PRESENTATION ON

HOVERCRAFT

CONTENTSCONTENTS

INTRODUCTIONINTRODUCTION HISTORYHISTORY DESIGN AND OPERATIONDESIGN AND OPERATION OTHER APPLICATIONSOTHER APPLICATIONS ADVANCEMENT IN TRANSPORTATION ADVANCEMENT IN TRANSPORTATION

METHODMETHOD FUTURE OF HOVERCRAFTFUTURE OF HOVERCRAFT SOME AVAILABLE HOVERCRAFTSOME AVAILABLE HOVERCRAFT

INTRODUCTIONINTRODUCTION

Known as Known as Air Cushion VehicleAir Cushion Vehicle (ACV). (ACV). It flies like as an aeroplane , float like a boat ,can It flies like as an aeroplane , float like a boat ,can

drive on land like a car. drive on land like a car. Its engine provides the power to drive large fans that Its engine provides the power to drive large fans that

blows air under the craft, this air is retained by a blows air under the craft, this air is retained by a rubber skirt that helps to move the hovercraft.rubber skirt that helps to move the hovercraft.

A hovercraft

Tchnical definitionTchnical definition

Any of the machines characterized by movement in Any of the machines characterized by movement in which a significant portion of the weight is supported which a significant portion of the weight is supported by forces arising from air pressure developed around by forces arising from air pressure developed around the craft, because of which they hover in close the craft, because of which they hover in close proximity to the Earth’s surface can be put under the proximity to the Earth’s surface can be put under the category of category of HOVERCRAFTHOVERCRAFT or or GROUND EFFECT GROUND EFFECT MACHINE.MACHINE.

HISTORYHISTORY

First man to introduced the concept of ACV was Sir First man to introduced the concept of ACV was Sir John Thornycroft in 1870.John Thornycroft in 1870.

First practical use was made in 1929 by German First practical use was made in 1929 by German Dornier DO X flying boat.Dornier DO X flying boat.

Work went on its peak during World War -2.Work went on its peak during World War -2. In 1960s,American aerodynamicist developed an In 1960s,American aerodynamicist developed an

experimental craft.Experiment went on many more experimental craft.Experiment went on many more experimental craft. But they remain experimental.experimental craft. But they remain experimental.

Finally invented by Christopher Cockerell of UK.Finally invented by Christopher Cockerell of UK. He patented it on Dec. 12, 1955.He patented it on Dec. 12, 1955.

Theory of sir CockerellTheory of sir Cockerell If air were pumped under the vessel through a narrow If air were pumped under the vessel through a narrow

slot running entirely around the circumference, the air slot running entirely around the circumference, the air would flow toward the centre of the vessel, forming would flow toward the centre of the vessel, forming an external curtain that would effectively contain th an external curtain that would effectively contain th ecushion.this system is known as the ecushion.this system is known as the Peripheral JetPeripheral Jet. . Once air has built up below the craft to a pressure Once air has built up below the craft to a pressure equaling the craft weight, incoming air has nowhere equaling the craft weight, incoming air has nowhere to go but outwards and experiences a sharp change of to go but outwards and experiences a sharp change of velocity on striking the surface. The momentum of velocity on striking the surface. The momentum of the peripheral jet air keeps the cushion pressure. the peripheral jet air keeps the cushion pressure.

DESIGN AND OPERATIONDESIGN AND OPERATION Basic elementsBasic elements Skirt arrangementSkirt arrangement Power plantPower plant Thrust propellerThrust propeller ACV operationACV operation

BASIC ELEMENTSBASIC ELEMENTS

A HULLA HULL A SKIRT SYSTMA SKIRT SYSTM A PROPULSION SYSTEMA PROPULSION SYSTEM A LIFT SYSTEMA LIFT SYSTEM

Skirt system is beneath the hull .On the skirt system accomodation for passenger, crew and fright is built.

Lift system feeds air into the plenum chamber below the craft in order to provide a cushion.

The propulsion and lift system can be driven by the same power plant or by separate unit.

The power to weight ratio is very critical and it detrmines not only the payload and performance of the craft but also the ground clearance between the surface and the skirt.

Hull structure are of marine aluminium skin,welded or riveted onto aluminium webs or frames.

The cavity or chamber in which the air is kept is called a ‘plenum’ chamber.

SKIRT ARRANGEMENTSKIRT ARRANGEMENT

The skirt is a shaped, flexible strip fitted below the The skirt is a shaped, flexible strip fitted below the bottom edges of the plenum chamber slot. As the bottom edges of the plenum chamber slot. As the hovercraft lifts, the skirt extends below it to retain a hovercraft lifts, the skirt extends below it to retain a much deeper cushion of air. The development of the much deeper cushion of air. The development of the skirt enables a hovercraft to maintain its normal skirt enables a hovercraft to maintain its normal operating speed through large waves and also allows operating speed through large waves and also allows it to pass over rocks, ridges and gullies. It is of it to pass over rocks, ridges and gullies. It is of semicircular shaped .semicircular shaped .

