As Eurocopter presses ahead with development of its X3 technology demonstrator with a view to introducing the radical high-speed technology commercially in six years, the key challenge is not technical development, but finding an agency to certificate the machine.
Chief executive Lutz Bertling, speaking at his annual state-of-Eurocopter briefing in Paris, said dealings with the Federal Aviation Administration or European Aviation Safety Agency will "take time", because the X3, with its main helicopter-style lifting rotor and side-mounted forward-drive propellers, may been seen as something in-between a helicopter and a fixed-wing aircraft.
Meanwhile, development of the X3 - which first flew in September 2010, is going "surprisingly" well, says Bertling. The flight simulator, which has been in operation for two years, turned out to be highly representative of the actual aerial performance, so development is proceeding with relative ease, he says.
Separately, Bertling pointed to a 2011 launch of the much-anticipated X4, which he promised will be a revolutionary step forward in helicopter technology.
Bertling insists the machine - destined to replace the AS365 Dauphin - will be a "game changer" that introduces a "completely different" way of flying compared with today's helicopters.
As for the X3, Eurocopter hopes to introduce the technology on most new models eventually - ideally as what would be in effect an alternative to a conventional helicopter, with a great degree of mechanical similarity. The first use of X3 technology is likely to come in about six years, as a replacement for the EC225 Super Puma.
Bertling says the X3 may not be the fastest helicopter on the market - Sikorsky's X2, with contra-rotating main rotors and a pusher prop, may be quicker - but he is confident it will win a "race for productivity" by offering "cost-effective speed".
Critically, he says, the notion of offering X3 technology as an option to standard lift in otherwise common machines will give operators vast potential to buy speed when it matters. For example, he says, for an oil company operating 80km (50 miles) offshore, X3 would add cost without much meaningful benefit. But if the oil rigs are 400km offshore, the high-speed option will shine, he predicts.
"We don't sell helicopters," says Bertling. "We sell mission capability."
The X3 demonstrator features a five-blade main rotor for vertical lift and single propellers mounted to short fixed wings either side for speed. Critically, the short fixed wings provide significant lift, allowing the main rotor to be slowed in forward flight - it provides lift only - to cut drag.
To keep development costs down, the aircraft is built around adapted existing components, including the airframe (from the AS365), main rotor (EC155) and main gearbox module (EC175), which has had lateral take-offs added for the lateral propulsion propellers.
The lateral propellers can be declutched independently of the main rotor, and thus stopped when the aircraft is on the ground for loading or unloading.
Eurocopter sees the X3 configuration proving suitable for long-range search and rescue, coastguard duties, border patrol, passenger transport and inter-city shuttle services. Military applications benefiting from vertical take-off and landing and cruise speed could include special forces operations, troop transport, combat, search and rescue and medical evacuation.