Session 3 at SOAR by Avembsys

The third session was held on 5^th Jan 2011.The session began with the discussion about the EMP pulses. These are the high density electromagnetic waves used in electronic war fares to destroy the electronic systems of the opponents. Due to the strong EMP pulses, the devices such as capacitors, transistors cannot withstand these high electromagnetic pulses, thus resulting in the explosion of the electronic systems. Then the discussion was about classification of aircraft. As of present, there are two main categories of aircrafts - heavier-than-air or aerodynes and lighter-than-air or aerostats. Then the discussion was moved on to the fundamental concepts of physics such as mass, weight, force, momentum, moment, density, viscosity and different types of pressure.

The mass is the fundamental measure of the amount of matter in the object. Weight is due to the gravity. Force is given by the product of mass and acceleration, similarly momentum and moment are given by the products of mass and velocity and force and distance respectively. Density is defined as it’s mass per unit volume. Density can be changed either using pressure or temperature. Increasing the pressure always increases the density of a material. Increasing the temperature generally decreases the density. Viscosity is a measure of resistance to flow of fluids. It increases with speed, with the increase in the temperature viscosity of liquid decreases where as that of gas increases.

Pressure

Pressure is defined as the force acting per unit area. Absolute pressure is nothing but the pressure in complete vacuum. Static pressure is the pressure at particular point. If the flow of the fluid is slowed down to zero, at that point the pressure is called as total pressure. Pitot static tube is used to obtain airspeed in turn the aircraft speed using static pressure and total pressure. Pitot tube is an instrument used to measure the speed by measuring the change in the pressure of air. Failure of the Pitot tube leads to flight crash for example flight number A447 crashed due to the failure of the pitot tube killing 228 people.

Pressure at any point is given by=gauge pressure/absolute pressure

Aircraft terminologies

Altitude is nothing but the height at which the aircraft is flying. There are three types of the altitude. They are altitude due to pressure, true or sea level altitude and absolute altitude. The following parameters vary with the altitude

                Pressure (Po) =101,325 N/m²

                Density (ρo) =1.225 kg/m³

                Temperature (To) =288.15 k

                Speed of sound (ao) =340.294 m/s

Aircraft Attitude

It is the angle of the aircraft reference line to the horizon. Mach number is defined as the ratio of speed of light to the speed of sound. Hypersonic aircraft have a speed of five times of speed of sound. Aircraft has six degrees of freedom. There are four forces acting on the namely thrust, lift, drag, weight.

Aircraft engine and wings 

The aircraft engine sucks air in at the front with a fan. A compressor raises the pressure of the air. The compressor is made up of fans with many blades and attached to a shaft. The blades compress the air. The compressed air is then blasted out with smaller opening at the back of the engine. As a result aircraft moves in the forward direction. Jet engines move the airplane forward with a great force that is produced by a tremendous thrust and causes the plane to fly very fast. Jet is a small and fast stream of fluid. Wings of aircraft provide the necessary lift for take off of the aircraft from the runway. Parameters with reference to the wings are given below

                              Lift coefficient (cl) =2L/ΡV²S

                                            L-Lift

                                            V-velocity of air

                                            Ρ-density of air 

                                            S-wing span

Major Parts of an aircraft

Cockpit-command and control

Fuselage-carries fuel and passengers

Flaps-is the extended portion of the aircraft wings. It is usually used for take off, landing and increase lift and drag. They are fully extended prior to landing to allow the aircraft to safely approach the runway at the lowest possible speed. The lift is directly proportional to the velocity of the aircraft.

Ailerons - The ailerons primarily control roll. Using ailerons causes adverse yaw that is the nose of the aircraft yaws in a direction opposite to the aileron application.

Spoilers –are used during landing of the aircraft.

Rudders - The rudder is used to control the airplane on the yaw axis (left and right.) It is most commonly used to turn the aircraft.

Slats - are used at takeoff and landing to produce additional force.

Horizontal and vertical stabilizers - The vertical stabilizer keeps the nose of the plane from swinging from side to side. The horizontal stabilizer prevents an up-and-down motion of the nose of the plane.

The post lunch session was even more interesting for me because it started with the discussion of a simple hardware module. Our task was to design a simple transceiver system with light/motion sensors. After the classes I and two of my friends went to S P Road and got some details about the components. Hopefully v will be able to submit the report on Friday. That’s it for this session, looking forward for the next session and implementation small transceiver module.