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Martin XB-51
par Luftag Mer 07 Juil 2010, 15:55
La série X avec l'improbable Martin XB 51 raconté sur Wikipedia.en
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The [Vous devez être inscrit et connecté pour voir ce lien] XB-51 was an [Vous devez être inscrit et connecté pour voir ce lien] "tri-jet" [Vous devez être inscrit et connecté pour voir ce lien] designed to a 1945 [Vous devez être inscrit et connecté pour voir ce lien]
requirement.
It was originally designed as an attack aircraft by the Air Force under specification V-8237-1 and was designated XA-45.
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The [Vous devez être inscrit et connecté pour voir ce lien] XB-51 was an [Vous devez être inscrit et connecté pour voir ce lien] "tri-jet" [Vous devez être inscrit et connecté pour voir ce lien] designed to a 1945 [Vous devez être inscrit et connecté pour voir ce lien]
requirement.
It was originally designed as an attack aircraft by the Air Force under specification V-8237-1 and was designated XA-45.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 15:57
The "A" ground attack classification was eliminated the next year, and the XB-51 designation was assigned instead.
The requirement was for low-level bombing and close support.
The XB-51 lost out in evaluation to the [Vous devez être inscrit et connecté pour voir ce lien] which entered service as the B-57.
The requirement was for low-level bombing and close support.
The XB-51 lost out in evaluation to the [Vous devez être inscrit et connecté pour voir ce lien] which entered service as the B-57.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 15:59
Design and development
The resulting unorthodox design, first flying on 28 October 1949, was (unusually for a combat aircraft) fitted with three engines, [Vous devez être inscrit et connecté pour voir ce lien] in this case: one at the extreme tail with an intake at the base of the tailfin, and two underneath the forward fuselage in pods.
The resulting unorthodox design, first flying on 28 October 1949, was (unusually for a combat aircraft) fitted with three engines, [Vous devez être inscrit et connecté pour voir ce lien] in this case: one at the extreme tail with an intake at the base of the tailfin, and two underneath the forward fuselage in pods.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:00
The innovative wings, swept at 35° and with 6° [Vous devez être inscrit et connecté pour voir ce lien], were equipped with [Vous devez être inscrit et connecté pour voir ce lien], leading-edge slots, full-width flaps and spoilers instead of ailerons.
The combination of variable incidence adjustment and slotted flaps allowed for a shorter takeoff run.
Four 954 lb (4.24 kN) thrust [Vous devez être inscrit et connecté pour voir ce lien] (RATO) bottles with a 14-second burn duration could be fitted to the rear fuselage to further improve takeoff performance.
Spectacular launches were a feature of later test flights.
The combination of variable incidence adjustment and slotted flaps allowed for a shorter takeoff run.
Four 954 lb (4.24 kN) thrust [Vous devez être inscrit et connecté pour voir ce lien] (RATO) bottles with a 14-second burn duration could be fitted to the rear fuselage to further improve takeoff performance.
Spectacular launches were a feature of later test flights.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:02
The main landing gear consisted of dual sets of wheels in tandem in the fuselage, similar to the [Vous devez être inscrit et connecté pour voir ce lien], with outrigger wheels at the wingtips (originally proved on a modified [Vous devez être inscrit et connecté pour voir ce lien] named "Middle River Stump Jumper").
The B-51 was a large but aerodynamically "clean" design which incorporated nearly all major systems internally.
The B-51 was a large but aerodynamically "clean" design which incorporated nearly all major systems internally.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:03
The aircraft was fitted with a rotating [Vous devez être inscrit et connecté pour voir ce lien], a Martin trademark; bombs could also be carried externally up to a
maximum load of 10,400 lb (4,700 kg), although the specified basic mission only required a 4,000 lb (1,814 kg) bombload.
Eight 20 mm (.79 in) cannons mounted in the nose would have been installed in production aircraft.
maximum load of 10,400 lb (4,700 kg), although the specified basic mission only required a 4,000 lb (1,814 kg) bombload.
