AEROSPACE

offensive weapons, has helped drag out the death, suffering and destruction on both sides. As Kyiv braces for whatever President Trump may bring, history will not look kindly over this dithering. The biggest of the big Radia has designed its enormous WindRunner to transport turbine blades to remote sites by air. Space professionals assemble The 75th International Astronautical Congress in Milan. 2024 Putting Bahrain back on the aviation map The Gulf region’s oldest flag carrier, Gulf Air, celebrates its 75th anniversary in 2025. Design, Build, Fly All the news from the 2024 President’s Conference. 20 Per Ardua Administration Bill Sweetman analyses what went wrong at UK hypersonic and thermal management specialists, Reaction Engines. 32 New challenges, but with old problems With a new US President, can Europe pull together at last to strengthen its common defence? 36 ESA Lockheed Martin 16 26 40 Radia 22 Simply complex The rotating detonation engine is now on a path to flight. Gulf Air GE Aerospace The Light Aircraft Company Blueprint Natilus 4 AEROSPACE Flexible layout The large volume of a blended wing body (BWB) cabin would allow for flexible interiors and potentially more space for passengers, compared to the traditional tube fuselage of a narrowbody airliner. Additional volume also opens the potential for 40% more cargo. Natilus Horizon Wingspan 118ft Passengers 200 Payload 28t Cruise speed 68mph Range 3,500nm Lightweight shape Building on the experience of its composite Kona cargo BWB drone, Natilus says that its all-carbon fibre-reinforced plastic (CFRP) Horizon will be 25% lighter than conventional aircraft, leading to 50% fewer emissions. AIR TRANSPORT BWB airliner breaks coverSan Diego-based start-up Natilus has revealed more details about its proposed Horizon blended wing body (BWB) airliner – scaled up from its flying wing cargo UAV design. The twin-engine, 200-seat design, is aimed to enter service in the early 2030s, and is claimed to use 30% less fuel than a conventional single-aisle aircraft of similar size while providing 40% more capacity and a 50% reduction in operating costs. Unlike other BWB proposals, Natilus claims that the Horizon will be able to operate from existing airports without the need for changes to infrastructure. . 5 DECEMBER 2024 Shielded engines No engine manufacturer has yet been named, but the placement of the twin engines above the rear fuselage helps reduce the noise footprint of the aircraft to those on the ground. Natilus says it aims to use already commercially available engines, landing gears and avionics in the Horizon. The company also says that the aircraft would have room to accommodate future propulsion technologies. BWB efficiencies Taking advantage of of the aerodynamic efficiency of BWB aircraft and lightweight materials means that the Horizon is expected to burn 25% less fuel than current narrowbody airliners. Wind tunnel testing is set to begin in 2025. Fitting into airports The 118ft wingspan (same as the A320neo) of the Horizon means that it can fit into existing airport infrastructure without the need for extensive modifications. Winglets also add to the aerodynamic effiency and reduce drag while keeping the wingsace within current airport limits. 6 Radome AEROSPACE NEWS IN BRIEF UK-based engine technology company, Reaction Engines has entered administration after attempts to secure a rescue deal failed. Some 173 of the firm’s 208 staff were made redundant. (See 'Per Ardua Administration' p20). COMAC has announced that Air China will be the launch customer for its C929 widebody airliner. Making the announcement at the Zhuhai Airshow, the number of aircraft ordered and timeframe were not disclosed. UK Defence Secretary, John Healey MP has announced that, in order to save half a billion pounds over the next five years, the British Army's Watchkeeper drone fleet is to be axed, 14 of the oldest Chinooks retired and the RAF's Puma force will not be extended beyond April 2025. The amphibious assault ships, HMS Albion and HMS Bulwark, a Type 23 frigate and two RFA support ships will also be cut. ABL Space Systems has announced it is to withdraw from the commercial launch market to focus on missile defence. The US company had suffered two high-profile launch failures and was also the rocket provider for Lockheed Martin UK’s Pathfinder vertical space launch from the UK. Piper Aircraft has announced that the regulators in Australia, Brazil and the EU have granted certification to its M-700 Fury turboprop. Having entered administration in early 2024 and been acquired by a private equity firm, Isle of Wight-based Britten-Norman has received what it refers to as “significant capital investment” from Northern Ireland-based Beechlands Enterprises. The move will allow the iconic Islander aircraft to return to production, with up to eight aircraft per year initially being manufactured at Bembridge Airport. A report in The Moscow Times suggests that the Kremlin has invited airlines from Kazakhstan and a so-far unnamed other Aerobatic aircraft maker to develop aerial firefighter GENERAL AVIATION German-based eVTOL developer, Lilium has filed for insolvency after being unable to secure €50m funding from the German Federal state to match an injection of funds from Bavaria. Meanwhile, rival German eVTOL firm Volocopter has announced that certification of its VoloCity will now slip into 2025 – with CEO, Dirk Hoke, set to step down in February 2025. Europe’s eVTOL developers hit turbulence The UK’s Vertical Aerospace has also pushed back its timeline for entry into service of its VX4 eVTOL from 2026 to 2028. In early November, it conducted an untethered flight of the second VX4. Notably the second prototype is understood to include an ejection seat for the pilot – as the company aims to expand the VX4's flight envelope. UKRAINE CONFLICT As AEROSPACE went to press, on 21 November, Russia fired a conventionally-tipped, experimental intermediate-range ballistic missile against the city of Dnipro, marking another escalation in the conflict. Six or more MIRVs (Multiple independently targetable reentry vehicle) or sub-munitions from the Oreshnik missile were said to have hit the city - a centre for Ukraine's missile production, with initial reports that two people were injured in the attack. Launched from Astrakhan by the Caspian Sea some 700km away, the missile was reported to be a intermediate-range ballistic missile, with a tested range of 5,800km and which entered service in 2015. It can carry thermonuclear payloads, conventional warheads or hypersonic glide vehicles. The attack also involved Kh-101 cruise missiles launched at the city. Saudi Arabian start-up, Riyadh Air has placed an order for 60 Airbus A321neo single-aisle aircraft, the first of which will be delivered in 2026. Following on from an order for 39 Boeing 787s, this takes the new airline’s overall fleet to 132 airframes. Meanwhile, the carrier also unveiled its 'digital-native' strategy. This includes features, such as a checkout ‘shopping basket’ to purchase tickets, as well as functions for booking hotels and transport so the airline resembles firms like Uber and Amazon. Russia uses conventional IRBM with MIRVs against Ukrainian city Arkansas-based Game Composites has announced plans to produce a next-generation single-engine aerial firefighting aircraft known as the GB2 Stormbird. The company, which was founded in the UK by Philipp Steinbach, is well known for its high-performance all-composite GB1 Gamebird aerobatic aircraft and has used that as the basis for the new, two-seat firebomber. Game claims the all-composite Stormbird will carry up to 1,200 gallons of fire retardant and reach speeds in excess of 200kt. The aircraft will have an empty weight of 6,000lb and a maximum take-off weight of 19,000lb. Flight testing is expected to begin in late 2025 with deliveries in 2026. AEROSPACE AIR TRANSPORT Riyadh Air Riyadh Air orders 60 A321s TASS AIR TRANSPORT DEFENCE 7 nation, to operate domestic flights within Russia. The move is thought to be in response to the limited number of serviceable airliners operational in Russia, with sanctions on parts continuing to bite the country. The Biden administration has granted Kyiv permission to use US-supplied long-range Army Tactical Missile System (ATACMS) rockets against targets on Russian soil. The first attacks were made on 19 November with strikes on targets in Russia's Bryansk region. On 19 November SpaceX conducted the sixth test flight of its Starship/Superheavy rocket from Boca Chica, Texas. However, on this occasion, the Superheavy booster was not caught by the launch gantry arms, instead landing vertically in the sea offshore. . Leonardo has signed a framework agreement with offshore energy lessor, GDHF, to provide ten AW189 transport helicopters for delivery during 2027-29. Announced at the European Rotors expo in Amsterdam, this delivery will take GDHF’s total AW189 fleet to 13 aircraft. NASA’s Lockheed Martin X-59 QueSST demonstrator fired up its engine for the first time at the manufacturer’s Skunk Works facility in Palmdale, California on 30 October. Designed to investigate quiet sonic boom technologies, the X-59 is powered by a modified F414-GE-100 engine. ATR has cancelled the ATR42-600S STOL variant of its airliner. Following a review of the ‘evolving market dynamics,’ the company will focus on its existing product portfolio. On 6 November, the Israeli Ministry of Defense ordered 25 F-15IAs from Boeing in a deal worth $5.2m, along with options for a further 25. The aircraft, an Israeli variant of the latest F-15EX, will be delivered between 2031 and 2036 at a rate of four-to-six jets a year. In a statement, the ministry said the deal was “part of a broader package of US aid approved by the US administration.” NASA's Advanced Aircraft Concepts for Environmental Sustainability (AACES) 2050 initiative has provided $11.5 million seed funding to four companies and one university to progress future airliner concepts and technology. The recipients include Electra (above), Georgia Institute of Technology, Pratt & Whitney, JetZero and Aurora Flight Sciences. Government to address accessible travel Chinese spaceplane breaks cover At the Zhuhai Air Show, China's Chengdu Aircraft Design Institute revealed its HaoLong-1 cargo spaceplane. Similar in concept to the Sierra Space’s Dream Chaser, the vehicle is 10m long, 8m wide with a 1.8t cargo capacity. The reusable spaceplane is one of two proposed uncrewed cargo designs, shortlisted by China Manned Space Agency (CMSA) to service the Chinese space station. AEROSPACE A new UK taskforce has been launched to tackle the biggest barriers to air travel for disabled passengers. Announced by UK Transport Secretary, Louise Haigh MP at an event at Manchester Airport on 7 November, the Aviation Accessibility Task and Finish Group will be spearheaded by Baroness Tanni Grey-Thompson. Airlines, including Jet2, Virgin Atlantic, Ryanair and British Airways, as well as ABTA and representatives from Stansted, East Midlands, Manchester and Glasgow Airports have all pledged to support the initiative. Meanwhile, the US DoT issued American Airlines with a $50m penalty for violations of laws protecting disabled airline passengers between 2019 and 2023. SPACEFLIGHT Carrier-based drones put through paces The Republic of Korea Navy has successfully launched a GA-ASI Gray Eagle UAV from one of its warships. The STOL UAV took off from the Landing Helicopter Dock ROKS Dokdo on 12 November and landed at an airfield ashore. The demonstration was carried out in co-operation with Hanwha Aerospace. Meanwhile, on 