50-year-old aircraft, goud van oud!

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IN FOCUS: Can the 50-year-old Chinook hit a century?

By:   Dave Majumdar Washington DC

09:00 7 Aug 2012 

This month brings the 50th anniversary of the Boeing CH-47 Chinook's service entry - and it is entirely possible that the venerable tandem-rotor helicopter might serve with the US Army for another half-century.

The service initially signed the contract to develop the Chinook in 1959 with what was then Vertol, says Boeing business development director for mobility rotorcraft Mark Ballew. The first prototype flew two years later on 21 September 1961 - but by then, Boeing had purchased the Vertol Aircraft Corporation, the former 20-year veteran Chinook aviator says. Less than a year later, the army took delivery of its first aircraft on 16 August 1962.

"Believe it or not, that aircraft is still flying," Ballew says. "It's gone through multiple iterations from the A-model to the D-model."

Currently that aircraft is being remanufactured once again into the latest F-model configuration. "It just came back from Afghanistan, and it's going to go back to Afghanistan probably in the January timeframe," Ballew says.

The Chinook has served through various iterations in Afghanistan

Although the initial contract was signed in 1959, the origins of the Chinook date back to the 1940s, when Frank Piasecki pioneered the tandem-rotor concept.

The first operational tandem-rotor designs to see service were the Piasecki Helicopter Corporation CH-21 and CH-25 helicopters. Their successors, the CH-46 Sea Knight and the CH-47, were designed nearly concurrently in the late 1950s, after Piasecki left the renamed company, says historian Jon Bernstein, curator of the US Army Air Defense Artillery museum in Fort Sill, Oklahoma.

For the US Army, the CH-21 was a very significant aircraft, Bernstein says. But with the development of new gas turbine engines, the service wanted a machine that could take advantage of the new technology.

"The army really wanted a turbine-powered heavy lift aircraft to replace the CH-21," he says. "And that's really where the CH-47 came from."

Half a century later, there are many original A-model Chinooks that have been remanufactured multiple times, and which have been serving continually since their original roll-out. It is the Chinook's robust tandem-rotor design which allowed the aircraft to evolve over the decades, while lesser aircraft fall by the wayside.

There are a number of advantages to the tandem-rotor concept, Ballew says. Firstly, unlike in a single-rotor machine where horsepower is siphoned off to power the anti-torque rotor, 100% of the engines' output is dedicated to providing lift. That gives the aircraft outstanding high-altitude performance, he says.

The air flow from the tandem rotors is also cleaner over parts of the airframe in flight, Ballew says. The Chinook also has a large area over which the aircraft's centre of gravity is spread due to its rotor design, he says. That gives the crews more flexibility when loading or unloading the aircraft.

What impresses Bernstein the most is the Chinook's sheer power. It is the helicopter's prodigious power margins and robust design that has enabled it to adapt various roles over the years.

The Chinook is also the fastest helicopter in the US inventory, Bernstein adds. The CH-47 is significantly faster than its escorting gunships, like the Boeing AH-64D Apache.

In places like Iraq and Afghanistan - where large numbers of Chinooks are currently serving - Apache pilots are constantly radioing their charges to slow down. "It was always fun trying to keep up with them," says Bernstein, a former Apache pilot. "They are fast as anything."

It is also extremely versatile. "It's done pretty much every role," Bernstein says. But hauling cargo is where the aircraft excels. The CH-47 was originally intended as a medium-lift machine. But during the Vietnam War, the Chinook proved to be such good cargo hauler that it ultimately replaced the Sikorsky CH-54 Sky Crane as the army's heavy-lifter, he says. But the Chinook has also been used for air assault, as a mobile refueling station, for special operations and even as a gunship.

The Chinook made its combat debut over the jungles of Vietnam. Since then, it has served in every major combat operation that the United States has been involved in since it entered service. Perhaps its most famous mission in recent years was during the mission to eliminate terrorist leader Osama bin Laden - Operation Neptune Spear. On 2 May 2011, a number of special operations MH-47 aircraft participated in a daring night-time raid deep inside Pakistan.

While details of the operations are murky, Chinooks and a specially modified stealthy variant of the Sikorsky MH-60 Black Hawk infiltrated that country from Afghanistan. While the Black Hawk(s) flew all the way to Abbottabad, the Chinook remained in reserve half-way between the objective and the border. Ultimately, the mission was successful when an elite team of US Navy SEAL operators successfully eliminated their target, however, one of the Black Hawk(s) crashed.