POWER PLANTPOWER PLANT

Early crafts used piston type engine.Early crafts used piston type engine. After that gas turbine engines were evolved.After that gas turbine engines were evolved. The engine has a main shaft having a compressor and The engine has a main shaft having a compressor and

a turbine .A starter motor is connected to one end of a turbine .A starter motor is connected to one end of the shaft and the other end is to lift fan and propeller the shaft and the other end is to lift fan and propeller gearbox.gearbox.

These engine creates a lot of noise.These engine creates a lot of noise. Newer engines are made to make engine noise low Newer engines are made to make engine noise low

and greater fuel efficiency.and greater fuel efficiency.

Centrifugal lift fan

THRUST PROPELLERTHRUST PROPELLER

Usually an aircraft type with variable pitch blades.Usually an aircraft type with variable pitch blades. The propeller can vary from four-bladed versions and The propeller can vary from four-bladed versions and

about 9 feet in diameter to the 4 propeller and 19 feet about 9 feet in diameter to the 4 propeller and 19 feet in diameter.in diameter.

ACV OPERATIONSACV OPERATIONS

Confined to commercial passenger-carrying ferry Confined to commercial passenger-carrying ferry service(5 to 40 KM), military operations.service(5 to 40 KM), military operations.

Also used for seismic survey parties,either over Also used for seismic survey parties,either over shallow-water areas or in deserts, search and rescue shallow-water areas or in deserts, search and rescue operations.operations.

US used these in Vietnam operations. Later used as US used these in Vietnam operations. Later used as mine-countermeasure works,antisubmarine mine-countermeasure works,antisubmarine works,aircraft carrying and missile launching.works,aircraft carrying and missile launching.

OTHER APPLICATIONSOTHER APPLICATIONS

Experiments are going on for hover car and hover Experiments are going on for hover car and hover train.train.

This principle is used for moving large or heavy This principle is used for moving large or heavy objects.objects.

Advancement in the transportation methodAdvancement in the transportation method

Air cushion concept was used for passenger carrying Air cushion concept was used for passenger carrying trains.In 1970s 235 mile/hr. speed was achieved.trains.In 1970s 235 mile/hr. speed was achieved.

French French got 300 mile/hr.French French got 300 mile/hr. Many experiments are going on this project but now Many experiments are going on this project but now

emphasis has diverted to magnetic trainsemphasis has diverted to magnetic trains

Future of hovercraftFuture of hovercraft

ACV vehicles have not yet fulfilled their origianal ACV vehicles have not yet fulfilled their origianal promise. These hovercrafts are not economical promise. These hovercrafts are not economical although they are idle in military application.although they are idle in military application.

So research is mainly going on for military purposes.So research is mainly going on for military purposes.

Some available hovercraftSome available hovercraft

Surveyor Mk3Surveyor Mk3     Type           Enclosed Cabin, high-class passenger style Type           Enclosed Cabin, high-class passenger style

hovercraft.hovercraft.

Length         10.0metresLength         10.0metres Width          4.1 metres Width          4.1 metres Capacity      18 passengers or 2,000kgCapacity      18 passengers or 2,000kg Engine         Deutz BF6M-1013ECPEngine         Deutz BF6M-1013ECP Application   Passenger transport, Coast Guard/Military Application   Passenger transport, Coast Guard/Military

Patrol, Search & Rescue, Medivac, FreightPatrol, Search & Rescue, Medivac, Freight

Pioneer Mk2  Type            Enclosed Cabin, high-class passenger style hovercraft. Length         11.6 metres Width          4.8 metres Capacity      30 passengers or 3,000kg Engine         Deutz BF6M-1015C (330 kW @ 1900rpm)Application   Passenger transport, Coast Guard/Military Patrol, Search & Rescue, Medivac, Freight.

Special Purpose Hovercrafts:AIRLIFT 950A          (Ambulance)Type            Enclosed Cabin. Installed ambulance equipment. Length         9.5 metres Width          4.2 metres Capacity      1 crew + 14 seats, centre 6 seats can be converted to 2 stretcher spaces or operating table. Engine         2 x Cummins 6BTA 5.9 diesel, 2 x 134kW @ 2600rpm Application   Ambulance, health services.

AIRLIFT 1060FT     (Fire Tender) Type            Fire-Fighting and Rescue hovercraft. Length         10.6 metres Width          4.6 metres Capacity      2 to 6 crew plus equipmentEngines       2 x Cummins 6BTA 5.9 diesel, 2 x 134kW @ 2600rpm Application   Fire fighting, Pollution control, Dive tender, Rescue.