Rotor-driven flights of fancy on course for reality

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Worries about the economic climate and uncertainty about when the next up-cycle will come thankfully are not preventing the visionaries from airing the concepts that could make a real difference to the way we fly in future.

Project Zero from Italian helicopter maker AgustaWestland has something in common with the wacky designs of science fiction enthusiasts and radio-control flyers. But the company’s 275 knot AW609 TiltRotor shows that fantasy can be made into business transport reality.

The model has been a long while in development from the Bell-Boeing military V-22 since AgustaWestland took over the project completely in 2011 from its partnership with Bell. But the aircraft is back on track for entry into service by 2016 as fast point-to-point executive transport.

The Project Zero proof-of-concept aircraft, which was on display at the Paris air show at the end of June, can hover like a helicopter but fly at speed like an airplane. It uses twin tilting rotors but puts them in the middle of wings that are blended into its body. Even better, it uses electric motors to drive the rotors, thus removing at a stroke the complexity and weight of gearboxes and shafts that would take drive from engine to rotors in a conventional helicopter.

A startling illustration of what can be done with technology that “adds lightness and simplifies”, to borrow an engineering catchphrase, is the flying bicycle demonstrated in the Czech Republic earlier in June. While a trifle cumbersome for city traffic, the bicycle – which uses two horizontal rotors driven by electric motors and guarded by cages – demonstrated that it can fly, if only for a few minutes.

Something that has yet to fly but promises much is the hybrid eConcept from Airbus. Seen in Paris, the distributed electrical aerospace propulsion (DEAP) project has a bank of electric fans integrated into each wing of an airliner, with a single gas turbine to provide power to the fans and the energy storage medium.

The turbine could be optimised for the demands of cruise power, with batteries boosting power to the fans for takeoff or climb performance. Adding extra power for takeoff has a long precedent – rockets have been bolted on to airplanes and even helicopters to shorten takeoff runs and get heavily laden aircraft off the ground.

With energy storage that is dense enough, there is even the promise in the more distant future of aircraft that can take off on electric power alone. This would have the huge benefit of reducing the noise signature of aircraft in the phases of flight where their sound is most intrusive. The European Commission has set a goal of cutting noise levels by 65 per cent between 2000 and 2050.

That could lead to all sorts of changes in aircraft use, particularly for people flying in tomorrow’s equivalent of business jets. Using airfields closer to city centres would not meet opposition on noise grounds.

That was one of the advantages of the hybrid helicopter shown at Farnborough three years ago by EADS Innovation Works, which came up with the E-Thrust engine concept at the heart of the eConcept in partnership with Airbus and Rolls-Royce. In the eCo2Avia hybrid helicopter, diesel motors provide power to batteries, which in turn power electric motors to spin the main and tail rotors. The idea is that takeoff and landing, which account for the majority of noise irritation caused by helicopters, could be performed on battery power alone.

All of this is some way down the line, though. Eurocopter’s X3 helicopter, a hybrid in a different sense, set a speed record of 255 knots in level flight early in June, bettering the 250 knots of Sikorsky’s X2 concept. Both are hybrids in that they have conventional main rotors, but the X2 has a pusher propeller at the rear, while the X3 has two forward-facing propellers on stubby wings. These propellors do the job of an anti-torque tail rotor but use their energy to speed the aircraft forward through the air.

This is current technology, like that of the AgustaWestland AW609. Such technology is set to provide benefits for business and other travellers in speed, if not yet in noise, in the very near future.

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