joint research program was being conducted by the Air Force's [Vous devez être inscrit et connecté pour voir ce lien] and the Army's [Vous devez être inscrit et connecté pour voir ce lien].
[Vous devez être inscrit et connecté pour voir ce lien] submitted the design for the [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] submitted the [Vous devez être inscrit et connecté pour voir ce lien], a retracting rotor design, and McDonnell submitted a design modified from its Model M-28 design.
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 17:34
On 20 June 1951, the Air Force and Army signed a Letter of Intent with McDonnell to award a contract to develop an aircraft based on their design.
McDonnell benefited from previous design work on the Model M-28 and had a complete [Vous devez être inscrit et connecté pour voir ce lien] ready for inspection by the Army and Air Force by November 1951.
McDonnell was given approval to begin fabrication of what was then designated the XL-25 ("L" for Liaison).
McDonnell benefited from previous design work on the Model M-28 and had a complete [Vous devez être inscrit et connecté pour voir ce lien] ready for inspection by the Army and Air Force by November 1951.
McDonnell was given approval to begin fabrication of what was then designated the XL-25 ("L" for Liaison).
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 17:35
As the aircraft was being constructed, the designation was changed to a helicopter designation, the XH-35.
Finally, the aircraft became the first vehicle in the convertiplane series as the XV-1.
Finally, the aircraft became the first vehicle in the convertiplane series as the XV-1.
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 17:36
The basic airframe came from an early post-World War II commercial airplane program for a four-place airplane in the [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] class.
[Vous devez être inscrit et connecté pour voir ce lien] McDonnell enlisted [Vous devez être inscrit et connecté pour voir ce lien], the Austrian helicopter designer of the [Vous devez être inscrit et connecté pour voir ce lien], to provide technical direction on developing the rotor system.
[Vous devez être inscrit et connecté pour voir ce lien] After 22 months of fabrication, the first aircraft (serial 53-4016) was ready for flight testing by early 1954.[Vous devez être inscrit et connecté pour voir ce lien]
[Vous devez être inscrit et connecté pour voir ce lien] McDonnell enlisted [Vous devez être inscrit et connecté pour voir ce lien], the Austrian helicopter designer of the [Vous devez être inscrit et connecté pour voir ce lien], to provide technical direction on developing the rotor system.
[Vous devez être inscrit et connecté pour voir ce lien] After 22 months of fabrication, the first aircraft (serial 53-4016) was ready for flight testing by early 1954.[Vous devez être inscrit et connecté pour voir ce lien]
Orst- CLUB
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Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 20:30
In turn, twin tailbooms and twin vertical surfaces, inter-connected by a horizontal stabilizer elevator, were mounted to the wings.
A three-bladed main rotor powered by blade tip pressure jets was mounted on top of the fuselage, above the wing roots.
A three-bladed main rotor powered by blade tip pressure jets was mounted on top of the fuselage, above the wing roots.
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 20:32
The convertiplane featured a single [Vous devez être inscrit et connecté pour voir ce lien] radial piston engine that powered twin air compressors.
The compressors pumped air via ducts to the main rotor for vertical flight, while the engine drove the two-bladed pusher propeller for horizontal flight.
During forward flight the main rotor is permitted to autorotate, which provides some additional lift.
The compressors pumped air via ducts to the main rotor for vertical flight, while the engine drove the two-bladed pusher propeller for horizontal flight.
During forward flight the main rotor is permitted to autorotate, which provides some additional lift.
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 20:33
The cabin was covered almost entirely with Plexiglas windows providing visibility in all directions, except directly underneath the aircraft.
The cockpit consisted of tandem pilot and copilot stations, or the aircraft could accommodate a pilot and three passengers, or a pilot and two stretchers.
The cockpit consisted of tandem pilot and copilot stations, or the aircraft could accommodate a pilot and three passengers, or a pilot and two stretchers.
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 20:34
Operational history
The XV-1 began tethered hovering flight tests on 11 February 1954, with [Vous devez être inscrit et connecté pour voir ce lien] John R. Noll.
The "tether" was lead weights intended to keep the aircraft in [Vous devez être inscrit et connecté pour voir ce lien] until issues with the rotor's [Vous devez être inscrit et connecté pour voir ce lien] system were solved.
On 14 July 1954, the lead weights were removed and the XV-1 conducted its first free hovering flight.
As flight testing continued, McDonnell completed the second machine (s/n 53-4017).
The XV-1 began tethered hovering flight tests on 11 February 1954, with [Vous devez être inscrit et connecté pour voir ce lien] John R. Noll.
The "tether" was lead weights intended to keep the aircraft in [Vous devez être inscrit et connecté pour voir ce lien] until issues with the rotor's [Vous devez être inscrit et connecté pour voir ce lien] system were solved.
On 14 July 1954, the lead weights were removed and the XV-1 conducted its first free hovering flight.
As flight testing continued, McDonnell completed the second machine (s/n 53-4017).
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 20:37
Ship number two was modified from the original XV-1 in an attempt to reduce [Vous devez être inscrit et connecté pour voir ce lien] during high-speed forward flight.
To achieve this end, the rotor pylon was reduced and the undercarriage was streamlined as well as strengthened.
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The second XV-1 also featured two small tail rotors mounted on the outboard side, at the end of each tailboom.
These were a result of the hover test flights by Noll who remarked on the lack of yaw authority.
The original XV-1 would later be modified with the tail rotors.
To achieve this end, the rotor pylon was reduced and the undercarriage was streamlined as well as strengthened.
[Vous devez être inscrit et connecté pour voir ce lien]
The second XV-1 also featured two small tail rotors mounted on the outboard side, at the end of each tailboom.
These were a result of the hover test flights by Noll who remarked on the lack of yaw authority.
The original XV-1 would later be modified with the tail rotors.
Orst- CLUB
- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 20:38
By the spring of 1955, the second XV-1 was ready to join the flight program.
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On 29 April 1955, the XV-1 made its first transition from vertical to horizontal flight, and on 10 October 1955, the second XV-1 became the first rotorcraft to exceed 200 mph (322 km/h), nearly 45 mph (72 km/h) faster than the helicopter speed record at the time.
[Vous devez être inscrit et connecté pour voir ce lien] After three years and nearly 600 hours between the two aircraft, the XV-1 contract was canceled in 1957.
[Vous devez être inscrit et connecté pour voir ce lien]
On 29 April 1955, the XV-1 made its first transition from vertical to horizontal flight, and on 10 October 1955, the second XV-1 became the first rotorcraft to exceed 200 mph (322 km/h), nearly 45 mph (72 km/h) faster than the helicopter speed record at the time.
[Vous devez être inscrit et connecté pour voir ce lien] After three years and nearly 600 hours between the two aircraft, the XV-1 contract was canceled in 1957.
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- Messages : 1112
Re: McDonnell XV-1
par Orst Mer 21 Juil 2010, 20:40
Ultimately, it was determined that the XV-1's convertiplane configuration was too complex for the small advantages gained over conventional helicopters.
The piston engine could not produce enough power to optimize the design advantages.
Technological advances in conventional helicopter rotor design and engines in the following years would eventually negate the XV-1's performance margin.McDonnell would try to capitalize on the tip-jet rotor technology with a small crane helicopter design, designated Model 120 and first flown on 13 November 1957.
The piston engine could not produce enough power to optimize the design advantages.
Technological advances in conventional helicopter rotor design and engines in the following years would eventually negate the XV-1's performance margin.McDonnell would try to capitalize on the tip-jet rotor technology with a small crane helicopter design, designated Model 120 and first flown on 13 November 1957.
Orst- CLUB
- Messages : 1112
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