Social Media continues to be flooded with images, stories and statistics about the Concorde, a troubled engineering marvel that retired in 2003. The ‘Concorde’ feed highlights the love and awe the aircraft inspired. The retirement had a sense of finality about it, like a curtain being drawn, not on just the Concorde but on Supersonic Travel itself, the reason being the issues were not about the aircraft but about the accompanying noise pollution at take off ,landing and the shadow called the sonic boom.

Boom Supersonic a startup founded in 2014, but birthed in the mind at least 2-3 years prior decided to do something about. Their CEO Blake Scholl decided he was going to make a supersonic aircraft that not only went supersonic , but was quiet and without an accompanying sonic boom over land. This is the story of The Overture and is part three of the QueSST series which you can read here. https://theaviationevangelist.com/2025/10/09/the-boom-xb-1-the-little-plane-that-could/ & https://theaviationevangelist.com/2025/11/04/the-lockheed-x-59-quesst-pinocchio-swordfish/

The Overture First Iteration

The first iteration of the Overture was unveiled in Nov 2016 along with the first iteration of the XB-1 the one third scale technological demonstrator of the Overture, and both of them looked extremely similar to what the Concorde looked like! The difference being the technologies available in 2016 vs 1969 when the Concorde first flew.

Overcoming the laws of physics means any supersonic aircraft needs to be shaped a certain way, and this is where the Concorde design was lightyears ahead of its time. Concorde was the only successful supersonic jet and it made sense to look at the Concorde baseline, the original Overture was to be a trijet as was the original XB-1.

By 2018 the XB-1 subscale model was ready for wind tunnel tests and the first set of tests confirmed the predicted aerodynamic calibrations that were arrived at through CFD was off by 30%. Such a difference keeps magnifying as it goes up in scale to the full sized Overture. The Team at Boom had to go back to the drawing boards after almost 4 years of work and rework the design of the XB-1 which in turn would impact the Overture.

Repeated finetuning of the design resulted in the XB-1 that broke the sound barrier in early 2025 with no apparent sonic boom (uses a concept called Mach Cutoff), the jet itself was still in a trijet configuration but looked considerably different from the original when it rolled out on Oct 7,2020.

The tests (both CFD & wind tunnel) highlighted the design on the final XB-1 was not scalable to the Overture and there would have to be a complete rework on the fuselage, wings and engines of the Overture. Some of the highlighted issues were high take off and landing speeds due to the very low aspect ratio on the reworked XB-1’s wing, the very high angle of attack that Boom addressed with an augmented reality system, a trijet would not produce enough thrust practically to push the bigger Overture to supersonic.

In July 2022 Boom unveiled its significantly reworked Overture. The unveiling was done after considerable CFD testing followed by wind tunnel testing across five locations in the USA & Europe covering various flight regimes.The fuselage and wings looked extremely sculpted and the aircraft featured four underwing podded engines instead of the original three.

The Design

At transonic speeds (Mach 0.8-1.2) local air flows accelerate over and around the aircraft fuselage and wings can reach the speed of sound. The minimum speed at which this occurs varies from aircraft to aircraft and is known as critical Mach number. The shockwaves formed at these localized zones cause a sudden increase in drag is called wave drag. To mitigate the strength and number of shockwaves an aircraft’s cross sectional area needs to transition smoothly from front to rear. This is known as Whitcomb Area Rule of 1952 .The phenomenon was observed in various forms by multiple aerodynamicists before Whitcomb.

In the case of the Concorde the area rule was applied at Mach 2 and the rear fuselage was extended by 12.2’ on the production aircraft over the prototype and reduced wave drag by 1.8%. A similar concept was applied to the first iteration of the Overture and XB-1, the results we have already spoken of. The final iteration of the Overture extensively uses the area rule to maximum effect.

