Presentation onHOVERCRAFTS

Contents

Introduction History Design Working Parts Piloting a Hovercraft Conclusion

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)

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

One Person Hovercraft

SRN 4 Hovercraft

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

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

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

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

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

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

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

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

References

Wikipedia – The free encyclopedia www.quicktechhobby.com Google search

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