Aircraft propulsion
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This document defines aircraft and propulsion, and provides examples of different aircraft types. It focuses on helicopters, describing their history and types. Helicopters generate lift through main and tail rotors. The main rotor blades create lift as air flows faster over their curved upper surfaces. The tail rotor controls direction and counteracts the spinning forces from the main rotor.
Aircraft propulsion
- 2. DEFINITION
- 3. AIRCRAFT A machine that is able to fly by gaining support from the air.
- 4. PROPULSION The word is derived from two Latin words: pro meaning before or forwards and pellere meaning to drive. Propulsion means to push forward or drive an object forward.
- 5. AIRCRAFT PROPULSION Lift – the force the causes an aircraft to overcome gravity, climb into the air and stay in the air. Weight – the force generated by the gravitational attraction of the earth on the aircraft. Thrust – the force which moves an aircraft through the air. Drag - forces acting opposite to the relative motion of any object moving.
- 8. AIRPLANE
- 9. TRIVIA It is a Boeing VC-25, a military version of Boeing 747. A plane can only use the call sign “Air Force One” if it is a military aircraft attached to the 89th Air Lift Wing and only when the President of the United States is on board.
- 10. HOT AIR BALLOON
- 11. TRIVIA The first human carrying flight technology. The large balloon on top is called an “envelope”. It holds hot air created by a heat source known as a burner. Hot air balloons can fly to amazing heights, the world record is over 21,000 meters.
- 12. AIRSHIP
- 13. TRIVIA Also called as Blimps These airships are filled with helium. The helium is maintained under low pressure. Goodyear Blimps uses this for advertising purposes and for use as a television camera platform for aerial views of sporting events.
- 14. SEAPLANES
- 15. TRIVIA Powered fixed-wing aircraft capable of taking off and landing on water. Motor-powered watercraft which uses hydrofoils to levitate their main hull above the water when running at a speed.
- 16. HELICOPTER
- 17. HISTORY The earliest known mention of a rotor-powered flying machine appears in a Chinese text written about A.D. 320. The design of this machine may have been based on a Chinese toy called the flying top. Such toys flew by means of feather rotors. In 1483, Leonardo da Vinci sketched a design for a helicopter. It had a large screw-like wing made of starched linen. In 1784, two Frenchmen named Launoy and Bienvenu built the first model helicopter in Europe that could fly.
- 18. Da Vinci’s sketch Model of Helicopter from Launoy and Bienvenu
- 19. HISTORY By early 1900’s, small, powerful petrol engines had been developed that made manned helicopter flight possible. The first ever was in 1907. The craft was a four-rotor helicopter built by Louis Breguet, a French Inventor. This helicopter lifted a human about 61 centimeters for a minute. Later in 1907, a French mechanic name Paul Cornu made the first free flight in a helicopter. He flew his tandem-rotor aircraft 2 meters for about 20 seconds.
- 20. Paul Cornu in his first helicopter Full length photograph
- 22. SINGLE-ROTOR HELICOPTER Has one main rotor mounted above its body. It also has a second, smaller rotor mounted on its tail. The main rotor may have 2 to 8 blades. It provides the helicopter’s lifting-power. The tail rotor has from 2 to 13 blades. It is mounted vertically on the either side of the tail and so spins at a right angle to the main rotor. The tail rotor is used to control direction. It also overcomes the tendency of the helicopter to spin around.
- 23. TWIN-ROTOR HELICOPTER Have 2 main rotors. The rotors turn in opposite directions and so it doesn’t need for a tail rotor. There are 2 types: The tandem-rotor helicopter which has a main rotor mounted above each end of the body and the coaxial-rotor helicopter which has one rotor above the other.
- 25. Tandem-rotor Helicopter Coaxial-rotor Helicopter TWIN-ROTOR HELICOPTERS
- 28. HELICOPTER PROPULSION Helicopter rotor blades are rotary wings. When an engine turns the rotors, the blades generate lift as they whirl through the air.
- 29. HELICOPTER PROPULSION Special type of wings help them create lift. A wing’s upper surface is curved and the lower is flat. As the wings move, air flows over and under the wing. The air flows faster over the wing than under the wing. There is less pressure on the upper surface than the lower. The air is pushing more strongly at the bottom thus creates the lift.
- 31. BLADE ELEMENT THEORY In rotary-wing aircraft e.g. helicopters, induced drag decreases with increased aircraft airspeed
- 33. HELICOPTER PROPULSION Angle of attack - the amount of lift by changing the angle that the wings make with the airflow.
- 34. TAIL ROTOR Newton's third law of motion requires that for every action there is an equal and opposite action. A typical single main rotor helicopter has a rotor system mounted on a rotor mast. The helicopter engine supplies power so that the helicopter can turn the mast. When the helicopter applies torque to the mast to spin it, there is an equal-and-opposite torque reaction which tries to turn the helicopter in the opposite direction.