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Boom XB-1 Supersonic Demonstrator

XB-1 is a one-third scale realization of the Boom passenger airliner. It will demonstrate in flight the key technologies for practical supersonic travel. XB-1 is the first independently developed supersonic jet and history's fastest civil aircraft. It is under construction now and will fly in late 2017. The engineering design was unveiled at the companys Centennial airport facility in Denver, Colorado. Dubbed Baby Boom, the delta wing aircraft is a one-third scale demonstrator for a small supersonic airliner which Boom aims to certificate for commercial service by 2023. The XB-1 is 68 ft. long.

Refined through 1,000+ simulated wind tunnel tests, Boom jets feature three major aerodynamic advances from Concorde: an area-ruled fuselage, a chine, and a refined delta wing. Supersonic performance is highly sensitive to airplane cross-sectional area. The aircraft feature a gentle tapering in the aft cabin, where the wings are thickest, reducing cross section and disturbances to the surrounding air.

The center of lift shifts aft as a supersonic airplane gains speed, creating challenges for balance and control. To mitigate this shift, we incorporate a chine. The chine is a wing extension that stretches toward the nose. It generates more lift supersonic than subsonic, contributing to natural balance across a wide range of speeds. At takeoff and landing, the chine generates a stable overwing vortex, increasing lift and reducing takeoff and landing speeds. The Boom wing features high-efficiency airfoils, a gentle camber, and a swept trailing edge. The swept trailing edge reduces supersonic induced drag and helps quiet the sonic boom.

Compared to aluminum, carbon composites can be manufactured efficiently in almost any shape, allowing us to implement the ideal aerodynamic design in a strong, lightweight structure. Further, composites handle the heat and stresses of supersonic flight better than aluminum. At Mach 2.2 (1,451mph), the nose and leading edges of the aircraft reach 307F (345F on a hot day). Concorde, built from aluminum, grew about 15" in length due to the heat of supersonic flight. Composites expand much less with heat, allowing a simplified and lighter design.

A high-precision mold is CNC machined from a block of high density tooling foam. Some of our molds are 3D printed. Layers of resin-infused carbon fabric are laid up in the mold. Skin components also receive a layer of copper mesh, providing lightning strike protection. The parts are then cured in an oven or autoclave at temperatures up to 450F, under vacuum. The pressure compacts the layers of fiber eliminating any bubbles or gaps, while the intense heat develops heat resistance in the material.

The XB-1 is powered by three General Electric J85-21 turbojet engines, fed by two variable geometry supersonic intakes. Each engine has a variable geometry nozzle system. The XB-1 uses a compact turbojet engine, while the production airliner uses a medium-bypass turbofan engine for additional quiet and efficiency.

An intricately-shaped variable geometry inlet uses shockwaves to compress oncoming Mach 2.2 air, efficiently slowing to the ideal subsonic speed for the engine. Digitally-controlled movable surfaces precisely position shock waves to achieve ideal compression at a wide range of speeds and flight conditions, while blow-in doors provide extra airflow for takeoff. A unique twin-bifurcated duct allows two intakes to feed three engines, two underwing and one in the tail.

A manually-controlled hydraulically-powered system allows pilots to fly with a lightweight touch, while giving precise, responsive control of roll, pitch, and yaw. Double-redundant engine-driven hydraulic pumps provide reliable power to actuators that control ailerons (roll), stabilator (pitch), and rudder (yaw). Center sticks and rudder pedals are available for both seats, allowing a pilot in either seat to fly the airplane. An electronic yaw damper is incorporated, providing precise control across a wide range of speeds while reducing pilot workload.

The environmental control system provides a comfortable pressurized cabin. The air conditioner uses compressed air tapped from the engine, cools it by passing it through a fuel/air heat exchanger, then expands it to a comfortable cabin pressure. As a side benefit, the warmed fuel burns more efficiently, increasing overall aircraft efficiency. A dual redundant oxygen system is available in case of loss of cabin pressure.

The XB-1 fuel system stores 7,000 lb of jet fuel in 11 separate tanks, including fuselage and wing tanks. Jet pumps provide a reliable stream of fuel to each of three engines. Like Concorde, an aft trim tank holds fuel during supersonic flight, shifting the aircraft center of gravity aft as the center of lift shifts rearward.

XB-1 is under construction at Boom's hangar at Centennial Airport, just south of Denver. First flight and subsonic flight tests will be conducted from Centennial; supersonic flight tests will be conducted in the supersonic test corridor near Edwards Air Force Base in Southern California, in partnership with Virgin Galactic.



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Page last modified: 29-01-2017 17:00:01 ZULU