Perhaps one of the most unique uses of the Chinook came during the Vietnam War, when the US Army adapted four aircraft into an experimental ACH-47A configuration in a programme dubbed Guns-a-Go-Go, Bernstein says. The concept was similar to the fixed-wing Douglas AC-47 Spooky or Lockheed Martin AC-130 gunship - both of which were developed during that conflict.

The ACH-47 served for about three years. However, though the gunship variant proved to be an effective machine, three of the four aircraft were lost either in combat or accidents, Bernstein says. The surviving aircraft is preserved in an army museum at the Redstone Arsenal, Alabama.

Ultimately, the army decided to cancel the programme because there were other, less expensive ways of carrying out the gunship mission. The emergence of the Bell AH-1 Cobra attack helicopter, for example, meant that the Chinook was not needed for that role, Bernstein says. "Using a high-value asset like a Chinook in gunship role didn't really make much sense, even though they were incredibly heavily armed," he says. "You could do the same job with [Bell UH-1] Hueys or Cobras and not risk as many people."

The Chinook has been upgraded over the years and throughout the various conflicts it has flown in. The aircraft has evolved from the original A-model through to the latest F-model and special operations standard G-model machines.

Over the years, materials and construction has changed. Engines and transmissions have been upgraded and the gross weight has increased. There has also been a quantum leap in avionics technology.

Compared to the original 33,000lb CH-47A, the F- and G-model machines weigh in at over 50,000lbs, and have state-of-the-art avionics. Boeing has added a common avionics architecture system which offers a full glass cockpit - greatly increasing a pilot's situational awareness. The company has also added a digital advanced flight control system (DAFCS), Ballew says, which vastly improves the Chinook's handling characteristics. The DAFCS offers stabilised hover capability, and a pilot can alter his position foot by foot in any direction.

Boeing is continuing to evolve the Chinook. One upcoming feature is a refined rotor blade design which will add 2,000lbs of lift, Ballew says. There are also other ongoing projects to continue improving the aircraft's performance.

The US Army is committed to flying some Chinooks till at least 2050, but unless there is some revolutionary breakthrough in propulsion technology that offers cost-efficient rotorcraft flight at high speeds, the Chinook looks to continue its dominance of the heavy-lift market indefinitely, says Richard Aboulafia, an analyst at the Teal Group.

The Chinook may not be heading off in to the sunset any time soon

"I know it's a bold statement to say we're going to be flying for [the] next 50 years," Ballew says. "But based on the army's projected usage for it until at least 2045, you going to have some residual aircraft out there flying somewhere for 100 years."

http://www.flightglobal.com/news/articles/in-focus-can-the-50-year-old-chinook-hit-a-century-375129/?cp=NLC-FGFDN20120815&attr=editorial

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US military sees virtue in 50-year-old aircraft

Ajai Shukla / New Delhi Aug 06, 2012

The United States military, the world's most technologically advanced force, paradoxically fields some of the oldest weapons' platforms on the planet. At least five aircraft, still in US military service, are already more than 50 years old. And, they are set to serve for three to four decades more.

The Indian Air Force has already bought one of these venerable platforms, the C-130 Hercules, in its newest avatar, the C-130J Super Hercules. The IAF is on course to buy another: the CH-47 Chinook helicopter. Trial evaluation has been conducted and a final decision is awaited.

The other half-century-old US aircraft (not on India's shopping list) are: the B-52 Stratofortress bomber that took to the air in 1952; the KC-135 Stratotanker mid-air refueller that first flew in 1956; and the T-38 Talon, the world's first supersonic trainer jet, flying since 1959. The US Air Force still trains pilots on the Talon.

The IAF's other big American buy, the C-17 Globemaster III transport aircraft, is more than 20 years old. The AH-64 Apache attack helicopter, which the IAF has trial-evaluated and is making a final decision on, is more than 35 years old. So is the F/A-18 Hornet, which the IAF evaluated in the $17-billion medium fighter competition before rejecting it.

