This document summarizes the key developments in helicopter technology from Leonardo Da Vinci's early sketches of an aerial screw in 1480 to modern innovations. Some of the major developments discussed include Paul Cornu building the first working helicopter in 1907, the gyroplane laboratoire setting new records for height, distance, and duration in 1933, and the invention of the turboshaft engine in 1951 which provided more power and allowed helicopters to be bigger and faster. The document also explains the aerodynamic principles that allow helicopters to fly using rotating airfoils and discusses how control mechanisms like the swashplate allow pilots to steer helicopters.

1. HOWHELICOPTERSFLY CESAR VANDEVELDE ··· 3IO ··· TECHNOLOGICAL DESIGN ENGINEERING

2. Da Vinci 1480: Leonardo Da Vinci sketches his flying machine. This is the first time an aerial screw is used for flying. His machine is considered to be the first helicopter. Cornu 1907: Paul Cornu builds the first working helicopter. It could hover 30cm above the ground for 20s, and was the first truly free flight with a pilot. Gyroplanelaboratoire 1933: The gyroplane laboratoire was the first practical helicopter. This helicopter set new records for height (158m), distance (circle with 500m diameter), and duration (1h 2m 10s). Civilianuse 1940s: The first widespread usage of helicopters for civilian purposes. in 1947, a helicopter is used to deliver air mail for the first time. Turboshaft 1951: The turboshaft engine is invented. The turbine engine is lighter and can provide more power than piston engines. Turboshaft helicopters are bigger, faster, and can lift more.

3. PRINCIPLE OF AN AIRFOIL Bernoulli’s principle: ½ ρ·v² + ρ·g·z + p = constant v = speed p = pressure The shape of the airfoil makes air travel faster above it than below RESULT: High speed = Low pressure The airfoil is lifted up above the airfoil: v↗ p↘ below the airfoil: v↘ p↗

5. Newton’s laws dictate that every action has an equal and opposite reaction.

7. Dual rotors: The helicopter uses 2 main rotors, spinning in opposite directions. Because of this, the anti-torque effect of both rotors negate each other.

8. Coaxial rotors: 2 rotors on the same shaft spin in opposite direction.

10. Certain areas of the rotor disk need to generate more lift than others.

11. The lift generated by an airfoil is changed by changing the angle of attack.

12. The angle of attack needs to be changed relative to the position of the blade.

14. Rotor systems are categorized by how many ways a blade can move independently from the rest of the rotor.

15. This helicopter has a semi-rigid rotor system.

17. Spins at 550 RPM

21. Prevents it from rotating with the main rotor.

22. Allows the lower swashplate to move up and down, and tilt.

24. Is controlled by the pilot using hydraulics.

26. Is connected using 2 angular contact ball bearings

28. Makes sure the upper swashplate rotates with the main rotor.

30. When one blade goes up, the other goes down.

32. Rotorblade is connected using a plain bearing made from PTFE (Teflon)

34. Rods connect the pitchhorn to the upper swashplate, the position and rotation of the swashplate assembly controls amount and direction of the lift.

46. Throttle:Rotorblades are designed for a specific RPM. The throttle allows the pilot to increase or decrease the engine’s power output, so he can keep the rotor speed constant.

47. Cyclic control: Controlled by a joystick in the middle. Tilts the swashplate assembly, which changes the rotor blades’ pitch cyclically, and thus moves the helicopter in that direction