Airbus Helicopters has hit the latest speed goal for its Racer demonstrator, with the compound rotorcraft achieving 240kt (444km/h) in level flight earlier in the spring.
Although some 15kt below the 255kt record set by its X3 predecessor, the Racer’s latest achievement is still above the 220kt targeted at the start of the programme.
Moreover, the 240kt cruise speed – reached on 28 April – was attained with the Racer having accumulated a little under 25 flight hours since its maiden sortie in April 2024.
Airbus Helicopters had increased the cruise speed target following the conclusion of the Racer’s first flight-test phase last summer, during which it had reached 227kt in level flight and 260kt in a descent.
Critically, the lower speed was arrived at with the rotorcraft in an early test configuration, lacking its low-drag main rotor fairing or landing gear covers.
Dominique Fournier, Racer flight-test engineer, says installation of those two components was vital to hit the revised high-speed goal.
“Thanks to the very good job done by the design office, specifically the fairing of the main rotor head… there is a huge gain in drag [performance] on this machine compared to what we anticipated.”
Fournier adds that at 240kt “thanks to the concept, the level of vibration was really low” even using, as the Racer does, a standard main rotor from the airframer’s H175 super-medium-twin.
For cruise flight, the majority of the propulsion comes from the Racer’s lateral pusher-configured rotors, while around 50% of lift is generated by the V-shaped box-wing.
This allows the main rotor to be slowed – it only receives around 20-25% of torque – removing the instability caused by retreating blade stall on a traditional helicopter.
Test pilot Olivier Gensse, who was at the controls for the milestone flight, says the target was “very easy” to achieve – despite not being as familiar with the platform as lead project pilot Herve Jammayrac – “because the concept is really mature”.
“I think the fact that we were able to fly at such a speed with a non-event is a great result for us.”
Both pilots are full of praise for the Racer’s stability, even without the autopilot engaged. After a six-month pause – ending in March – to install new parts, the rotorcraft is now flying twice weekly and visitors to the Paris air show will also catch a glimpse of the Racer performing in the flying display every day except Wednesday.
“We discovered the concept with the X3 and the Racer is clearly a step further,” says Jammayrac, who was the chief pilot for the record-breaking predecessor – itself a Le Bourget veteran.
“The handling qualities are like the X3 but could be even better in terms of stability, particularly at high speed.”
Although the Racer has demonstrated excellent straight-line speed, this has not been achieved at the expense of manoeuvrability: the aircraft has comfortably performed 2g turns at 190kt, says Fournier.
But the Airbus Helicopters pair are not the only pilots to have flown the Racer: a crew from the French government’s DGA Essais en vol (DGA-EV) test centre in Istres – not far from the airframer’s Marignane site – have also recently flown the aircraft, says Brice Makinadjian, chief engineer for the demonstrator.
“We had excellent feedback from both the pilot and flight-test engineer,” he says. “They were really impressed by the behaviour of the aircraft and said the transition between helicopter and airplane mode was really smooth.”
In fact, all that was required was a 30min briefing for the crew prior to the flight, he adds.
Those flights by the DGA-EV crew are a vital part of Airbus Helicopters’ Racer roadmap which foresees passenger-carrying demonstration flights before year-end.
However, permission to carry non-flight-test personnel must first be obtained from France’s DGAC civil aviation regulator, with the DGA-EV informing that assessment process.
Fournier says the application has come much earlier than is typical for a demonstrator programme, with the DGAC expecting the Racer to have reached around 50 flight hours rather than the current sub-25h total.
“When you look at the aircraft it looks as though it is ready to be delivered, but from the authority’s point of view they see a prototype with just 25h on it; we have to convince them and explain and demonstrate the maturity of the aircraft,” he says.
But he points to the fast pace compared with the flight-test campaign on the X3, which took 17 flights over eight months before it reached 220kt; the Racer, in contrast, hit that milestone after just two months and seven flights.
Makinadjian says there has so far been a “good exchange” with the DGAC “in a very transparent manner” and is confident of receiving the approval before the third quarter.
“We are listening to the DGAC’s requests, and we will answer as soon as possible any points they raise,” he adds.
Airbus Helicopters is continuing to work with a select group of operators to define the demonstration flights, which are likely to consist of missions including search and rescue, patient transfer, and city-to-city transport.
But before it reaches that point, the Racer will be laid up towards the end of the year for the installation of the equipment required to enable the so-called “eco-mode” function on the rotorcraft’s twin Safran Helicopter Engines Aneto-1X powerplants.
Eco-mode sees one of the two turboshafts shut-down as a fuel-saving measure in cruise, but with sufficient power from the remaining engine to enable an 180kt airspeed; engine restart, meanwhile, will take around 5-7s.
Makinadjian says the final parts required to support the installation are now being manufactured, allowing the lay-up to proceed as planned towards the end of September or early October.
Depending on how long that process takes, testing of the eco-mode could take place this year “if we are lucky”, says Fournier.
But besides high speed and lower fuel consumption, one of the project’s goals is to demonstrate that the Racer has a noise footprint that is 30% lower than a conventional helicopter.
In particular, Airbus Helicopters believes the compound architecture will allow the rotorcraft to fly quieter departure and arrival profiles.
“We have an additional degree of freedom with the lateral rotors, we can control the attitude and speed of the trajectory at each point,” Makinadjian says.
“Using that we will define the best trajectory in take-off and approach so the sound on the ground is reduced by one-third.”
But proving the thesis is “quite complex”, he says: first the team will measure the sound produced by the Racer before “we optimise the trajectory of the aircraft” and then conduct additional confirmatory demonstration flights.
Makinadjian sees at least another 18 months of flight testing, running up until the end of 2026. But although the European Union’s Clean Sky 2 programme part-funded the construction of the Racer, the costs of the flight-test programme are borne by Airbus Helicopters and some of its project partners.
However, the progress so far has given Makinadjian confidence in the future prospects for the architecture. “Up until now we have not encountered any show-stoppers to an eventual development,” he says. “There are some minor issues, but nothing that would prevent us going further.”