The external specs of the Boom Overture are a length of 201 feet ,a wing span of 106 feet and a height of 36 feet. The interior cabin is expected to be 79 feet in length with an aisle height of 6.5 feet, good enough for a tall person to walk through at full height. It will be capable of Maxh 1.7 at 60,000 feet cruising altitude and a max range of 4.250 NM approx 350NM more than the Concorde. https://apnews.com/press-release/pr-newswire/technology-airlines-climate-and-environment-7e88c34a01a4194c6f1e6b4760d2bb86

A front view of the nose is the first observation of the rule. Where subsonic aircraft bodies in general are circular to oblong in appearance the Overture’s nose and body behind has a distinct oval shape (left ↔️right) like an egg starting from a singular point the tip of the nose. Much like the final XB-1 the nose slopes upwards at a much higher angle from the nose tip than the bottom, like a cone that has been pushed down flattening the bottom. The oval shape of the nose permits the cabin to have the maximum permissible height allowing for passenger comfort as they walk through the aisle while at the same time minimizing aircraft front on cross section. The reason for the differing angles top and bottom of the nose tip is to control shockwaves. One of the main lessons learnt from the XB-1 was shockwaves tend to be unpredictable when the nose is a perfect cone and sometimes tend to blanket the vertical stabilizer, doing so prevents the occurrence and ensures a smooth flow over the nose and aft across the fuselage.

The nose slopes up to the cockpit windshield, the cockpit is the widest and tallest part of the fuselage. Much like the XB-70 Valkyrie where the wasting is clearly visible as the fuselage narrows down towards the tail from the cockpit the Overture does the same. In Fact the black stripes that extend from the cockpit and run rearwards forming an incomplete loop around the widest part of the fuselage looks almost Jumbo Jetish from a top view. The fuselage belly is comparatively flat and a similar design is seen on the XB-1. 

Where the Concorde had a drooping nose which was had heavy hinges and actuators, the Overture does away with the entire mechanism and instead has an augmented reality system tested on the XB-1. If the Overture’s system is like the XB-1’s it will have two 4K cameras that are mounted on the nose gear (so they can be retracted completely in flight), the cameras will be at least one large bird’s wingspan apart to build redundancy against bird strikes. The screen inside the cockpit will display a composite image along with airport markings etc if at ground level. The system is a huge weight saving over the Concorde of approx 1650 pounds.

The gull wings of the Overture have a complex geometry.

Boom – FlyBy – It’s About Time For a Bold New Era of Supersonic Flight . The modified delta planform has several special design tweaks to it. The wing appears to have a dihedral angle at the wing root and inboard section which transitions to an almost flat to anhedral angle at the outboard sections. A positive dihedral (approx 3-5° upward angle) helps with lateral stability and keeps the passenger cabin level at cruise. The flat to slight anhedral angle of approx 1° helps optimize supersonic wave drag while maintaining aileron command. The underside of the wings appear to be blended into the fuselage to soften shockwaves.

A look at the leading edge from the top shows off a clear kink much like a cranked delta on the inboard form. The kink slows down the air over the wing even as the aircraft is supersonic. Imagine if you were running towards a fence that is perpendicular to you, when you hit the fence all of you hits it at once, now imagine the fence is at an angle and kinks slightly towards you, when you first run towards it the first bit goes much faster than the rest of the wing after the kink, even though you are running at the same speed and only a little bits of you hits the fence as you keep running, the same is good for the gull wing. The inboard kink generates a powerful vortex at high AoA over the inboard wing which generates lift at takeoff & landing. The vortex prevents air separation and stalling at high angles of attack.

The steep inboard sweep which is in the region of 70-75° transitions to a shallower sweep in the region of 50°, the sweep change happening at the kink or crank, the leading continues its transitionary sweep through to the wing tips The steep inboard geometry delays shock formation and reduces wave drag at Mach 1.7 while the shallower outboard sweep increases wing area which in turn boosts lift while at the same time delaying stall formation. The crank or kink creates a natural break between the inward vortex lift and the outboard attached flow, such geometry results in superior roll authority across the speed regime.

The leading edge further shows a thicker front view profile than the Concorde did, this helps generate more lift across the speed range while at the same time exhibiting heavy contouring. Where the Concorde had an S curved leading edge that was sharp and thin, the Overture has a more ‘traditional airfoil’ although there is nothing traditional about it. At the wing roots the wings tend to blend upwards (dihedral angle) into the tapering fuselage while they drop downwards (neutral to slight anhedral angle) and lower towards the cropped wingtips. Such a design naturally helps with managing roll and gives the wings the distinctive gullwing shape.

