As many comedians have stated in the past, helicopters are relatively ugly machines, very complex in nature and, on the surface, have absolutely no business to fly. AVIATOR takes a closer look at rotary aircraft, the research going on in labs worldwide; and the key issues confronting an industry that is by most accounts, on the ascendency.
Apart from the advantage of being able to lift off and land vertically, many would suggest there is very little else going for the helicopter. The rotor system becomes inefficient at higher speeds and despite enormous research and development, the speed limit for most helicopters remains well below 200 knots. Even when cruising at reasonably sedate speeds, the machines are still grossly inefficient by comparison to their fixed wing cousins.
Aeroplane pilots would often compare the Beechcraft King Air with the popular Bell 412 helicopter. The point of this comparison was that while both machines had similar engines, the performance was markedly different, highlighting the inefficiencies of the helicopter design. Bar room discussions would often hinge around the fact the King Air could fly twice as fast, twice as high, twice as far and carry twice as much as the Bell 412.
But despite this, the modern helicopter is an accumulation of innovations, whereby modifications have improved performance significantly. For example, the rotor stabiliser bar, invented by Arthur Young in the 1940s, may look small and insignificant, but this piece of technology revolutionised vertical-lift flight. After a series of unsuccessful trial flights, whereby Young’s model aircraft would tip over after takeoff, the inventor decided to try a stabiliser bar, which was linked directly to the rotor so the rotor plane was controlled independently of the mast. With the addition of this device, the model performed remarkably, showing great stability. Genius.
Fast forward to the new millennium and one significant advancement in the last decade has been the no-tail rotor, or NOTAR, helicopter. NOTAR is the name of a helicopter anti-torque system which replaces the use of a tail rotor. Developed by McDonnell Douglas Helicopter Systems (through their acquisition of Hughes Helicopters), the name is an acronym derived from the phrase no tail rotor. Benefits of the NOTAR system include increased safety (the tail rotor being vulnerable), and greatly reduced external noise. NOTAR-equipped helicopters are among the quietest certified helicopters in the world.
Some helicopters are now being equipped with a second engine, which can operate the main rotor if the main engine fails. For example, the Black Hawk helicopter features this design improvement. Either engine can keep the aircraft aloft on its own, enabling the pilot to land safely in the event of an emergency.
Scientists have also been busy studying the main rotor assembly in an attempt to simplify one of the most complex parts of a helicopter. In the late 1990s, researchers developed a solid-state adaptive rotor system incorporating piezoelectric sheets. A piezoelectric material is one in which its molecules bend and twist in response to an electric field. In a rotor assembly, piezoelectric sheets – not mechanical linkages – twist sections of the blade root, thereby changing the pitch of the blades as they rotate. This eliminates parts in the rotor hub and decreases the chance of a mechanical failure.
It’s also worth mentioning those strange machines, known as tilt rotors, which bring together the best features of helicopters and aeroplanes. A tilt rotor aircraft takes off like a helicopter, with its two main rotors upright. But when it’s airborne, the pilot can tip the rotors forward 90 degrees, enabling the machine to fly like a conventional turboprop aeroplane.
The United States military has persevered with tilt rotor technology and their success with these large and extraordinarily expensive aircraft has been significant. This is because these weird looking machines utilise the best of both worlds; providing a distinct advantage over long distances because they’re able to climb like a small airliner to high cruising levels where turbine-powered aircraft obtain an enormous advantage both in speed and range.
Meanwhile, the civilian development of a smaller tilt rotor machine has stumbled along with little interest. But that may not be the case for much longer. Over the past decade designers and manufacturers have been studying the problem of oil rigs being located further offshore. The major concern about this is the inefficiency of using helicopters to travel over such vast distances.
In Australia, the construction of an 850 km underwater pipeline from the North-West Shelf in Western Australia to Darwin in the Northern Territory provides enormous potential for tilt rotor technology … but only if it can be developed at a reasonable cost. The concept of supporting fly-in and fly-out crews often numbering thousands working on these remote construction sites, far out into the ocean, confirms the range and speed of tilt rotor machines would easily outclass the existing heavy helicopters.
Technologically, the tilt rotor helicopter leads the cutting edge of rotary innovation and is likely to continue to do so for some time.
However, that doesn’t mean the industry’s inventors and engineers have been sitting idle, twiddling their thumbs. In fact, in recent years there have been several weird and wonderful innovations that have attracted the attention of many people, both within and beyond the industry. While some of these innovations may not be of any practical use, others will be. Included among these innovations are the discovery that the bumps (known as tubercles) along the leading edge of humpback whales can improve the design of rotor blades, thus allowing helicopters easier manoeuvrability. Then there’s unmanned helicopters being utilised in warfare in Afghanistan; electric helicopters; plastic helicopters; helicopters powered by human pedal-power. And last but not least, there’s the latest state-of-the-art aircraft being produced by the major manufacturers such as Bell, Eurocopter, Robinson and Sikorsky. The innovations not only continue to grow, they also continue to amaze. Keep reading and take a look for yourself.
