Rolls-Royce develops LiftSystem for the F35-B Joint Strike Fighter

  By Ellie Zolfagharifard

As the iconic Harrier heads for the scrapyard, the UK’s vertical lift expertise lives on in the F-35B combat aircraft

Looking up: the F-35B will achieve vertical lift

When, in December, Britain’s Harrier jets landed at RAF Cottesmore for the final time, the sombre mood weighed on all those present. In a ritual known as the ’walk of honour’, the pilots disembarked from their aircraft and walked away without taking a single look back.
The walk marked the end of the Harriers’ 41-year career and closed an illustrious chapter in British aviation history. The iconic aircraft has become one of the country’s greatest technical achievements, being the only military jet that could hover above the ground and fly in areas other fighter aircraft were unable to reach.

   Despite this capability, the Harrier jets fell victim to the cuts outlined in the government’s strategic defence and security review. The UK has no plans to replace the Harrier and many remain concerned for the loss of military capability. But while the UK may be losing the Harrier, it is not losing the engineering expertise to develop the technology.

At an aero engine test base in Bristol, Rolls-Royce engineers are working on a new power system for the F-35 Lightning II Joint Strike Fighter (JSF), the latest generation of combat aircraft. Dubbed the LiftSystem, the technology will enable short take-off and vertical landing operations for the F-35B variant of the JSF programme, which is planned to enter service with the US Marine Corps in 2012.

Rotating fan: situated behind the cockpit

The LiftSystem will allow a fighter aircraft to achieve both vertical lift and supersonic capabilities. Like the Harrier, the F-35B will be able to land without a runway and take off like a helicopter, while performing as a fighter aircraft. At the heart of the system is a component known as the Liftfan. This a 50in (127cm), two-stage, counter-rotating fan capable of generating 20,000lb (9,000kg) of thrust. Situated just behind the cockpit, it produces the aircraft’s forward vertical lift. ’The Liftfan is effectively an engine turned on its end,’ said Neil Mehta, programme director. ’This means the air has to turn through 90° before entering into the aircraft, causing huge distortions in airflow.’

Counter-rotating blisks are manufactured using hollow blades joined to the disc through linear friction welding

A normal aircraft engine is usually cleared to around a 30-knot cross wind. The F-35B, however, has to deal with winds up to 300mph (483km/h). ’To put that into context, Hurricane Katrina measured at about 75mph at its max, so we’re getting an awful lot more distortion,’ he said. To address this, the team has used computational fluid dynamics to model airflow behaviour and aerodynamic performance.
’Our programme for one cycle of the simulation uses as much processing power as a PlayStation running for 14 years,’ said Mehta. ’We’ve done more than 1,000 of those simulations.’

Landing:a runway is not needed

Designed around the airflows are two counter-rotating bladed discs, or ’blisks’, manufactured using individual hollow blades joined to the disc through linear friction welding. The blisks take air from the top of the fuselage and blast it through a vane box at the bottom of the craft. Each vane box can be directed independently, so the air can be generated fore and aft.
At the rear of the aircraft, thrust is produced from a rotating nozzle known as the three-bearing swivel module (3BSM). In normal flight, the nozzle points rearwards, propelling the aircraft forwards at speeds of up to Mach 1.6. When vertical thrust is required, the nozzle swivels downwards in less than two seconds, creating a vertical thrust of up to 20,000lb, equalling the force generated by the Liftfan.
Stabilising this force are two small ’roll posts’ in the wings. These ducts each direct 2,000lb of thrust during short take-off and vertical landing. Compact flap mechanics regulate the amount of thrust produced by each of the roll posts. During short take-off, the roll posts are opened and the clutch is engaged, the 3BSM is swivelled
’One of the big challenges for the LiftSystem is that we only use it for short take-off and landing,’ said Mehta. ’In a normal mission, that is only around five per cent of the total activity. So, at that point, we have to make sure the system is low weight, otherwise it’s not earning its keep in there.’

Inner workings:schematic shows how the system will be positioned

For the blisks, Rolls-Royce is using hollow titanium blades. The technology, derived from civil turbofans, cuts weight by around 40 per cent. Mehta said the current version of the LiftSystem is about 320kg lighter than the original demonstrator but is also stronger and more reliable.
He added: ’This time last year, we did our first hover and first vertical landing. Those two events were the start of proving that all our work the preceding year was accurate. We did vertical landings and nothing untoward happened. We’ve since done 58 vertical landings, 79 hovers, 90 slow landings and 95 short take-offs, and nothing has gone wrong.’

