260 likes | 405 Views
The Fly Higher Tutorial II. Aircraft in the air: What Jet Engines Do. Image Source: Rolls Royce Plc. 2013. Introduction : How can birds fly in the air?.
E N D
TheFlyHigher Tutorial II Aircraft in the air: What Jet Engines Do Image Source: Rolls Royce Plc. 2013
Introduction: • How can birdsfly 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://gimnasio-altair.com/webquest/flight/
Introduction: • How can birdsfly 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
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.
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?
Introduction: • Aircraftinforwardmotion 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?
History • Howdiditbegin? 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/library/policy/army/fm/1-506/Ch2.htm
History • Howdiditbegin? 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
History • Howdiditbegin? 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 single-winged, metallic tubes; their engines were more powerful and fuel-efficient…but this principle did not change. Most modern, small light aircraft still use propellers… Can you suggest why?
History • Howdiditbegin? 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=viewDoc&docId=15&level=top NO PROPELLER!! The engine’s exhaust would propel the aircraft
Fundamentals • Enginefunction
Fundamentals • Enginefunction 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.
Fundamentals • Enginefunction 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
Types of Engine • Why are differentenginesused? 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
Types of Engine • Turbofans are nottheonlychoice 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/64e5d996fcdce95195acd4621cb79fb4f8ec776a_large.jpg https://upload.wikimedia.org/wikipedia/commons/d/d3/Atlantis_taking_off_on_STS-27.jpg https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQ1V5eCFRbPSkLKrz68Ab_AGlud0UDUDQ0vR7dmp_OhHr1Xqu8NDg Ramjet Rocket
Types of Engine • Turbofans are nottheonlychoice 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/wp-content/uploads/2012/07/hb350i_vM1uz_25013.jpg http://air-and-space.com/20050812%20Hawthorne/DSC_3008%20An-2%20N2AN%20cn43798%20left%20front%20landing%20l.jpg
Types of Engine • Engynesection • 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.
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
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
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
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
Types of Engine • Rocketengine 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
EngineSummary • TurbojetAnimation Summary Please watch video 3 Turbojet Animation Source Youtube Acknowledgement : www.rendermedia.co.uk Edition Fly Higher
FurtherLearning • GE EngineSimulator Link for Engine Simulator: http://www.geaviation.com/education/engines101/