Conestoga Valley High School Aerospace Technology Rotary Aircraft Conestoga Valley High School Aerospace Technology "The idea of a vehicle that could lift itself vertically from the ground and hover motionless in the air was probably born at the same time that man first dreamed of flying." Igor Sikorsky

Today’s Topics History of Rotary Aircraft Define a helicopter Define the mechanics of a helicopter Explore the advantages of helicopters Explore the disadvantages of helicopters

Rotary Aircraft History Chinese Tops-400 BC Inspired from maple tree seeds Leonardo da Vinci-1485 Drawings of his aerial screw Launoy and Bienvenue-1784 French inventors Created a toy with a rotary-wing that produced lift Ponton D'Amecourt-1863 French first person to coin the term "helicopter" from the two greek words meaning spiral and wings

Rotary Aircraft History Paul Cornu-1907 French bicycle engineer First person to design and build a helicopter that achieved free flight while carrying a passenger Igor Sikorsky -1909 Father of modern day helicopters Russian Aviator/Engineer First design failed VS-300 in 1939 First successful mass produced helicopter 4

Helicopter Capabilities Lets compare: Train = 2 directional movements Car = 4 directional movements Airplane = 5 directional movements Helicopter has 6 directional movements In addition it can rotate and hover “Autorotation” if power is lost

How do helicopters work? Definition: an aircraft whose lift is derived from the aerodynamic forces acting on one or more powered rotors turning about a vertical axes Fly upward against the force of gravity by using their rotors to throw air down beneath them Each blade in a helicopter's rotor is an airfoil When the blade spins around, it forces air over its curved upper surface producing an upward lift

How do helicopters work? Pitch of the blades can be manipulated to produce greater or less lift depending on the operation Done using the collective pitch stick Lateral movements are performed operating the cyclic control (Front, Back, Left, Rt) Pedals Controls the left/right movement of the tail rotor blades Left pedal noses the aircraft left How Helicopters Work

How do military helicopters work? The blades are shaped like airfoils so they generate lift as they spin around. Each blade can swivel as it spins around. Vertical rods push the blades up and down, making them swivel as they rotate. A central axle connected to engine makes the entire blade assembly rotate. The cap above the rotors is missile proof to protect against enemy attacks. There are two turbo-shaft jet engines, one on either side of the rotors. If one engine fails, there should still be enough power from the other engine to land the helicopter safely.

Blade Pitch Angles Takeoff angle Collective Pitch Control AOC increased slowly to generate lift Collective Pitch Control Raising the CPC increases the pitch angle on all the blades the same amount.

Fundamental Parts of a Helicopter Main Rotor-a helicopter's main rotating wing assembly Tail Rotor-counteracts the main rotors reactive torque to stabilize the aircraft

Configurations of Helicopters Different designs to counter act reactive torque

Aircraft Limitations Not as fast as most airplanes Burns more fuel then compare sized airplanes As the forward speed increases: Vibrations in the aircraft are increased Shock noise is increased Fuselage and other parasitic drag increases

Aerodynamic Limitations

Review helicopter? What are the basic mechanics of a helicopter? Who is known as the father of the modern day helicopter? What are the basic mechanics of a helicopter? In how many directions can a helicopter maneuver? What is an advantage that a helicopter has over a airplane? Igor Sikorsky Main Rotor & Tail Rotor Six Vertical takeoff, small landing area, fly backwards, autorotation, hover & rotate 360 o