At this point last year Airbus Helicopters was gearing up for final assembly of the Racer – or Rapid and Cost-Effective Rotorcraft – a demonstrator it is building under the EU’s Clean Sky 2 programme, setting the experimental aircraft on course for a first flight in late 2021.
Fast forward 12 months, a period during which the aerospace industry has been ravaged by the coronavirus pandemic, and the project is further on, albeit much less than hoped.
Faced with Covid-19 disruption to its unusually dispersed supply chain – that complexity is a result of the Clean Sky framework – timelines have slipped: final assembly will only start in the coming weeks, pushing the Racer’s maiden sortie into the beginning of the second half of 2022. A separate project to develop rotor blades for high-speed flight has also stalled amid the wider health crisis.
But after a year where frustrations were more evident than progress, a sense of excitement is finally starting to build for all those involved as the demonstrator becomes “concrete”, says Brice Makinadjian, chief engineer for Racer at Airbus Helicopters.
This sense of renewed optimism has been triggered by the arrival of the main fuselage at the airframer’s site in Donauworth, Germany from supplier RoRCraft – a partnership between INCAS and Romaero in Romania.
Subsequently the structure has been mated with the canopy – designed for high-speed applications by FastCan, a consortium of German motorsport specialists – which had already been supplied to Donauworth.
And elsewhere in Europe it is a similar story as suppliers gear up to ship parts to Airbus Helicopters’ facilities. In the next three months the manufacturer is expecting to receive major components including the tail section, fuel system, box wings, electrical harnesses and landing gear. Meanwhile, the Racer’s two Safran Helicopter Engines Aneto-1X powerplants are due in mid-year.
Final assembly of the Racer will take place at Airbus Helicopters’ main site in Marignane, France.
Makinadjian estimates that around 50% of the major parts have been built, with manufacturing launched on all components.
There is, he says, “a very positive dynamic” across the programme partners “because we are starting to see this baby growing”.
That animation was absent while the Racer remained as a digital rendering – “it was not really concrete” says Makinadjian, “but now we have it and people are starting to get excited”.
The images of the individual structures do not really encapsulate the ambition or complexity of the eventual compound rotorcraft. Once complete, the Racer will feature V-shaped box-wings for additional lift, mounted at the apex of which are twin pusher propellers. That architecture necessitates flexible driveshafts running from the main gearbox, down the upper wing to a pair of lateral gearboxes. While it builds on research conducted with Airbus Helicopters’ X3 demonstrator in the middle of the last decade, the Racer is built from the ground up.
Makinadjian is reluctant to specify the Racer’s maximum take-off weight – it is somewhere in the 7-8t range – but he reveals that the cabin is around the same size as that of the 8-10-passenger H145 light-twin. The design is “scalable within some limitations” – 25 passengers would require more engines, he notes – it nonetheless has “potential to grow”.
“There is some margin, some room to improve in one direction or another, larger or smaller.”
While Makinadjian is keen not to use the Covid-19 crisis as an excuse for all of Racer’s travails – even before the pandemic hit, first flight had slipped from an initial 2020 target – it is clear that numerous coronavirus-related issues have weighed on the project.
These have ranged from multiple cases of Covid in the fuselage assembly hangar – requiring staff to quarantine and a week-long closure each time – to small suppliers struggling with factory shutdowns before social distancing measures could be implemented, which he says “caused some delays to deliveries to our Romanian partners”. Other small suppliers went out of business, necessitating alternatives to be brought on board. And a plan for Airbus Helicopters’ prototyping staff to assist the Romanian team on site was delayed by travel restrictions.
Despite these multiple setbacks, Makinadjian sees light at the end of the tunnel. “I think we have been able to mitigate most of the risk and topics we have faced and we now have the fuselage in house,” he says.
Better news too on the development of the gearbox, which had long been an item of concern, where delays have been “partially recovered”. The first castings will be made on 16 April, and machining of the gears by partner Avio Aero will begin shortly.
Two gearboxes will be shipped to Marignane during the first quarter of 2022, one for ground testing and the other for installation in the Racer.
“And so it will be at that moment we will be able to finalise the complete assembly of the aircraft,” he says.
Before the first Racer’s first ground run the gearbox will have to be successfully validated, however, to produce “results that allow us to turn the rotor”.
But in a departure from previous development programmes, the airframer will not employ its whirl tower for ground-test activities. This, explains Makinadjian, is due to the Racer using the main rotor blades from the H175 super-medium-twin rather than developmental high-speed blades. The H175 blades – one of the few repurposed components on the Racer – are a known quantity on which “the risks are already mitigated”. However, he admits that they are “not the best design ever for high speed.”
Despite the absence of the bespoke blades, Makinadjian is confident that the Racer will still reach its target speed of 220kt (407km/h), although constant monitoring will take place “to ensure we are still in the domain where we have no risk for the blade and mechanical components”.
Around 200h of test flights are proposed, with the team intending to advance relatively quickly towards the Racer’s goal. “This is really clear for us. If we don’t face any unplanned behaviour I think within six months we can reach the high speed [target],” he says. Even if modifications to the helicopter are required, these will only add another six months to the timeline, he believes.
Following the initial 12 months of development testing, the Racer will then transition to use as a mission demonstrator – essentially proving its viability for a number of roles including search and rescue, emergency medical services and VIP transport.
Evaluation of the “Ecomode” on the Aneto engines – the ability to idle one of the two powerplants during cruise as a fuel-saving measure – will only take place during the second phase of testing.
Aside from the simple goal of flying faster, the Clean Sky 2 programme also requires that the Racer cut by 20% carbon dioxide, nitrous oxide and noise emissions.
To address the last of those targets, the Racer’s upper and lower box wings and tail are fitted with flaps. While these will not be primary control surfaces they can be used to “tune” the aircraft’s attitude allowing “some adaptations of the trajectories to lower the noise”, says Makinadjian.
The Racer’s unique configuration provides a “higher degree of freedom” to tweak speed, attitude and position during approach and take-off, allowing higher rates of climb and descent than in a conventional helicopter. “Theoretically this brings some good results [on noise],” he says.
Part of the design ethos underpinning the Racer is to ensure that the pilot of a conventional helicopter will be able to transition rapidly onto the new design. So far, around 20-30 pilots have flown the Racer in the simulator and have “confirmed it was really easy to switch between a conventional helicopter and this formula”.
Airbus Helicopters has also selected the pilot for the first flight: Herve Jammayrac will reprise his role on the X3, taking the controls of the Racer for its maiden sortie.