The Overture’s cropped wingtips represent an evolution over the Concorde’s pointed ogival delta tips. On the Concorde the tips maximized the wings aspect ratio (span to average chord ratio) while helping minimize wave drag, however they were vulnerable to flutter (vibrations at high speed) on the overture the cropped wingtips ensure the aircraft maximizes area ruling through the whole profile cross section, while details of the crop are not available, we can expect the wing to be about 10-15% more efficient in fuel burn per passenger. Since a large portion of the flight time will be in the subsonic/transonic regime, the cropped wings lessen induced drag aiding quieter takeoffs (the Overture aims to be below 75dB). At supersonic speeds the sharp tips of the Concorde amplified the sonic boom , while the Overture’s cropped wingtips combined with the gullwing design soften the boom signature.

The trailing edge of the wing has a very obtuse lambda (Λ) on it. The first function of the Λ is vortex control, if you look at it relative to the leading edge kink (the vortex generator) it is slightly outboard from it. The shape helps break up and weaken these vortices as they exit the wing surfaces by inducing geometric discontinuity. The trailing edge shape also acts a sonic boom diffuser by preventing the coalescence of shocks and softening the boom overland. The trailing edge Λ and the kink on the leading edge means the wing is also called a cranked arrow.

The Λ on trailing edge helps low speed handling and stall characteristics by promoting an earlier flow separation at the root encouraging an inboard to outboard stall pattern. The overall wing design should have a washout. The trailing edge Λ further reinforces the area rule ethos of the aircraft. The edge has an inboard flap  inboard of the kink and an outboard flap that appears to begin exactly on the kink. On the outermost part of the edge is the aileron. https://boom-press-assets.s3.us-west-2.amazonaws.com/Newsroom-Media-Assets/Overture/Videos/Overture-Systems-Configuration.mp4

The four symphony engines of the Overture appear staggered  and spaced out with the inboard engines about 5 feet in front of the outboard engines (no specifics available). The staggering enables the coke bottle design (area rule) and synergizes with the wing’s highly sculpted gull wing design to minimize shockwaves at Mach 1.7, increasing range. The offset also helps with yaw control in the case of asymmetric thrust and improves low speed handling as against the Concorde’s close engines placed further back on the aircraft fuselage.The engine setup looks like a B-58 Hustler from the 1950-60s. The Hustler itself was yet another troubled but genius engineering marvel, from a time when supersonic aerodynamics understanding was still in its infancy.

The wings transition towards the empennage of aircraft. Unlike the Concorde that had an ogival delta that used elevons (combination elevators and ailerons) the Overture has a traditional aircraft’s tail with vertical and horizontal stabilizers. The vertical stabilizer’s slanting leading edge appears to land on the top of the wasting fuselage at the same spot the wingtip’s trailing edge outboard corner finishes, respecting the area rule principle. With a height of approx 18-20 feet and an area of 450-500 sq ft the stabilizer has more area than the Concorde’s at 380 sq ft and height of 27 feet. The rudder on the vertical stabilizer enhances directional stability at high AoA and provides authority in an engine out situation.

The span of the horizontal stabilizers is approx 55-60’ and an area of approx 350-400 sq ft. The stabilizers are set at a slight anhedral angle of 3-4° (cannot confirm) work closely with the vertical stabilizer and provide the aircraft with pitch authority. The control surfaces on the horizontal stabilizers are actually at the very tail of the plane and are again placed in such a manner once again to respect area ruling. The stabilizer is trimmable to manage the angle of incidence for various speed regimes and centre of gravity shifts.

The landing gear of the Overture is a tricycle setup with the nose gear having two wheels which retracts into itself and forward into the fuselage to lessen its volume profile. The main landing gear features six wheels on each bogie , which is highly unusual for an aircraft weighing in at approx 415,000 pounds. So why take on the additional weight and space? Delta winged aircraft have a normal landing speed of approx 140-160 kts which is considerably faster than a normal subsonic airliner which 135 kts such a speed will require additional braking power plus the added redundancy in case of a blow out.

