hovercraft presentation
DESCRIPTION
I had this seminar to give on hovercraft and this is what I made, hope you'll like it. The seminar was to improve our ways of speaking English and I'm an engineering student so my lecturer gave me this topic, the seminars finished now so I'm free to share my works. Check it out and leave me a comment...TRANSCRIPT
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Presentation onHOVERCRAFTS
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Contents
Introduction History Design Working Parts Piloting a Hovercraft Conclusion
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Introduction
An amphibious military or civilian vehicle Travels on any kind of surface (flat) Supported by a cushion of pressurized air It is closely related to aircrafts then
automobiles or boats Also called Air Cushion Vehicle (ACV)
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History
1716 Emmanual Swedenborg recorded a design, but was short lived
1870 Sir John Thornycroft filled patents involving air lubricated hulls
Christopher Cockrell began experimenting He built a 2-ft prototype 1959 one person hovercraft was built
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One Person Hovercraft
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SRN 4 Hovercraft
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Design
Can be powered by one or more engines Small crafts have a single engine with the
drive split through a gearbox Usually one engine drives the fan
responsible for lifting the vehicle The other forces air from the back and
pushes the craft forward
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Working
Two main principles:– Lift– Propulsion
A skirt is required to quarantine airflow No contact with ground, hence friction is
eliminated The shape of the body affects stability All parts are essential for proper working
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Parts
Lifting fanLifting fan: Usually used is a centrifugal fan
When rotated air is sucked into the center hole
It is coupled via a gearbox and connected to the engine
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Parts (Contd.)
Thrust propellersThrust propellers: An aircraft type with variable type pitch blades
Diameter ranges from nine feet to nineteen feet
In bigger crafts, the propellers are rotated
In smaller ones, rudders are used
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Parts (Contd.)
SkirtSkirt: Flexible strip fitted below bottom edges of the plenum chamber
Most sensitive design, it protects the craft and helps to lift it even higher
EngineEngine: Earlier engines were piston type, now gas turbines are used
Consists of a compressor, to compress air
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Parts (Contd.)
Air boxAir box: Placed right above the fan Prevents air from escaping the fan PowerPower: 15 ft long and 7 ft wide weighs
about 2000 lbs, power taken would be 19 lbs/sq.ft
Requires 4 Hp/sq.ft = 176 Hp to lift the craft 1ft above the ground
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Piloting a Hovercraft
The friction with the ground is minimum People say best way to ride is by leaning
back and forth like a jet ski It is possible to do a 360 degree turn
without stopping even once
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Conclusion
In theory hovercrafts are simple machines But a plethora of problems exist to make a
functioning hovercraft The plans and designs must be flawless To build a hovercraft one must be well
aware of the demands of construction Only then can one design a hovercraft
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References
Wikipedia – The free encyclopedia www.quicktechhobby.com Google search
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THANK YOU