The Fly Higher Tutorial II Aircraft in the air: What Jet Engines Do
Image Source: Rolls Royce Plc. 2013
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Introduction: How can birds fly in the air? Birds are able to fly because of a variety of specialised adaptations. They need extreme level of energy to fly in the air which comes from their high metabolisms. Because of their very light bodies, birds are able to produce both the required lift and propulsion using their ‘flight feathers’. Image source http://gimnasioaltair.com/webquest/flight/
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Introduction: How can birds fly in the air? A short video to demonstrate how birds can fly in the air :
Please watch video 1 How do birds fly? Source Youtube Acknowledgement : www.pendulumswingmedia.com Edition Fly Higher
Video source – Youtube Acknowledgement: www.pendulumswingmedia.com
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Introduction: Thrust Like birds, for aircraft to stay in the air we need thrust and lift. Where do these come from? Why can we not just copy the birds?
Image source http://www.kids.ct.gov/kids/cwp/view.asp?q=330926
And what is Thrust ? Let us look at the basic concept. www.flyhigher.eu
Introduction: The physics behind thrust Based on Newton’s Third Law: Every action has an equal and opposite reaction
Demo: Fill the balloon with air and let it go in free space - What happens ? Source http://www.bloodhoundssc.com/shop/balloon-car-kit
So what happens to an aircraft fitted with a jet engine? www.flyhigher.eu
Introduction: Aircraft in forward motion Hot exhaust gases from the aircraft’s jet engines push on the air which in return produces opposite reaction on the engines. As the engines are securely fitted to the aircraft body, the aircraft moves in the forward direction.
Who came up with this brilliant idea? www.flyhigher.eu
History How did it begin? In the 18th Century – Sir Isaac Newton, an English physicist and mathematician proposed a theory of ‘rearward-channelled explosion’ which could propel a machine forward at a great speed. He foresaw a use of his third law of motion which we now take for granted.
Newton’s Steam Wagon
Source http://www.globalsecurity.org/military/libr ary/policy/army/fm/1-506/Ch2.htm
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History How did it begin? In 1903 , the year of the Wright Brothers’ first flight, their wooden and canvas bi-plane was fitted with a 12 horse power petrol engine.
Their engine was a basic mechanical design, remarkably similar to a modern, four-cylinder car engine.
Image courtesy: http://wright.nasa.gov/airplane/Images/eng2.gif
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History How did it begin? Their aeroplane, Kitty Hawk, depended upon the propeller to give her thrust; the engine simply turned the propeller. In the next 30 or 40 years, aircraft became singlewinged, metallic tubes; their engines were more powerful and fuelefficient…but this principle did not change.
Most modern, small light aircraft still use propellers… Can you suggest why? www.flyhigher.eu
History How did it begin? In 1930 Sir Frank Whittle from England patented the Turbo jet engine. By April 1941 (early in World War II), the new engine was ready for flight testing. The first flight of a Turbojet, the Gloster E28/39, was made on 15th May 1941 at Cranwell in Lincolnshire, England.
Source: www.frankwhittle.co.uk/content.php?act=vie wDoc&docId=15&level=top
NO PROPELLER!! The engine’s exhaust would propel the aircraft www.flyhigher.eu
Fundamentals Engine function
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Fundamentals Engine function In the basic “internal combustion engine” the “combustion” is, in truth, an explosion. This explosive energy is used to drive a set of pistons, and the exhaust is regarded as waste. The pistons can then turn the wheels of a car, the blades of a pump…. or the propeller of an aircraft.
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Fundamentals Engine function In the Jet Engine, the exhaust is not simply waste, but the source of the thrust that moves the aeroplane forward.
Please watch video 2 Inside a Jet Engine Source Youtube Acknowledgement : www.wydea.com Edition Fly Higher
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Types of Engine Why are different engines used? There are even different kinds of jet engines. The Airbus A380 – with 525 Passenger the largest long range civil aircraft in the world – uses turbofan engines, refined versions of Whittle’s original that include a massive fan to accelerate the air entering the jet engine as well as contribute to the thrust exactly as a propeller does .
Turbofan
Turbofan
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Types of Engine Turbofans are not the only choice Different aircraft need different types of engine… Can you guess what these are and why they are used?
Turbojet http://img.bhs4.com/64/e/64e5d996fcdce9 5195acd4621cb79fb4f8ec776a_large.jpg
Rocket https://upload.wikimedia.org/wikipedia/co mmons/d/d3/Atlantis_taking_off_on_STS27.jpg
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Ramjet
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Types of Engine Turbofans are not the only choice Different aircraft need different types of engine… Can you guess what these are and why they are used? Piston-prop
Turbo-prop http://www.instablogs.com/wpcontent/uploads/2012/07/hb350i_vM1uz_25013.jpg
http://air-and-space.com/20050812%20Hawthorne/DSC_3008%20An2%20N2AN%20cn43798%20left%20front%20landing%20l.jpg
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Types of Engine Engyne section The choice of engine is based on : • Thrust Required • Performance • Efficiency • Cost • Maintenance • Civil aircraft require fuel efficient engines. • Military Aircraft require high performance engines.
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Types of Engine Turbojet Engine Components (Turbojet)
Whittle’s original was a Turbojet engine like this source: http://commons.wikimedia.org/wiki/File:Turbojet_operation-axial_flow-en.svg
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Types of Engine Turbofan
The airlines’ choice. Turbofans are like Turbojets but also have a large fan accelerating the air’s entry into the engine and adding to the thrust as an internal propeller.
source : http://upload.wikimedia.org/wikipedia/commons/c/c0/Turbofan_operation.png
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Types of Engine Turbo-prop Turbo-Props have external propellers but use the jet engine idea to drive them
Unlike Piston-Prop engines, Turbo-Props do not have pistons
Source http://upload.wikimedia.org/wikipedia/commons/4/4e/Turboprop_operation.png
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Types of Engine Ramjet Ramjet do not have compressors, fans and turbines like other jet engines.
Technically, ramjets are the simplest form of jet engine. But they cannot produce thrust at zero speed, so Ramjet aircraft need other mechanisms to start their flight. source - http://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Ramjet_operation.svg/300px-Ramjet_operation.svg.png
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Types of Engine Rocket engine
Unlike an aircraft engine, rocket engines carry both fuel and oxygen to energise the gas in the combustion chamber, before it exits through nozzle.
Why do you think this is? source: http://www.grc.nasa.gov/WWW/k-12/VirtualAero/BottleRocket/airplane/Images/rockth.gif
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Engine Summary Turbojet Animation
Summary
Please watch video 3 Turbojet Animation Source Youtube Acknowledgement : www.rendermedia.co.uk Edition Fly Higher
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Further Learning GE Engine Simulator Link for Engine Simulator: http://www.geaviation.com/education/engines101/
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Consortium
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For further information
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