19 November, the Turkish MoD conducted shipborne drone trials with its amphibious assault ship TCG Anadolu when a Baykar TB3 UAV took off and landed from the aircraft carrier. Taking off using the ski-jump, the propeller-powered TB3 drone conducted a 46min flight over the Mediterranean, before recovering back on board. Models of the TCG Anadolu at trade exhibitons have revealed that Türkiye plans to use the ship as a dedicated drone carrier with an air wing that would also include the jet-powered Bayraktar Kızılelma stealth UCAV. DECEMBER 2024 NASA funds future airliner studies State Media CCTV NASA AEROSPACE 8 The EU has selected a consortium led by SES, Eutelsat and Hispasat to provide the bloc with a sovereign satellite broadband system. Current plans are for a 12 year concession contract to be signed by December in order to reduce reliance on providers, such as Starlink. Beta Technologies has received a ‘deposit-backed order’ from EMS aircraft operator, Metro Aviation for up to 20 ALIA eVTOLs. The US medevac operator currently operates 170 aircraft across 27 US states and plans to use the ALIA to “carry out both inter-hospital and scene transports.” US supersonic start-up, Exosonic has shut down after failing to secure financial support. The company, which was founded in 2019, was aiming to bring a Mach 1.8 airliner to market – as well as develop high-speed military drones. Ethiopian Airlines has taken delivery of its first Airbus A350-1000, making the carrier the first to operate this model in Africa. With four examples on order, this will allow Ethiopian to enhance its premium offering to destinations in the US and Europe. Saab's Gripen E has made its debut in an international exercise. CRUZEX 2024 ran from 3-15 November and involved over 100 aircraft from 15 countries. The Brazilian Air Force deployed its Gripen Es, which bring the service new capabilities, including AESA radar. On 19 October, a telecommunications satellite, built by Boeing, broke up in geostationary orbit after experiencing a sudden power loss. Operator Intelsat confirmed the loss of iS-33e and the US Space Force said it had broken into 20 pieces. The reason for the breakup remains unclear. The FAA issued a Special Airworthiness Certificate to the Skyryse One helicopter on 3 October. The modified Robinson R66 uses Skyryse’s SkyOS system in place of the existing flight controls and actuators. The pilot interface is now a single control stick and two touchscreen displays and the helicopter has Radome AIR TRANSPORT AEROSPACE NEWS IN BRIEF DEFENCE The UK has completed the first guided end-to-end test firing of MBDA’s SPEAR 3 ‘mini cruise missile’. A derivative of the Brimstone anti-tank missile, but powered by a turbojet, the test SPEAR missile (which lacked a warhead) was fired from an RAF Eurofighter Typhoon at the Vidsel range in Sweden. With a range of around 120-140km, the missile will arm the UK’s F-35B fleet – which will be able to carry up to eight in its internal bay. The Australian government has cancelled a major programme to deliver a sovereign military communications satellite capability. The $5bn JP9102 project was for Lockheed Martin Australia to deliver an array of three to five satellites in geostationary orbit to provide secure communications for the Australian Defence Forces. Launched in 2021 the contract was only awarded in 2023. The government justified the decision by saying: “With the acceleration in space technologies and evolving threats in space since the project’s commencement, Defence has assessed that a single orbit GEO-based satellite communications system would not meet strategic priorities,” hinting that cheaper, multi-orbit solutions were now the way forward. Next-gen airship makes untethered flight On 24 October, US start-up, Lighter Than Air’s (LTA) Pathfinder One airship made its first untethered flight from Moffett Federal Airfield, California. The 80m long, electrically-powered, dirigible is the biggest rigid airship in 80 years and is aimed at cargo and humanitarian missions. Long-range A321XLR enters commercial service with Iberia Spanish flag carrier, Iberia completed the first commercial revenue flight with the long-range Airbus A321XLR narrowbody airliner on 6 November. The aircraft flew from Madrid to Paris CDG as part of the introduction into service of the newest and longest-range (4,700nm) variant of the A321 family. On 14 November, the aircraft stretched its transatlantic legs for the first time with an 8hr 45min flight from Madrid to Boston. The aircraft is configured for 182 passengers in a two-class layout and lie-flat business class seats. Iberia parent company, IAG was the launch customer for the A321XLR and had originally planned to allocate the 14 aircraft to Aer Lingus but strikes led to the aircraft being diverted to Iberia. SPACEFLIGHT Australia cancels GEO MilSatCom project SPEAR 3 thrown downrange LTA MoD demonstrated automated autorotations without any pilot intervention. The company says it will now begin flight testing the production version of the helicopter with a view to achieving supplemental type certification approval next year. An Eclipse 550 business jet has been used to test the Daedalean visual awareness system. Based on AI technology, this system aims to enhance awareness of traffic, including in GPS denied environments. An accident report from the Egyptian Civil Aviation Authority into the Egyptair 804 crash has suggested that the presence of explosive material behind the cockpit led to the A320 being lost with all on board during May 2016. (see 'Deafening silence', AEROSPACE, October 2024). The Vietnam Air Defence Air Force has received the first five of an eventual twelve Beechcraft T-6C Texan II trainers – the first US military aircraft to be supplied to Vietnam since the end of the Vietnam War. The remaining aircraft are to be delivered in 2025. The world’s first wooden satellite, LignoSat, has been launched into space. Deployed on a SpaceX rocket on 5 November, the CubeSat is designed by Japanese researchers with the objective of discovering how timber can be used to reduce space junk by burning up on re-entry. Gulfstream has announced that it will make the Starlink wi-fi system available on its G650 business jets. Having been granted FAA approval for this service, Gulfstream is now looking to fit the system to other products in its portfolio. Airbus Helicopters has announced that it conducted the first unpiloted test flight of its CityAirbus NextGen eVTOL from its Advanced Air Mobility flight test centre in Donauwörth, Germany, on 6 November. Australian flag carrier Qantas has retired its fleet of Boeing 717 regional airliners. The final 717 flight from Sydney to Canberra took place on 26 October under the Qantas Link brand. The aircraft will now be replaced by the Airbus A220-300. AEROSPACE GENERAL AVIATION DECEMBER 2024 9 Bizav to be hit with 50% hike in APD in UK budget As part of the Autumn Budget on 30 October, UK Chancellor, Rachel Reeves announced proposed new Air Passenger Duty (APD) rules for private jet passengers. Under the suggested new rules, the higher rate of APD, which is currently charged for passengers travelling on the largest business aircraft over 20t, will be increased by AUKUS partners announce hypersonic collaboration 50% and also extended to all private jets. The change is intended to come into effect from April 2025. The budget also included an increase in APD for passengers departing on commercial airlines with £1 for domestic flights, £2 for short-haul sector and £12 for long-haul flights. This increase will be effective from 26 April 2026. Australia, the UK and the US have announced that they will co-operate on flight testing hypersonic technology as part of the AUKUS agreement. The three countries will pool work already done on a national basis under the Hypersonic Flight Test and Experimentation (HyFliTE) project arrangement. Going forward, the partners will collaborate on airborne tests as part of steps towards developing hypersonic technology, with missiles being a key application. Up to six trilateral test flights will take place between now and 2028 with a total funding pool of $252m. Expertise on high-temperature materials, advanced propulsion systems, and control and guidance systems as well as testing facilities will also be shared. New Zealand rocketplane breaks time-to-altitude record Multinational spaceplane developer Dawn Aerospace has set a new record for time-to-altitude with its New Zealand-designed and built rocket-powered Mk-II Aurora uncrewed prototype. The demonstrator, flying from Glentanner Aerodrome New Zealand, exceeded Mach 1 in an 85º climb and reached 66,000ft in 118.6 seconds – beating the previous time-to-height record set by the F-15 Streak Eagle by 4.2 seconds. The aircraft reached an apogee of 82,500ft. On 12 November, the world’s largest wet lease specialists, Avia Solutions Group placed an order for 40 Boeing 737 MAX airliners with an option for 40 more. The deal is the first order Boeing won since the end of the IAM strike which lasted seven weeks and ended on 5 November. Dawn Aeropsae DEFENCE AIR TRANSPORT Lessor signs for up to 80 MAXs Boeing Radome NEWS IN BRIEF 10 AEROSPACE ON THE MOVE Lars Wagner will succeed Christian Scherer as CEO of Airbus’ Commercial Aircraft business. Currently, the CEO of MTU Aero Engines AG, Wagner will take over once his current contract expires on 31 December, 2025. Prof Graham Braithwaite becomes Director of Aerospace and Aviation at Cranfield University. Textron Inc has announced Robin Wendling as its new Managing Director for Europe. Stéphane Cueille has been appointed CEO of Safran Aircraft Engines, effective during the first few months of 2025, while Bruno Bellanger has been named CEO of Safran Electrical & Power. GENERAL AVIATION Spirit Airlines flies for Chapter 11 Sweden selects C-390 Sweden has selected the Embraer C-390 Millennium as its new tactical transport aircraft. The country will become the sixth European nation to fly the type. The aircraft will replace the C-130 in SwAF service, although it has not yet been announced how many will be procured. Meanwhile, the Swedish government said, on 8 November, that Brazil had opted to extend its existing contract for 36 Saab Gripen E/F fighters by 25%. The UK government has announced £975m of funding into the aerospace industry over the next five years. This comes as part of an extension to the Aerospace Technology Institute (ATI) programme and will benefit areas of the country, including Broughton, Filton and Derby. Funding applications will open in January with awards made in the autumn. £49m of funding has also been confirmed for projects in Wales. No.10 said: “Aerospace will also be at the heart of the government’s Industrial Strategy, while also having an important global role in achieving our net zero targets and defence, with the RAF and Royal Navy both relying on its technology.” AEROSPACE Florida-based US budget carrier, Spirit Airlines has filed for Chapter 11 bankruptcy protection, the first American airline to go bust in over a decade. However, it has assured customers that travel plans and repayments to aircraft lessors will not be affected – with creditors agreeing to pump $300m into the airline through the bankruptcy process. The airline made the announcement on 18 November, expressing a hope that it will emerge from bankruptcy early next year as it restructures its operations and negotiates with creditors. The airline has grappled with losses and grounding of aircraft due to engine issues, as well as a failed $3.8bn merger with JetBlue that was