US defence experts have questioned the rationale for spending a fortune, as the Pentagon has, on cutting-edge platforms like the F-22 Raptor and the F-35 Lightening II, both next-generation fighters that cost hundreds of billions of dollars to develop. Or, by extending this logic, for India to spend tens of billions on newly designed fighters like the Rafale, rather than implement the IAF's suggestion to buy upgraded versions of the proven Mirage-2000 fighter.

Expensive, custom-designed platforms are a waste, avers Admiral Jonathan Greenert, America's new chief of naval operations (CNO). In a controversial article just published in 'Proceedings', the journal of the United States Naval Institute, the influential CNO has argued for a "paradigm shift" that emphasises "payloads over platforms".

Greenert's argument is: fancy platforms (like the F-35 fighter, though he does not name it) whose superiority is based on design attributes like 'stealth', get technologically overtaken by an adversary's evolving electronics capability. But sturdy, flexible payload carriers (like an aircraft carrier, or like the B-52 and the C-130) get outdated far more slowly since they are "inherently reconfigurable, with sensor and weapon systems that can evolve over time for the expected mission." He argues, "the weapons, sensors, unmanned systems, and electronic-warfare systems that a platform deploys will increasingly become more important than the platform itself." That justifies the logic of a 50-year-old platform, with continuously improving electronics, and "stand-off weapons" that can be fired at the enemy from far away without endangering the platform itself. Some of America's half-century-old legacy aircraft, which will serve 80-90-year service lives, are:

B-52 Stratofortress
The giant, eight-engine B-52 Stratofortress (aficionados call it the BUFF, or Big Ugly Fat Fu**er) was designed in the early Cold War to strike the Soviet Union with thermo-nuclear weapons. B-52 deterrence patrols remained permanently airborne near the Soviet Union's borders, ready to nuke designated targets. When the US entered Vietnam in the 1960s, B-52s were modified to carry 27 tonnes of conventional bombs, achieving notoriety for their 'carpet-bombing' of communist areas.

Today, the US Global Strike Command still fields 85 B-52H bombers. This carries 31.5 tonnes of bombs, mines and cruise missiles to targets 14,000 kilometres away. In Operation Desert Storm against Iraq in 1991, 40 per cent of the high explosive used was dropped by B-52s. In the post 9/11 Iraq and Afghanistan campaigns, B-52s have led the bombing, fitted with banks of computers that aim with deadly accuracy.

CH-47 Chinook
August 16 will mark the 50th anniversary of the first Chinook delivered to the USAF. The heavy-lifting helicopter was quickly deployed to Vietnam, where it became a battlefield icon, carrying up to 55 troops into combat and lifting artillery guns to perilous mountain positions.

Like the B-52, Chinooks periodically return to their factory in Philadelphia for replacing mechanical and electronic components in a phased modernisation. New capabilities are added, such as the 'pinnacle manoeuvre', in which avionics permit the pilot to lower the Chinook's rear onto a pinnacle, or the roof of a house, even as the front overhangs the drop. This allows it to pick up or deposit soldiers or stores in areas inaccessible even to smaller helicopters. The Chinook will remain in service till 2050, by when it would be 90 years old.

C-130 Hercules
The C-130 four-engine turboprop, which entered service in the 1950s, has had the longest continuous production run of any aircraft in history. In service with more than 60 countries, the Hercules has accumulated more than 20 million flight hours.

The aircraft has steadily evolved with additional range, updated avionics and night vision capability. It has been used for transport and special forces tasks, as well as for weather reconnaissance, flying into the eye of hurricanes, and for aerial spraying to suppress mosquito-borne diseases. The latest version, the C-130J Super Hercules, which the IAF has procured, takes off and lands in a shorter distance, climbs faster, flies further and operates in pitch darkness. It will remain in service for another 30 years.

KC-135 Stratotanker
This mid-air refuelling aircraft was developed with the Boeing 707 and designed to refuel Cold War bombers that carried nuclear weapons. It has, however, been the primary US refueller in all operations since then. While the US has started the process of building a new refuelling aircraft, many of the KC-135 fleet would remain in service till 2040.

T-38 Talon
Built by Northrop, the T-38 was the world's first supersonic trainer aircraft. It continues to train USAF pilots, with an estimated 50,000 pilots having already honed their skills on the T-38. The US has begun the process of identifying a new trainer, but the T-38 looks set to continue in that role for some more years to come.

http://www.business-standard.com/india/news/us-military-sees-virtue-in-50-year-old-aircraft/482466/