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aeronewsline :: Accueil :: Histoire :: Aéronefs 1945 à 1955
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 16:25
Le H 21 sur Wikipedia de langue anglaise :
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The Piasecki H-21 Workhorse/Shawnee is an American helicopter, the fourth of a line of [Vous devez être inscrit et connecté pour voir ce lien] helicopters designed and built by [Vous devez être inscrit et connecté pour voir ce lien] (later [Vous devez être inscrit et connecté pour voir ce lien]).
Commonly called the "flying banana", it was a multi-mission helicopter, utilizing wheels, skis, or floats.
The H-21 was originally developed by Piasecki as an Arctic rescue helicopter.
The H-21 had winterization features permitting operation at temperatures as low as -65 degrees F, and could be routinely maintained in severe cold weather environments.
[Vous devez être inscrit et connecté pour voir ce lien]
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The Piasecki H-21 Workhorse/Shawnee is an American helicopter, the fourth of a line of [Vous devez être inscrit et connecté pour voir ce lien] helicopters designed and built by [Vous devez être inscrit et connecté pour voir ce lien] (later [Vous devez être inscrit et connecté pour voir ce lien]).
Commonly called the "flying banana", it was a multi-mission helicopter, utilizing wheels, skis, or floats.
The H-21 was originally developed by Piasecki as an Arctic rescue helicopter.
The H-21 had winterization features permitting operation at temperatures as low as -65 degrees F, and could be routinely maintained in severe cold weather environments.
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- Messages : 257
Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 16:27
Design and development
[Vous devez être inscrit et connecté pour voir ce lien] designed and successfully sold to the [Vous devez être inscrit et connecté pour voir ce lien] a series of [Vous devez être inscrit et connecté pour voir ce lien] helicopters, starting with the [Vous devez être inscrit et connecté pour voir ce lien] of 1944.
The HRP-1 was nicknamed the "flying banana" because of the upward angle of the aft fuselage that ensured the large rotors did not hit each other in flight.
The name would later be applied to other Piasecki helicopters of similar design, including the H-21.
[Vous devez être inscrit et connecté pour voir ce lien] designed and successfully sold to the [Vous devez être inscrit et connecté pour voir ce lien] a series of [Vous devez être inscrit et connecté pour voir ce lien] helicopters, starting with the [Vous devez être inscrit et connecté pour voir ce lien] of 1944.
The HRP-1 was nicknamed the "flying banana" because of the upward angle of the aft fuselage that ensured the large rotors did not hit each other in flight.
The name would later be applied to other Piasecki helicopters of similar design, including the H-21.
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- Messages : 257
Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 16:28
In 1949, Piasecki proposed the YH-21A Workhorse to the USAF, which was an improved, all-metal derivative of the HRP-1.
Using two tandem fully-articulated three-bladed counter-rotating rotors, the H-21 was powered by one 9-cylinder [Vous devez être inscrit et connecté pour voir ce lien] supercharged 1150 hp [Vous devez être inscrit et connecté pour voir ce lien].
After its maiden flight in April 1952, the Air Force ordered 32 H-21A SAR models and 163 of the more powerful H-21B assault transport variant.
Using two tandem fully-articulated three-bladed counter-rotating rotors, the H-21 was powered by one 9-cylinder [Vous devez être inscrit et connecté pour voir ce lien] supercharged 1150 hp [Vous devez être inscrit et connecté pour voir ce lien].
After its maiden flight in April 1952, the Air Force ordered 32 H-21A SAR models and 163 of the more powerful H-21B assault transport variant.
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 16:29
The H-21B was equipped with an uprated version of the Wright 103 engine, developing 1425 shaft [Vous devez être inscrit et connecté pour voir ce lien]
(1063 kW), and featured rotor blades extended by 6 inches (152 mm).
With its improved capabilities, the H-21B could carry 22 fully-equipped infantrymen, or 12 stretchers, plus space
for two medical attendants, in the MedEvac role.
With its Arctic winter capabilities, the H-21A and H-21B were put into service by both the U.S. Air Force (USAF) and the Royal Canadian Air Force (RCAF) to maintain and service [Vous devez être inscrit et connecté pour voir ce lien] (Distant Early Warning) radar installations stretching from the [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] across the [Vous devez être inscrit et connecté pour voir ce lien] to [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien].
(1063 kW), and featured rotor blades extended by 6 inches (152 mm).
With its improved capabilities, the H-21B could carry 22 fully-equipped infantrymen, or 12 stretchers, plus space
for two medical attendants, in the MedEvac role.
With its Arctic winter capabilities, the H-21A and H-21B were put into service by both the U.S. Air Force (USAF) and the Royal Canadian Air Force (RCAF) to maintain and service [Vous devez être inscrit et connecté pour voir ce lien] (Distant Early Warning) radar installations stretching from the [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] across the [Vous devez être inscrit et connecté pour voir ce lien] to [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien].
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 16:32
The uprated 1425 hp Wright engine used in the H-21B was also used in subsequent variants sold to both the U.S. Army (as the H-21C Shawnee) and the military forces of several other nations.
In 1962, the H-21 was redesignated the CH-21 in U.S. Army service.
In 1962, the H-21 was redesignated the CH-21 in U.S. Army service.
