WHAT IS A GLIDER?

   WHAT ARE GLIDERS?

What are gliders?

In simple words, a glider is a special kind of aircraft that has no engine. Gliders require little or no human assistance while travelling. They harness the wind energy due to their aerodynamic design. Lets first explore the origin of gliders.

History of gliders:-

Wright brothers different designs of glider

Glider

The gliders are also known as unpowered aircraft which were built and flown by the Wright brothers between 1900-1992. The Wright brothers also used these gliders to learn the basics of aerodynamics and flight control. They often flew these aircraft as kites to determine and verify aircraft performance. The interesting thing is that they also learned how to fly by using these unpowered aircraft over 1000 times as piloted gliders.The Wright brothers were facing problem in controlling the flight of the aircraft. So, they started observing the soaring birds and they designed a technique to obtain roll control by warping or changing the shape, of a portion of the wing. The Wright brothers devised a technique to control multiple lines, the flyer could twist the wing tips of the kite and make it move from side to side at will. Wright brothers used this technique to make their first successful glider and tested it at North Carolina.  At the end of 1902, the Wright brothers were the two most experienced glider pilots in the world. The stage was now set for the development of powered aircraft.

Importance and Use of a glider:-

1)  The gliders were used in olden days for studying the basic concepts of aerodynamics and flight control. In earlier days all the new design experiments were done by making a glider as it was cheap than to make an engine aircraft for testing purpose.

        2) Wright Brothers also used the gliders to design the most accurate and effective design of aircraft. They were the most experienced        glider pilots in the world.

    3)  Nowadays, there are many research projects are based on glider like:-

        a)  X-Gliders - This is a research done by NASA to explore the different flight techniques by the use of experimental gliders. 

  

        b)  Underwater Gliders for Ocean Research - There are many research paper displayed on this nowadays. Simply an underwater glider is an autonomous, unmanned underwater              vehicle used for ocean science. 

    4) Nowadays, Glider flying has turned out to be a sport and it is known as gliding. Gliding is a recreational activity and a                      competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne.

Gliding

How does a Glider fly: -

During the flight, a glider has three forces(lift, drag, weight) acting on it as compared to the four forces(lift, drag, weight, thrust) that act on a powered aircraft. The glider, as well as the aircraft( use engine), are subjected to the forces of lift, drag, and weight. The only different force is that the powered aircraft has an engine that generates thrust, while the glider has no thrust. The weight of an aircraft or glider acts through the center of gravity and is always directed towards the center of the earth.  The lift and drag are aerodynamic forces. Now the direction of drag is opposite to the flight direction, and the lift is directed perpendicular to the flight direction. There are various factors that influence the magnitude of the lift and drag forces but the direction of the forces are unaffected. Now, in order for a glider to fly it must generate enough lift to oppose its weight. To generate lift, a glider must move through the air but due to this drag force is also produced on the glider. Now, this drag force is necessary to be overcome to get a successful flight. Now, in a powered aircraft, the thrust force is generated from the engine opposes the drag force, but if we compare this with a glider it has no engine to generate thrust. In a glider the drag is not opposed, due to this the glider quickly slows down until it can no longer generate enough lift to oppose its own weight, and it then falls to earth. The glider flies in the air with the help of aerodynamic shape of the body and wings.

Different types of glider aircraft:-

1)  Paper airplanes are the simplest gliders to build and fly.

They are given velocity necessary to fly or in technical language thrust by throwing it by hand or by using a launching mechanism.

2)  Balsa wood or Styrofoam toy gliders are an inexpensive & frequently used by students while learning the basics of aerodynamics.

Balsa wood glider

      This below figure gliders are made by me. I have made this glider by using Styrofoam. Styrofoam is light in weight and is strong enough to make a good glider. I used this                glider in a glider competition organized by ASME(American Society of Mechanical Engineers) and fortunately I won the          competition as my glider travelled the highest distance of 20m and the flight time of 10 seconds.

Models

3)  Hang-gliders are piloted aircraft having cloth wings and minimal structure. Some hang-gliders look like piloted kites while others look like a parachute.

Hang Glider

Conclusion:-

1) Gliders are one type of aircraft which does not contain an engine.

    2) Gliders have been a very essential part of the aviation field since earlier times. They were used to study the basics of aerodynamics and flight control principles, test different aircraft designs and other design related principles.

    3) Gliders are cheap as compared to aircraft which runs on an engine. Gliders have many uses like they are used in                         adventure sports, to study the design and flight control features of an aircraft, many competitions are organized related to glider etc.