AoA at take off and landing has always been the central focus to the Concorde’s design. At take off the Concorde’s AoA was between 15-18° and landing approx 15-17°, such an angle was steep enough to entail the droop nose to manage visibility. The Overture with it’s wing and tail design is expected to have a take off AoA of approx 12-14° and a landing AoA of approx 11-13°. Visibility is managed by the augmented reality cameras spoken of earlier. For reference the 777 has a take off AoA of between 12-18° and touchdown of between 6-8°. The Overture aims to have an almost subsonic aircraft type of landing angle.

Design reference points: Boom – Overture & https://boom-press-assets.s3.us-west-2.amazonaws.com/Newsroom-Media-Assets/Overture/Videos/Overture-Systems-Configuration.mp4

The Engines

Engines are the key to any aircraft’s success and in the case of SST’s they assume an added importance. They need to be capable of speed, be quiet & efficient in addition to being 100% SAF (Sustainable Aviation Fuel) compatible. Such engines can be expensive to develop and need fresh though and innovation at each step of the design and construction process. To understand SAF read here. https://theaviationevangelist.com/2025/09/25/alternative-aviation-fuels/

By 2017 Boom was on the lookout for an engine partner and Rolls Royce looked the part with their previous experience developing Concorde’s Olympus Snecma 593 turbojets. The partnership with Boom looked like the natural step forward ushering in the sustainable supersonic era (the engines were to be 100% SAF compatible) and the partnership was announced with much fanfare in July 2020. After two years embedded with the Boom Team in Colorado as they narrowed down engine specs and characteristics and then the partnership fell through in September 2022 and by December 2022 Boom decided it was going to develop the Boom Symphony engines inhouse. The parting was cordial but stiff with RR saying that developing a supersonic engine was low on their priorities list and Boom stating they were appreciative of RR’s work.

The reality was RR was wary of another Concorde like disaster where they lost the equivalent of $1.32 Bn per aircraft and did not have the wherewithal to go through the development pains in the tough economic scenario the World was currently in (COVID). Boom for their side felt the engines offered, a low bypass Pearl 700 used in Bombardier Jets aiming for 30-35,000 pounds of thrust per engine with modifications such as the inlets and exhaust with chevrons would seriously compromise efficiency by approx 23-30% below Boom’s targets. Several options were studied but nothing came off. There was added pressure on RR with the worldview on emissions (supersonic aircraft burn 3X fuel compared to subsonic aircraft) and RR’s failed partnership with Airion developing the infinity engine which ended in 2021 with Airion folding up.

Further partnerships were explored by Boom with GE, Pratt & Whitney and even Safran but all of them declined to partner, this is when Boom decided they are going it alone.

The exterior dimensions of the Symphony engine are a length of 42 feet & height of 7 feet. The supersonic inlet is 12 feet in length with the variable geometry exhaust at 19 feet, the turbofan and sprint sore section at 11 feet.The Symphony is a medium bypass twin spool engine with 3 low pressure & 6 high pressure compressors with no afterburner developing 40,000 pounds of thrust per engine.The design of the engine is optimized to the Overture and is 100% SAF compatible.

All engines have three phases suck, bang & blow. The suck is done by the main frontal fan and compressors. The bang is in the sprint core and the blow is through the high & low pressure turbines just before the exhaust.

The inlet of any SST engine is where the magic happens. While the aircraft is supersonic the engines can only gulp in air at between 400-500 mph. The inlet is where the air is slowed down by use of shockwave creation. In the case of Concorde a series of ramps and bleed valves for excess air was used to slow the air down to approx 500 mph from Mach 2. The architecture of the Overture and Symphony is different where the engines are podded below the wings instead of being integrated into them in a cluster as on the Concorde. The Inlet of the Symphony is axis symmetric with a spike at the central axis (much like the Lockheed SR-71). The spike moves back and forth as per the speed of the aircraft and manages the inlet shockwave. In the case of the SR-71 the central spike moved back up to 26” at high supersonic flight. The Symphony will probably be up 18” (speculation).

Boom is currently in the advanced prototyping phase and last month they announced that 95% of all parts were done and have been moved to manufacture. Boom is making use of extensive 3D printing of parts at their printer farm (additive manufacturing) for a number of parts being used in the Symphony prototyping phase. The Sprint Core currently being tested has 193 3D printed parts. The alloy used is Haynes 282 a nickel based alloy that can withstand extreme heat and stress.Such an approach enables rapid prototyping & iteration. An example of the speed they work at is they prefer vertical integration (in-house manufacture) vs waiting upto six months for parts to be delivered and choose to spend a couple of million dollars on the required machine instead.

