Tag Archives: engineering

Whittle jet engine and how a plane flies

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FRANK WHITTLE: Genius inventor of the jet engine

IT’S quite amazing to consider that we are able to fly. We have built huge, metal birds they are able to take up to 800 people 11 000 metres above the ground without flapping their wings. Granted that aeroplanes are by no means perfect; but having achieved flight, and moreover being able to launch rockets into space, is certainly an achievement to be proud of. And it’s all thanks to the turbojet engine, or rather the man behind its invention.

Whenever one thinks of flight, the immediate names and imagery that might pop into one’s head are those of the Wright Brothers. Media coverage of such events, and consequently their recording into the history books, has a lot to do with that. History tends to neglect those without the proper status, family background or financial backing. In fact, the working class genius that thrust Britain firmly into the jet age was largely ignored by the British government and air ministry. They didn’t even bother to send a cameraman to the first (and successful) test flight of Britain’s first jet.

Frank Whittle (born 1907) is the genius to thank for our modern day aviation industry. Whittle began working as a fitter for the RAF (Royal Air Force) at the age of 16. Soon after he was air-born and performing stunt shows for the public. At 21 Whittle wrote a thesis titled Future Developments in Aircraft Design, in which he foresaw the entire future of flight. At 22, Whittle took out a patent for a jet turbine. He was also given a model aeroplane at age 4.

What made Frank Whittle’s jet engine unique is that it consisted of only one moving part – as opposed to the hundreds of moving parts used in conventional piston engines. Whittle’s piston-less jet engine also had no propeller, and drove planes through the air by thrust alone. Once patented and produced, Whittle’s remarkable engine successfully thrust Britain into the jet age and turned the aviation industry on its head.

The Airbus A380

The Airbus A380 – currently the largest passenger aeroplane in the world (image: wikipedia.org)

The Airbus A380 – currently the largest passenger aeroplane in the world (image: wikipedia.org)

How a jet engine works

The single moving part in a jet engine is the bladed turbine that spins at a remarkable speed and makes that familiar noise as a plane prepares for take-off. Air is sucked in and accelerated into large combustion chambers where fuel is injected and ignited. The ejection and burning of fuel heats and expands the air and gives it enough energy to drive the turbine. The turbine, in turn, accelerates the hot air at high ‘jet speed’ providing enough thrust to drive an aeroplane forward.

Actually getting into the air and staying there is all to do with working against opposing forces. It’s all a matter of lift versus weight and thrust versus drag. One also needs to consider the air as fluid – a sea of scattered water molecules that has density. In other words, an aeroplane sails across the sky rather than flies while a fish flies through the sea rather than swims. This is why it’s difficult to take off where the air is thin and why we should hope for a cold day whenever we fly.

It has to be said that Frank Whittle was a bit of an unapplauded genius. Being able to simplify a complex mechanism consisting of hundreds of moving parts into the single turbine jet engine, is nothing short of elegant. Being able to predict the next 50 years of an entire industry, is nothing short of visionary.

3D printing technology and 3D printers

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3D PRINTING: Producing abundance with tech

MANY fantasize about designing and building their dream home. If achieved, the feeling must be one of great pride and involvement. The sad reality is that building a house from scratch requires a whole team, and a group of wholesalers. For starters you would need an architect, electrician, a plumber, mechanical engineer and a surveyor, not to mention all the chain stores you would have to visit to furnish your new home. In the end, it may not feel like you were involved at all – apart from having dished out all the necessary funding.

But what if you could play a bigger and cheaper role in your home’s creation? Of course it would be wise to get the professionals to assess the ground and foundations, but when it comes to furnishing and decorating, the power lies in 3D printing. Most homes are, after all, built from the inside-out.

3D PrinterAs jaw-dropping as it may sound, 3D printing is essentially the creation of solid three dimensional objects using a large oven-sized printer. Objects are “printed” by laying down successive layers of material. The “ink” generally consists of molten plastics, but the more hi-tech 3D printers are able to use workable metals such as nickel, bronze, titanium and stainless steel.

Most 3D printing methods use melting or softening material to produce the layers. Others lay liquid materials that are then cured with other technologies. Some 3D printers can even reproduce themselves entirely.

3D printing3D Printers work by being fed digitised files or schematics. The design for a particular object is created using 3D modeling software and then sent to the printer for creation. Wikipedia explains the process thusly: “A 3D printer works by taking a 3D computer file and using and making a series of cross-sectional slices. Each slice is then printed one on top of the other to create the 3D object.”

Since 2003 there has been large growth in the sale of 3D printers for industrial use, but they are now finding their way into consumers’ homes (at around R100 000). The technology is generally used in the fields of industrial design, engineering, construction, auto mechanics, and the dental and medical industries, and is also known as the “architect’s dream tool”. 3D printing is even used for creating jewellery and footwear prototypes before they are mass produced.

3D printingOne fantastic application is the use of 3D printing for reconstructing fossils in paleontology. Ancient and priceless artifacts can be replicated with flawless precision. As exciting, is the reconstruction of bones and body parts in the field of forensic pathology as well as the reconstruction of heavily damaged evidence acquired from crime scene investigations.

Meanwhile in the biology department, 3D printing technology is currently being studied by biotechnology firms and academia for possible use in tissue engineering. Its applications are to build living organs and body parts. Layers of living cells are deposited onto a gel medium which slowly builds up to form three dimensional structures. This field of research has been termed as organ printing, bio-printing or computer-aided tissue engineering. I’m surprised that no one has called it “playing God”.

3D printingThe thought that 3D printing could be the means for producing abundance, excites me. High quality metal parts or tools could be mass produced and then donated to relief efforts or developing communities. Taps, tools, light fixtures, cutlery, hip replacements, 3D models, cogs, prosthetics and nuts and bolts could all be mass printed. Gone are the dreary days of the assembly line; 3D printers could even run overnight while the goods cook in the oven.