The device only stayed airborne for 11.4 seconds, but thanks to the diligence of a team of 50 students at the University of Maryland, a human-powered helicopter called the Gamera recently broke a duration record in the U.S.A.
The flight, accomplished by student and “test pilot” Judy Wexler, rose slightly off the floor inside the university’s Reckord Armory, and was recognised as an official U.S. duration record by the National Aeronautic Association.
The Gamera, which is built from lightweight carbon fibre, balsa, foam and mylar, weighs just 95 kg, including the weight of the student pilot. It requires constant hand and foot pedalling — with 90 per cent of the power generated by the lower body. No fuel required, just plenty of human sweat.
Meanwhile, a helicopter with an electric motor was recently able to get slightly higher off the ground than the human-powered Gamera. French aviation engineer and helicopter pilot, Pascal Chretien hovered his aircraft – built from welded aluminum tubing and running solely on battery power – for two minutes and 10 seconds, hovering one metre over the ground.
With helicopters being notorious energy wasters, how did the Frenchman achieve this milestone? Simple, he replaced the most energy-intensive components with ultralight alternatives. And instead of a tail-rotor, which exacts a heavy load on the helicopter’s battery, Chretien’s helicopter uses a coaxial design with two counter-rotating rotors on top. This is a torque-balanced program that only requires a simple lightweight tail in the back in order to maintain its balance. Further reducing the load, Chretien created a new weight-shifting system that replaces cyclic control and variable blade tilting with a big set of handlebars.
Chretien’s achievement didn’t go unnoticed as he also beat heavyweight U.S. manufacturer Sikorsky to the punch. Sikorsky had been working on its own project to get the first manned electric helicopter in the air. In fact, in July 2010, it unveiled its pre-flight Firefly prototype at Oshkosh.
But unlike Chretien’s creation, the Firefly is a much more conventional helicopter. It uses a conventional enclosed body shape, a single top rotor with a conventional swashplate and cyclic control, and a tail rotor – all of which add considerable weight, requiring additional heavy battery packs. Will Sikorsky continue developing an electric-powered aircraft now that Chretien has stole their thunder? We certainly hope so.
Unmanned aerial vehicles are becoming exceedingly common, but an unmanned helicopter called the Kaman K-MAX, recently made its first combat resupply mission in Afghanistan. A modified K-MAX intermeshing rotor helicopter with the ability to lift a payload of over 6,000 pounds (2,721 kg), the aircraft is a joint venture between Lockheed Martin and Kaman Aerospace. After testing demonstrated its ability to exceed the Navy and Marines’ requirement to deliver 6,000 pounds (2,721 kg) of cargo per day over a five day period, two unmanned test flights were flown without a load to one of the forward operating bases in Afghanistan.
Although the unmanned K-MAX removes the helicopter crew from danger, in an effort to keep it safe and away from unnecessary danger, the craft will only be used at night and at high altitude.
Kiwi outfit Composite Helicopter has built the world’s first plastic helicopter, the KC518, which uses the same carbon-fibre technology as that found in America’s Cup boats and the new Boeing 787 “Dreamliner”.
The helicopter features a four-blade aluminum main rotor and shrouded composite tail rotor. Preliminary specifications are based on kit helicopters fitted with the Rolls-Royce RR250-C20B/J engine and call for the KC518 to be available in five-to-six-seat configurations, have a cruise speed of 135 knots, an endurance of 3.6 hours (96-gallon tanks) and a useful load of 1,450 pounds (657 kg). With a full complement of passengers and baggage the endurance slips to 2.6 hourS.
Anticipated IGE and OGE hover ceilings are 10,000 and 8,000 feet, respectively, with a maximum altitude of 14,000 feet and a 1,000-fpm rate of climb. Certified models will be equipped with either the Rolls-Royce 300 or 500 series engine and cargo sling and spray system options will be available. The version with the 300 engine will have a maximum takeoff weight of 2,850 pounds (1,293 kg); the derated 500-powered model will see that increased to 3,200 pounds (1,451 kg) and be dedicated primarily to users with high/hot requirements.
At the time of writing, the company already had orders for 41 units and was scheduled to showcase the machine at Oshkosh 2012.
Hmmm, now what’s this about humpback technology? Apparently, the bumps (known as tubercles) along the leading edge of Humpback whales have inspired an innovation designed to improve the speed and manoeuvrability of helicopters.
