Do you know THEORY OF FLIGHT

BASIC AERODYNAMICS

•  GENERAL INTRODUCTION OF AIR CRAFT

3.1.1                              

   The idea of human flight has engaged the thoughts' of many men since the beginning of history. The achievement of mechanical flight, unlike so many pursuits of science, was not brought about by any pre­ssure of need, but envy. There are always men, who look at the birds and envy them as they ride the winds. This dream of mechanical flight needed courage, a science of aerodynamics, experience of construction and control and the achievement of a light and powerful engine to drive the propellers. All this was conceived by Sir George Clayey who is often called as 'the father of aerial navigation', at the beginning of the 19th century. Thus the foundations for aerial navigation were laid, in a true sense, between 1799 and 1809.

*    On the foundations laid down by Clayey, many people tried to plan devise and design and to construct models and even full size vehi­cles in pursuit of mechanical flight The essentials of wing form stability and propulsion began to emerge and by the 1880's were accompanied by the concrete achievements in automobile engineering, the sphere which aviation used later on very successfully

*    Then, in 1890's Lilienthal in Germany started riding the air in gliders and it was his example which fired the imagination of Wright brothers in America and turned their attention to solving the practical problems of aviation. Taking into their hands the varied threads of aerodynamics, construction, pilot age engine technology and propeller design, the Wright brothers wove them into a fabric, the aero plane.

*    Ballooning after its first period of excitement was over, settled down to become the sphere of showmen, sportsmen and the scientists who were interested in high altitude research. The balloon was joined by the parachute in 1797 when the Frenchman, Garner in made the first human drop at Paris. In 1852 the steam driven 'airship' became feasible, and also the 'light pressure airship' of Santos and Dumont.

*    The powered aero plane took ten years (1895-1905) to emerge from the glider that was perfected by the Wright brothers. In 1905 Wright Flier III emerged which could be banked, turned, circled and flown with ease and which could comfortably stay in the air for more than half an hour at a time. In 1910 Roe's tractor biplane appeared.

*    With the advent of War the British, the French and Germans proceeded methodically to develop various types of aero planes and the quality gradually improved with competitions. In 1919 the Rolls-Royce Eagle Engine was the outstanding achievement. In 1928 the Hele-Shaw Beacham Propeller was designed. The Bristol Centaurs Engine was de­veloped in 1947. The Whittle W-1 Turbojet was developed in 1941. In 1954 the Rolls Royce Vertical Lift Test Rig was developed. The German V-2 Rocket Engine took its shape in 1942.

TERMS AND DEFINITION

 

• AERO FOIL 

A surface design to produce when driven through the air a reaction at right angle to the direction of motion.

 BERNOULLI’S PRINCIPLE

 Bernoulli’s principle states that when a fluid (air) flowing through a tube reaches a constriction, or narrowing of the tube, the speed of the fluid flowing through that constriction is increased and its pressure is decreased. The cambered (curved) surface of an airfoil (wing) affects the airflow ex­actly as a constriction in tube affects airflow. This resemblance is illustrated in 

01.LIFT    

           The components of the resultant aerodynamic force at right angle to air flow.

02.DRAG

           The component of the aerodynamic force parallel to the air flow.

03. THRUST

           The component of the resultant air flow on air screw parallel to the air screw axis.

 

CENTRE OF PRESSURE

               The point of intersection of the resultant aerodynamic force and the chord line of an aerofoil.

 CHORD     

    The length of the part of the chord line which is intercep­ted by aerofoil section.

 

 CHORD LINE

   The straight line through the centre of curvature at the leading and the trailing edges of an aerofoil section.

 

    CAMBE

             Curvature of a surface of an aerofoil.

     ANGLE OF ATTACK

 

           ANGLE OF ATTACK

 Is the acute angle formed between the chord line of the Aerofoil and the relative wind direction.

 ANGLE OF INCIDENCE

 Angle of incidence is the angle at which the wing is permanently inclined to the longitudinal axis of the Air plane.

WING SPAN

            The overall distance from the wing tip

FUSELAGE

            The main structural body of an aerodyne except in the case of a flying boat.

           

            UNDER CARRIAGE

          That part of the alighting gear which embodies the main wheels, skids or floats. This does not include tail skid.