“Our programme for one cycle uses as much power as a PlayStation running for 14 years”

NEIL MEHTA, ROLLS-ROYCE

Orders for the LiftSystem are expected to total more than 600, and the US Marine Corps and the Italian Navy have already acquired the system. There are still several years of flight tests remaining, and shipborne trials are due to take place later this year. Production of the system for use in training aircraft is under way and Rolls-Royce is delivering one LiftSystem per month.
Mehta said the UK is in a strong position to continue developing the technology. ’We developed the Pegasus engine that goes in the Harrier, and we’ve now developed the LiftSystem,’ he said. ’There are no other Western countries with that kind of expertise.

Read more: http://www.theengineer.co.uk/in-depth/rolls-royce-develops-liftsystem-for-the-f35-b-joint-strike-fighter/1008008.article#ixzz1Hw4VULsI

Automotive Engineers Bend New Materials into Futuristic Shapes

New materials for car bodies may soon transform the auto industry. Auto engineers can mold these carbon-fiber-reinforced plastics into virtually any shape. The materials are both strong and light -- increasing fuel efficiency and safety at the same time.

http://www.sciencedaily.com/videos/2006/0211-cars_of_the_future_plastic_makes_perfect.htm#

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TROY, Mich.-- Cars built entirely out of plastic could be the wave of the future, making metal a thing of the past when it comes to cars.
New, innovative cars made almost entirely of plastic are paving the way for what you may be driving in the future. Guan Chew, a mechanical engineer at Porsche Engineering Services in Troy, Mich., says, "With plastics you can design cars which are very bold, and that gives you an advantage to sell nicer cars."
Plastics have gained a lot of ground over traditional metals used in cars, making it possible to build almost an entire vehicle completely of non-metal material. Paul Ritchie, CEO and engineer at Porsche Engineering Services, says: "The Carrera GT is what we would refer to as a proving ground for one of our new materials. It's made essentially from reinforced plastic."
Mechanical engineers use a lightweight, high-strength aerospace material called carbon-fiber-reinforced plastic. It's used in the doors, hoods, fenders, chasis and also in support frames for the engine and transmission.
"You can mold the plastics into very complicated shapes that maybe you can't do in steel," Chew says. Looks aren't the only perks of plastic; plastics help cars lose weight to go farther on fuel.
New materials, like plastic, are usually tested on high-end vehicles first. Once the materials are proven to be more efficient and cost effective, they eventually filter down to affordable consumer vehicles.
BACKGROUND: Student designers at the College for Creative Studies are creating new plastic polymer materials as alternatives for automobile elements typically made of steel. The designs were part of a semester-long project sponsored by the American Plastics Council and the automotive division of the Society of Plastics Engineers.
ADVANTAGES: Among other advantages, plastics can significantly reduce the weight of a vehicle, improving fuel efficiency by reducing drag, and also cutting down on emissions. Because plastic can be more easily molded, components can be tailored for more comfortable human-ergonomic features, as well as more streamlined, aerodynamic shapes. Less material can be used than with steel components, and the durability of plastics results in a longer, more reliable vehicle lifetime.
ABOUT PLASTICS: Plastics are a type of polymer, a chemical substance made up of many very large, chain-shaped molecules. These molecules in turn form thousands of repeating units, much like the links in a chain. Different plastics are made by linking together different monomers into different length chains. Mixing polymers with various additives gives them many useful properties, which is why plastics are used so often in our everyday lives. Thermoplastics soften with heat and harden when cooled, such as polyvinylchloride (PVC) and Teflon. They are used in food packaging, milk and water bottles, electrical insulation, carpet fibers, and credit cards, among other applications. Thermosetting plastics harden with heat, such as epoxy and polyester. They can be found in mattresses, cushions, varnishes, glues, and coatings on electrical circuits.
http://www.sciencedaily.com/videos/2006/0211-cars_of_the_future_plastic_makes_perfect.htm#

