The Boom XB-1 Baby Boom is a one-third-scale trijet supersonic demonstrator designed by Boom Technology as part of development of the Boom Overture supersonic transport airliner. It is planned to maintain Mach 2.2, with over of range. Powered by three General Electric J85s, it is expected to be flight tested in 2021.
Development
The design was unveiled in Denver on November 15, 2016 and it was initially intended to make its first subsonic flight in late 2017, powered by three General Electric CJ610 turbojets, with subsequent supersonic flight testing at Edwards AFB. By April 2017, enough financing was secured to build and fly it. Its preliminary design review was completed by June 2017, with a switch of engine to the military version of the J85 to take advantage of the extra thrust. It was then anticipated that flight tests would start late 2018. In 2017, the composite wing spar was load tested while being heated in an hydraulic testbed at, above the heat soak operational temperature. First expected supersonic flight slipped to 2019. By July 2018, the aerodynamic design was completed, the horizontal tail assembled and the engines received. The Spaceship Co., manufacturer of Virgin Galactic’s vehicles, was announced as a partner for flight tests in Mojave, California. Flight tests were delayed again for 2019 due to challenging aerodynamics and engines change from J85-21 to J85-15. The XB-1 design went through three sets of wind-tunnel tests: The first indicated that predicted calibration was off by 30%. The second set of tests confirmed accurate calibration, and a third set of tests confirmed design safety. Tunnel testing finished in November 2018, including takeoff and landing with gear doors impact on stability; and supersonic inlet testing. These tests had taken a decade on Concorde. The carbon-fiber layup of the fuselage halves was to begin in early 2019 for final assembly of the forward fuselage at the beginning of Spring. With total investment rising to $200 million, Boom was funded for XB-1 flight-testing to the end of 2020. At the June 2019Paris Air Show, Blake Scholl announced the date for first flight was pushed out to 2020, six months later than previously planned after including a stability augmentation system for better safety at high speed and at take-off and landing. Static wing loading tests were carried out in March 2020, and the wings were mated to the fuselage in April with the aft fuselage nearing completion in May. On July 8, 2020, Boom announced the roll-out date as October 7, 2020.
Design
The XB-1 Baby Boom is long, has a wingspan and a maximum take-off weight. Powered by three, non-afterburning J85-15 engines with variable geometry inlets and exhaust, the prototype should be able to sustain Mach 2.2 with more than of range. It has a two-crew cockpit, chined forebody and swept trailing edges. For thermal control, the environmental control system uses the fuel as a heat sink to dump cabin heat.
Materials
The XB-1 is constructed of lightweight composites. Materials for the hot leading edges and nose, and epoxy materials for cooler parts, are provided by Dutch TenCate Advanced Composites, high-temperature materials supplier for the SpaceX Falcon 9. The airframe will be primarily intermediate-modulus carbon fiber/epoxy, with high-modulus fibers for the wing spar caps and bismaleimideprepreg for the high-temperature leading edges and ribs.