rejected on competition grounds. A previous merger attempt in 2022 with Frontier also collapsed. Spirit had already cut over 50 routes in an attempt to save money. AIR TRANSPORT During the RAeS President's Conference (see p 22), Dr Bill Brooks revealed images and video of his Skyfly Axe eVTOL design performing its maiden flights. Skyfly CEO, Michael Thompson was the first test pilot, with the aircraft performing both hovers and horizontal ‘hops’ under CAA e-conditions approval. The VTOL Axe can also perform conventional ‘fixed-wing’ operations, thanks to its control surfaces. Collaborative Combat Aircraft UCAV designs from two American companies have both cleared their critical design reviews. The Gambit design from General Atomics and Anduril Industries' Fury, are both therefore expected to fly for the first time next year with entry into service by the end of the decade. On 3 November, three Chinese taikonauts returned to Earth following a six month mission on the country’s Tiangong space station. The Shenzhou 18 crew carried out scientific experiments and a spacewalk prior to handing over to the crew of Shenzhou 19, meaning China briefly had six taikonauts in space. Australian-based Xplorate has completed the inspection of 550km of pipeline using a beyond visual line of sight (BVLOS) drone. The Perth-based AI company partnered with SwissDrones for the exercise, which is claimed to be a world first. As its bid to reduce costs continues, Boeing is reportedly considering selling Jeppesen, which is the world's largest provider of aviation charts and air navigation material. According to Bloomberg, it is asking $6bn for the company. £975m boost for UK aerospace R&D Embraer Skyfly DEFENCE Axe takes to the skies 11 DECEMBER 2024 News Analysis US boosts deterrence in the Gulf DEFENCE Held on 13-15 November at the Sakhir Air Base in the south of the country, by the end of the week, the Bahrain Air Show had seen 55,000 visitors, 177 organisations, 78 companies and 125 aircraft on display (up 25% since 2022). Royal Bahraini Air Force Commander General Sheikh Hamad Bin Abdulla Al Khalifa commented on the significance and aim of the airshow. “The event has been designed to reflect aerospace and defence industry demands, in addition to Bahrain’s exponential development, and will harness global expertise to provide crucial thought leadership and insight.” He noted that global partnerships were at the top of the agenda: “We are pleased to continue forging trade with Western military and aviation manufacturers, especially as the geopolitical situation in the area is very attractive to ensure the protection of our sovereignty. Bahrain will continue supporting and maintaining world peace, stability and prosperity by all means.” One highlight of the show was an appearance by not one, not two but three USAF Boeing B-52Hs (one static, two in a flypast) currently forward-deployed in an 'undisclosed location' in the region as a projection of US air power and a message of deterrence to Iran just across the Gulf. The B-52H on the static line, meanwhile, drew the attention of the Deputy King, His Royal Highness Prince Salman bin Hamad Al Khalifa, who opened the show on behalf of His Majesty King Hamad bin Isa Al Khalifa. Other US military aircraft on static display included a A-10C, C-130J, CH-53E Sea Stallion and F-16C, as well as a flypast by a US Navy P-8 Poseidon. The RBAF itself in no stranger to working with the US and its international allies, with RBAF Commander General Sheikh Hamad Bin Abdulla Al Khalifa telling AEROSPACE: “Our allied exercises and co- ordination are continuously ongoing all year long. We have conducted many national, regional and international exercises that include Neon Defender exercise with the US Navy, Sky Soldiers exercise (national), Victory Spears exercise (regional partners), TUWAIQ exercise (Multinational), Dawn of Storms exercise (national), Intrepid Falcon exercise with US NAVCENT, and RIAMDEX exercise (multinational).” Introduction of F-16V, a ‘watershed moment’ While Bahrain’s air force is undoubtedly smaller than its neighbours in Saudi Arabia, Qatar and the UAE, its air power has been strengthened recently by the introduction into service of new equipment. RBAF Commander, General Sheikh Hamad Bin Abdulla Al Khalifa said: “The Kingdom of Bahrain has successfully completed purchasing the top three priority projects during the past year, which include the most advanced and first production of 4.5-generation F-16 Block 70 Viper fighter jets (2017), AH-1Z Cobra Helicopters (2018), and Patriot Air Defence System (2019).” For the latest F-16Vs, of which Bahrain is the launch customer and is set to receive 16, Gen Al Khalifa said “So far, RBAF has received more than half the purchased F-16V aircraft during 2023 and 2024. As we are awaiting the delivery of the rest, currently we are working on supporting the available aircraft as they are fully operational for training missions.” The latest evolution of the 50-year-old F-16, the Block 70, features a Northrop Grumman APG-83 AESA radar, improved engine, larger cockpit displays and CFTs – bridging the gap between legacy F-16s and F-35 as a ‘4.5 generation’ fighter. It is also set to be equipped with L3 Harris’ next-generation Viper Shield EW system – a necessity as the modern battlespace shifts from ‘dogfighting to datafighting’. While the F-16V was not on static display, its significance showing Bahrain at the forefront of modern air power in the Gulf was stressed by Gen Gary L North, USAF (Ret), VP for Customer Requirements at Lockheed Martin Aeronautics, who described the integration of the RBAF’s current F-16 Block 40 and its new Block 70s as a “watershed moment” for the region. One interesting UAV on the static line on the Friday of the show was a Airbus Flexrotor UAV from the US Navy-led Task Force 59 – a unit dedicated to exploring uncrewed systems, AI and commercially operated/owned UAVs to help make up for a shortfall in naval vessels in patrolling these waters. The drone was acquired under a rapid acquisition programme with US destroyers currently taking a couple to sea to bolster their embarked helicopters and giving extra surveillance capabilities, whether it is looking for pirates, smugglers or insurgent activity. Strategic ally in the Gulf Furthermore, its strategic position as a key US ally and home of the US Fifth Fleet (as well as a Royal Navy base) boosts its military importance, despite its small size and also gave Washington an opportunity to send a clear message of the air power it has on call to defend its allies and interests. With increased tensions and, despite the introduction of F-16Vs and AH-1Zs, Bahrain is also focused on bolstering its defences – particularly against drone and missile attack. Reflecting on this, the Commander of RBAF told AEROSPACE: “Air defence needs constant advancement to counter swarm attacks of drones and missiles. AD development must continue in the modernisation process to overcome the unconventional weapons development and hypersonic missiles.” He added: “Laser AD technologies must be expedited to counterstrike threatening missiles and weapons as the process of development in both fields are vastly evolving worldwide.” Read the full Bahrain International Air Show report with this QR code Tim Robinson FRAeS One of three USAF B-52s that appeared at the show Tim Robinson/RAeS 12 AEROSPACE By the Numbers Understanding the world of Aerospace through data The value of Combat Air to Britain Lockheed Martin BAE Systems/Oxford Economics BAE Systems’ Air Sector business’ procurement spending by local authority district – 2023 Air Sector business’ total GDP impact across the UK by region and nation BAE Systems’ Air Sector business’ contribution to UK GDP – 2023 BAE Systems’ Air Sector business’ contribution to employment in the UK – 2023 2023 GDP contribution by nation and region BAE Systems Air Economic Impact to the UK just as a rocket engine acts on the hopper. Directional control for the rocket itself came from gimbaling the entire engine, as it is quite small. The two propellants used in the bi-prop F-100 engine were nitrous oxide (N2O) and isopropyl alcohol (IPA) and the unit could produce up to 1.2kN of thrust and a minimum of less than 0.5kN. “For our engine, we have 20% throttling, up to 125%,” Marciacq said. This range of throttling for a rocket engine is deemed necessary to have the ability to make a propulsive landing, hover and translate. The N2O nitrous oxide and IPA are ignited with an in-house designed torch igniter, which is a miniature bi-liquid engine that itself is ignited by a spark plug. The torch igniter also utilises IPA and N2O as propellants. In developing the engine, the GSP team switched from a ball valve to a needle valve for more precise, finer thrust control. Marciacq and his colleagues tethered their hopper and conducted 45 tethered flights this year from the end of May to September. These flights helped identify an instability caused by propellant sloshing, which was solved with improved GNC. Between 14-17 October, they then flew eight untethered flights with launches up to 328ft, followed by successful landings. The future In Europe, Spain’s rocket developer, PLD Space is developing its Miura 5 booster whose first stage is recovered by parachute – and ESA’s Themis programme is expected to demonstrate a test booster’s launch and vertical landing. However, there is no ESA effort to create a European Falcon 9. Despite this, the GSP colleagues have no intention of using their experience to start a VTVL company. In their view, the European launch vehicle market is saturated. Instead, they have the goal of providing in-orbit satellite servicing (IOSS) and they point out that the GNC developed for Colibri is also applicable to highly mobile satellites that have to rendezvous and dock with another spacecraft. The team has a goal of an in-orbit inspection mission in 2027 and an IOSS life extension mission by the end of 2030 – but this time tethered test flights will not be possible. Mention of rockets that launch, hover and land vertically and people will immediately think of Elon Musk’s SpaceX and its Falcon 9 and Starship launchers. However, in Gruyère, Switzerland, a team of students working with dozens of corporate supporters as part of the Gruyère Space Program (GSP) have created a vertical take-off, vertical landing (VTVL) rocket hopper technology demonstrator within just four years. In doing so, they became the first people in Europe to conduct VTVL operations. “The last flight we did at 100m was the goal of the programme and was what we had promised everyone that we would do,” said the GSP co-founder and president, Jérémy Marciacq. In addition to being president, Marciacq worked on guidance, navigation and control (GNC) and sponsorship. His fellow co-founders were Julie Böhning (listed as an ‘adviser’ but who worked on strategy, GNC and communication) and Simon Both, whose title was treasurer, although he worked on structure and propulsion. Pierre Morin was the project secretary but also worked on propulsion and Lionel Isoz oversaw telecoms. The group began GSP in 2018 during their studies at École Polytechnique Fédérale de Lausanne and started the VTVL project in 2021 by creating the Colibri demonstrator. Colibri is 2.45m tall, has a footprint of 1.4×1.4m and a 21cm diameter tank. The vehicle has a dry mass of 63.2kg and can weigh up to 100kg when fuelled. Micro Fly (μMouche) In 2020, the team started work on its in-house F-100 bipropellant test engine, as well as a drone called μMouche [micro mouche, where mouche is the French word for fly]. Marciacq explained that the drone was custom-built so its flight control electronics, avionics and software would also form the hopper’s flight computer, and the drone would use what would become the rocket’s sensors. This enabled the team of students to just “fly our drone and see if the software is right,” as Marciacq put it. Rather than being a conventional quadcopter, the μMouche had a propeller at its base, so its thrust acted upon the drone’s body Pushing the Envelope Design, build, launch (and vertically land) Robert Coppinger 13 DECEMBER 2024 THE DRONE WAS CUSTOM- BUILT SO ITS FLIGHT CONTROL ELECTRONICS, AVIONICS AND SOFTWARE WOULD ALSO FORM THE HOPPER’S FLIGHT COMPUTER, AND THE DRONE WOULD USE WHAT WOULD BECOME THE ROCKET’S SENSORS Exploring advances on the leading edge of aerospace AEROSPACE 14 Transmission f ONLINE f in @aerosociety Find us on LinkedIn Find us on Facebook www.aerosociety.com in Girls into Engineering Response to ‘Three schools joined us for a day of engineering activities, including our own glider challenge, as part of Boeing’s Girls into Engineering event.’ Mark C Fava What a great event. A glider or paper aeroplane challenge is always a lot of fun! #girldad Karen R It’s always fabulous to see their confidence and interest grow through the day, and we had some outstanding people to come in and speak to the girls this year. Women of diversity in engineering were well represented. LETTERS In defence of the British F-35B buy I read Mr Sweetman’s recent article on the USAF NGAD programme [‘Alternatives to the $300m fighter’, AEROSPACE November 2024] with some interest, and I would like to respond to some of his comments regarding the STOVL Lockheed Martin F-35B. I was involved with the F-35 programme twice during my career. The the Royal Navy, I was posted to the British Embassy in Washington DC as a technical officer supporting UK/US collaborative defence programmes and UK procurement of US equipment. After I left the Navy, I worked for BAE Systems as part of a team based in the US – our task was assessing and ensuring the compatibility of the F-35B and F-35C with a defined set of ships, including UK and US carriers. One of my tasks was to assess how the F-35B was meeting the UK’s ship integration requirements. There was a requirement to be compatible with the flight deck and hangar layouts of the Invincible-class ships. In practice, this simply meant that the F-35B could be parked on the flight and hangar decks. This requirement had zero impact on the design of the F-35B. There was no requirement for the aircraft to fit on an Invincible-class lift. While LM engineers did check the predicted aircraft layout against the Invincible lifts (and found that the wingspan exceeded the lifts’ width) no changes were made to the aircraft design to rectify this. I was, therefore, surprised to read Sweetman repeating the wholly erroneous (and oft-repeated) claim that ‘the F-35 owes its rotund shape to a limit on overall length that was set by the elevators of the Invincible-class carriers’. This is not the case. The layout and size of the F-35B was driven by the overriding need to develop a viable STOVL aircraft which, in turn, placed a severe limit on overall weight and, therefore, overall size. I freely concede that costs did, in the event, run away – but other factors drove that. There were other aspects of the article that concerned me. Sweetman refers to a “lack of enthusiasm” for the aircraft’s “elaborate spherical-coverage infrared video system.” He appears to be referring to the AN/AAQ-37 Distributed Aperture System. This is not merely a ‘video system’, it provides missile detection and tracking, countermeasure cueing, as well as aircraft detection and tracking. It also provides imagery for cockpit displays and has demonstrated the ability to detect and track ballistic missiles to ranges exceeding 800 miles. Sweetman also displays a similar lack of understanding about the F-35’s datalink system (he means the ‘Multifunction Advanced Data Link’ [MADL] system). MADL can now talk to other platforms apart from another F-35, including other aircraft and USN warships. Finally, he calls for the use of “less advanced and highly sensitive technology” to avoid “burdensome ... rules”. I am curious what sort of “sensitive technology” he thinks a modern combat aircraft could do without to avoid having to comply with security classification rules? The UK and the US have an extremely close security relationship that helps both parties navigate the (necessarily) onerous regulations. It is probably still hard work – but it is vital hard work. Cdr Stephen George RN FRAeS (Retd) RAeS I am responding to the article about Istanbul International Airport [‘Building an airport that works’, AEROSPACE October 2024]. While the article was very informative, there was a glaring absence of any mention concerning the issue of noise impacts on surrounding communities. Long considered a topic to be avoided, there is sufficient scientific and medical evidence on the adverse effects on people that we can no longer ignore. Airport planning modernisation should address these issues well in advance and not merely act surprised when communities later oppose changes. Noise abatement procedures should not be voluntary, and night-time ‘Fly Quiet’ programmes should be mandatory. We should remember that airlines are for-profit businesses and airports are commercial operations often subsidised by taxpayer dollars in addition to passenger charges. While efficiency is essential, sustainability and people’s health are equally important and should not be ignored. Not all noise issues can be solved, but those that can be mitigated or eliminated should be. Tom Lintner FRAeS Airports need to think about the neighbours Response to ‘They say it’s good to talk – but do we still need to talk in person? Why do young people not visit lectures or join aviation groups?’ Joe McGrath To quote a 26- year-old airshow organiser at a recent conference: “If you’re not on TikTok, Instagram and YouTube, you don’t exist in our world.” It is good to talk Steph Smith MRAeS I have tried many aviation in-person talks. I’m usually the youngest by around 20 years. Perhaps it’s the age gap or perceived lack of anything in common with the older generation that puts the younger lot off? Katy Lee Would I, as a 30-something woman, join an interest group made up exclusively of older men? No, because there’s an implicit barrier there that life experiences, etc will be too different to gain anything from it. Likewise, workplaces have become increasingly high pressured and expectations are huge. Finding the time for social events is tough. Simon Jakubowski Back in my youth, clubs and groups were the only places you could engage and find out information. Today’s generation has all the information they need in their pocket. Peter Reoch There are lots of younger (Gen Z) enthusiasts, but they operate differently. They’re talking on WhatsApp groups and chatting while gaming, etc. It is just a sign of the times. Oliver Stevenson There is no lack of enthusiasts around my age (20). Conversations just happen in different mediums. I’m really too young to be of the generation where internet forums were widespread, but social media has made a huge impact on things. All generations are discussing the same topics - just through different methods. Pieter Johnson Technology has surpassed face-to-face engagement and young people are not developing interpersonal skills. Fingers through the airport fence, have been replaced with live YouTube coverage. 15 DECEMBER 2024 1. aerosociety.com/news/per-ardua-administration/ Mark Munzel I’m imagining a younger person writing a similar post questioning why older enthusiasts don’t listen to podcasts or post on Instagram. Adam Landau [Intentional hyberbole begins]: I’ll turn the question on its head: why on earth are some modern humans choosing to spend their evenings sitting to attention in rooms, listening to lectures about English Electric Lightnings, when they could be collaboratively trying to master pulling of a nine-ship formation Lightning loop in DCS? Why listen to someone talking about low level flying in the Mach Loop when you could join a virtual squadron, have someone set realistic tutorials and missions for you, and actually learn how to do it? Lectures and presentations were adequate ways of engaging with aviation until technology gave us more interactive, challenging, non-linear ways to engage and learn. [Intentional hyperbole ends] I don’t think for a moment that aviation interest groups are disappearing. It’s just migrating to forms that not everyone is aware of or chooses to recognise. I am in friendship groups comprising people in their 20s and 30s who fly together virtually. They’ll chat aviation while casually flying. I think that’s as fulfilling and worthwhile as the ‘legacy’ aviation groups? Imagine if a Red Arrows’ pilot participated in live tutorial sessions through a Discord channel, instead of occasional lectures at legacy clubs. If properly promoted, I’d wager the interest would be huge. Rich Cooper In a lot of cases there is a genuine fear amongst teens and people in their early twenties to actually talk amongst people or even one-to-one. They won’t even talk on the phone. Fear of judgement is massive. eVTOL exit options The Trump effect? Per Ardua Administration Response to ‘Reaction Engines enters administration.’[1] Ashraf Miah It’s not clear to me whether we know the actual technical limitations, if any, of the technology. Perhaps the argument was not sufficiently convincing for someone to stick it in a flight vehicle – maybe it was ahead of its time. Chris French GAvA Seems like a lost opportunity but is there a solid requirement for it? Paul Harvey It’s the same old story, sadly. Reaction Engines The White House A Typhoon renaissance Keeping the noise down Editor-in-Chief wins air power advocacy award Response to ‘Will a second Trump term be the ultimate wake-up call for Europe to finally get serious on defence?’ @Erik_Slot It should be, and we already have aircraft, ship, gun and tank builders. It is time to spend our cash on great European products. @ValkStrategy Some nations have always been serious. France maintains a nuclear dyad and a full range of sovereign technologies. If Norway’s armed forces were scaled to the US population they’d have 3,000 F-35s. @bulkeley_john He will give them a simple choice – spend more on defence or the US will reduce its NATO commitment. Possibly by only stationing forces in countries that spend 2%+ of GDP on defence. @KimBoiLee I hope so, and not only in terms of hardware, but also to revamp its decision-making. The term ‘hybrid war’ should be removed and war treated as what it is: a war. Response to ‘In the latest AEROSPACE: eVTOL training and will next-gen supersonic airliners need flight deck displays to monitor boom profiles?’’ @bscholl Supersonic and eVTOL: a great mix when you can catch an eVTOL to the airport for your supersonic flight. Yup, Overture will have real-time boom prediction. Response to ‘Red ejection- seat triangle symbol on side of Vertical VX4 cockpit.’ @nealteamgibson If it ever has to be used I hope that the seat lifts cleanly and vertically. @TheCeefax Thinking on that, I would design a system with explosive bolts to discard the closest propeller blades to the cockpit prior to ejection. Response to ‘Spain to sign for 25 more Typhoons, Qatar looking at second batch of 12, Saudi for 54, Türkiye looking at 40 and potentially 32 for Poland.’ @praxeological00 A success story – but is it time we developed it? Stealthy shape, RAM, thrust vectors working together with the canard and a strengthened airframe for carrier landings? @SouthernMan7 Europe perhaps, but the UK certainly not. Expect the SDR to be big on bold decisions for lots of permanent capability holidays across the services on the grounds that geography makes us safe. UK Lightning update Tim Robinson/RAeS @FoxTwo2022 Plus 24 for Italy and 20 for Germany – which would more than offset the 32 for Poland (which I do not consider very likely). That would get the total production run close to 900 aircraft – getting into Tornado territory. @Thomas977673521 We also need the UK to get a load. Plus we need to build a load for Ukraine to get ahead of the US who will want to export to them once the war is over. @NadsDogs Just need to gift all the T.1s to Ukraine! Response to ‘LMUK reveals UK F-35B Full Operational Capability set to be declared in 2025.’ @GarethJennings3 I think that milestone is for Carrier Enabled Power Projection (CEPP), which comprises the F-35s and the carriers. More to do with the jets being able to operate from the ships and the ships being able to host the jets than them being at their ‘full operating capability’. @riksbar1 With Brimstone and Meteor, right? @tinman197474747 No Brimstone, we are putting SPEAR 3 on it. On 19 November at the Air & Space Power Association Industry Dinner at the IET, AEROSPACE Editor-in-Chief, Tim Robinson FRAeS (seen here with ASPA Chair, Mark Roberts) was awarded the Air & Space Power Association Advocacy Award 2024 for his promotion and ongoing coverage of air and space power topics. During the same event, the ASPA’s Annual Award was presented to the RAF’s 22 Group and Babcock International for Operation Interstorm, which has successfully provided Elementary Flight Training to Ukrainian Air Force student pilots. Described as a ‘no-fail’ programme of national importance, the operation has seen 1,100hr flown to date and 24 pilots trained, with more students also advancing through the training system. Carol Reed Vertical Aerospace 16 AEROSPACE AEROSPACE Radia WindRunner Radia has designed its enormous WindRunner to transport turbine blades to remote sites by air. CHRIS POCOCK investigates a project that could result in the world’s largest aircraft. The biggest of the big He describes himself as a “serial entrepreneur” but Mark Lundstrom’s latest venture must surely be his most enterprising yet. An aerospace engineer by training, Lundstrom plans to build the world’s largest aircraft by volume, specifically to carry the very largest wind turbines. Lundstrom founded Radia in 2016 with a mission to radically expand the scale and economic viability of the onshore wind energy industry. The company says that wind turbine blades of up to 105m in length are desirable, similar to those at some offshore installations and at least 20m longer than any of those that have been installed onshore to date. Taller turbine masts and longer blades produce more energy at up to 30% lower cost, Radia explains. They would triple the economically viable land area in the US for onshore wind. Over one million of these turbines could be built by 2050, the company believes. It calls this scenario GigaWind. From A to B The problem is how to transport such blades from manufacturing sites to onshore wind farms? At present, they can only be moved by road, if at all, with great difficulty and expense. Siemens Gamesa and Vestas, two of the world’s largest suppliers of wind turbines, jointly declared in 2017 that transport was becoming a significant constraint. “It takes a year and a half to plan a move of these things down a highway,” Paul Hanna, vice-president of marketing for Radia 17 DECEMBER 2024 told AEROSPACE. “You’ve got road bridges to get underneath, traffic signs that need to come down, homes that are near the off-ramp that may have to be moved.” Hanna said that the company conducted a comprehensive analysis of alternative transport solutions, including airships, VTOL, segmenting the blades or manufacturing them in situ. “The only viable solution was to build a plane that could land and take off from semi-prepared dirt strips next to the wind farms,” he continued. WindRunner So Lundstrom quietly began building a team to further define the requirement, and design the WindRunner, a huge airlifter that would measure 356ft in length with a wingspan of 261ft. The payload bay of 272,000ft³ would be nearly six times greater than that of the Antonov An-225, which was the largest air cargo carrier until it was destroyed in the Russian invasion of Ukraine in 2022. Radia’s design could carry three 80m blades, or two 95m ones, or one 105m blade and deliver them to a 6,000ft unpaved runway. Despite the WindRunner’s size, Radia says that it can successfully negotiate existing runways and taxiways at airports, where the blades are likely to be loaded. The wingspan has been intentionally limited and, although the fuselage is so long, the minimum turn width is close to that of a Boeing 747. The company downplays potential problems in transporting the blades to airports for loading. It notes that the manufacturers have found ways to move large blades for offshore wind farms over short distances to the ports where they are loaded on to barges to complete their journeys. It is the long overland transits that pose the big problems, Hanna insisted. Lundstrom has recruited a team that shares his vision for a profitable transition to green energy and, moreover, has impressive aerospace industry credentials. Radia now employs 80 people. They include Cristine Bloch, formerly Vice-President of Operations at Embraer; Rachel Kelley, who was a senior engineer and Executive Director at Boeing; Melvin Johnson, previously Director for Airworthiness and Compliance at the FAA; and Brian Bauer, a former engineer and manager at the Lockheed Martin Skunk Works. They are all on the management team, alongside other aerospace professionals, plus power and energy experts. In addition, Radia’s line-up of advisers include Ernest Moniz, a former US Secretary of Energy; Carolyn Corvi, who was Head of Commercial Aircraft at Boeing; Marion Blakey, a former FAA Administrator; and Malcolm Turnbull, former Prime Minister of Australia. Out of the shadows Radia kept its aircraft plan secret until March of this year. The company’s first major public appearance was at the Farnborough Air Show in July when it revealed a design that is essentially complete. This was thanks to finite element modelling, computational fluid dynamics and wind tunnel testing. The philosophy has been to incorporate existing aerospace industry components and fabrication techniques that are already certified. “We’re commissioning the aviation supply chain to build this plane for us,” said Hanna. The company says it has been working with potential suppliers for some time. M a r k L u n d s t r o m ,_ F o unde r, C E O , _ R a d i a ( R a d i a ) All images via Radia AEROSPACE 18 that it is the first such design since Boeing’s C-17 military airlifter, and that the Russia-Ukraine war has drastically reduced the available Antonov An-124 fleet. WindRunner’s nose opening cross section is 10m x 10m, which compares favourably with both of those aircraft, and is much bigger than the Boeing 747-400F. Admittedly, the WindRunner’s payload of 72 tonnes is one-third less than the Boeing but no large commercial airlifter in service today can land on dirt strips. Radia has not revealed how it has been funded to date. Presumably the wind turbine OEMs have During the show, officials revealed partnerships with Leonardo’s aerostructures division in Italy for the fuselage, and with Spanish aerostructures company, Aernnova for the wing and engine pylons. Radia has not yet said which engine company might supply the WindRunner’s four large turbofans. Further potential The WindRunner clearly has potential as a carrier of other heavy and outsize cargo. Lundstrom notes AEROSPACE Radia WindRunner  With a nose opening measuring 10m x 10m, the WindRunner can carry even the largest turbine blades.  WindRunner can land on dirt strips adjacent to wind farms. All images: Radia 19 DECEMBER 2024 new aircraft. This could provide another capital input and revenue stream. Hanna said that Radia’s plan was to be flying and delivering blades by the end of the decade. The company says that certification would be to FAA Part 25. “We have the opportunity to take a dramatic and lasting amount of CO2 out of the atmosphere, and we’re giving the aerospace industry the opportunity to participate in reducing the cost of energy by as much as 30%,” Hanna declared. helped. Looking forward, Lundstrom admitted to AEROSPACE that launch costs would be “more than $300m.” Hanna said that Radia “has a robust capital structure that leverages very little equity. So there’s all sorts of debt financing opportunities.” Some funding in the form of green energy grants could come from the governments of countries that participate in the manufacture of the WindRunner, he added. Radia is also inviting turbine manufacturers and wind farm developers to collaborate on fresh locations that it has identified, to which access is made possible by the 20 AEROSPACE AEROSPACE Reaction Engines As Reaction Engines enters administration, BILL SWEETMAN looks at what the company promised and what went wrong. Per Ardua Administration People used to call Reaction Engines Ltd (REL) “the world’s oldest start-up.” Created in 1989 to pursue founder, Alan Bond’s vision of a fully reusable single- stage-to-orbit (SSTO) vehicle, the company entered administration at the end of October after failing to secure new investment. SSTO is a challenge that has defeated all comers for more than 60 years, including two multibillion- dollar US efforts, the 1980s’ National Aerospace Plane and the 1990s’ Lockheed Martin X-33. Sabre-powered Skylon REL’s Sabre engine, fitted to the Skylon vehicle, was designed to be more efficient than a rocket in two ways: by using atmospheric air as an oxidiser at speeds below Mach 5, and using heat energy in the inlet air to boost thrust. The key technology was a heat exchanger (Hx) in the engine inlet to chill and densify the incoming air. The Hx was a helium loop that dumped heat into the Skylon’s liquid hydrogen (LH2) fuel. The hydrogen expanded through a turbine, driving a compressor that pumped cold, densified air at high pressure into a rocket combustion chamber and nozzle. Above Mach 5 the Sabre would convert to a conventional rocket. For most of its lifetime REL focused on building an Hx that could pull 400MW out of the airstream without impeding it, and by 2009 had designed a ‘flight-weight’ unit comprising ‘many thousands’ of 1mm diameter Inconel tubes, with 40 micron walls, with a frost control system so that it would not turn into the world’s best icemaker the moment it was started. Ambitious goals The idea of a start-up in an Oxfordshire science park building a spaceplane never computed. The goal was to get Sabre far enough in test and demonstration that REL would bring solid, low-risk and hence valuable intellectual property (IP) to a partnership, return its backers’ investments, and keep control even with a large partner, or with American involvement. 