Nano-Bricks' May Help Build Better Packaging to Keep Foods Fresher

ScienceDaily (Mar. 27, 2011) — Scientists are reporting on a new material containing an ingredient used to make bricks that shows promise as a transparent coating for improving the strength and performance of plastic food packaging. Called "nano-bricks," the film even looks like bricks and mortar under a microscope, they say. The coating could help foods and beverages stay fresh and flavorful longer and may replace some foil packaging currently in use, they note. The scientists described the new, eco-friendly material in Anaheim, California at the 241st National Meeting and Exposition of the American Chemical Society (ACS) on March 27.
Ordinary plastic soda bottles tend to loose their fizz after just a few months of storage on grocery store shelves. If manufacturers apply the new coating to these bottles, the material could slow the loss of carbon dioxide gas and help sodas stay bubbly for several more months or even years, the scientists said. The coating could also extend the shelf life for those portable food packages known as MREs (Meal, Ready to Eat) that sustain soldiers in the field, with the added benefit of being microwavable, they noted. Although made to last for at least three years, their shelf life can drop to as little as three months when exposed to harsh conditions such as high heat.
"This is a new, 'outside of the box' technology that gives plastic the superior food preservation properties of glass," said Jaime Grunlan, Ph.D., who reported on the research. "It will give consumers tastier, longer lasting foods and help boost the food packaging industry."
Grunlan notes that manufacturers currently use a variety of advanced packaging materials to preserve foods and beverages. These materials include plastics that are coated with silicon oxide, a material similar to sand, that provide a barrier to oxygen that can speed food spoilage. Another example is the so-called metalized plastics -- plastics with a thin coating of metal or foil -- used in many potato chip bags.
These and other packaging materials have drawbacks, Grunlan said. Some plastics crack easily during transport or impact. Metalized plastics are non-transparent -- a turn-off to consumers who would like to be able to see their food prior to purchase. The presence of metal also prevents their use in the microwave. Food pouches made out of metal, such as MREs, provide impact resistance, but they lack both transparency and microwavability. Consumers need better food packaging options.
Grunlan has identified a promising alternative in the form of "nano-bricks." The new film combines particles of montmorillonite clay, a soil ingredient used to make bricks, with a variety of polymer materials. The resulting film is about 70 percent clay and contains a small amount of polymer, making it more eco-friendly than current plastics. The film is less than 100 nanometers thick -- or thousands of times thinner than the width of a single human hair -- and completely transparent to the naked-eye.
"When viewed under an electron microscope, the film looks like bricks and mortar," said Grunlan, an associate professor in the Department of Mechanical Engineering at Texas A&M University in College Station, Texas. "That's why we call it 'nano-bricks'."
When layered onto existing plastic packaging, it adds strength and provides an improved barrier to oxygen, he said. Grunlan demonstrated in lab studies that the film is 100 times less permeable to oxygen than existing silicon oxide coatings. This means that it's also likely to be a better oxygen barrier than a metal coating, whose permeability is similar to that of silicon oxide, the scientists noted.
"Others have added clay to polymer to reduce (gas) permeability, but they are thousands of times more permeable than our film," Grunlan said. "We have the most organized structure -- a nano-brick wall -- which is the source of this exceptional barrier. This is truly the most oxygen impermeable film in existence."
Grunlan is currently trying to improve the quality of the film to make it more appealing to packaging manufacturers, including making it more moisture resistant. He envisions that manufacturers will dip plastics in the coating or spray the coating onto plastics. In the future, he hopes to develop nano-brick films that block sunlight and contain antimicrobial substances to enhance packaging performance.
The new coating also shows promise for use in flexible electronics, scratch-resistant surfaces, tires, and sporting goods, Grunlan said. It could potentially help basketballs and footballs stay inflated longer than existing balls, he added.
http://www.sciencedaily.com/releases/2011/03/110327191031.htm

For Discovery, a farewell spin

Space shuttle Discovery's next mission will be to awe and inspire those who visit it at the Smithsonian Institution. NASA's workhorse shuttle was retired after completing its trip last week to the International Space Station -- that’s 39 missions covering 5,750 orbits, 150 million miles, and almost a year in space since it first lifted off in 1984. It's name was inspired by the exploring ships of the past, including one that plied the Hudson Bay in the early 1600s seeking a northwest passage from the Atlantic to the Pacific oceans. Discovery carried some of NASA's most-distinguished astronauts, including Eileen Collins, the first female commander, Sergei Krikalev, the first Russian to fly on a shuttle, and Senator John Glenn, who returned to space at 76. In its last mission, Discovery dropped Robonaut 2, the first dexterous humanoid robot in space, at the space station. 

http://www.boston.com/bigpicture/2011/03/for_discovery_a_farewell_spin.html-- Lloyd Young