Currently the Sprint core is being tested at Georgia Tech’s Combustion laboratory where the hot section is currently being put through its paces. Similarly each component of the engine will be tested independently, such an approach saves time and helps with iterations. Once testing is complete across all the engine components, they are integrated into the prototype engines, fired up and parameters checked.

Blake says the Symphony expects to generate thrust early 2026. Such a tight timeline places great pressure on the propulsion team.

Generating 40,000 pounds of thrust on-time is critical to Boom’s future funding (will speak about this).

Symphony Reference: Fact Sheet

The Superfactory, Construction, Assembly & Partners

The 180,000 sq ft Boom Superfactory has been constructed by BE&K building group and cost approx $100 Mn to construct. Boom Supersonic Overture Superfactory | BE&K Building Group . The superfactory is at Piedmont Triad International Airport in North Carolina on 65 acres of leased land, which incidentally will also host the factory producing JetZero’s Z4 Blended Wing Body Aircraft. As per a press release, Boom plans to invest $500 Mn in NC of which the building is $100 Mn, that leaves approx $400 Mn in terms of tooling yet to come in. Governor Cooper Announces Boom Will Manufacture Supersonic Aircraft in North Carolina Creating More Than 1,750 Jobs by 2030 . The Superfactory is where the final assembly of the Overture will take place and there is an entire ecosystem of partners involved in constructing the individual parts. Some of them are Aernova for the wings (they list Boom as a top innovation). https://www.aernnova.com/products/wings . Safran Landing Systems will be manufacturing the Overtures beautiful landing gear. https://boomsupersonic.com/press-release/boom-supersonic-and-safran-landing-systems-sign-supplier-agreement-for-overture . The Overture’s empannage is manufactured by Aciturri.There are several other key component suppliers who are part of the ecosystem to help make the Overture flight ready.Fact Sheet. All of them are currently design ready .

Most of the Overture will be carbon composite including the fuselage, wings & empennage. Titanium will probably be used in high stress areas such as the landing gear, engine bays and wing & stabilizer leading edges. The engine internals will have alloys such as Inconel in addition to Haynes 282 mentioned earlier. The Superfactory will have autoclaves (large ovens that cure the layered prepeg under pressure). To put a cost perspective autoclaves can cost up to $4 Mn a pop.

Cash Runway

Developing the Overture is estimated to cost approx $8 Bn up from a previous estimation of $6 Bn. Boom has so far raised approx $700 Mn through 12 rounds of funding and the investors have shown patience through the iterations process. However Boom is still well short of the required number by a long way. An IPO might be a way forward, but it will not bridge the gap.

The last funding round in late 2024 was termed as a series A showing a reset within the company, the valuation down to $584 from peak valuations of $1Bn and even $6Bn after the Aug’24 funding. Looking at the volatility of the valuation, it is extremely important for Boom’s Symphony engines to generate 40,000 pounds of thrust in early 2026, this can very well pitch the valuation up skywards and open a round of extremely high funding, Boom should target at least $1 Bn or more (thrust is the single most important milestone from here on) raised after the thrust milestone. 

In Nov ’23 Neom Investment Fund invested in Boom as a strategic investment. NIF is a subsidiary of Saudi Arabia’s Public Investment Fund (PIF) and is a key vehicle to Prince Mohd Bin Salman’s Vision 2030, an ambitious plan to diversify Saudi Arabia from its oil dependence. If PIF’s investment in Lucid Motors is any indicator where they have become a majority shareholder with over $8 Bn invested in a relatively short period. Boom has much to look forward to as they generate thrust and tool up their superfactory.

An IPO will probably be at either the Overture’s first supersonic flight or just as FAA certification progresses past 50%. Boom has been working very closely with the FAA at each step and only moves with each part after the FAA certifies it, this vastly cuts lead time. Some of the other aerospace startups like Joby & Archer Aviation have valuations that are at ± $10 Bn and Boom should target at least that much if not more.

Innovation at Work.

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