Helicopter

[|Helicopter] - lift and thrust are supplied by rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally. This allows helicopters to be used in congested or isolated areas where fixed-wing aircraft would usually not be able to take off or land or maneuver safely.

The earliest references for vertical flight have come from China. Since around 400 BC, Chinese children have played with bamboo flying toys. The bamboo-copter is spun by rolling a stick attached to a rotor. The spinning creates lift, and the toy flies when released.

In the early 1480s, Leonardo da Vinci created a design for a machine that could be described as an "aerial screw" for vertical flight. Drawing of a machine incorporating a fusee, by Leonardo da Vinci circa 1490. This is one of the earliest drawings of a fusee.

More about helicopters
 * [|Indoor Flying Robots] (5:37) - Learn the physics behind how quadrotors fly and find out how they can by themselves without human help.


 * [|Human powered flight competition winner] - delivered to the craft's four rotors through the bicycle pedals he steadily pumps throughout his flight. It's that fragile machine, built by Reichert's Canadian team, which has now won a long-coveted international prize that lay unclaimed for years. The AHS Igor I. Sikorsky Human Powered Helicopter Competition was established in 1980 for the first successful controlled flight of a human powered helicopter that could reach a height of three metres while hovering for at least one minute in a 10-square-meter area.


 * [|Robot Fly Mimics Insect Flight, Hovers With Ultrathin Wings] The device uses layers of ultrathin materials that can make its wings flap 120 times a second, which is on a par with a housefly's flapping rate. This “required tremendous innovation in design and fabrication techniques”. The robot's wings are composed of thin polyester films reinforced with carbon fibre ribs and its 'muscles' are made from piezoelectric crystals, which shrink or stretch depending on the voltage applied to them.


 * Helicopters at work**

[|Aerial Saw Trimming] (video 5:08) - a specially designed saw with multiple blades is suspended from a helicopter to trim back trees and brush along power lines through remote dense woodlands and steep terrain.
 * **Ask** - What is the tree trimming job? Why is it difficult to do?
 * **Imagine** - How can a helicopter help do this work? What are the limitations?
 * **Plan, Create** - What are the components of the system? How are they transported to the work site? How is it assembled?
 * **Improve** - How does the helicopter saw improve getting the trimming work done?


 * That's engineering**
 * [|Coaxial rotors] - uses a pair of helicopter rotors mounted one above the other to produce both lift and thrust. Sikorsky’s high speed technology demonstrator the X2 uses this design as well as many Russian helicopters. To neutralize the torque, the rotors spin in opposite directions creating equal and opposite torques that cancel each other and eliminate the need for a tail rotor. Yaw control is achieved by increasing the collective pitch of one rotor and decreasing the collective pitch on the other.

> lift, thrust, rotors, human-powered, vertical flight, hover, fusee, carbon fiber, ultra-light materials
 * Engineering ideas**

Here are some challenges for you to work on...
 * Do it**
 * [|Paper helicopter] - blade rotates due to air resistance - [|print pattern]
 * make this [|rubber band helicopter]


 * News, updates**
 * [|Helicopter Sounds Visualized For the First Time] - In a newly published research project Markus Raffel of the German Aerospace Center in Göttingen has created a technique to take photos of the sound generating vortices that form around the end of helicopter blades.


 * Learn more...**
 * [|Igor I. Sikorsky Historical Archives] - Lots of photographs and information about helicopters and the man who invented them.
 * [|Leonardo da Vinci Museum] -This online gallery displays images and other information related to Leonardo da Vinci. The "West Wing" of the gallery has images of helicopters and other flying machines.

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