Dan

Chapter-01
Introduction.
Hovercraft
Hovercrafts are those vehicles that have the capability of gliding over land, sea and
many other surfaces. Sir Christopher Cockerell created the hovercraft, which he
described as ''neither an airplane, nor a boat, nor a wheeled land craft.'' Some of these
vehicles can fly at an altitude of up to 10 feet, while others hover just a few inches off
the ground.
A hovercraft is a vehicle that hovers just above the ground, or over snow or water,
by a ‘cushion of air’ (Spedding, 2001). Also known as air cushion vehicle, it is a craft
capable of travelling over land, water or ice and other surfaces both at speed, and when
stationary. It operates by creating a cushion of high pressure air between the hull of the
vessel and the surface below. Typically this cushion is contained between a flexible skirt.
Hovercrafts are hybrid vessels operated by a pilot as an aircraft rather than a captain as a
marine vessel. They typically hover at heights between 200mm and 600mm above any
surface and can operate at speeds above 37km per hour.
A Formula 1 racing hovercraft
A hovercraft, also known as an air-cushion vehicle or ACV, is a craft capable of
travelling over land, water, mud or ice and other surfaces both at speed and when
stationary. Hovercraft are hybrid vessels operated by a pilot as an aircraft rather than a
captain as a marine vessel. A hovercraft is a vehicle that moves along a surface on a
cushion of air. The physical body of a hovercraft consists of, at minimum, a deck and a
skirt. A fan mounted in the deck blows air towards the ground, creating higher air pressure
below the fan than above it and lifting the deck. They operate by creating a cushion of

high-pressure air between the hull of the vessel and the surface below. Typically this
cushion is contained within a flexible "skirt". Instead of fan we have used Leaf Blower
which also blows the air as per the requirement. The skirt surrounding the deck contains
the pressurized air chamber. They typically hover at heights between 200 mm and 600 mm
above any surface and operate above 20 knots and can clear gradients up to 20 degrees.

Chapter-02
Hovercraft History
2.1 Earliest Efforts :-
The first recorded design for a hovercraft was in 1716 put forward by Emmanual
Swedenborg, a Swedish designer and philosopher. The project was short-lived and a craft
was never built. Swedenborg realized that to operate such a machine required a source of
energy far greater than any available at that time. In the mid-1870s, the British engineer
Sir John Thornycroft built a number of model craft to check the air-cushion effects and
even filed patents involving air-lubricated hulls, although the technology required to
implement the concept did not yet exist. From this time both American and European
engineers continued work on the problems of designing a practical craft.In 1955 he
obtained a patent for a vehicle that was "neither an airplane, nor a boat, nor a wheeled land
craft." He had a boat builder produce a two-foot prototype, which he demonstrated to the
military in 1956 without arousing interest. Cockerell persevered, and in 1959 a
commercially built one-person Hovercraft crossed the English Channel. In 1962 a British
vehicle became the first to go into active service on a 19-mi (31-km) ferry run. They
typically hover at heights between 200 mm and 600 mm above any surface and operate
above 20 knots and can clear gradients up to 20 degrees. The first practical design for
hovercraft derived from a British invention in the 1950s to 1960s
2.2 Invention of modern hovercraft :-
In the early 1950s the British inventor Christopher Cockerell
began to experiment with such vehicles, and in 1955 he obtained a
patent for a vehicle that was "neither an airplane, nor a boat, nor a
wheeled land craft." He had a boat builder produce a two-foot
prototype, which he demonstrated to the military in 1956 without
arousing interest. Cockerell persevered, and in 1959 a commercially
built one-person Hovercraft crossed the English Channel. In 1962 a
British vehicle became the first to go into active service.
Chapter-03
Classification of Hovercraft
3.1 Type-1 Hovercraft
CHRISTOPHER COCKERELL

