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The world’s most advanced aircraft

Composite materials technology means flying further, faster and in more comfort.

BY  Nick van der Leek , 3 January 20120 comments

The Lockheed Martin F-22 Raptor is capable of reaching twice the speed of sound, or 2 410 km/h.The Lockheed Martin F-22 Raptor is capable of reaching twice the speed of sound, or 2 410 km/h.

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In 1777, a young Joseph Montgolfier observed laundry drying over a fire. That simple observation, of hot air billowing into shirts, was the source code that would lead to modern aviation.

Five years later, the Montgolfier brothers launched their globe aérostatique (a hot air balloon) from Paris’ western fringe. The balloon climbed over 900 vertical metres and flew for 25 minutes, covering a distance of nine kilometres, before landing between windmills on a hill. The fire on board released embers that occasionally floated upward, setting the balloon material on fire (wet sponges were used to prevent the fabric from burning.) Eventually the pilot removed his coat to beat down the flames. One year passed. Then a hydrogen balloon was piloted for two and a half hours across the English Channel by the American Dr John Jeffries and a French colleague. More than a century went by, however, before a heavier-than-air craft (powered, and controlled) took flight in Kitty Hawk, USA. Just 66 years later, Neil Armstrong, who grew up a short distance from Kitty Hawk, and had his flying licence before his driving licence, flew to the moon for a two-and-a-half-hour walk. Since the moon landings, aviation has evolved at breakneck speed, but despite the sophistication of modern aircraft design, the public attitude towards intercontinental air travel has become facile. Advances in aviation are mostly due to improving materials technology built over the platform of super-energetic fuels.

The US Congress does not allow export of the F-22 Raptor outside of the USA.The US Congress does not allow export of the F-22 Raptor outside of the USA.

Nowhere are the advances in aircraft technology more profound than in fighter aircraft such as the $361 million F-22 Raptor. The Raptor, designed and built by Lockheed Martin and Boeing, was conceived to fight Soviet jets over Europe, and came into operation at the end of 2005.

The fifth generation super-manoeuvrable, twin-engined single seater is capable of reaching twice the speed of sound, or 2 410 km/h. According to Lockheed Martin: “The F-22 is the only aircraft that blends super-cruise speed, super-agility, stealth and sensor fusion into a single air dominance platform.”

The Raptor in action appears to defy the principles of flight. It is capable of flying tight angles and demonstrates superb control even at low speeds. Part of this agility can be explained by the dual Pratt & Whitney turbofans capable of altering the pitch axis of engine thrust by an estimated 20 degrees.

The Raptor, 18.9 metres in length, and with a wingspan of 13.56 metres, is unusual for carrying its payload weapons internally, a feature that streamlines flight and minimises its radar signature. In early 2007, the F-22 reported a 97 percent sorties rate, with a 144-to-zero kill ratio during air-to-air exercises over Alaska. The US Congress does not allow export of the Raptor outside the USA as the craft is considered too good to sell. It is widely considered to be the most advanced fighter in the world. A former Chief of the Australian Defence Force claimed in 2004 that the ‘F-22 will be the most outstanding fighter plane ever built’.

But the most advanced fighter is also high maintenance. In 2009, the Air Force admitted that the Raptor requires 30 maintenance hours per hour of flight, costing $44 000. The Pentagon requires no more than 12 hours of maintenance per hour in the air. An additional concern is the average of critical failures (one every 1.7 hours) and the F22’s accident rate (the highest of all USAF fighters in service).

Design feature

The F-22 Raptor final assembly line in Marietta, Georgia.The F-22 Raptor final assembly line in Marietta, Georgia.

Hazards also apply to Raptor pilots. In 2009, test pilot David Cooley briefly lost consciousness while performing a high g-force manoeuvre in his flight profile. Although Cooley regained consciousness, he found himself too close to the ground to recover control of the aircraft and ejected. The blunt force of the windblast that met Cooley outside the cockpit killed him. The debris field of the crash extended over 16 kilometres. The incident was blamed entirely on pilot error.

The same composite materials technology used in military aircraft is now being developed to enhance commercial aviation. Enhancements for airlines in these carbon crunch times tend to revolve around fuel efficiency. The famous double-decker A380, made by Airbus and seating 525, is the largest passenger airliner in the world. With a design range of 15 200 kilometres, and 900km/h cruising speed, the A380 has wings designed to lift 650 tonnes. The A380 consumes less than three litres of fuel per passenger over 100km, a rate competitive with an economical family car. Wingtip fences are a design feature adopted by both Airbus and Boeing for lowering drag and improving airliner performance.

Meanwhile, Rolls-Royce claims to be developing the world’s most advanced civil aircraft engine for the European Airbus’ long-haul routes. The more powerful engine is capable of carrying a full load of passengers 400 nautical miles further than is currently possible.

According to Rolls-Royce: “[P]ayload-range capability will perfectly support the development of long-haul routes for emerging markets…while burning 25 percent less fuel than its nearest competitor.”

The president of Rolls-Royce civil aerospace, Mark King, calls the ‘Trent XWB engines currently on test…the most advanced civil aero-engines in the world today’. Fabrice Bregier, CEO of Airbus, believes the Rolls-Royce engines “will unequivocally assure…[Airbus’] position as the most efficient aircraft in its category.”

While Rolls-Royce is undoubtedly the world leader in aircraft engines (with a 50 percent market share), Boeing’s 787 Dreamliner, the first major airliner to use composite materials, is the most fuel-efficient. The Dreamliner consumes 20 percent less fuel than earlier iterations. Beyond efficiency imperatives, composite materials reduce noise levels and lower requisite air pressures while its higher relative strength allows for larger cabin windows. Extreme lightness means more space, comfort and services can be allocated to in-flight passengers.

We’ve come a long way from daubing sparks on balloon material using sponges and jackets.