Helicopters

Topics: Helicopter rotor, Drag, Force Pages: 3 (853 words) Published: March 25, 2014
Helicopters
Part 1 stimulus material: Research and collecting secondary data How the turning rotor makes a helicopter move upwards:
The blades or rotors on a helicopter are used to produce a lifting force which gets the helicopter off the ground. As they spin around they cut into the air and produce lift, each blade providing an equal share of the lift. To produce this lifting force air must flow over each rotor. This is why the blades spin at an angle against the air. The shapes of the rotors are designed allowing air to move faster over the upper surface as the angle changes (the shape of the rotor is known as the aerofoil). To fly straight up the rotors are all at the same angle knows as collective pitch. They rotate and the difference between the pressure in the upper and lower surfaces of the aerofoil creates the upward force, lift [1]. Once the rotor is spinning enough the total lift overcomes the weight of the helicopter. This causes it to move upwards vertically [2]! How the rotor is made to turn in a helicopter and in an autogyro: In a helicopter the engine turns the rotor shaft which is connected to upper and lower swash plates. As the rotor shaft turns it also turns the upper swash plate causing the rotor blades to turn because they are connected. This enables the helicopter to fly [3]. Different to helicopters autogyros flight depends completely on autorotation. This is the rotor blades revolving automatically due to the movement of air. The blades are normal blades, just like the ones on helicopters. However in helicopters these rotor blades are attached to a motor. In an autogyro air resistance increasing in the wings making them turn, they have to move fast enough in order to lift off the ground. Two methods can be used to make the rotor turn. The first is by attaching a motor to the autogyro to drive it along the ground until it reaches a great enough speed. The second method is to jump-start the rotor, this happens by attaching the rotor to an...

Bibliography: 1. http://archive.excellencegateway.org.uk/VLSP22/030/005/010/005/e_030_005_010_005.htm
2. http://www.rotorhead.org/how.asp
3. http://science.howstuffworks.com/transport/flight/modern/helicopter5.htm
4. http://www.unc.edu/~franco/autogyro/physics.html
5. http://www.todayifoundout.com/index.php/2012/05/helicopters-wont-just-fall-like-a-rock-if-the-engine-dies-they-usually-can-be-landed-safely-this-way/
6. http://www.decodedscience.com/what-happens-when-a-helicopters-engine-fails/21296
7. http://www.helis.com/howflies/autorotation.php
8. http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/forces/forcesvelocityrev1.shtml
9. http://hypertextbook.com/facts/JianHuang.shtml
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