Marc Poland of Sikorsky lifts the lid on the safer, faster helicopters of tomorrow.
Igor Sikorsky didn’t invent the helicopter, but he did come up with the design and rotor configuration on which all subsequent helicopters were based. So, for Marc Poland, vice-president of the company that bears Igor’s name, and man in charge of its commercial helicopters business, looking out onto a helicopter technology exhibition is almost like overseeing a family legacy.
‘That’s a fair characterisation,’ he said, in a conference room off the bustling exhibition floor at the recent Helitech event. ‘But we’ve pushed the boundaries of size on from Igor Sikorsky’s very first helicopter, which was a very small, single-seat aircraft, and through our history have made bigger and bigger aircraft. We’re now the biggest providers of what you might call government helicopters, for military missions and for offshore oil industry personnel transport, and search and rescue.’ Among Sikorsky’s helicopters are the workhorse S-92, which can carry 22 passengers; the smaller S-70, the basis of the military Black Hawk; and the enormous, heavy-lift S-80 Super Stallion, whose newest model will be able to lift 27,000lb.
It’s been a bad year for helicopters, as Poland freely admits. In the UK alone this year there have been eight serious accidents and 22 fatalities. ‘I don’t honestly believe it’s a downward trend in operations or the attributes of the helicopters; it’s the roll of the dice that they’ve all happened this year. All the incidents have been unrelated to each other and any of them could have happened at any time, but the fact that they’ve been close together has refocused us within the industry on the sensitivity of flight and the costs of accidents, which is very high, of course. Safety is at the front of people’s minds, in a way that it perhaps wasn’t a year ago.’
All of the major helicopter producers are therefore addressing safety, even though it’s always been a paramount consideration. ‘We look at three general areas where we can improve safety,’ Poland explained. ‘There’s what happens in the cockpit, to do with the activities of the pilot and the way that information is presented to him. Then there’s the mechanics of the aircraft itself and, finally, there’s the maintenance of the helicopter.’
Within the cockpit, development is focused on automating aspects of flight, such as autopilot functions to stabilise the approach to oil rigs, freeing the pilot up from complex multi-tasking. ‘Other companies have put helicopters in the water on rig approach and that’s partly down to the demands on the pilot, communicating with the rig and the passengers while checking on the weather, observing what’s around the rig, watching the instruments and flying the aircraft,’ he said. ‘The only thing that stopped it happening to us wasn’t the excellence of the product, it was just that we weren’t struck with bad luck. So we’re actively developing automated systems, such as enhanced ground-proximity warning and autopilots that work out and fly approaches to oil rigs from any position, and get the aircraft to a set distance and direction from the landing platform. These things make the pilot’s job easier and the whole thing safer.’
Sikorsky’s engineers are focused on mechanical problems that occur in flight. ‘Current aviation regulations are relatively demanding in terms of fault tolerance and flaw tolerance, but even aircraft that are fully certified can fail. We keep looking for failure modes that perhaps might have been tolerated in the past and our engineering department uses those to see how we can make the aircraft safer.’
Throughout the lifetime of the helicopter, the mechanical stresses and strains make them more vulnerable to failure, and they certainly require more stringent inspection than other aircraft, Poland said. ‘We have more moving parts and a higher degree of vibration all over the aircraft. There are mechanical actuators that have to move at 17Hz, driveshafts spinning at ungodly speeds, unbelievable torques moving through the whole airframe — if you wanted to design a way to torture metal, this is it.’
Apart from making the craft safer, Sikorsky’s development programme is focused on the same goals as any other aircraft manufacturer. ‘Range, payload and cost, but safety above all,’ Poland said. In particular, the company is looking at speed and range, with an innovative type of helicopter currently under development.
Meanwhile, Poland said, the UK is a particular focus for the helicopter sector. ‘The SAR-H programme here, which is looking at commercialising coastal search and rescue, makes the UK one of the most hotly contested markets right now,’ he said. Currently, CHC Helicopters has two S-92 search and rescue helicopters operating out of Stornaway and Sumburgh in Scotland, which is acting as an advance trial of a larger network of 24 helicopters to operate around the British coast. CHC has formed a consortium with Thales and the Royal Bank of Scotland to bid for the SAR-H contract, which will run from 2012. ‘That’s a big deal, a huge deal — 24 aircraft of that size, with all the accompanying operations, for 20 years. It’s approaching a £1bn programme,’ Poland said. ‘We’re in a leading position.
We believe CHC’s S-92s are being run very well and we’re told the contract will be decided by the end of this year.’
Q&A – Designing the helicopter of the future
Is there likely to be a step-change in helicopter design in coming years, or will there be incremental development of the existing design?
In the 1950s, fixed-wing aircraft got faster and faster until we hit the sound barrier. That forced a step change. Helicopters have a physical limitation that’s perhaps more imposing than the sound barrier. We generate lift by moving aerofoil blades through the air. In a hover, the wind on all those blades is the same through the rotation, but as you move forward, you have an advancing blade moving towards the front of the aircraft and a retreating blade on the other side. The speed of the advancing blade is its tip speed from the rotation added to the forward speed of the helicopter and on the retreating side you subtract the helicopter speed from the rotational speed. The barrier comes where the tip is retreating at the same velocity as you’re going forward, which means you can’t generate lift. That’s called retreating blade stall; it affects all helicopters and it occurs at around 170-180 knots.
How can you avoid it if you are still using a rotor to generate lift?
We’re doing it by having two rotors mounted one on top of the other, rotating in opposite directions. That means that we have advancing blades on both sides of the helicopter, so we don’t have to care so much about the retreating blade. This craft also has a pusher prop on the back. We don’t have to generate forward thrust by tilting the main rotor forward, which is how conventional helicopters work; that becomes very inefficient at high speed. We can keep level, with the fuselage and the rotor plane horizontal, and push ourselves through the air with the prop.
So the thrust comes from the pusher prop and the main rotors only provide lift?
Exactly. We have a demonstrator craft, called the X2, flying now. It hovers off the main rotors, transitions into forward movement by tilting the rotor, but over the range of speed it trims back out as the pusher prop starts to deliver thrust. The view from the development engineers is that we’ll get well north of 200 knots, maybe as far as 240–250 knots, with a power level roughly the same as a conventional helicopter.
What’s the potential market for these new craft?
There are some missions that require speed and the military would be very quick to adopt it. For example, if you’re transporting troops in V-22 Ospreys, they can fly faster than a helicopter gunship escort. Jet fighter escorts have to keep doing passes and meanwhile, the V-22 is up there on its own. The X2 configuration would give us a ship that can go at the cruise speed of the V-22 and even a bit faster for defensive dashes. As it matures, we think it’ll have commercial applications as well, especially in search and rescue and emergency services where faster speeds and longer ranges could be important.
How soon could this be seen in the field?
With the first demonstrator now flying, I think we could see a production version at air shows in maybe five years.
Biography ofMarc Poland, Vice-president, global helicopters Sikorsky
BA in Mechanical Engineering, Carnegie-Mellon University
MBA Georgetown University Graduate School of Business
1980 Joined Sikorsky on Management Leadership Development Programme. Subsequently headed up engineering programme on MH-60K Blackhawk and was business and programme manager for S-92
2001 Lead for business management supporting commercial sales, managed all proposal operations
2007 Vice-president in charge of commercial business unit
2009 Vice-president in charge of newly created Sikorsky Global Helicopters unit
Poland has also served as a guest lecturer and project advisor at the University of New Haven and the US Military Academy at West Point