21 DECEMBER 2024 The latter was seen as a possible necessity, both for funding and for a flight-test location, the UK being short of massive deserts. The novel features of Sabre could be tested incrementally, starting on the ground and transitioning to a conventional aircraft; with NASP, X-33, and other projects, the problem was that ground tests could not close all the risks, and sponsors had to commit to building a large and expensive X-vehicle with no guarantee that it would work at all. Sabre simply shut down the air inlet and Hx when it changed to rocket mode – much simpler than the flow-switching of a combined-cycle engine, a common problem area. Change of direction SSTO was still a long-odds target. Skylon would need new lightweight materials, and was decades and billions of pounds away. Under CEO, Mark Thomas, who joined REL from Rolls-Royce in 2015 when Bond became Chairman, the company took two new directions. One was to look for non-aerospace applications for what was a powerful and efficient Hx. The best-known one was the intercooler for the Mercedes-Benz F1 team, but REL was looking at mass-market uses in electronics and batteries, and in fuel-cell power units. The other avenue was first talked about in 2019. As REL adviser, (and RAeS Past President), Simon Henley noted on LinkedIn, the company had developed a “pre-cooled propulsion system (for) the high-speed/hypersonic regime.” Henley noted that the engine would enable “reusable vehicles capable of operating between zero and high Mach for as long as the vehicle has fuel.” A single-cycle zero-to-M3+ engine would be remarkable enough, but that final clause was the key. Pre-cooling works and was used in the 1960s to set speed records in F-4 Phantoms by spraying a water- methanol mixture into the inlet duct. Evaporation reduces temperatures at the compressor exit, allowing the engine to run to higher Mach without exceeding material limits, but the mass of water required limits it to sprints. (US start-up, Hermeus is using water pre-cooling in its Quarterhorse uncrewed demonstrator, but is initially limited to Mach 2.5.) REL’s system used an Hx in the inlet and dumped the heat into the fuel, and was efficient enough to run continuously to sustained speeds well above Mach 3, allowing a fighter-size vehicle to have a significant supercruise radius – numbers of up to 750nm were hinted at. Airframe integration was no more complex than any other turbojet engine. Hypersonic Air Vehicle Experimental Air Vice-Marshal ‘Rocky’ Rochelle, the Royal Air Force’s chief of future capabilities, and in charge of the RAF Rapid Capabilities Office, showed interest. REL and Rolls-Royce announced a teaming agreement in August 2020, and the Hypersonic Air Vehicle Experimental (HVX) project was unveiled at Farnborough in July 2022 with RCO and other UK government agencies as sponsors. By that time, discussions of a UK-US demonstration programme had moved ahead, and Hx-cooled turbojet ground tests were under way. Earlier this year, an RR Gnome engine was tested to M=3.5 conditions – that may seem like an odd choice, but the UK had a stock of unused Gnomes from the Sea King/Commando fleet, and the Gnome’s low pressure ratio was a positive for a high- Mach test. However, I am told, higher levels of the UK MoD did not see a long-term high-Mach project as a priority (perhaps as a result of ground war in Europe and the emergence of low-and-slow air threats), and the RCO did not get the funding that it needed. There may have been some impact from Rolls- Royce’s new CEO, Tufan Erginbilgiç’s ‘stick to your knitting’ approach, which has seen the company shed many activities to concentrate on commercial aviation. One US hypersonics expert who was involved with REL faults the company with “not wanting to surrender autonomy to its US subsidiary,” which slowed development and made it harder to get US funding into the project. Without the promise of a compelling flight demonstration, REL could not attract more outside investors. Thermal management matters There are no indications that the technology itself failed, so it is likely to be acquired cheaply by former partners or new investors. The F-35 has hammered home the lesson that thermal management matters, and that capability has been stressed as a feature of the Global Combat Aircraft Programme. If eVTOLs turn out to be practical, they will also need efficient cooling. REL’s cooled turbojet engine solves a long-standing problem – but which customer has an appetite for addressing it again? The UK seems to have decided against it; US high-speed research suffers from having three sponsors – NASA, the Air Force Research Laboratory, and the Defense Advanced Research Projects Agency – who seldom co-ordinate effectively. Could that be a real job for venture capitalists? A SINGLE- CYCLE ZERO-TO-M3+ ENGINE WOULD BE REMARKABLE ENOUGH, BUT THAT FINAL CLAUSE WAS THE KEY. PRE-COOLING WORKS  Earlier this year, an REL engine was tested to M=3.5 conditions.  From top to bottom: Reaction Engines and Rolls-Royce announced the Hypersonic Air Vehicle Experimental (HVX) project at Farnborough in July 2022. Reaction Engines promised a variety of military and civilian applications for SABRE. More than three- quarters of Reaction Engines’ workforce were immediately made redundant by administrators, PwC, following the collapse of the company. All images: Reaction Engines 22 AEROSPACE AEROSPACE The 2024 President’s Conference The 2024 RAeS President’s Conference saw a packed audience from around the globe discussing how best to instigate a system that would allow university students to design, build and, ultimately, fly their own aircraft. STEPHEN BRIDGEWATER FRAeS reports. “You have my permission” “You have my permission to get on and do this.” Those were the closing words of RAeS 2024/25 President, David Chinn at the conclusion of his Design, Build, Fly (DBF) Conference, which took place at No.4 Hamilton Place on 15-16 October. DBF takes its inspiration from the German Akaflieg movement, which sees university students coming together to design, build and fly their own gliders and light aircraft [see AEROSPACE July 2024 for a detailed article about Akafliegs]. It was, therefore, gratifying to see representatives of academia, legislators and industry sharing a packed room with the CEOs of British light aviation groups to discuss how best to turn this plan into a reality. The event kicked off with a keynote speech by Mike Kane MP, the new UK Minister for Aviation, Maritime and Security. In his virtual address Kane spoke of the aerospace sector’s importance to the UK economy, supporting 230,000 jobs and contributing £22bn annually to GDP but flagged up the problems of attracting and retaining diverse talent. Calling for enhanced collaboration and highlighting the work of Skills England and the success of various apprenticeship schemes, he reminded delegates of how the Akafliegs came into being a century ago. Flagging up the Society for its “unending passion and ambition in the sector,” Kane described the RAeS as “a beacon of excellence, a hotbed of doers and thinkers, bringing together the brightest minds to work on the exciting innovations in transport,” and concluded by emphasising that “people matter.” “The primary purpose of leadership, is to create new leaders, not followers,” said Kane. “The Society is doing that by attracting, retaining and upskilling the workforce [and] I love how the language of the conference – ‘design, build, fly’ – summarises the scale of that vision.” Academic viewpoint The DBF concept can be best summarised in that the UK is producing first-class aerospace graduates, but the vast majority of them have not had the practical experience to match their academic knowledge. They have never cut metal, carved wood or shaped composites. Chinn was keen to emphasise that German Akafliegs operate separately to university courses and, while tutors and departments support the projects, the work does not count towards any formal qualifications. The Minister’s address was immediately followed by a keynote speech from Prof Mark  Students at UK universities have a proven track record of designing, building and flying aeroplanes. This is the Cranfield A1, which first flew in 1976 and later evolved from a single-seater to two-seat configuration, with the design and construction of the modification carried out by students. Other MSc students modified the rear fuselage from metal to composite construction. Charlie Jones 23 DECEMBER 2024 Westwood FRAeS, Head of Centre and Professor of Aeronautics at Cranfield University, discussing how best to develop aircraft design skills for the future. Westwood began by showing an alarming slide to the audience detailing the falloff in high-value aircraft built in the UK since the 1950s. This, he explained, has a knock-on effect with aerospace engineers as the number of complete aircraft design cycles that they might experience during their career has much reduced and that has implications on skills, morale and inventiveness. Looking back at his own career, Westwood recalled how his younger years developing aircraft navigation systems saw him conducting flight trials in a real-world environment. “I learned a huge amount,” he explained. “Not just from the trial itself but from being in the air, interacting with crew, listening to the radio, etc. It filled in gaps around my wider aeronautical knowledge and it found its way into lots of later projects that I was involved in. It makes me reflect that this practical experience is a really important part of people’s careers.” Cranfield already offers its students a lot of hands-on experience and Westwood added that “practical DBF is key to our ethos.” The university has recently been involved in the Sherwood eKub electric conversion programme, with Dr Guy Gratton FRAeS conducting flight tests on the prototype. The substitution of the conventional engine with a battery-powered electric motor resulted in what Westwood referred to as “pretty interesting EMC effects” which included the radio and compass not working as intended. He cited this as an example of why the ‘fly’ element of DBF was just as important as the ‘design’ and ‘build’ processes, as the faults only materialised during the test flight programme. Another university in a similarly privileged situation is Embry-Riddle Aeronautical University (ERAU) in Florida, whose Dean of the College of Engineering, Dr Jim Gregory FRAeS, gave a presentation. ERAU uses both model aeronautics and full-scale aviation as part of its equivalent to DBF. Around 20-25 students take part in the annual American Institute of Aeronautics and Astronautics (AIAA) contest where, just like in industry, a request for proposals (RFP) is issued and the students have eight months to design, build and fly a model aeroplane that satisfies the criteria of that year’s contest. “I am impressed by how the students help one another learn,” said Gregory. “It is done in a co-curricular environment, where there’s some connection to the curriculum, but largely this is an extracurricular activity for the students. They are actually teaching one another and they even host workshops to recruit the incoming class of students for the next year’s contest.” Like Cranfield, ERAU has also branched out into full-scale piloted aircraft and its current project is a highly modified Diamond HK36 Super Dimona motorglider, which has been fitted with an electric motor. Dubbed the eSpirit of St Louis, the aims of the project are to refine electric propulsion technologies and establish some sustainable aviation world firsts and world records. The team  Clockwise from left: Professor Andreas Strohmayer from the University of Stuttgart discusses the e-Genius. The packed auditorium at the President’s Conference. Dr Jim Gregory FRAeS, Dean of the College of Engineering at Embry- Riddle Aeronautical University in Florida. The Chair of the RAeS Next Generation Board, Robin Saaristo, moderates a panel of industry experts, including Sue Partridge