The Type-1 hovercraft is a very basic model; in fact, it's so straightforward in its
design that it would make a suitable project for high school students. It is essentially a
plywood circle base attached to a wet/dry vacuum motor set on reverse. The one occupant
sits atop a chair and flips the switch on the wet/dry vacuum. Depending on the weight of
the pilot, the hovercraft may get up to an inch off the ground and glide along the surface.
The limitations, of course, include the length of the extension cord that the wet/dry vacuum
is attached to.
3.2 Sport Hovercraft
Sport hovercrafts are built to seat two to four people. Although the main
purpose for owning one of these types of hovercrafts is recreation, these have been used
for search and rescue missions. The Hovertrek model by Hovercraft is capable of handling
a 700 lb. payload and can reach speeds as high as 50 mph. This model also has an optional
fully enclosed cabin.
3.3 Industrial or Commercial Hovercraft
For transporting gear, lumber and laborers, the industrial or commercial
models of hovercrafts are ideal. They glide across land and water and enable equipment to
only require one mode of transportation. The 19XR-IC model from Hovercraft is just one
of these types of hovercrafts. It allows for quick conversion from hauling equipment to
transporting workers.
3.4Flight-Capable Hovercraft
At the speeds hovercrafts travel, it is possible to add wings for limited flight
capabilities. The 19XRW-Hoverwing by Hovercraft has that option and is capable of
reaching altitudes of 20 feet to clear rough wakes and some obstacles. This model can
carry up to six passengers and reach speeds of more than 75 mph. Due to the limited nature
of the flight time and altitude, a pilot's license is not necessary to operate this vehicle.
Chapter-04
Constructional Features of Hovercraft
4.1 Construction’s

 Radar: apparatus that detects objects through the use of microwaves.
 Pylon: supporting post.
 Dynamic propeller: two-bladed apparatus that provides motion.
 Fin: steering device.
 Rudder: apparatus that prevents drift.
 Lift-fan air intake: opening to allow air to enter.
 Main level drive gear box: compartment that contains and protects the gear mechanism.
 Skirt finger: part of the flexible skirt.
 Passenger entrance: opening on the side wall that provides access to the passenger cabin.
 Flexible skirt: lower flexible part.
 Bow door ramp: opening at the front.
 Control deck: cubicle from which a hovercraft is operated.
4.2 Legal Issues
To understand the principle of the air cushion effect, assuming of dropping a ‘cark’
tablemat on to the table cloth, so that it falls completely silent. If the mat is dropped
perfectly horizontal, it is bought to a stop guide gently by the air trapped underneath it. Of
course the air escapes, but it makes temporary ‘cushion’. In a hovercraft a similar cushion
of air is maintained by pumping in a steady supply of air. There is always some leakage
because the craft has to be free to more, but the designers use various methods to keep

leakages as small as possible so that only minimum power is required to keep up the air
supply (McPeak, 2004).
Fig. 01 Simple Hovercraft Air Cushion Supply
The simplest arrangement for creating air cushion and reducing leakages is like a
bowl turned upside down and fitted with engine and a propeller which sucks in air through a
hole at the top and forces it into the hollow part beneath. Increasing air pressure pushes on
the sides of the bowl But the bowl is not elastic, and so instead of forcing the rubber to
stretch, the air pressure forces the bowl up off the ground.
4.3 Design Concept
Fig shows the assembly and orthographic views of the hovercraft respectively
Component Parts of
Ite
m
Description
1 The hull base

Fig-02 Assembly View of Hovercraft
2 Lift duct
3 Seat assembly
4 Thrust duct assembly
5 Thrust engine and fan
assembly
6 The skirt
7 Stand
8 Rudder
9 Body cover front
10 Seat assembly main
11 Lift engine mount

