Principle of Flights.

Newton's Law of Motion : 

First Law: 

Law of Inertia: A body at rest tends to remain in rest and body in motions tends to remain in motion in  a straight line at a constant velocity unless acted upon by some unbalanced force. 

F=ma

F=Force, m= mass, a = acceleration

Second Law: 

The Law of Accelerations: A force(F) required to produce change in motion of a body is directly proportional to its mass(m) and the rate of change of velocity or acceleration(a). 

a=F/m

Third Law: 

Action and Reaction: For every action there is equal and opposite reactions. 

Bernoulli's Principle:

The principle was first derived by the Swiss mathematician Daniel Bernoulli. It gives interrelationship between pressure and velocity in a moving fluid (liquid or gas). 

It states that energy is conserved in a moving fluid and the pressure decreases as the speed of the fluid increases. Since there is no addition or subtraction of energy in closed system, the total energy in closed system,the total energy of airflow remains constant throughout the length of the stream tube. 

Venturi -Tube:

The venturi tube is specially shaped tube with a large opening at the front and the rear end with  a restrict or between them. Within a venturi tube ,pressure is decreased to accelerate the speed of the airflow. 

The curved upper surface of a wing could be taken as bottom half of the venturi tube. Airflow over the wing at upper surface air accelerates, the result is a decrease in pressure on the upper surface of the wing that results as one of the source of the "lift". 

The Basic Parts of Helicopters (Rotor Wing)

The basic parts of a helicopter are the fuselage.tail boom,landing gear or skid,engines,vertical stabilizer(tail),horizontal stabilizer,main rotor and tail rotor guards etc. The rotors are mounted on mast. 

Main Rotor: The main rotor has two or more blades. Each blade is an airfoil having a profile similar to that of an airplane wing. The main rotor is driven by the engines. The lift force is produced by aerodynamics action. The main rotor is subject to  a number of special conditions that must be given consideration to evaluate a helicopter. The rotor blades are subject to centrifugal force,gyroscopic procession,torque etc.

Tail Rotor: The tail rotor is small rotor mounted at the end of tail boom. According to Newton's third law of motion for every force there is equal and opposite force. To counter act the torque force produced by the main rotor,the tail rotor produces equal and opposite the torque force in opposite direction. Without the tail rotor the helicopters would keep rotating unless the corrective measures were taken,similar reaction would occur if the tail rotors fails in the flight. 

The Tandem rotor and Co-axial rotor helicopters use two synchronized rotors rotating in opposite direction. The opposite direction of the rotors causes the one to cancel the torque of other rotor,thus eliminating the need of the tail rotor. 

The Basic Parts of Aeroplane

Fuselage : It is the central portion of the body of an airplane,designed to accommodate the crew,passengers and cargo. The Fuselage must be strong ans streamlined since it must withstand the forces that are created in flight. Five types of stress act on an airplane fuselage in flight. They are tension,compression,bending,shear and torsion. Fuselage extends from the nose to tail of the airplane. the wings and the tail are attached to the fuselage. The part of the pilot compartments is called cockpit or flight deck. 

The fuselage could be pressurized or non pressurized . The fuselage of pressurized aircraft has additional capacity to withstand structural load and the pressure differences between high cabin pressure and low outside atmospheric pressure. The pressurized aircraft can fly at very high altitude (low atmospheric pressure) with low altitude(higher) atmospheric cabin pressure for the comfort of passengers.

Parts of Airplane: Source

Wing: The cross section of the wing of an airplane is shaped like an airfoil and generates lift. It is attached rigidly to the fuselage. It extends outward from each side of the fuselage. It is nearly flat on the bottom and curved on the top. The top surface of the wing is more critical surface and generates lift. Thus,airplane carries the engines under the wing but not on top where they would interfere with lift. 

The high wing airplane the wing is placed on high above the fuselage. Mid wing positioned in the middle of the fuselage. Low wing is placed below the fuselage. The ailerons,flaps,slats and spoiler are attached to the both sides of the wings. Except in some T-tail aircraft,the engines are attached to the wings. The main fuel tanks are also generally located inside the hollow space of the wings. 

Shape and Size of the Wings:

1. The Straight (Rectangular) Wing:  It has its leading edge is at almost at right angle to the fuselage. 
2. The Tapered Wing: It has round leading edge and or trailing edge. 
3. The Sweep Back Wing: It has its leading edge at slant back from root to tip of the wing. It is used on high speed jet aircraft.
4. Forward Sweep Wing: It has its leading edge swept toward the front of the airplane. 
5. The Delta Wing : It is shaped like triangle which has the root almost as long as fuselage and leading edge is sharply swept back. 
6. Variable Swing Sings: It can vary the sweep of their wing in flight.

Using the computer and wind tunnel experiment, the performances of different shape and sizes of wings area evaluated for the particular airplane requirements. The shape and size plays the very important role, on fuel consumption,speed,payload etc

Tail (Empennage):  It is the rear part of the airplane. It consists of vertical stabilizer or fin and horizontal stabilizer. Rudder is attached to the vertical stabilizer(fin) and elevators are attached to the horizontal stabilizer. The trim tabs are attached to the ailerons,rudder and elevators. 

Landing Gear or Undercarriage: Landing gear is the part of an airplane that supports the aircraft weight on the ground. It includes wheels,shock absorbers and support struts. There is a landing gear unit under the nose of the aircraft as well as approximately midway back,under the fuselage or near the root of the wings. Landing gear normally includes rubber tires,but may have skis for landing on snow or floats for landing on water. 

The front wheel is called the nose wheel. The nose wheel is used for taxing. Rear wheels are called main wheels. The big jests like B-747 and A380 have multiple landing gears. Each landing gear assembly carries 4 to 6 wheels. Some small airplane has main wheels on the front and small wheel on the tail like Pilatus Porter. 

Landing Gear

Nose Wheel and Landing Gear

Aircraft

Aircraft: Any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth’s surface.

Example:airship · air superiority fighter · attack aircraft · biplane · bomber · delta wing · fighter · glider · hang-glider · helicopter · Hot air balloon · jumbo jet · para glider · sea plane · training aircraft · Zeppelin · human powered aircraft

What is Aeroplane ?

Aeroplane: A power-driven heavier-than-air aircraft, deriving its lift in flight chiefly from aerodynamic reactions on surfaces which remain fixed under given conditions of flight.