Yu Fly Air Show in Shaastra

Shaastra, the technical festival of IIT-Madras started with overwhelming response. ‘Yu-Fly’, a project undertaken by the second year students of IIT-M, featuring Vertical Take Off and Landing) VTOL aircrafts was demonstrated yesterday. The Yu-Fly project implements a working model of the VTOL aircraft based on a principle called the “Coanda Effect”.

In general, a lift is produced when there is a pressure difference in the wings of the aircraft, i.e, low pressure in the top and high pressure in the bottom of the wing. Since atmospheric pressure is high enough, if we just create a low pressure on the top of the wing, we can generate lift. This is where the Coanda Effect can help us in providing vertical thrust. The Coanda Effect states that fluid flowing on a surface sticks to the surface rather than flowing tangentially to it. It is easily demonstrated by holding the back of a spoon vertically under a thin stream of water (See the figure below).

The Coanda Effect works with any of our usual fluids, such as air at usual temperatures, pressures, and speeds. The air stream gets pushed against a surface, even when the surface is curved away from the direction of flow. The air pressure between the air stream and surface is lower if the surface is curved away from the flow. When blowing an air stream close to a solid surface, there is a drop of air pressure in between the air stream and the surface. The ambient air at the other sides of the air stream and surface pushes the two together as it has higher pressure than the pressure in between the two. And further if surface is curved, the curved surface causes a continuing acceleration of the air stream, and thus a continuing area of low pressure between the air stream and the surface. Thus, applying Coanda Effect on the top of the wing will produce a lift as there is ambient pressure at the bottom of the wing. If we apply the Coanda Effect in addition to the conventional propeller lift, the aircraft will have a higher efficiency than most other VTOL aircraft of today.

The IIT Students used a quadrotor structure (consisting of 4 individual units working together) to minimise net unbalanced torque. For their model, they used special light weight foam called Depron for the body of the craft. The quadrotor configuration gives superior stability, and hence better control. Their craft can lift up to 1.2 meters and stay stable.

Here is the video taken by IITM Students on the eve of Shaastra. Watch It!

NDTV Video on Yu-Fly