The Need for Speed

Ian Frain looks at the RACER, a new highspeed helicopter concept unveiled by Airbus Helicopters

Airbus Helicopters revealed the RACER high speed demonstrator during the second day of the Paris Air Show 2017.Standing for Rapid And Cost Effective Rotorcraft, RACER is being developed as part of the European Union (EU) Clean Sky 2 initiative. RACER is designed to achieve high speed in rotorcraft while sustaining mission performance and cost efficiency. The RACER demonstrator is also being designed with an ease of maintenance in mind.

International Co-operation

The Clean Sky initiative is funded by the EU Horizon 2020 programme and its aim is to reduce CO2 emissions and aircraft noise by developing cutting-edge technologies. The organisation is made up of a public private partnership.

There are 13 industrial partners involved in the RACER project. These include the Italian company Avio Aero, UK-based GKN Aerospace, the DLR(Deutsches Zentrum für Luft und Raumfahrt or German Aerospace Centre) and ONERA (Office National d’Etudes et de Recherches Aérospatiales or French Aeronautics, Space and Defence Research Centre).

Avio Aero will be manufacturing the entire power transmission which includes the two side and one main gearboxes, while GKN is involved in manufacturing the box wing. The DLR is playing a key role in the RACER by designing the wing and the tailplane.

For this the DLR Institute of Aerodynamics and Flow Technology, based in Braunschweig, is involved in improving the tailboom aerodynamics with the aim of producing good manoeuvrability, stability of the airframe and reducing air resistance.

Lastly, the DLR is conducting analysis of the acoustic properties of the RACER under different conditions. This is carried out in co-operation with ONERA; they are also contributing to the design of the propellers and the vertical stabilisers.

X3 and Bluecopter Heritage

Eurocopter, as Airbus Helicopters was then known, had built and own the X3 high speed demonstrator between 2010 and 2013. The X3 validated the idea of combining both the traditional configuration of main rotors and lateral rotors successfully, thus proving the compound helicopter concept. The X3 had own more than 140 hours by June 2013.

Airbus Helicopters first flew the Bluecopter demonstrator in June 2015. The Bluecopter engines had a unique ‘eco-mode’ which works by shutting off one engine. This function is based on an automatic control system that assists the crew and ensures safe operation of the aircraft. Subsequently the remaining engine operates more efficiently and the fuel consumption is drastically reduced. These elements of the X3 and Bluecopter will be found in the RACER.

Unique Design

The RACER has a number of unique and interesting features such as the box wing design, which provides aerodynamic efficiency and lift in the cruise. The box wing design is also intended to provide lift by two plates and subsequently protect the passengers from the props.

Another key feature of the design is that the downwash from the main rotor blades is minimised by reducing the vertical signature. The fully faired rotorhead is intended to have drag and weight reduction in forward flight and a low vibration level within the full speed range.

The low drag fuselage is designed with various missions in mind and also includes the retractable undercarriage which can land in all kinds of adverse terrain.

The RACER airframe will be made of a hybrid metallic composite structure, which reduces weight. Also contributing to reduced weight is a high voltage direct current electrical generation.

The unique box wing of the RACER is designed to provide maximum aerodynamic efficiency and lift in the cruise.
All photos Airbus Helicopters
Airbus Helicopters says the RACER, which is due to fly in 2020, will offer a 50% increase in speed over a conventional helicopter.

In terms of safety, the RACER will have full autorotative capability and no transition between hover and cruise.

High-Speed, Low-Cost Eco

The RACER is expected to fly at a speed in excess of 220kts (407km/h) and operate at a range of 400nm (1,370km). It will be powered by twin Rolls-Royce/Turbomeca RTM322 engines, which have an eco mode built into the system. The eco mode works on the principle of providing a ‘stop and start’ of one engine in flight, thus saving fuel and operating at a reduced cost. The advantage of the eco mode is it is possible to fly at the longer range. The push prop design is there to generate thrust in forward flight while having the option of flying with one engine; a speed of 140kts (259km/h) is achievable.

The Golden Hour

Speed is of the essence when it comes to parapublic roles and search and rescue (SAR). The RACER will be capable of responding to incidents and subsequently fly the victims/patients to a hospital far quicker than current conventional rotorcraft.

This will hopefully narrow the margins in the Golden Hour where the medical profession determines that a trauma patient has more of a chance to recover if treatment is administered in that time.

Elements of the X3 and Bluecopter, which respectively demonstrated the compound helicopter concept and an engine eco mode, are part of the RACER design.

Air support is a vital tool of any law enforcement unit, so the RACER can be seen as an ideal platform for many of the missions expected of it. This can range from searching for suspects or missing individuals to rapid response to an incident. The RACER’s range and speed can also mean fewer bases are needed across the country.

Another mission that requires greater distances to be covered in a shorter time is passenger transportation, especially for those involved in offshore oil exploration. Currently in a number of countries there is need for oil workers to fly in a commercial fixed wing airliner to an airport and subsequently complete their journey by helicopter. The RACER might be able to remove the need for a fixed wing element from these missions.

The RACER demonstrator is expected to undergo final assembly during 2019 and subsequently fly the following year. The cost of the RACER will be around 20% to 25% more than current conventional rotorcraft today. It is also expected that the industry as a whole will accept the increase as a compromise for the 50% increase in speed compared to current helicopter types.