A helicopter that consumes up to 40 per cent less fuel and produces significantly less noise than conventional rotorcraft has been developed by Airbus.
The Bluecopter demonstrator has been equipped with an advanced rotor, improved airframe design and intelligent engine power management system, in a bid to improve fuel efficiency and reduce noise.
The technology demonstrator paves the way for a new generation of quieter and more environmentally friendly helicopters, according to Marius Bebesel, program manager for research and innovation at Airbus Helicopters, who has overall responsibility for Bluecopter.
The helicopter produces approximately 10 decibels of effective perceived noise (EPNdB), which is below International Civil Aviation Organisation certification limits, and well below any other rotorcraft, said Bebesel.
“We compared Bluecopter with the world fleet, and we are the world champion, we are between 3-5 EPNdB [quieter] than conventional helicopters,” he said.
The helicopter includes an advanced Fenestron – a rotor fitted inside a protective duct within the tail – that reduces losses caused by drag induced by rotating air trailing from the tip of each blade. It is also much quieter than a conventional tail rotor design.
The demonstrator, which was built using one of the company’s light medium twin-engine rotorcraft as a platform, will also be equipped with an acoustic liner integrated into the rotor’s protective duct, to further reduce noise.
The helicopter also has a newly-developed main rotor. This consists of a five-blade rotor system incorporating the company’s BlueEdge blades. These are designed to reduce the noise produced by helicopters as a result of blade-vortex interaction. This is when the rotor blade hits the wake vortex produced by the blade in front.
The design of the BlueEdge rotor blades means that this interaction with the wake vortex is reduced, resulting in less noise being produced.
The rotor blades also have an increased diameter, and a significantly reduced tip speed of 180 metres per second. That is because the lower the tip speed, the lower the amount of noise produced, said Bebesel.
To improve fuel efficiency and reduce carbon dioxide emissions, the Bluecopter can also switch to “eco-mode” during cruise, by shutting off one of its two engines, and running the other at a higher load. This means the single engine operates more efficiently, and this eco-mode alone reduces fuel consumption by up to 25 per cent, said Bebesel.
To reduce drag, the helicopter’s main rotor and landing skids are both equipped with aerodynamic shells, known as fairings.
The Bluecopter was developed as a short-term skunk works-style project, funded largely by Airbus itself. Some of the technologies were developed as part of the European Clean Sky programme.