FRAeS from event sponsor, Airbus. Stephen Bridgewater/RAeS Saurav Roy Chowdhury/RAeS Stephen Bridgewater/RAeS Saurav Roy Chowdhury/RAeS AEROSPACE 24 solar-powered motorglider – which first flew 37 years ago in 1986 – and the current e-Genius project. The latter began life as a battery-powered aircraft in 2011 but has since been powered by hybrid-electric and hydrogen propulsion, achieving numerous world records. A highlight for many attendees at the conference was the joint presentation by two of Prof Strohmayer’s students from Stuttgart. Both members of the Akaflieg, Jan-Felix Sentosa and Tom Everwin took it in turns to give details about their work developing a revolutionary fly-by-wire glider, as well as ongoing work on the Fs-35 motorglider. Jim Scanlan, Professor of Aerospace Design at University of Southampton, attended the conference to discuss the students’ work developing and flying fixed-wing drones, including work that, ultimately, led to the WindRacers ULTRA [see AEROSPACE July 2024]. He also revealed fascinating insights into the CASCADE EPSRC multi-university drone research programme, particularly a project that saw UoS partner with the University of Bristol and a group of volcanologists to fly a drone through a volcanic plume at 12,000ft and some 20km away from their take-off point in the jungle. Industry speaks The first panel discussion of the conference saw Sue Partridge FRAeS, Head of Airbus’ Wing of Tomorrow Programme, Professor John Chudley, Chair of the Engineering Council, Stephen Phipson, CEO of Make UK, Ben Alcott, Professional Services Group Director at the CAA and Bernice Huntley, Future Workforce Lead at the UK Space Agency discuss the challenges facing young people entering the aerospace sector and the reason many choose other career paths. has so far designed, built and tested battery packs capable of producing 825V at 120A for one hour and has been actively researching issues surrounding thermal runaway. In this instance, the work is co-curricular and forms part of a graduate’s thesis work. “Our students are getting real-world experience with airworthiness standards, regulators, safety management systems and all types of fundamental safety concerns,” concluded Gregory. Also flying in for the conference was Joris Melkert, Associate Professor and Director of Education at the Faculty of Aerospace Engineering at TU Delft in the Netherlands. Melkert and his colleagues offer an aircraft manufacturing course where students get to build a Vans RV-12 kit plane. “The course has six learning objectives,” he told the audience, “the most crucial of which is about safety culture. In aviation this is one of the most important things. It is vital that our students understand that making a mistake is not a big issue, but hiding a mistake is a serious problem.” Skills like this are perhaps the unseen, unquantifiable benefits of any prospective DBF project. German know-how Germany has run Akafliegs, on and off, for a century. Professor Andreas Strohmayer, Head of Department at the University of Stuttgart’s Institute of Aircraft Design, spoke enthusiastically about the Akaflieg’s aims to “advance technology, performance, on-board systems and even meteorology and the refinement of ground support equipment.” While the Akaflieg work is conducted in students’ free time, Strohmayer noted that this is done willingly and happily. “Our students invest a lot of time in their projects and it gets into their blood,” he told the audience. Like other delegates, Strohmayer was keen that students involved in the design and build of an aircraft see it through to the flying stage. He studied at the University of Munich, and was involved with the Akaflieg München Mü30 Schlacro (SCHLepp- ACRObatic) aerobatic glider tug project. “It took 20 years to complete the project and I was the middle of three generations, so I knew I would never see it fly – and that’s very discouraging.” “Akafliegs are generally very independent,” explained Strohmayer, “but we allow them to use our facilities and equipment if and when they need it.” Proven track record Akafliegs have a history of designing, building and flying their own gliders since 1920 and in the post- war years this evolved to include powered aircraft. In recent times, the Akaflieg Stuttgart has been one of the most successful and prolific manufacturers and Strohmayer gave an overview of the Icaré 2 AEROSPACE The 2024 President’s Conference The Light Aircraft Company  Could the single-seat deregulated microlight route be an avenue worth pursuing? This is the Sherwood Kub, an electric version of which has just been tested under e-conditions. 25 DECEMBER 2024 Stephen Bridgewater/RAeS Of particular note, Chudley voiced concerns over how apprenticeships are still undervalued as a route into the workforce and schools and parents push youngsters towards a degree-based education derived from ageing biases and stereotypes. He stressed the need to value all routes to professional registration and called for greater gender equality, as just 7.7% of new engineering apprenticeships registered in 2023 were to female students. Phipson added to this view, emphasising the growth potential of the UK sector. Manufacturing, he said, makes a £200bn contribution to the UK economy each year and supports 2.6m employees. Yet, whereas the government is keen to emphasise the success of recent apprenticeship programmes, just 41% of all apprentices who have begun work since 2016 have joined the engineering sector. Jacqueline Castle FRAeS, Chief Technology Officer at the ATI, also provided an overview of how the organisation is supporting and promoting projects that fit the DBF remit through its ACCEL project. Castle emphasised the importance that these initiatives play in nurturing skills needed in aviation professionals. The GA sector In the UK, the types of aircraft likely to be design, built and flown by a DBF group are likely to fall under the auspices of three main organisations: the British Microlight Aircraft Association (BMAA), the Light Aircraft Association (LAA) and the British Gliding Association (BGA). The CEOs of all three organisations spoke at the conference with the BMAA’s Rob Hughes taking to the stage first. Since the first microlights appeared in the UK in the 1980s the technology has advanced significantly. The category that perhaps best suits any future DBF initiative is the fairly recent single-seat deregulated (SSDR) class of airframes. These are single-seat aircraft, weighing less than 300kg (MTOW) and stalling slower than 35kts and, crucially, they require no airworthiness oversight. “You can design, build and fly whatever aeroplane you want to,” Hughes told delegates with a smile. “You can go home to your garage, pick up your pieces of aluminium tubing and your wheelbarrow tyres and build your own aeroplane. You will still need a pilot licence, a medical and insurance to fly it – but you can build whatever you like.” The BGA is slightly more prescriptive in what its members can build and fly but gliding, undoubtedly, offers one of the cheapest ways of getting into the air. BGA CEO, Pete Stratten told the audience that there is tremendous scope for innovation in the sector, often driven by the urge to improve performance in endurance or speed contests. Examples of this were the large winglets that are now seen on modern airliners but also ‘bug wipers’ which extend down the leading edge of the wing to clean off dead insects and maintain the optimum aerodynamic cleanness of the wing. At present, most new gliders are designed according to ASA Part 21 regulations and CS22, which Stratten describes as “a handicap” due to the costs involved. Could this be an opportunity for a DBF scheme similar to the Akaflieg Stuttgart’s programme to develop a new – or even modified – glider? The LAA’s Simon Tilling explained that his organisation now has around 7,000 members, most of whom are building and flying their own aeroplanes. An LAA registered aircraft can seat up to four people and can either be built from plans or a kit or even be designed and built from scratch. There are currently 2,800 with a valid Permit to Fly (PtF) in the UK – which is around 20% of all UK- registered aircraft. Many of the German Akaflieg projects take the form of modifications to existing aircraft and Tilling suggested a way the LAA could assist with any future DBF initiative is through its extensive network of 331 inspectors and in excess of 800 approved modification programmes. He also urged groups to consider new modifications, particularly the electrification of existing, proven kit plane designs. He also added that “a lot of our members have got a lot of scars from building their own aeroplanes, so I would advise that those running DBF programmes engage early with local builders and pilots. There is a lot of opportunity to learn from other people’s mistakes.” Racing to space Alongside DBF, the second of Chinn’s Presidential themes is “the professionalisation of the space sector,” and the conference saw these two themes overlap.  To conclude the conference, David Chinn was joined on stage by Lydia Price (Head of Aviation Skills at the Department for Transport) along with the CEOs of the LAA, BGA and BMAA to sign a Letter of Intent to promote further collaboration between the associations. AEROSPACE 26 A thoroughly inspiring presentation on Day 1 by Dr Alistair John from the University of Sheffield detailed how he had formed the Race2Space (R2S) student rocketry competition. Using 3D-printed liquid rocket engines, the initiative aims to provide students with hands-on experience of designing, building and flying rockets. In 2023, ten student teams took part and seven engines were tested. This year saw nine engines reach running status. Spaceflight DBF is also a major focus at ERAU, with Prof Gregory telling delegates about a recent programme that saw a student design and build a camera CubeSat that was launched in February 2024 and made it all the way to the Moon. “I’ve never seen our campus so rallied,” he told the audience. Gregory also emphasised that Polaris Dawn mission commander, Jared Isaacman is an alumni of ERAU and the camera system designed and built by current students at the university was on board his recent mission to conduct the first civilian spacewalk. Colin Baldwin, Executive Director at Ukspace, and Chris White-Horne, Deputy CEO of the UK Space Agency, both addressed delegates on the second day of the conference with Baldwin noting that 52% of space companies struggle to grow their workforce. With particular problems surrounding recruitment in software and data areas, he advocated for diverse recruitment strategies and said, if it were expanded to the space sector, DBF could form an ideal way of plugging the space skills gap. Competition? A number of delegates suggested that the best way to roll out DBF would be in the form of a national (or international) competition centred around specific aircraft design challenges. Kingston’s Scanlan commented that “competition is a key driver so if you can package DBF into a competition format you’ll get a lot of engagement and motivation from the university teams.” Building an aeroplane – even a simple one – is a time-consuming exercise. With students spending an average of four years on a degree course, some delegates expressed concern that those who design and/or assemble the first component for an aircraft will have graduated long before the aircraft finally takes to the skies. Perhaps the answer to this lies in the modification of existing designs to meet a specific challenge or need, thus speeding up the entire