Scientists from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, or DLR) glued a series of six-millimetre-wide rubber bumps onto the edges of all four of a helicopter’s rotor blades – 186 on each blade – just like the tubercles on a Humpback. The bumps have been patented as Leading-Edge Vortex Generators (LEVoGs).
After showing promising results in wind tunnel tests, the helicopter was tried out in actual flights by test pilots, who noticed a definite improvement in performance. Hmmm, humpback whales and rotary aviation? Who would have thought there was a connection?
Eurocopter EC130 T2
Speaking of improvement in performance, Eurocopter recently unveiled the brand new EC130 T2, the updated version of its single-engine EC130. Around 70 per cent of the aircraft’s airframe has been modified and the aircraft is now powered by the Turbomeca Arriel 2D engine, which boasts 10 percent more average power and lower specific fuel consumption than the current powerplant.
The EC130 T2’s new and updated features include an active vibration-control system, improved air ventilation, distribution and demisting systems, a redesigned cabin interior with full flat floor, and enhanced man-machine interface in the cockpit. New energy-absorbing seats and a crashworthy fuel tank provide safety enhancements. Performance improvements include a higher maximum gross takeoff weight (2,500 kg for internal loads and 3,050 kg with sling loads) and a speed increase of up to 10 knots, while optionals include new-generation air conditioning, tinted windshield and a right-side sliding passenger door. Future development plans will see a 1,500 kg cargo sling and Eurocopter’s Stylence interior added to the mix.
Eurocopter isn’t the only aircraft manufacturer producing the goods, with the Bell 429 – now with a maximum gross weight of 7,500lbs (3,402 kg) – making an impact on the local rotary environment since its introduction in 2009.
A state-of-the-art machine bristling with the latest technology, the response to the 429 has been positive, with 22 aircraft already in service in the Asia Pacific region. Locally, there are a few Bell 429s in service in New Zealand and Australia, with further corporate aircraft to be delivered later in the year. The first of three Bell 429 helicopters was delivered to Raytheon Australia in March 2012, to support the Royal Australian Navy’s Retention and Motivation Initiative (RMI) Program. These helicopters replace the three AgustaWestland A109Es currently performing the role.
Additional options such as Helicopter Terrain Awareness Warning System (HTAWS), a radar altimeter, cockpit voice/flight data recorder and strobe lights, enables the additional weight increase to be incorporated.
The increased gross weight directly translates to greater range and loiter times. The weight deviation improvement will have the capability to be retrofitted to the existing fleet through the installation of a minimal kit available through Bell Helicopter, while the modification can be completed by Hawker Pacific’s facility at Bankstown Airport.
The 429 isn’t the only Bell aircraft making its mark, with the 407GX making some waves. Built on the success of the 407, the 407GX is the only helicopter equipped with the innovative Garmin G1000HTM integrated glass flight deck, making it an advanced light, single-engine rotorcraft.
The 407GX’s integrated glass flight deck provides aircrews essential flight information at a glance for greater situational awareness, improved operational capability and increased safety. The advanced cockpit features two 10.4” high resolution LCD displays with an intuitive, easy to scan layout and an integrated avionics system that presents flight instrumentation, navigation, communication and engine information.
So, now that we know that innovation and state-of-the-art machinery remain key components in rotary aviation, what are the major issues confronting the rotary industry?
According to Australian Helicopter Industry Association convener Rob Rich, there are a number of issues presently confronting the industry, including global military trends, energy and mineral exploration, new technologies and in Australia and New Zealand, the shortage of qualified pilots to meet future demand.
GLOBAL MILITARY TRENDS
The popular, long-running television series, MASH (1972-1983), based on the Korean War, alerted the world to the aeromedical capabilities of even small helicopters. Other nations quickly followed this trend, although the advantages in low level reconnaissance were also quickly recognised.
The long years of the Cold War drove helicopter development along a somewhat more sinister path where the ability to carry heavy weapons against large armoured forces became the vogue. During this era the Vietnam War highlighted the advantages of carrying large numbers of troops quickly into a battle zone and supporting them with gunships. The more recent wars in Afghanistan and Iraq has seen the development of armed helicopters which have extraordinary night capabilities, and also the widespread use of very heavy helicopters for logistic resupply in countries where safe roads are rare.
“Today, the manufacturers of military helicopters are preparing for the downsizing of many armed forces around the world,” Rich says. “No doubt this is partly due to the demise of the Soviet Union. However, helicopters are still required in the war on terrorism, although this threat does not require expensive tank-busting helicopters. There is still a trend towards the heavy cargo-carrying helicopters needed to haul large loads around countries such as Iraq and Afghanistan.”