Eight 20 mm (.79 in) cannons mounted in the nose would have been installed in production aircraft.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:05
Crew provision was for a pilot under a "fighter"-type bubble canopy and a[Vous devez être inscrit et connecté pour voir ce lien] (short-range navigation and bombing system) operator/navigator in a compartment located lower than and to the rear of the cockpit (only a small observation window was provided).
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Both crew members were provided with a pressurized, air-conditioned environment, equipped with upward-firing ejection seats.
The XB-51 was the first Martin aircraft equipped with ejection seats; the ejection seats being of their own design.
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Both crew members were provided with a pressurized, air-conditioned environment, equipped with upward-firing ejection seats.
The XB-51 was the first Martin aircraft equipped with ejection seats; the ejection seats being of their own design.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:08
Operational history
In 1950, the [Vous devez être inscrit et connecté pour voir ce lien] issued a new requirement based on early [Vous devez être inscrit et connecté pour voir ce lien] experience for a night
intruder/bomber to replace the [Vous devez être inscrit et connecté pour voir ce lien].
The XB-51 was entered, as well as the [Vous devez être inscrit et connecté pour voir ce lien] and the [Vous devez être inscrit et connecté pour voir ce lien].
The Canberra and XB-51 emerged as the favorites.
The XB-51 was a highly maneuverable aircraft at low level, and substantially faster than the Canberra (its "turn-of-speed" was faster than most fighter aircraft of the era).
In 1950, the [Vous devez être inscrit et connecté pour voir ce lien] issued a new requirement based on early [Vous devez être inscrit et connecté pour voir ce lien] experience for a night
intruder/bomber to replace the [Vous devez être inscrit et connecté pour voir ce lien].
The XB-51 was entered, as well as the [Vous devez être inscrit et connecté pour voir ce lien] and the [Vous devez être inscrit et connecté pour voir ce lien].
The Canberra and XB-51 emerged as the favorites.
The XB-51 was a highly maneuverable aircraft at low level, and substantially faster than the Canberra (its "turn-of-speed" was faster than most fighter aircraft of the era).
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:09
However, its load limiting factor of only 3.67 g (36 m/s2) restricted tight turns, and the XB-51's endurance was substantially poorer than the Canberra's; this latter proved to be the deciding factor.
Additionally, the tandem main gear plus outriggers of the XB-51 was thought unsuitable for the requirement to fly from emergency [Vous devez être inscrit et connecté pour voir ce lien].
Additionally, the tandem main gear plus outriggers of the XB-51 was thought unsuitable for the requirement to fly from emergency [Vous devez être inscrit et connecté pour voir ce lien].
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:14
The Canberra was selected for procurement and the XB-51 program ended.
Martin did not end up the loser, however, for they were selected to build the 250 Canberras ordered under the designation [Vous devez être inscrit et connecté pour voir ce lien].
Furthermore, the rotating bomb bay was incorporated in the B-57.
Martin did not end up the loser, however, for they were selected to build the 250 Canberras ordered under the designation [Vous devez être inscrit et connecté pour voir ce lien].
Furthermore, the rotating bomb bay was incorporated in the B-57.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:15
A proposed B-57 Super-Canberra also included XB-51 features, such as swept wing and tailplane.
In the end it was never built, mainly because it was a new design and would have taken too long to put in production,
although it promised much better speed and performance.
In the end it was never built, mainly because it was a new design and would have taken too long to put in production,
although it promised much better speed and performance.
Luftag- CLUB
- Messages : 2639
Re: Martin XB-51
par Luftag Mer 07 Juil 2010, 16:16
Flight testing for research purposes continued after program cancellation.
The second prototype, 46-686, which first flew in 1950, crashed on 9 May 1952 during low-level aerobatics.
The second prototype, 46-686, which first flew in 1950, crashed on 9 May 1952 during low-level aerobatics.
Luftag- CLUB
- Messages : 2639
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