Rob Arndt
2006-09-27 21:46:54 UTC
Discussion:
(too old to reply)
r***@aol.com
2006-09-27 22:36:01 UTC
SNIP
Looks like a response to the North American B-28
The Martin B-33 Super Marauder (Martin Model 190) was conceived by
Martin as a high-altitude derivative of the Martin B-26 Marauder, that
might eventually replace it. The design was different in many ways,
most notable in its twin tail (the B-26 had a single tail). It also
featured pressurised crew compartments.
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The first version of the B-33 design, the XB-33, was a twin-tailed
medium bomber with two Wright R-3350 engines and pressurised crew
compartments; its design began in 1940. It would carry around 4,000 lb
(1,800 kg) of bombs. Soon after design of the XB-33 began, Martin
engineers decided it would be more productive to make a drastic
overhaul to the design than to continue polishing it. This resulted in
the XB-33A. For this reason, no XB-33s were built.
Specifications (as designed):
· Length: 71 ft 0 in (22 m)
· Wingspan: 100 ft 0 in (30 m)
· Height: 22 ft 6 in (6.86 m)
· Engines: 2× Wright R-3350 radial engines of 1,800 hp (1,300 kW)
each
The XB-28 (North American model NA-63) was originally conceived as a
high altitude version of the B-25 medium bomber. The resulting design,
while maintaining the same overall configuration of the Mitchell (with
the exception of a single vertical tail instead of B-25's twin tail),
was visually more reminiscent of the B-26 Marauder. Other differences
in the XB-28 design included a pressurized fuselage and three
remote-controlled twin .50 caliber gun turrets (upper, lower, and
tail). Two prototypes were ordered in February 1940, with the first
flight taking place on April 26, 1942. After testing of the two
prototypes, the project was canceled with no further examples being
built. The reason for this, according to the USAF archives, was that
"although the XB-28 was a successful design, the aircraft never went
into production. One reason for this was high altitude bombing was too
susceptible to errors caused by wind, cloud cover, etc. especially in
the Pacific Theater of Operations. Another was the increasing
effectiveness of medium bombers at low and medium levels along with
improved tactics. Finally, the performance gains were not considered
great enough to interrupt production of proven combat models." The
second prototype XB-28 was built as a high altitude photo
reconnaissance aircraft, and was designated XB-28A, but like the first
XB-28 prototype it was the only one of its kind.
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Type: high-altitude medium bomber
Crew: 5
Armament: six .50 cal machine guns
up to 4,000 lbs. of bombs
Specifications:
Length: 56' 5"
Height: 14' 0"
Wingspan: 72' 7"
Gross Weight: 35740 lb
Propulsion:
No. of Engines: 2
Powerplant: Pratt & Whitney R-2800 "Double Wasp" radial
Horsepower: 2000 each
Performance:
Range: 2040 miles
Cruise Speed: 255 mph
Max Speed: 372 mph
Ceiling: 33500 ft
Eventually the B-33 "jest grew" and became a competitor of the B-29
As design progressed, it became clear that a two-engine aircraft would
not achieve the performance requested by the army. Instead of refining
its original design, Martin engineers chose a major alteration of the
design, increasing the number of engines to four, and the size of the
aircraft was increased to that of the B-29 Superfortress; its bombload
was to have been 12,000 lb, as much as that of the B-24 Liberator, the
heaviest bomber flown in combat prior to the B-29. This new design,
dubbed the XB-33A, was impressive enough that the Army Air Force
ordered two prototypes.
Where the original XB-33 was to be powered by the Wright R-3350, the
redesigned XB-33A was to use less powerful Wright R-2600 engines. The
main reason for this was that the R-3350 was needed for production of
the B-29, one of the most highly valued projects of the Army Air
Forces.
On 1942 January 17, the Army Air Force placed an order for 402 B-33A
Super Marauders. They were to be produced at the government-owned plant
in Omaha, Nebraska operated by Martin. However, the entire B-33 project
was cancelled on November 25 1942, with the goal of allowing the
Martin-operated Omaha plant to concentrate on manufacturing the B-29.
Specifications (B-33A, as designed)
General characteristics
· Crew: 7
· Length: 79 ft 10 in (24.3 m)
· Wingspan: 134 ft (40.8 m)
· Height: 24 ft (7.32 m)
· Wing area: 1,646 ft² (153 m²)
· Empty weight: 85,000 lb (39,000 kg)
· Loaded weight: 95,000 lb (43,000 kg)
· Powerplant: 4× Wright R-2600-15 radial engines, 1,800 hp (1,300 kW
each) each
Performance (estimated)
· Maximum speed: 345 mph (300 knots, 555 km/h)
· Cruise speed: 242 mph (210 knots, 389 km/h)
· Range: 2,000 mi (1,700 nm, 3,000 km)
· Service ceiling: 39,000 ft (12,000 m)
· Rate of climb: ft/min (m/s)
· Wing loading: 58 lb/ft² (280 kg/m²)
· Power/mass: 0.076 hp/lb (55 W/kg)
Armament
· Guns: 8× .50 in (12.7 mm) machine guns
· Bombs: 10,000 lb (4,500 kg)
Looks like a response to the North American B-28
The Martin B-33 Super Marauder (Martin Model 190) was conceived by
Martin as a high-altitude derivative of the Martin B-26 Marauder, that
might eventually replace it. The design was different in many ways,
most notable in its twin tail (the B-26 had a single tail). It also
featured pressurised crew compartments.
