Helicopters   Though unusual the helicopter is a useful aircraft. Since they can vertically take off and land in a very limited space, turn in any direction very quickly and hover in air, helicopters can be put to many uses. They have been successfully used for passenger, mail or goods’ transportation, or for prospecting, aerial photography, sea and land rescue work, crop spraying and a host of other purposes. A helicopter...

Submarines   A submarine is a ship capable of moving underwater and is used either for exploration or by the Navy for defensive or offensive purposes. Most modern submarines are powered by nuclear reactors, which produce heat, the water vapour from this heat causes the turbines to rotate thus giving mechanical energy to the propeller shafts and electric generators, this drive provides the required propulsion. These craft are equipped with a...

Hovercraft and Hydrofoils The hovercraft is a unique vehicle capable of running both on land and water. The hovercraft generates an air cushion on it’s underside with the help of turbo electric engines. The operating principle is very simple, air is taken in and compressed, it is then pushed under the hovercraft. A skirt made of rubber surrounds the underside of the craft thus preventing the air from escaping from the sides....

Ships and Ocean Liners   There are various types of ships which include ‘Cargo Carriers’ for carrying various types of cargo in the holds or on the deck in containers, .Oil Tankers’ for carrying oil, ‘Naval Battleships’ for defence and ‘Aircraft Carriers’ which carry aeroplanes for the Navy. There are also the ‘Ocean Liners’ which are large ships used for transporting people at sea. Ships of all types may be built...

Electric Locomotives The first Electric locomotives were run on batteries but modern day electric locomotives draw their power from over head wires or a third rail which runs parallel to the tracks. Electric locomotives have an arm on the top called the ‘pantograph’, when raised, this arm touches a high voltage un-insulated wire which runs overhead. The power drawn from this wire powers the electric motors in the engine thus allowing...

Steam Locomotives The first steam locomotive was built by George Stephenson in the year 1825 and was called ‘Locomotion’. The steam locomotive simply defined is a large water boiler on wheels. The front of the engine comprises of a boiler which houses a large number of metal tubes, in the middle is the driver’s cab and in the rear is a separate cab in which coal is carried. Water is filled...

Automobiles Technology The first cars were developed in the 18th century with steam engines. Modern day cars have internal combustion engines which comprise of a number of air tight chambers in which a series of flat topped pistons are located. The lower end of these pistons is connected to a shaft which allows them to move up or down within the cylinder. A mixture of petrol and air is sprayed into...

Motorcycles The first motorcycle was built in the year ‘1885 by a German called Gottlieb Daimler. It was a very crude version of the modern day motorcycle, it was only a wooden bicycle frame fitted with a small petrol engine. Today motorcycles in contrast are complicated machines. They have engines which are similar to a car but smaller in size and are generally two stroke or four stroke internal combustion air...