A supersonic transport (SST) or a supersonic airliner is a civilian supersonic aircraft designed to transport passengers at speeds greater than the speed of sound. To date, the only SSTs to see regular service have been Concorde and the Tupolev Tu-144. The last passenger flight of the Tu-144 was in June 1978 and it was last flown in 1999 by NASA. Concorde's last commercial flight was in October 2003, with a November 26, 2003 ferry flight being its last flight.
A propfan, also called an open rotor engine, open fan engine or unducted fan, is a type of aircraft engine related in concept to both the turboprop and turbofan, but distinct from both. The design is intended to offer the speed and performance of a turbofan, with the fuel economy of a turboprop. A propfan is typically designed with a large number of short, highly twisted blades, similar to the (ducted) fan in a turbofan engine. For this reason, the propfan has been variously described as an "unducted fan" (UDF) or an "ultra-high-bypass (UHB) turbofan".
The Boeing X-32 is a concept demonstrator aircraft that was designed for the Joint Strike Fighter competition. It lost to the Lockheed Martin X-35 demonstrator, which was further developed into the Lockheed Martin F-35 Lightning II.
The Boeing X-48 is an American experimental unmanned aerial vehicle (UAV) built to investigate the characteristics of blended wing body (BWB) aircraft. Boeing designed the X-48 and two examples were built by Cranfield Aerospace in the UK. Boeing began flight testing the X-48B version for NASA in 2007. The X-48B was later modified into the X-48C version, which was flight tested from August 2012 to April 2013. Boeing and NASA plan to develop a larger BWB demonstrator.
A blended wing body (BWB), also known as blended body, hybrid wing body (HWB) or a lifting aerofoil fuselage, is a fixed-wing aircraft having no clear dividing line between the wings and the main body of the craft. The aircraft has distinct wing and body structures, which are smoothly blended together with no clear dividing line. This contrasts with a flying wing, which has no distinct fuselage, and a lifting body, which has no distinct wings. A BWB design may or may not be tailless.
A supersonic aircraft is an aircraft capable of supersonic flight, that is, flying faster than the speed of sound. Supersonic aircraft were developed in the second half of the twentieth century. Supersonic aircraft have been used for research and military purposes, but only two supersonic aircraft, the Tupolev Tu-144 and the Concorde, ever entered service for civil use as airliners. Fighter jets are the most common example of supersonic aircraft.
The General Electric GE36 was an experimental aircraft engine, a hybrid between a turbofan and a turboprop, known as an unducted fan (UDF) or propfan. The GE36 was developed by General Electric Aircraft Engines, with its CFM International equal partner Snecma taking a 35 percent share of development. Development was cancelled in 1989.
A regional jet (RJ) is a jet-powered regional airliner usually defined by having less than 100 seats. The first aircraft considered part of this category was the Sud-Aviation Caravelle in 1959, followed by the more widespread Yakovlev Yak-40, Fokker F-28, and BAe 146. The 1990s saw the emergence of the Canadair Regional Jet and Embraer Regional Jet families, followed by the larger Embraer E-Jet and multiple competing projects. This time period also saw the bankruptcy of Fokker in 1996 and departure of BAE Systems from the market in 2001, significantly reducing the number of RJ manufacturers.
A hydrogen-powered aircraft is an aeroplane that uses hydrogen fuel as a power source. Hydrogen can either be burned in a jet engine or another kind of internal combustion engine, or can be used to power a fuel cell to generate electricity to power an electric propulsor. It cannot be stored in a traditional wet wing, and hydrogen tanks have to be housed in the fuselage or be supported by the wing.
The Boeing 720 is an American narrow-body airliner produced by Boeing Commercial Airplanes. Announced in July 1957 as a 707 derivative for shorter flights from shorter runways, the 720 first flew on November 23, 1959. Its type certificate was issued on June 30, 1960, and it entered service with United Airlines on July 5, 1960. A total of 154 Boeing 720s and 720Bs were built until 1967. As a derivative, the 720 had low development costs, allowing profitability despite relatively few sales.
Boeing Truss-Braced Wing are airliner designs studied by Boeing with braced, high aspect ratio wings.
The fuel economy in aircraft is the measure of the transport energy efficiency of aircraft. Fuel efficiency is increased with better aerodynamics and by reducing weight, and with improved engine brake-specific fuel consumption and propulsive efficiency or thrust-specific fuel consumption. Endurance and range can be maximized with the optimum airspeed, and economy is better at optimum altitudes, usually higher. An airline efficiency depends on its fleet fuel burn, seating density, air cargo and passenger load factor, while operational procedures like maintenance and routing can save fuel.
The Aerion AS2 was a proposed supersonic business jet that was being developed by Aerion Corporation. In May 2014, it was announced that the Aerion AS2 would be part of a larger Aerion SBJ redesign, which aimed for release after a seven-year developmental period. Aerion partnered with Airbus in September the same year. In December 2017, Airbus was replaced by Lockheed Martin. Its General Electric Affinity engine was unveiled in October 2018. In February 2019, Boeing replaced Lockheed Martin. Development stopped when Aerion ceased operations in May 2021.
Boom Technology, Inc. is an American company designing a supersonic airliner named the Overture. The company is also developing a one-third-scale demonstrator: the Boom XB-1 Baby Boom.
The ecoDemonstrator Program is a Boeing flight test research program, which has used a series of specially modified aircraft to develop and test aviation technologies designed to improve fuel economy and reduce the noise and ecological footprint of airliners.
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. Powered by three General Electric J85s, it is planned to maintain Mach 2.2, with over 1,000 nautical miles of range. The XB-1 began taxi tests in December 2022, and conducted its maiden flight on March 22, 2024.
The Boom Overture is a proposed supersonic airliner under development by Boom Technology. Its design will be capable of traveling Mach 1.7, with 64–80 passengers depending on configuration, and 4,250 nmi of range. The Overture is planned to be introduced in 2029. The company claims that with 500 viable routes, there could be a market for up to 1,000 supersonic airliners with fares similar to business class. The aircraft is planned to have a delta wing configuration, but will be built with composite materials. Following a redesign revealed in 2022, it is intended to be powered by four dry (non-afterburning) 35,000 lbf (160 kN) turbofans.
A hybrid electric aircraft is an aircraft with a hybrid electric powertrain. As the energy density of lithium-ion batteries is much lower than aviation fuel, a hybrid electric powertrain may effectively increase flight range compared to pure electric aircraft. By May 2018, there were over 30 hybrid electric aircraft projects, and short-haul hybrid-electric airliners were envisioned from 2032.
The Boom Symphony is a medium-bypass turbofan engine under development by Boom Technology for use on its Overture supersonic airliner. The engine is designed to produce 35,000 pounds of thrust at takeoff, sustain Overture supercruise at Mach 1.7, and burn sustainable aviation fuel exclusively.
Marty Bradley is an American aerospace engineer who specializes in advanced propulsion, electric aircraft, and sustainable aviation. He is a fellow of the American Institute of Aeronautics and Astronautics (AIAA), an adjunct professor of aerospace and mechanical engineering practice at the University of Southern California (USC), and a sustainable aviation consultant.