DBF process? Scanlan also emphasised the importance of rapid progress. “I tell my students to be adventurous and innovative, and allow themselves to make mistakes. It is really important that they have the space and the confidence to do really adventurous things, and this means numerous AEROSPACE The 2024 President’s Conference iterations. I always tell my students not to write up and hand in a report about the ‘mark one’ aircraft – it has to be at least the ‘mark two’, which is normally substantially better than the first one.” A UK success story The conference also heard from noted microlight designer, Bill Brooks as an example of commercial light aircraft success. It has now been four decades since Brooks – who is also the Chair of the RAeS Human-Powered Flying Group – designed, built and flew his first aeroplane. Brooks took an enthralled audience through a whistle-stop tour of his ‘greatest hits’ from the hang-glider he designed during his Industrial Design principles course at university through to the SkyFly Axe eVTOL that recently performed its maiden flight [see News, p10] and the SkyCycle roadgoing trike that he has been designing in his ‘spare time’. Having heard from such luminaries of our industry as Brooks, and had the opportunity to speak to the likes of John Edgley during the breakout sessions, it was fitting that the last session of the conference was handed to Jack Jenner-Hall. The teenage glider aerobatic pilot is a DfT Ambassador of Aviation and no one who heard him speak about his passion of flying could fail to be inspired by what aviation can offer the next generation of designers, builders and flyers. So what next? An earlier panel discussion, chaired by Dr Rashid Ali FRAeS, had discussed the legal and legislative hurdles, including input from Andy Devereaux, Space Systems Lead at the CAA, Peter Neenan, Chair of the RAeS Air Law Specialist Group, Professor Rob Howell, Head of New Interdisciplinary Engineering Programmes at the University of Sheffield and Kathie Bowden, Skills Manager at the Satellite Applications Catapult. The conclusion was that there was no legal or regulatory reason why DBF could not be feasible, practical and useful. In his closing remarks, Chinn noted that the conference had “generated as many questions as answers” but had “brought together the people who could find the answers. Doing anything in aviation is difficult. That is a direct result of legislation and legislation is there because there is a risk to life. I think our responsibility is to develop people who can manage that risk to life and be accountable and I would suggest, at least in the UK, that is not something that is taught in many places. I do feel that introducing a competitive element would be beneficial. Yes, money may be a constraint but, if I’m honest, I think sometimes people are more constrained by their imaginations. However, there is proportional regulation and a permissive environment. You have my permission to get on and do this stuff!”  Jan-Felix Sentosa and Tom Everwin from Akaflieg Stuttgart delivered a memorable and thought- provoking presentation. Saurav Roy Chowdhury/RAeS RAES FLIGHT OPERATIONS CONFERENCE 2025: SINGLE PILOT OPERATIONS - LOGICAL PROGRESSION OR A STEP TOO FAR? RAeS HQ, LONDON 19-20 MARCH 2025 The debate surrounding single pilot operations (SPO) represents a paradigm shift, being one of the most hotly contested issues in commercial aviation today, and the industry faces tough questions as it navigates these potential changes. Technological advancements have historically reshaped the flight deck. Now, with the industry poised for future growth amid cost pressures and a shrinking pool of aviation professionals, SPO is emerging as a critical conversation. With the RAeS Flight Operations Conference 2025, we do not necessarily endorse the inevitability of Single Pilot Operations but encourage discussion of the subject and the developments such as eMCO that may take place as traditional means of crewing are reviewed. The conference will examine how integrating Human Factors and Technology - two pillars essential to the proposed changes - alongside innovations in ground-based decision-making, pilot training, and flight deck design will redefine the industry’s future. The RAeS Flight Operations Conference 2025 will gather industry leaders from manufacturers, regulators, academics, operators and others to discuss SPO’s latest developments, concerns, and opportunities. Join us in March 2025 to explore the potential benefits and risks of this groundbreaking innovation. Find out more by scanning the QR code or visiting www.aerosociety.com/single-pilot-ops 28 AEROSPACE AEROSPACE Rotating detonation engines An invention too challenging to be engineered for 60 years, the rotating detonation engine is now on a path to flight. ROB COPPINGER investigates. Simply complex Alighter, more efficient propulsion system that can provide more thrust, from a standing start to hypersonic speeds, was invented six decades ago in the Soviet Union but is now being developed into an operational engine for everything from lunar landers to long-range missiles. The work now spans the US, Europe and Japan, although these so-called rotating detonation engines (RDE) present a number of challenges that have hindered their development into fully operational propulsion systems for space exploration and the battlespace. An RDE could melt itself, such are the temperatures and stresses that its operation induces. A significant reason for its development now is that manufacturing methods, including additive manufacturing, have made the combination of materials needed for a robust engine possible. In appearance, an RDE is a very simple engine, it has no moving parts and it is simply tubular. However, it is also a tube within a tube and the geometry of its construction must be carefully designed. The detonation takes place between the inner cylinder’s exterior surface and outer cylinder’s inside wall. The geometry of the radii of the chamber’s outer and inner tubes is extremely important. The tubular chamber’s geometry is key to starting the rotating shock waves that deliver the thermodynamic efficiency that makes the RDE so attractive. This efficiency is expected to deliver up to a 15% improvement in fuel burn for the same thrust output, compared to a conventional rocket engine. The thermal shock wave starts from the point where the fuel is injected, and detonation begins travelling at supersonic speeds down the tube combusting that fuel. An optimal shock wave speed is 2,000m per second, and this supersonic combustion is what detonation is defined as. The shock waves rotate down the annular chamber, hence the name. With a detonation occurring with every fuel injection, this process is called a continuous combustion cycle. As complex as this sounds, a rotating detonation engine can start the same way as a traditional rocket with a pre-detonation tube and, like a conventional engine, the simple flow of propellant. In the US, RDE development work is publicly at its most advanced. The US Defense Advanced Research Projects Agency (DARPA) has its ongoing Gambit programme for an RDE for a long-range missile. NASA is interested in RDE for in-space propulsion, including lunar landers. It is working with industry partners, hypersonic flight specialist, Venus Aerospace and propulsion technology firm, In-Space and Purdue University. The US Air Force Research Laboratory (AFRL) has been working on RDE fuel with Purdue University, who in turn has been working with Nagoya University researchers from Japan. Announced in July 2022, DARPA’s Gambit programme is focused on developing RDE Venus Aerospace 29 DECEMBER 2024 because of the advantages over conventional rockets, ramjets and gas-turbine engines, and their maximum range, speed and affordability. DARPA gives the examples of RDEs being more compact than ramjets, allowing them to carry more fuel and being less complex than gas turbines. The first phase of Gambit was to create the preliminary design of a test article and substantiate that design with combustor and inlet testing. The second phase is focused on the detailed design, fabrication and testing of the test article. Raytheon was awarded a contract in October 2023 to conduct “iterative development of performance models which will be anchored by real-world data from incremental system tests,” according to its announcement. GE Aerospace In December 2023, NASA announced that it had achieved a “new benchmark in developing an innovative propulsion system called the rotating detonation rocket engine (RDRE).” NASA Marshall Space Flight Center had test fired a 3D printed RDRE for 251 seconds and produced more than 5,800lb/thrust. That duration of engine burn emulates the propulsion needed for a lander touchdown or a Moon to Mars mission course correction, according to NASA. The publicity stated that the RDRE’s first hot fire test at Marshall took place in mid-2022 in partnership with In-Space and Purdue University. NASA’s Glenn Research Center in Cleveland has also been carrying out RDRE research with Venus Aerospace to understand how to scale the technology for higher performance. The Glenn engineers fired an RDRE for about 60 seconds producing about 4,000lb/thrust. Again, in December 2023, GE Aerospace unveiled progress on its hypersonics programme at its Research Center in Niskayuna in New York state. In Niskayuna, GE claimed to have demonstrated a “world-first, hypersonic, dual-mode ramjet” rig test with rotating detonation combustion in a supersonic air flow. The company claimed its new engine architecture with rotating detonation combustion could propel vehicles faster than Mach 5 and for a longer range. Advances in high- temperature ceramic matrix composites, silicon carbide power electronics, additive technologies and advanced thermal management made the high- speed propulsion dual-mode rotating detonation combustion ramjet demonstration possible. In a July 2024 announcement, GE Aerospace repeated the successful dual-mode ramjet demonstration claim but referred to testing that had occurred in March at a test facility in Evendale, Ohio. It made no mention of rotating detonation combustion. Venus Aerospace In March, Venus Aerospace, which was founded in mid-2020, announced it had achieved its first ‘long-duration’ RDRE engine test in partnership with DARPA. While the test firing announcement was made in March this year, Venus Aerospace co- founder and Chief Technology Officer, Dr Andrew Duggleby told AEROSPACE that the company was not involved in Gambit. However, the firm has been awarded contracts by several US government agencies to develop  Venus Aerospace hopes that its Stargazer M4 will be the world’s first hypersonic, reusable commercial aircraft. Using the Venus RDRE ramjet, the vehicle is designed to accelerate from taxi to cruise speeds of Mach 4 at 110,000ft with a top speed capable of Mach 9.  Chinese manufacturer, Yunxing, exhibited its JINDOU400 RDE during November’s Space Tech Expo in Bremen. Constructed of just three components – the intake duct, combustion chamber and a payload cabin – the engine is 2.6m long and expected to produce 400kg of thrust. The company claimed that a maiden flight was expected before the end of 2024.  Venus Aerospace successfully completed the first long-duration, high- thrust hot fire test of an RDRE in September. This achievement brings the company closer to flying an RDRE in the near future, as the engine’s thrust-to- weight ratio is now on par with leading rocket engines in the industry. Venus Aerospace AEROSPACE 30 young company’s vision vehi