Boom Overture

The Boom Overture is a proposed supersonic airliner under development by Boom Technology. Its design is capable of traveling 1.7 Mach, 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 (similar to Concorde), 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 turbofans.

Market
The company says that five hundred daily routes would be viable: at Mach 1.7 over water, New York/Newark and London would be 3 hours and 30 minutes apart; Newark and Frankfurt would be 4 hours apart. With 4,500 nmi range, transpacific flights would require a refueling stop: San Francisco and Tokyo would be 6 hours apart. There could be a market for 1,000 supersonic airliners by 2035. Boom targets a $200 million price, not discounted and excluding options and interior, in 2016 dollars. The company claims that operational costs per premium available seat mile will be lower than subsonic wide-body aircraft. The Boom factory will be sized to assemble up to 100 aircraft per year for a 1,000- to 2,000-aircraft potential market over 10 years.

Boom plans to target $5,000 fares for a New York-to-London round-trip, while the same on Concorde cost $20,000 adjusted for inflation; it was its only profitable route. The same fuel burn enables fares similar to subsonic business class among other factors. For long-range routes like San Francisco–Tokyo and Los Angeles–Sydney, 30 lie-flat first-class seats could be proposed alongside 15 business-class seats.

In March 2016, Richard Branson confirmed that Virgin Group held options for 10 aircraft, and Virgin Galactic's subsidiary The Spaceship Company will aid in manufacturing and testing the jet. However, in 2023, Virgin Group announced that its purchase options had expired. An unnamed European carrier also holds options for 15 aircraft; the two deals total 5 billion dollars. At the 2017 Paris Air Show, 51 commitments were added for a backlog of 76 with significant deposits. In December 2017, Japan Airlines was confirmed to have pre-ordered up to 20 jets among the commitments to 76 from five airlines. Boom CEO Blake Scholl thinks 2,000 supersonic jets will connect 500 cities and one-way tickets between London and New York will be priced around £2,000, comparable with existing subsonic business class.

On June 3, 2021, United Airlines announced it had signed an agreement to purchase 15 Overture aircraft with an additional 35 options, expecting to start passenger flights by 2029. On August 16, 2022, American Airlines announced an agreement to purchase 20 Overture aircraft with an additional 40 options.

Development
By March 2016, the company had created concept drawings and wooden mockups of parts of the aircraft.

In October 2016, the design was stretched to 155 ft to seat up to 50 passengers with ten extra seats, its wingspan marginally increased, and a third engine was added to enable ETOPS with up to a 180 minutes diversion time. The plane could seat 55 passengers in a higher-density configuration. In June 2017, its introduction was scheduled for 2023. By July 2018, it was delayed to 2025. At the time, it had undergone over 1,000 simulated wind tunnel tests.

Boom initially targeted a Mach 2.2 cruise speed to fit with transoceanic airline timetables and allow higher utilization, while keeping airport noise to Stage 4, similar to subsonic long-range aircraft. The plane configuration was intended to be locked in late 2019 to early 2020 for a launch with engine selection, supply chain, production site. Development and certification of the airliner and its engine were estimated at $6 billion, requiring Series C investors. Enough money was raised in the B round of fundraising to be able to hit key milestones, including flying the demonstrator (XB-1) to prove the technology, building up an order backlog, finding key suppliers for engines, aerostructures, and avionics, and lay out the certification process, with many special conditions but with precedents.

At the June 2019 Paris Air Show, Boom CEO Blake Scholl announced the introduction of the Overture was delayed from 2023 to the 2025–2027 timeframe, following a two-year test campaign with six aircraft. In September 2020, the company announced it has been contracted by the United States Air Force to develop the Overture for possible use as Air Force One.

On October 7, 2020, Boom publicly unveiled its XB-1 demonstrator, which it planned to fly for the first time in 2021 from Mojave Air and Space Port, California. It expected to begin wind tunnel tests for the Overture in 2021, and start construction of a manufacturing facility in 2022, with the capacity to produce 5 to 10 aircraft monthly. The first Overture would be unveiled in 2025, with the aim of achieving type certification by 2029. Flights should be available in 2030, as estimated by Blake Scholl.