One helicopter used for multiple roles in the Middle East is the Sikorsky H-60M Black Hawk, of which the 500th was recently delivered to the U.S. Army.
The need for an all-new ‘M’ Black Hawk platform emerged during the late 1990s with the requirement to upgrade the analogue UH-60A and UH-60L aircraft with an integrated digital cockpit, dual digital flight controls, wide-chord rotor blades, more powerful engines and structural enhancements. The resulting ‘M’ model saw measurable improvements to aircraft control, survivability, lift, range, navigation and situational awareness, engine durability and maintenance costs.
The 500 H-60M aircraft are part of a planned production run of 1,375 ‘M’ models (956 UH-60M and 419 HH-60M aircraft) the Army plans to order through 2026. By then, the Army’s total Black Hawk fleet, including upgraded UH-60A and UH-60L aircraft, is expected to reach more than 2,100 aircraft.
In fact, Sikorsky has just announced a huge deal with the Australian Defence Force comprising a four year ongoing contract to provide engineering and logistics support to the Black Hawk and Seahawk fleet. George Cheetham, the MD of Queensland based support outift, Sikorsky Helitech, points out the helicopters’ (and the Sunshine State) essential role in keeping our country protected.
“Brisbane is emerging as the hub for helicopter and aviation maintenance in Australia,” he explained. “For the last twenty-five years, Sikorsky’s Black Hawk and Seahawk helicopters have played a crucial role as part of the ADF.
Stephen Smith, the Defence Minister, went on to observe how much the local economy depends upon our rotary brethren: “During the 2011 flood disasters in Australia, our Black Hawk aircraft were critical in search and rescue missions and relief provisions. Every flight hour requires many more ground hours of repair and maintenance. This contract will ensure local jobs and investment in Brisbane and Queensland.
ENERGY AND MINERAL EXPLORATION
In the past decade the world’s economy has been moving forward at a faster pace with an increasing consumption of energy. As a result, this has resulted in huge efforts to locate energy and mineral resources.
“Although onshore operations are driving the helicopter industry along at a steady pace; the offshore operations are creating serious problems because many rigs are moving out into deeper water in search for oil and gas,” Rich explains. “Many experts believe the current helicopter capabilities are now approaching their limits in relation to how far they can fly off-shore in relative safety.”
MOST POPULAR HELICOPTER
The US-made, four-seat Robinson R44 helicopter has been an outstanding success because of its relatively low cost, the use of a derated piston engine and a very simple, efficient design. After many years of deliberation the factory finally managed to develop a turbine version known as the R66.
“This five seat helicopter has such great potential that Bell has discontinued production of the much loved Bell 206 family,” Rich says. “The company stated they could not compete with this machine and other smaller machines coming from the European stables. In Australia for example, the Robinson products represent around 50 per cent of the Australian fleet. We are one of the few countries where the smaller R22 helicopter is more numerous than the R44. The reason is the widespread use of the two-seat R22 in the cattle mustering industry.”
INDUSTRY ON THE ASCENDANCY
It is predicted that by the end of winter, Australia’s helicopter fleet will exceed 2,000 units.
“Based on the fact we grew from 649 helicopters 15 years ago to 1,937 in March 2012, we should see our fleet grow to about 2,970 in five years using the past nine per cent annual expansion rate,” Rich says. “This is an increase of 1,033 helicopters or around 200 per year, an increase of four new helicopters on the CASA Register each week.”
It is assumed that each new airframe creates 1.3 new jobs when the normal attrition of 15 per cent due retirement, sickness and change of careers, etc is considered. According to Rich, an extra 1,350 jobs may be created over the next five years, which equates to around five jobs per week.
“Each year we lose three per cent of pilots due retirement,” Rich says. “However, as we have an older workforce (by about three years) this rate will increase. Add to this the natural increase in numbers, say nine per cent, then we have a need to provide annually 12 per cent of our pilot numbers each year. But not everyone flies all his working life; some move to management, a few become ill and others leave the industry. It is estimated this figure could be around eight per cent. When these losses are added together, we need 20 per cent of the existing pilot group number trained each year to keep with the losses and the growth rate.
“Using March 2012 figures and applying this formula to the 2,132 existing commercial pilots and say 20 per cent of the 1,202 private pilots (many who are actually working), then we need to be producing 470 new pilots each year in Australia. In theory each of the 30 active flying schools need to train around 16 students each. This represents a minimum of 55,000 training hours in 2012.”
Based on these figures, plus the savvy individuals involved in rotary research and development, not to forget the state-of-the-art equipment on offer, rotary aviation in Australia certainly has plenty to look forward to.