Boom Supersonic, the company behind what is touted to be the next supersonic passenger aircraft – Overture – has finally secured an engine maker to deliver the powerplants for its jet. In fact, it has secured three, although none are well-known in the commercial aviation space.

Announced today at its Greensboro site, the home of its future manufacturing facilities, Boom revealed plans to work with Florida Turbine Technologies, StandardAero and GE Additive, a unit of GE Aerospace, to develop the engines it needs for the Overture.

The engine being developed has been dubbed the 'Symphony.' and is described by the company as a new propulsion system designed and optimized for the Overture. Blake Scholl, Founder and CEO of Boom Supersonic, commented on the partnership, saying,

“Developing a supersonic engine specifically for Overture offers by far the best value proposition for our customers. Through the Symphony program, we can provide our customers with an economically and environmentally sustainable supersonic airplane—a combination unattainable with the current constraints of derivative engines and industry norms.”

Boom Supersonic overture engine Symphony
Photo: Boom Supersonic

​​​​​​​

Boom had faced being shut out by many of the world’s largest engine makers, with the likes of Pratt & Whitney, Rolls-Royce, GE Aviation, Honeywell and Safran all publicly stating they had no interest in developing engines for the jet. Nevertheless, Boom maintained it would find and announce an engine maker before the end of 2022. Today, it has delivered on that promise.

Boom Overture in air
Photo: Boom Supersonic

Who are these engine makers?

These manufacturers are no Rolls-Royce or Pratt & Whitney, but they do have a strong track record in propulsion technologies. Florida Turbine Technologies (FTT) is based in Jupiter, Florida, and has offices all over the world. It’s been around since 1988 as an engineering services firm, but evolved into a turbomachinery designer and manufacturer, specializing in manufacturing and developing gas turbines for both military and commercial applications.

Kratos Engine
Photo: Kratos

The company was bought out in March 2019 by California-based Kratos Defense & Security Solutions. At the time, Kratos CEO Eric DeMarco noted that the acquisition was part of Kratos’ goal to develop advanced, affordable engines for a new class of hypersonic propulsion system. The arm of Kratos that FTT occupies has so far been working on high-performance jet engines for cruise missiles and unmanned aerial systems, so although the Overture project will be a new venture for the company, it’s not exactly entering unknown territory.

StandardAero has a legacy dating back to 1911, when it was founded as Standard Machine Works in Manitoba, Canada. It began life repairing, overhauling and rebuilding engines for cars, trucks and tractors. In the ‘30s it formed an aero engine division and began rebuilding piston powerplants, subsequently becoming authorized MRO providers or Pratt & Whitney, de Havilland, and more. It began overhauling turbine engines in 1960 and has grown from there.

Standardaero working on a CFM-56 engine
Photo: StandardAero

At present, the firm doesn’t make its own engines, but it does work on MRO for business, commercial and military aviation. The firm is approved to provide services for CFM International, Rolls-Royce, Safran, Pratt & Whitney and many more, including rotorcraft.

GE Additive is a metal additive manufacturing company and a subsidiary of GE Aviation. Metal additive manufacturing is also known as metal 3D printing, using a heat source such as a laser or electron beam to heat metal in power or wire form. The molten metal is then formed into an object. This sort of process offers exemplary design freedom with improved efficiency and, most importantly for Boom, to increase the speed to market or stronger and lighter parts.

GE additives 3d printed fabrication
Photo: GE Additives

Specifications for the engines so far

From Boom's information, the specifications of the engine's design features are:

  • Architecture: twin-spool, medium-bypass turbofan engine, no afterburner
  • Thrust: 35,000lbs at takeoff
  • Fuel: optimized for 100% Sustainable Aviation Fuel
  • Single-stage fan designed for quiet operation
  • Passively cooled high-pressure turbine
  • Additive manufacturing for low weight, low part count, and reduced assembly costs
  • Certification: compliant with FAA and EASA Part 33 requirements

Alongisde this, we know there are now going to be four. Original concept designs of the Overture pegged it as a twinjet; later, it became a trijet. But the most recent and final iteration of the design has the aircraft as a quadjet. Two pod engines under each wing will be tasked with propelling the aircraft across the world at supersonic speeds. The firm previously told Simple Flying,

We selected a four-engine configuration after extensive R&D and efforts to understand the supply chain capabilities of our partners. Using four engines lets us shrink the size of each engine, allowing production to fall within current supply chain and manufacturing capabilities—all while reducing the noise levels of the aircraft.

The use of four engines instead of three also keeps weight and temperature within existing technology constraints while allowing Overture to work within established supply chain and maintenance norms.

Boom Supersonic Overture 2022 design
Photo: Boom Supersonic

Crucial to this four engine design is the need to be able to reach supersonic speeds without requiring afterburners, a feature that made Concorde so very loud and inefficient. The engines are pitched to be small, quiet turbofans, hence the need for four, as opposed to two very large and heavy units. They will be designed to run on 100% sustainable aviation fuel from the outset.

Boom also says it’s designing to make maintenance of the aircraft easier, which is why it moved away from the trijet design. Engines under the wings are far easier to work on than one mounted on the tail. For weight and balance, the engines will be located toward the rear of the aircraft.

What’s next for Boom’s Overture?

With engine makers in place, the race is on to develop and test the propulsion technology in time for Boom’s goal of starting manufacturing in 2024. That’s not long to create a complete engine and test it to the extent that it could be installed on a flying Overture.

Boom wants to roll out the first Overture in 2026, with a view to beginning its test flight campaign in 2027. That's a quiet pushback of the deadline, which was stated at Farnborough Airshow to be 2025 and 2026, respectively. Both the aircraft and the engine will need to be certified before either can enter into service, although the firm could begin flight testing with an uncertified engine as an experimental aircraft. Nevertheless, the road ahead is going to be long and expensive for Boom, despite today’s progress on its goals.

Untied Boom Supersonic Overture
Photo: Boom Supersonic

But Boom has had some strong indications of confidence in its project. It has secured orders from the likes of Japan Airlines, United Airlines, American Airlines, and the Virgin Group, as well as some from unidentified customers. In all, it says it has orders in for more than 200 of the type. That’s ten times the number of Concorde ever built. While there’s a way to go yet, today’s announcement adds a new layer of confidence for the project to eventually become a reality.