Few observers of the rotorcraft industry have a more informed perspective on where it has been and where it is going than Sergei Sikorsky. As a child, he flew as a passenger in his father Igor's VS-300, the world's first practical helicopter. In the evenings, he sat at the dining table as Igor, himself an aviation legend, entertained many others, including Charles Lindbergh and Eddie Rickenbacker.
Some 75 years later, the octogenarian former Sikorsky salesman is still watching the rotorcraft industry undergo massive structural change, as declining government spending threatens companies too dependent on military sales, while a sudden burst of interest in new forms of vertical lift technology imperils decades-old business models throughout the industry.
In his role as strategic adviser to the eponymous manufacturer, Sergei Sikorsky attended the roll-out of the US Marine Corps’ CH-53K, and drew upon all his decades of experience when asked where he sees the industry that his father invented heading into the future.
“Fundamentally, that’s a very interesting question. You start getting a little bit philosophical about it,” Sikorsky says. “I think that probably in the next 10 years, I personally – and, please, this is a very much a personal opinion and in no way connected with any aircraft company – I personally think that probably we will see at least one manufacturer going out of business.”
The USA supports three of the world’s five largest helicopter manufacturers – Bell Helicopter, Boeing and Sikorsky – and several smaller, independent firms, including MD Helicopters and Robinson.
Of the three largest companies, Bell and Boeing are facing the end of production for the V-22 in the next few years, unless the joint venture can secure new sales for the tiltrotor. Meanwhile, production is scheduled to end over the next decade for the Bell H-1 upgrades, remanufactured Boeing CH-47s, Sikorsky UH-60s and Boeing AH-64s.
Each of those programmes entered development before the 1990s and the only clean-sheet, solely military helicopter programme launched during the interim – the Sikorsky/Boeing RAH-66 Comanche – was cancelled in 2004.
The possible exception to this rule is the CH-53K, which shares a numerical designation, rotor diameter, shipboard footprint and general resemblance to its predecessors. Everything else – including the rotor system, transmission, engine, cabin structure, flight controls and flightdeck – is a new design.
Sergei Sikorsky recalls how the company leaped from the 408kg (900lb) VS-300 with a 90shp engine to the 23,600kg CH-53A with two, 4,000shp (2,980kW) engines within 25 years.
Externally, the CH-53K’s familiar looks can be deceptive, but it is packed with new technology. It is scheduled to become the first military helicopter with fly-by-wire flight controls, while producing 20% more lifting power than the CH-53E with no change in rotor diameter thanks to new blades, a more powerful engine and lighter, composite structures.
“This is progress, so to say, under the skin of the helicopter but it’s critically important,” Sikorsky says. “I think and I hope that the -53 Kilo would be as great a step forward as [the CH-53A] was 50 years ago.”
Military planners, of course, are hoping to make even greater leaps in rotorcraft technology within the next two decades. The CH-53K is designed to achieve a maximum speed of 170kt (315km/h), the limit imposed by a phenomenon unique to helicopters called retreating blade stall.
The joint multirole (JMR) technology demonstration programme seeks to overcome this speed barrier by validating a range of potential high-speed technologies, including Sikorsky’s compound, coaxial rotor S-97 Raider, the Bell Helicopter/Lockheed Martin V-280 Valor, the AVX compound coaxial rotor design and the Karem Aircraft optimum speed tiltrotor. Though not aligned directly with JMR, high-speed rotorcraft research is also well under way all over Europe, including Russia.
Sikorsky, the company, has been at the forefront of the high-speed movement, investing $50 million to develop and test the Collier Trophy-winning X2 prototype and launching the S-97 with a combined investment of a “couple hundred million dollars” by itself and suppliers.
“Long-range I think that there are good grounds for looking at the [X2] as the next major speed breakthrough,” Sergei Sikorsky says. “I would like to think that when the Raider flies some time late this year that we may have a machine performing as well as the X2 did.”
Perhaps unsurprisingly, Sergei Sikorsky is less optimistic when asked about other forms of high-speed, vertical-lift technology in which the company founded by his father has no interest.
“The future of the helicopter – the only thing I can tell you right now, being a very conservative character – I think you’re going to see pure helicopters around for a long, long time,” he says.
Almost 75 years after the first flight of the VS-300, the conventional helicopter may still not have reached the end of its potential. Sergei Sikorsky believes there is still no more efficient way to lift an object vertically than the lightly loaded rotor disc of even a large helicopter, such as the Erickson Aircrane.
There are still ways to make the conventional helicopter configuration more efficient. Five years ago, the Sikorsky company attempted to fly an all-electric version of the Schweizer 333 called the Firefly, but abandoned the project after determining that battery technology had not advanced far enough.
But the idea of offloading the propulsion system with electric power still lives. In the past two years, interest has been growing in using an electric tail rotor. Airbus Helicopters has filed a patent for such a device, AgustaWestland has an acknowledged research programme in electric tail rotors and the US Navy has launched a small research programme to investigate its potential.
By converting the tail rotor to electric power, the main rotor could focus 100% of the power generated by its engines for vertical lift rather than divert 10-20% of the thrust to the tail to counter the torque produced by the spinning rotor blades.
“We are looking very seriously right now at electric-driven tail rotors,” Sergei Sikorsky says. “I wouldn’t be surprised to see an electrically-driven tail rotor but it would have to be a very small machine. At the given moment our smallest machine is the S-76. So if we ever go and when we do go it will probably be tested on the S-76.”