Loading Image...
The first version of the B-33 design, the XB-33, was a twin-tailed
medium bomber with two Wright R-3350 engines and pressurised crew
compartments; its design began in 1940. It would carry around 4,000 lb
(1,800 kg) of bombs. Soon after design of the XB-33 began, Martin
engineers decided it would be more productive to make a drastic
overhaul to the design than to continue polishing it. This resulted in
the XB-33A. For this reason, no XB-33s were built.
Specifications (as designed):
· Length: 71 ft 0 in (22 m)
· Wingspan: 100 ft 0 in (30 m)
· Height: 22 ft 6 in (6.86 m)
· Engines: 2× Wright R-3350 radial engines of 1,800 hp (1,300 kW)
each
The XB-28 (North American model NA-63) was originally conceived as a
high altitude version of the B-25 medium bomber. The resulting design,
while maintaining the same overall configuration of the Mitchell (with
the exception of a single vertical tail instead of B-25's twin tail),
was visually more reminiscent of the B-26 Marauder. Other differences
in the XB-28 design included a pressurized fuselage and three
remote-controlled twin .50 caliber gun turrets (upper, lower, and
tail). Two prototypes were ordered in February 1940, with the first
flight taking place on April 26, 1942. After testing of the two
prototypes, the project was canceled with no further examples being
built. The reason for this, according to the USAF archives, was that
"although the XB-28 was a successful design, the aircraft never went
into production. One reason for this was high altitude bombing was too
susceptible to errors caused by wind, cloud cover, etc. especially in
the Pacific Theater of Operations. Another was the increasing
effectiveness of medium bombers at low and medium levels along with
improved tactics. Finally, the performance gains were not considered
great enough to interrupt production of proven combat models." The
second prototype XB-28 was built as a high altitude photo
reconnaissance aircraft, and was designated XB-28A, but like the first
XB-28 prototype it was the only one of its kind.
Loading Image...
Loading Image...
Loading Image...
Type: high-altitude medium bomber
Crew: 5
Armament: six .50 cal machine guns
up to 4,000 lbs. of bombs
Specifications:
Length: 56' 5"
Height: 14' 0"
Wingspan: 72' 7"
Gross Weight: 35740 lb
Propulsion:
No. of Engines: 2
Powerplant: Pratt & Whitney R-2800 "Double Wasp" radial
Horsepower: 2000 each
Performance:
Range: 2040 miles
Cruise Speed: 255 mph
Max Speed: 372 mph
Ceiling: 33500 ft
Eventually the B-33 "jest grew" and became a competitor of the B-29
As design progressed, it became clear that a two-engine aircraft would
not achieve the performance requested by the army. Instead of refining
its original design, Martin engineers chose a major alteration of the
design, increasing the number of engines to four, and the size of the
aircraft was increased to that of the B-29 Superfortress; its bombload
was to have been 12,000 lb, as much as that of the B-24 Liberator, the
heaviest bomber flown in combat prior to the B-29. This new design,
dubbed the XB-33A, was impressive enough that the Army Air Force
ordered two prototypes.
Where the original XB-33 was to be powered by the Wright R-3350, the
redesigned XB-33A was to use less powerful Wright R-2600 engines. The
main reason for this was that the R-3350 was needed for production of
the B-29, one of the most highly valued projects of the Army Air
Forces.
On 1942 January 17, the Army Air Force placed an order for 402 B-33A
Super Marauders. They were to be produced at the government-owned plant
in Omaha, Nebraska operated by Martin. However, the entire B-33 project
was cancelled on November 25 1942, with the goal of allowing the
Martin-operated Omaha plant to concentrate on manufacturing the B-29.
Specifications (B-33A, as designed)
General characteristics
· Crew: 7
· Length: 79 ft 10 in (24.3 m)
· Wingspan: 134 ft (40.8 m)
· Height: 24 ft (7.32 m)
· Wing area: 1,646 ft² (153 m²)
· Empty weight: 85,000 lb (39,000 kg)
· Loaded weight: 95,000 lb (43,000 kg)
· Powerplant: 4× Wright R-2600-15 radial engines, 1,800 hp (1,300 kW
each) each
Performance (estimated)
· Maximum speed: 345 mph (300 knots, 555 km/h)
· Cruise speed: 242 mph (210 knots, 389 km/h)
· Range: 2,000 mi (1,700 nm, 3,000 km)
· Service ceiling: 39,000 ft (12,000 m)
· Rate of climb: ft/min (m/s)
· Wing loading: 58 lb/ft² (280 kg/m²)
· Power/mass: 0.076 hp/lb (55 W/kg)
Armament
· Guns: 8× .50 in (12.7 mm) machine guns
· Bombs: 10,000 lb (4,500 kg)