Boom currently targets a slower Mach 1.7 cruise. In January 2022, Boom announced a grant of US$60m from the US Air Force’s AFWERX program to further develop the Boom Overture supersonic airliner. In July 2022, Boom announced a partnership with Northrop Grumman to develop a 'special mission' variant for the U.S. Government and its allies. As of January 2022, the Overture's first flight is planned for 2026 with introduction into service expected in 2029.

On July 19, 2022, Boom unveiled a revised proposal for the production version of the Overture at the Farnborough Airshow. This version has four engines and a tailed delta wing.

On December 13, 2022, Boom announced that it would develop its own turbofan engine after "Big Three" engine manufacturers Rolls-Royce, Pratt & Whitney and General Electric, as well as CFM and Safran previously declined to develop a new engine due to high capital costs. Named Symphony, the engine will be developed under partnership with three entities: Kratos subsidiary Florida Turbine Technologies for engine design; StandardAero for maintenance; and General Electric subsidiary GE Additive for consulting on printing components.

Design
Boom's original design for Overture was a trijet, which resembled a 75% scale model of Concorde and the XB-1 "Baby Boom" test vehicle was designed and built on this basis, which took its first flight in March 2024. However, in mid-2022, the company announced a radical redesign of Overture into a quadjet, to closely resemble the unsuccessful Boeing B-2707-300 design from the 1970s.

A major change is that the new design features four large external engine pods rather than the two more compact engine 'box' nacelles, used on Concorde. This design has not been seen in high speed aircraft since the Convair B-58 Hustler bomber of the 1960s, due to high supersonic wave drag implications. It also now features a small horizontal stabilizer. Due to the low 1.5 wing aspect ratio, low-speed drag is high, and the aircraft requires high thrust at take-off. Boom also needs to address the nose-up attitude on landing. Airframe maintenance costs are expected to be similar to those of other carbon fiber airliners. The Overture should have lower fuel burn than Concorde by relying on dry (no afterburner) engines, composite structures, and improved technology since Concorde's development, although until Overture flies, Concorde remains the only Mach 2.0 supercruising aircraft in history and carried 30% more passengers than Boom is currently projecting.

In 2017 the FAA and International Civil Aviation Organization (ICAO) were working on a sonic boom standard to allow supersonic flights overland. NASA plans to fly its Low Boom Flight Demonstrator for the first time in 2022 to assess public acceptability of a 75 PNLdB boom, lower than Concorde's 105 PNLdB. The Overture is expected to not be louder at take-off than current airliners like the Boeing 777-300ER. Supersonic jets could be exempted from the FAA takeoff noise regulations, reducing their fuel consumption by 20–30% by using narrower engines optimized for acceleration over limiting noise. In 2017, Honeywell and NASA tested predictive software and cockpit displays showing the sonic booms en route, to minimize its disruption overland.

Design changes announced in July 2022 included an increase in the number of engines to four to allow for smaller less technically challenging engines and to allow takeoff at derated levels to lower noise, and redesigned gull form wing and fuselage to reduce drag.

Engines
The Boom Symphony is planned as a two-spool medium-bypass turbofan engine for use on Overture. The engine is intended to produce 35,000 pounds (160 kN) of thrust at takeoff, sustain Overture supercruise at Mach 1.7, and burn sustainable aviation fuel exclusively.

Boom announced in December 2022 that development of the engine will be conducted in partnership with Kratos subsidiary Florida Turbine Technologies for engine design, General Electric subsidiary GE Additive for additive manufacturing consulting, and StandardAero for maintenance. FTT/KTT is currently a maker of microturbines for drones and cruise missiles.

Boom aims for initial production of the engine to begin in 2024 at the Overture Superfactory at Greensboro, North Carolina.

Environment
Drag increases (and therefore fuel efficiency decreases) with cruising speed, and there is a particularly severe increase in drag around the sound barrier. Boom agrees that the fuel efficiency of the aircraft will be lower than subsonic competition, but states that operators of the aircraft "must use sustainable aviation fuel (SAF) and/or purchase high-quality carbon removal credits" to reduce the environmental impact. However, sustainable aviation fuel is not yet widely available, with large-scale production relying on technology that does not yet exist, and carbon-offsetting schemes have been widely criticized as being unable to deliver net-zero.