1. HELICOPTER FLIGHT THEORY

2. CONTENTS  Historical background  Airfoil theory and propeller action  Configuration of helicopters  Main rotor and design considerations – Dissymmetry of lift – Gyroscopic precession – Vibration – Torque  Cyclic control  Momentum theory  Strength and design considerations  conclusion

3. Helicopter is one of the earliest ideas for achieving flight HISTORICAL DEVELOPMENTS  CHINESE TOPS  LEONARDO DA VINCI'S CRAFT

4. Sir George Cayley’s powered models  W H Phillips constructed steam driven helicopter Weighed about 9kg. Weighed about 9kg.  Driven by elastic devices  Attained an altitude of 90ft

5. MODERN HELICOPTER HISTORY  Paul Cornu constructed first manned helicopter Two propellers Two propellers Used 18kw,90rpm engine. Used 18kw,90rpm engine. A set of vanes below rotor for control A set of vanes below rotor for control

6. Corradino D’ Ascanio set first recognized helicopter record  At an altitude of 18m for 8min 45secs.  It had contra rotating coaxial rotors.  Controlled by flaps on the rotor blades.  Flew over a distance of 1.5 mile.

7. FIRST TRUE HELICOPTERS  FA-61 helicopter designed by Heinrich Focke in 1936.  FL-282 helicopter designed by Anton Flettner – Utilized twin inter meshing rotors – Altitude of 3965m – Pay load of 360kg

8.  VS-300 designed by Igor Sikorsky – Tail rotor

9. AEROFOIL THEORY AND PROPELLER ACTION  Aerofoil features  Bernoulli’s Principle

10. propellers  Production of thrust

11. Configuration of helicopters  Single rotor helicopter  Tandem rotor helicopter

12.  Side by side helicopter  Co axial helicopter  Tilt rotor aircraft

13. Design considerations  Dissymmetry of lift

14.  Articulated rotors

15.  Torque Main rotorMain rotor Tail rotorTail rotor

16.  Gyroscopic precession  Vibration Lateral Lateral VerticalVertical High frequencyHigh frequency Ground resonanceGround resonance

17. CYCLIC CONTROL  Forward flight Tilting the rotor hub is not practical.Tilting the rotor hub is not practical. Tilt the tip path planeTilt the tip path plane Swash plates are usedSwash plates are used

18. MOMENTUM THEORY  First analytical theory Determination of thrust and induced velocityDetermination of thrust and induced velocity

19. STRENGTH AND DESIGN REQUIREMENTS  Rotor structure  Vibration  Service life oCorrosion oCreep oFatigue  Structural materials oHigh strength to weight ratio oStiffness oCorrosion resistance oSpecific weight oResistance to impact loads oTemperature effects oRate of crack propagation oFatigue strength

20. CONCLUSION  There are still rooms for development.  Owing to its wide advantages it cannot be shunt down. down.  Its numerous applications include o Air taxi service oPolice work oRescue work oPower line patrolling etc..

21. THANK YOU