|
Air Power |
At the end of 1944, the US Army issued a design competition for a jet-powered bomber. This urgent requirement given to aircraft manufacturers was precipitated by the discovery of secret documents and actual German jet aircraft captured during World War II. The first two American jet bombers produced were the North American B-45 Tornado and the Convair XB-46. The B-45 filled a critical gap in the US defense posture. The Air Force took initial delivery of the B-45C in May 1949. While a few of the aircraft were deployed overseas in late 1950, B-45 units reached initial operational capability (IOC) in 1951. As an Air Force bomber, it saw limited service with the Tactical Air Command during the 1950s.
With a first-flight date of March 17, 1947, the North American B-45 Tornado was the first jet-powered bomber to be put into production in the United States and the first to enter operational service with the USAF. The more capable B-45C model differed from earlier models of the B-45 in several respects; the most obvious difference in the appearance of the C model was the 1200-gallon fuel tank mounted at each wingtip.
The configuration of the B-45 is reminiscent of' a World War II bomber equipped with jet engines instead of propellers driven by reciprocating power plants. The unswept wing had an average airfoil thickness ratio of about 14 percent and was equipped with trailing-edge single-slotted flaps for lift augmentation in landing and takeoff. Lateral control was accomplished with the use of conventional ailerons.
All control surfaces were hydraulically boosted, and an electrically actuated tab on the elevator was used to maintain longitudinal trim. The aerodynamic power of the trim-tab-elevator combination was so great that, in the event of an inadvertent maximum tab deflection, the pilot's strength was insufficient to overcome the resulting large elevator hinge moments if the hydraulic boost system failed or was turned off. Total in-flight destruction of at least one B-45, the aircraft operated by NACA, was probably caused by this combination of circumstances that resulted in a normal load factor far greater than the design value. The technology of power-assisted controls was in its infancy at the time of development of the B-45, and much was yet to be learned about the effective and safe application of such control techniques.
In performing the landing maneuver, pilots found that speed and flight-path angle during the approach as well as touchdown point on the runway were difficult to control with precision because of the absence of speed brakes or some other means of increasing the drag of the aircraft. As a result of the low drag, only a small amount of engine thrust was required in the approach configuration. In this low thrust range, changes in thrust with throttle movement required a relatively long period of time and rendered control of flight path and speed difficult. At higher thrust levels, changes in thrust with time were more rapid. Hence, higher aircraft drag and consequently higher required thrust would have been desirable in the approach and landing configurations. Somewhat similar problems with speed control were experienced with the Messerschmitt Me 262, the first jet fighter to enter operational service. Again, experience taught important lessons applicable to the design of later jet-powered bomber aircraft.
Manned by a crew of four, the B-45 had two pilots seated in tandem under a transparent canopy, a bombardier located in the nose, and a tail gunner. Only the pilots were equipped with ejection seats. In an emergency, the bombardier, located in the nose of the aircraft, was expected to evacuate through a hatch located in the side of the fuselage. To minimize the hazards associated with the high-velocity airstream, a fuselage flap was deployed ahead of the hatch to deflect the airstream away from the exiting bombardier. An escape hatch with deflector flaps was also provided for the tail gunner. Environmental control for the crew included pressurization, heating, and cooling.
With a gross weight of 110 050 pounds, the B-45 was in the same weight class as the wartime Boeing B-29 but had a maximum speed advantage over the B-29 of more than 200 miles per hour. A 10 000-pound weapon load could be delivered by the B-45 at a mission radius of 1008 miles. Ferry range of the aircraft was 2426 miles. The maximum lift-drag ratio of the B-45 was 16.3, about the same as that of the B-29, and its zero-lift drag coefficient was a much lower 0.0160 as compared with 0.0241 for the earlier aircraft.
The Tornado first entered service with the Strategic Air Command in November 1948, and final retirement of the type from operational service took place in 1958. The Air Force accepted a total of 142 B-45s in various configurations, 51 aircraft fewer than originally ordered. The B-45 program included 3 experimental XB-45s aircraft (one of which was completed as a preproduction example), 96 production B-45As (some of which were designated as B-45A-5s reflecting in-production improvements), 10 B-45Cs , and 33 RB-45Cs. The aircraft were produced by North American Aviation, Incorporated, of Inglewood, California, with most of the aircraft being built in a former Douglas facility at Long Beach, California.
The B-45 served well as a reconnaissance aircraft during the Korean war. The reconnaissance models were designated RB-45Cs and assigned to the Strategic Air Command. The Tornado performed classified, deep penetration photographic intelligence missions over many cold war communist countries. The reconnaissance version of the B-45 became the forerunner of the U-2 and SR-71 surveillance aircraft.
In 1952, using in-flight refueling, two RB-45Cs made the first nonstop trans-Pacific flight by multi-engine jet bombers. In flying the 3,640 miles from Alaska to Japan in 9 hours and 50 minutes, one of the pilots won the Mackay Trophy for the most meritorious flight of that year.
Specifications:
Manufacturer: North American Aviation
Primary Role: Bomber
Engines: Four General Electric J47s of 6,000 lbs. thrust ea.
Crew: Four (pilot, Co-pilot, Bombadier, Tailgunner)
Number Built: 143
Cost: $1,081,000
Dimensions:
Span: 89 ft.
Length: 75 ft. 4 in.
Height: 25 ft. 2 in.
Weight: 110,000 lbs. max.
Performance :
Maximum speed: 570 mph.
Cruising speed: 500 mph.
Range: 1000 miles
Service Ceiling: 37,550 ft.
Armaments:
Two .50-cal. machine guns in the tail;
22,000 lbs. of bombs
All information and photos Copyright of their respective websites