Chapter-05
Working Principle
Hovercrafts work on the two main principles of lift and propulsion. When dealing with
a hovercraft, the existence of lift is imperative for the proper function of the vehicle. lift is an
essential factor because it is that which allows the craft to ride on a cushion of air several inches
off the ground. This process, the process of attaining lift begins by directing airflow under the
craft. In order to quarantine the air under the air cushion, a skirt is required. This is done in
order to create pressure under the hovercraft which forces the vehicle off the ground. Attaining
the proper amount of airflow is imperative for the maintenance of the craft’s stability. If too
much airflow is directed under the craft, it will then hover too high above the ground, resulting
in the hovercraft to tip. Not enough lift will cause the craft to remain on the ground which
defeats the very purpose of the hovercraft altogether. The source of the airflow which propels
the craft of the ground is a fan. The fan can be used for lift and thrust. It can be dedicated to lift
or thrust or even both simultaneously. In either case the passage where the air flows through to
reach the air cushion affects the stability of the hovercraft. This passage is a hole located on
the base of the craft. Another vital component is the motor. The motor is usually located in the
rear of the vehicle and is the heaviest of the components. Due to the weight of the motor, extra
pressure is required under the area where the motor is positioned in order to attain hovering
capabilities.
That which makes hovercrafts so efficient and different from other vehicles of its
category is that very little force is required for it to move. Propulsion is that which makes the
craft move. The source of this effect is the fan, which is used to move the air for propulsion.
However odd as it may seem, the fan produces more than enough force for the hovercraft to
move. This is achieved through the existence of another major factor:

friction, or better yet, the elimination of friction. Hovercrafts have no contact with the ground,
therefore any resistance the ground may produce under other circumstances is now non-
existent for the craft. As explained above, the propulsion of the craft requires a fan but a normal
fan is not sufficient. This is because a normal fan does not blow air straight back. Instead it
spins the air in a spiral shape. Therefore engineers decided to use turbines or stationary blades,
that un-spin the air. When air does not spin more of its kinetic energy can be used for translation
and less is required for rotation.
The shape of the body also affects the stability of the hovercraft. The larger the area of
the base, the more stable it will be. Wider base greater stability. Longer and narrower shapes
increase speed but decrease stability. Most hovercrafts have rounded ends, and offer both
stability and speed.
Fig No. 03
The skirt is another vital component. The common skirt is known as a bag skirt. It
is comprised of a bag that covers the bottom of the base and has holes in it to allow air to
escape and push the craft off the ground.
When the hovercraft is finally able to move it will most definitely require steering
capabilities. This is achieved through the use of rudders. These rudders can be controlled by a

variety of devices including computers. Rudders cannot be too heavy otherwise they will weigh
down the craft because they are located very close to the motor. The shape of the rudder dictates
how well it will be able to move air.
Chapter-06
Merits, Demerits and Application’s
6.1 Merits
1. Air cushion vehicle
2. Pollution free
3. Light in Weight
4. Compact and Simple design
5. Low Energy consumption
6. Low Maintainance
7. Low Operational cost
8. Low overall cost
9. Also works on Non-Conventional Energy Sources.
6.2 Demerits
1. Require smooth surface
2. Maximum weight 25kg
3. Replacement of Skirt Material after fixed interval
4. Require plane and flat surface.
5. Potential of skirt damage/puncture.

6.3 Application
1. Commercial
2. Civilian non-commercial
3. Military
4. Recreational/sport
5. Hoverbarge
6. Hovertrains
7. Non-transportation- Hoover Constellation (vacuum cleaner)
8. Flood and Ice Rescue
9. Wetland Hydrological Survey
10. Flood and River Control

6.4 Some Applications
a .Single Seated Racing Hovercraft.
b.A Formula 1 Racing Hovercraft.
c.Passenger-Carrying Hovercraft
d. Hovercraft Lifeboats.

e. The Hovertravel Service.
f.Fire Department Using A Hovercraft To Practice A Rescue.
g. Military Hovercraft.
Chapter-07
Future scope
1. It can be a commercial vechicle in future.

2. it can work on non-conventional energy sources.
3. It can be used for material handeling in modern industries.
4. By automation various field applications can be generated.
5. it can be highly efficient vehicle by automation.
6. It can replace today’s conventional vehicles. ( bike, cars, etc)
Chapter-08
Conclusion
Hovercrafts are generally simple mechanisms in theory. Yet the process from
theory to manifestation is not as easy as it may seem. One must take under consideration
the weight and the shape of each component in order to avoid problems such as
instability and dysfunction. One thing is certain; when building a hovercraft, be well

aware of the demands of construction. Be prepared and willing to embrace failure for
it is the only way to success.

Dan

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