Best of both whirls: the RACER synthesises speed with VTOL capability
The RACER, which combines the vertical agility of a helicopter with the pace of a fixed-wing aircraft, demonstrates the possibilities of pan-European aeronautical collaboration facilitated through the Clean Sky ecosystem.
The RACER (Rapid And Cost-Effective Rotorcraft) demonstrator almost defies categorisation. It’s a type of rotorcraft that resembles a helicopter, but augmented with wings and lateral propellers, enabling vertical takeoff and landing but with a targeted cruise speed in excess of 400 km/h, opening up new possibilities for time-critical missions. Making the RACER's winning formula even more compelling, its speed and versatility are complemented with cost-efficiency and sustainability attributes.
‘The RACER is a pretty complex machine with extra components. But despite all that the target is to develop a complete rotorcraft, aiming for demonstrating time-critical missions,’ says Antonello Marino, project officer at Clean Sky. ‘A major aspect of the challenge is to reconcile the environmental targets — to reduce CO2 by 20%, NOx by 20% and noise by 20 — without adding weight. We need to add wing boxes and two lateral rotors to achieve the boost in speed, while staying within the weight envelope of a conventional helicopter. This means having to integrate new techno-bricks, lighter materials and innovative thinking.’
To be ready for its first test flight, slated for September 2021, RACER has to reach ambitious manufacturing, assembly and ground testing milestones over the next year and a half — an intricate process involving dozens of stakeholders brought on board via Clean Sky under the European Commission’s prestigious funding programme, Horizon 2020.
‘We're talking about a programme involving more than fifty organisations, ranging from universities and small enterprises to large international companies that may never have been in touch without this kind of initiative,’ says Marino.
The partnerships that are nurtured thanks to Clean Sky incorporate expertise from outside of aeronautics, but at the same time major aerospace entities cast a watchful eye over the process to ensure compliance for safety and airworthiness certification. ‘In the RACER programme we see different competences coming from every part of Europe, joining forces to develop this very innovative technology demonstrator,’ Marino adds.
Examples of these non-aeronautical partners include companies like KLK Motorsport GMBH and Modell und Formenbau Blasius Gerg GmbH, which have been teamed up as the FastCan consortium within Clean Sky, to add motor-sport knowhow for RACER's canopy.
Airbus Helicopters' Chief Engineer of the RACER technology demonstrator, Brice Makinadjian, says that the project is more or less on track to achieve its goals:
‘In 2019 we performed the Critical Design Review (CDR) of all the sub-systems and also the aircraft CDR — this is the stage when we are able to validate the drawings and start manufacturing the aircraft.’ Makinadjian is responsible for coordinating all technical activities within Airbus Helicopters as well as the activities of the programme's different partners on Clean Sky programmes.
Two elements are slightly lagging in the RACER programme, yet, thanks to versatile and agile management and scheduling, the overall programme remains on track, as Makinadjian explains:
“The first one is the main gearbox, where we are a bit late in terms of maturity of the design — we are not yet at the CDR level — but there is no impact on the global development of the demonstrator. This is because we have secured the external interfaces of the main gearbox so that we can progress the development of the whole aircraft — the gearbox will come later in the assembly.
In 2019 we tested the lateral drive line, a big shaft which turns at 3,000 rpm, linking the main gearbox to the lateral gearbox. The challenge is to balance it correctly and to check that it is stable. And in 2020 we will perform the fatigue and endurance test to check that we can rely on this design for the test campaign.’
As part of the manufacturing and assembly process, the sequential flow of the RACER project is being managed, to allow for an ambitious Flight Demonstration campaign. The ground testing and assembly process has been adjusted so that the overall RACER project keeps its momentum.
‘We are creating a mission demonstrator because we want to stimulate the market. If market stimulation is positive, later on there may be a decision within Airbus to launch a programme exploiting the RACER results. This is a possibility. But at the moment we are concentrating on making the RACER fly to demonstrate its technologies, and capability to perform missions with more efficiency and speed," says Makinadjian.
2020 sees the start of the RACER's assembly, plus testing of some of the main elements: "At the moment our partner INCAS (The National Institute of Aerospace Research “Elie Carafoli”) and ROMAERO (both in Romania) are producing and assembling the fuselage. Our colleagues from Airbus Helicopters Spain and Aernnova (Spain) are already manufacturing and assembling the tail boom in readiness for static testing. The fuselage will be delivered to our factory in the middle of 2020, and we will then officially start the RACER's assembly sequence," says Makinadjian. From mid-2020 it will take approximately one year to obtain a permit to fly, with a first test flight planned for Q4, 2021.