petak, 2. travnja 2010.

B-1 Lancer

The Rockwell (now part of Boeing) B-1 Lancer is a strategic bomber used by the United States Air Force. First envisioned in the 1960s as a supersonicbomber with sufficient range and payload to replace the B-52 Stratofortress, it developed primarily into a low-level penetrator with long range and supersonic speed capability. Its development was stopped and restarted multiple times over its history, as the theory of strategic balance changed from flexible responseto mutually assured destruction and back again. It eventually entered service more than 20 years after first being studied.

The B-1B production version has been in service with the United States Air Force (USAF) since 1986. The Lancer serves as the supersonic component of the USAF's long-range bomber force, along with the subsonic B-52 and B-2 Spirit. The bomber is commonly called the "Bone" (originally from "B-One"). With the retirement of the EF-111 Raven in 1998 and the F-14 Tomcat in 2006, the B-1B is the U.S. military's only active variable-sweep wing aircraft.

The first post-B-70 study was known as the Subsonic Low Altitude Bomber (SLAB), which was completed in 1961. This was followed by the similar Extended Range Strike Aircraft (ERSA), which added a variable-sweep wing planform, something then very much in vogue in the aviation industry. ERSA envisioned a relatively small aircraft with a 10,000 lb (4,500 kg) load and a range of 8,750 nautical miles (16,200 km), with 2,500 nmi (4,600 km) being flown at low altitudes. In August 1963 the similar Low-Altitude Manned Penetrator (LAMP) design was completed, which called for an aircraft with a 20,000 lb (9,000 kg) load and somewhat shorter range of 7,150 nautical miles (13,200 km).

These all culminated in the October 1963 Advanced Manned Precision Strike System (AMPSS), which led to industry studies at Boeing, General Dynamics, and North American. In mid-1964, the USAF had revised its requirements and retitled the project as Advanced Manned Strategic Aircraft (AMSA), which differed from AMPSS primarily in that it also demanded a high-speed high-altitude capability, albeit slower than the Valkyrie at about Mach 2. Given the lengthy series of design studies, Rockwell engineers joked that the new name actually stood for "America's Most Studied Aircraft".

The B-1 has a blended wing body configuration, with variable-sweep wing, triangular fin control surfaces and four turbofan engines, to improve range and speed with enhancedsurvivability. Forward-swept wing settings are used for takeoff, landings and high-altitude maximum cruise. Aft-swept wing settings are used in high subsonic and supersonic flight. The wings of the B-1B originally were cleared for use at settings of 15, 25, 55 and 67.5 degrees. The 45-degree setting was later cleared in 1998–99 timeframe. The length of the aircraft presented a serious flexing problem due to air turbulence at low altitude. To alleviate this, Rockwell included small canards near the nose on the B-1. An accelerometer would actuate the canards automatically to counteract turbulence and smooth out the ride.

Unlike the B-1A, the B-1B made no attempt at Mach 2+ speeds. Its maximum speed at altitude is Mach 1.25 (about 950 mph or 1,530 km/h), but its low-level speed increased to Mach 0.92 (700 mph, 1,130 km/h). Technically, the current version of the aircraft can exceed its speed restriction, but not without risking potential damage to its structure and air intakes. To help lower its radar cross section (RCS), the B-1B uses fixed air intake ramps with serpentine baffles, which limit its speed compared to the B-1A.

The B-1's defensive electronics include the Eaton AN/ALQ-161 radar warning and defensive jamming equipment, linked to a total of eight AN/ALE-49 flare dispensers located on top behind the canopy, which are handled by the AN/ASQ-184 avionics management system. The AN/ALE-49 dispenser has a capacity of 12 MJU-23A/B flares each. The MJU-23A/B flare is one of the world's largest infrared countermeasure flares having a gross weight of ~1170 g. The cylindrical Magnesium/Teflon/Viton pellet has a net weight of ~1470 g. The Plans for a defensive systems upgrade program (DSUP) were canceled for budgetary reasons. The B-1 has also been equipped to carry the ALE-50 Towed Decoy System. The Lancer has an additional Doppler tail-warning radar to detect aircraft or missiles approaching from the rear.

Also aiding the B-1's survivability is its relatively low radar cross-section (RCS). Although not technically a stealth aircraft in a comprehensive sense, thanks to the aircraft's structure, serpentine intake paths and use of radar-absorbent material its RCS is about 1/50th that of the B-52 (probably about 26 ft² or 2.4 m²), although the Lancer is not substantially smaller in mass than the Stratofortress.













Specifications (B-1B)

General characteristics

  • Crew: 4 (aircraft commander, copilot, offensive systems officer and defensive systems officer)
  • Payload: 125,000 lb (56,600 kg) ; internal and external ordnance total
  • Length: 146 ft (44.5 m)
  • Wingspan:
    • Extended: 137 ft (41.8 m)
    • Swept: 79 ft (24.1 m)
  • Height: 34 ft (10.4 m)
  • Wing area: 1,950 ft² (181.2 m²)
  • Airfoil: NA69-190-2
  • Empty weight: 192,000 lb (87,100 kg)
  • Loaded weight: 326,000 lb (148,000 kg)
  • Max takeoff weight: 477,000 lb (216,400 kg)
  • Powerplant: 4× General Electric F101-GE-102 augmented turbofans
    • Dry thrust: 14,600 lbf (64.9 kN) each
    • Thrust with afterburner: 30,780 lbf (136.92 kN) each
  • Fuel capacity, optional: 10,000 U.S. gal (38,000 L) fuel tank for 1-3 internal weapons bays each

Performance

Armament

Avionics

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