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 16:35
Operational history
French Service in the Algerian War
In 1956, seeking a way to use helicopters in a ground attack role in the[Vous devez être inscrit et connecté pour voir ce lien], the French Air Force and French Army Aviation ([Vous devez être inscrit et connecté pour voir ce lien], Aviation Légère de l'Armée de Terre) experimented with arming the [Vous devez être inscrit et connecté pour voir ce lien], then being superseded in service by the more capable Piasecki H-21 and [Vous devez être inscrit et connecté pour voir ce lien] helicopters.
Some French Air Force and Army aviation H-21C helicopters were subsequently armed with fixed, forward-firing rockets and machine guns. A few even had racks for bombs, but tests subsequently determined that the H-21C lacked the
maneuverability and performance needed in the ground-attack role.
French Service in the Algerian War
In 1956, seeking a way to use helicopters in a ground attack role in the[Vous devez être inscrit et connecté pour voir ce lien], the French Air Force and French Army Aviation ([Vous devez être inscrit et connecté pour voir ce lien], Aviation Légère de l'Armée de Terre) experimented with arming the [Vous devez être inscrit et connecté pour voir ce lien], then being superseded in service by the more capable Piasecki H-21 and [Vous devez être inscrit et connecté pour voir ce lien] helicopters.
Some French Air Force and Army aviation H-21C helicopters were subsequently armed with fixed, forward-firing rockets and machine guns. A few even had racks for bombs, but tests subsequently determined that the H-21C lacked the
maneuverability and performance needed in the ground-attack role.
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- Messages : 257
Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 17:03
The H-21C was far more successful as a troop transport, and most H-21Cs in service were eventually fitted with flexible door-mounted guns such as the .50 cal. (12.7 mm) Browning machine gun or the (ex-[Vous devez être inscrit et connecté pour voir ce lien])[Vous devez être inscrit et connecté pour voir ce lien] 20 mm aircraft cannon for defensive use when landing assault forces under fire.
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 17:06
Though the H-21 had been removed from the ground attack role, official Army evaluations at the time indicated that the type was actually more likely to survive multiple hits by ground fire than was the Sikorsky CH-34; this was assumed to be a consequence of the location and construction of the CH-34's fuel tanks.
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 17:07
By the close of the Algerian War, troop-carrying H-21C helicopters were being used in concert with H-34 ground-attack helos in large-scale counterinsurgency operations.
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 17:09
U.S. Army Operations
The H-21C saw extensive service with the U.S. Army, primarily for use in transporting troops and supplies.
On August 24, 1954, with the assistance of in-flight refueling provided by a U.S. Army [Vous devez être inscrit et connecté pour voir ce lien], a H-21C known as
Amblin' Annie became the first helicopter to cross the United States nonstop.
Various experiments were made by the Army in arming the H-21C as a gunship; some Shawnees were armed with flex guns under the nose, while others were fitted with door guns.
The H-21C saw extensive service with the U.S. Army, primarily for use in transporting troops and supplies.
On August 24, 1954, with the assistance of in-flight refueling provided by a U.S. Army [Vous devez être inscrit et connecté pour voir ce lien], a H-21C known as
Amblin' Annie became the first helicopter to cross the United States nonstop.
Various experiments were made by the Army in arming the H-21C as a gunship; some Shawnees were armed with flex guns under the nose, while others were fitted with door guns.
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- Messages : 257
Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 17:16
One experimental version was tested stateside with a Boeing B-29 Superfortress .50 cal. remote turret mounted beneath the nose.
The H-21C (later designated CH-21C) was first deployed to [Vous devez être inscrit et connecté pour voir ce lien] in December 1961 with the Army's 8th and 57th Transportation Companies, in support of ARVN (Army Republic South Vietnam) troops.
The H-21C (later designated CH-21C) was first deployed to [Vous devez être inscrit et connecté pour voir ce lien] in December 1961 with the Army's 8th and 57th Transportation Companies, in support of ARVN (Army Republic South Vietnam) troops.
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 17:18
In Army aviation service, the CH-21C Shawnee could be armed with 7.62 mm (.308 in) or 12.7 mm (.50 in) flexible door guns.
Relatively slow, the CH-21's unprotected control cables and fuel lines proved vulnerable to the enhanced threat posed by NVA and Viet Cong ground forces, which were increasingly well-supplied with automatic small arms and heavy (12.7 mm) AA machine guns.
Relatively slow, the CH-21's unprotected control cables and fuel lines proved vulnerable to the enhanced threat posed by NVA and Viet Cong ground forces, which were increasingly well-supplied with automatic small arms and heavy (12.7 mm) AA machine guns.
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Re: Piasecki PD 22 Vertol H 21
par Helloboy Lun 19 Juil 2010, 17:20
The shooting down of a CH-21 Shawnee near the Laotian-Vietnamese border with the death of four Army aviators in July 1962 were the U.S. Army's first Vietnam casualties.
Despite these events, the Shawnee continued in service as the U.S. Army's helicopter workhorse in Vietnam until 1964 when it was replaced with the [Vous devez être inscrit et connecté pour voir ce lien].
Despite these events, the Shawnee continued in service as the U.S. Army's helicopter workhorse in Vietnam until 1964 when it was replaced with the [Vous devez être inscrit et connecté pour voir ce lien].
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aeronewsline :: Accueil :: Histoire :: Aéronefs 1945 à 1955
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