Engineers pursue the ‘Blue Whale’ - the helicopter that can exceed 700km/h

In the past decade, China has commissioned its first aircraft carrier, put its first astronauts into orbit and built a high-speed rail system that is the envy of many developed countries.

The country's engineers and scientists accomplished much of this by adapting and applying technologies developed elsewhere. Now, they are looking to break new ground altogether by building the fastest helicopters in the world.

Among the most ambitious of such aircraft in the works is the four-rotor "Blue Whale", a project by the China Helicopter Research and Development Institute. By tilting its four rotors from a horizontal to vertical position, the helicopter promises to reach speeds of more than 700km/h - which would make it the fastest "tiltrotor" in the world, 40 per cent faster than Boeing's V-22 Osprey, according to the institute.

With a cruising speed of 538km/h, developers say the Blue Whale will lift 20 tonnes of cargo and fly more than 3,100 kilometres without refuelling. It will fly as high as 8,600 metres, also higher than the V-22.

Qiu Guangrong , a director of the institute, told the Global Times last year the group hoped to produce functioning prototypes of its high-speed helicopter within the next five years, although he did not specify which models would be the first produced.

Even today, most conventional helicopters are not suited for speeds exceeding 200 km/h. Above certain speeds, airflow between blades can throw the aircraft off balance. Huge stresses are also placed on engines and mechanical parts, which can fail or break apart.

Over the decades, helicopter designers have tried numerous solutions to break the speed barrier. The twin rotors on Boeing's CH-47 Chinook, for instance, spin in opposite directions to cancel out each other's turbulence. The experimental Eurocopter X3, which has a conventional rotor plus twin propelling rotors on fixed wings, reached 486km/h in June.