Helicopters

Helicopters
By Zach

A helicopter is a type of aircraft that uses spinning blades called rotors to fly. A rotor is a huge propeller that is pointed straight up into the air. When the helicopter’s engine makes the rotor spin fast enough, the helicopter lifts off the ground.

There is one main problem that makes helicopters complicated – torque. Torque is when the rotors are spinning fast and the main body of the helicopter wants to spin the other direction. The most basic solution to torque is a small rotor on the back of the helicopter called the tail rotor. This small rotor spins and pushes the body of the helicopter in a direction opposite of the torque. Another solution is tandem rotors. In this approach there are two large rotors and they each spin in a different direction. This allows the torque of the two rotors to equal each other out. Either of these approaches allows the helicopter to fly straight.

When on the ground, helicopters rest on either wheels or skids. Skids are mostly used because they weigh less than wheels. On big helicopters wheels are used and not skids. Why? Guess.

Why do you think that on bigger helicopters wheels are used instead of skids?

Most helicopters can fly about 200 to 350 miles per hour or 322 to 563 kilometers per hour. The farthest most helicopters can travel on one tank of fuel is 600 miles or 966 kilometers. This is not as fast as a plane but you don't want helicopters to go too fast. They aren't used for speed. They're used for hovering, landing in small places, and other things planes can't do.

Helicopters have many benefits. They go much faster than cars, so they are an obvious way to get from place to place quickly. Since they can land in places that airplanes cannot, business people often use them for convenience. Helicopters are great for rescuing, because they can land in small spots. Sometimes helicopters are used to rescue people from places that cars can’t even get to. Helicopters are also used for the military, because they can move people quickly and lift heavy things.

Helicopters with two rotors are useful for lifting very heavy loads. Because all the engine power goes to the main rotors, and not to a tail rotor, full power goes toward lift. The most powerful helicopter in the world can carry 22 tons.

As early as the 1500’s, the Chinese played with a toy that when spun with your hands would lift into the air. Later, the Italian inventor Leonardo Da Vinci made drawings of a machine that we would later call a helicopter.

How many years have today’s modern helicopters been around?

While early inventors tried to invent a helicopter, two problems kept them from making their dream a reality: an understanding of the concept of lift and a good engine. Over hundreds of years, many great minds worked on understanding lift for both airplanes and helicopters. As time went on, everyone got to know how wings and rotors create lift. However, there was still not enough power available to turn the rotors of a helicopter. At the end of the nineteenth century the invention of a gas powered engine was a great help to creating a helicopter. There were still a lot of problems that still had not been solved. Early helicopters did not have good solutions for torque. Over time the tail rotor and the double rotor were invented.

Over the short history of helicopters they have already proven to be very useful. I can’t wait to see what they come up with next!

Citations

Online Resources

Crossley, William A. "Helicopter." World Book Online Reference Center. 15 December 2004. <http://www.worldbookonline.com/wb/Article?id=ar251640>.

"Rotor Configuration." helis.com. 17 December 2004 <http://www.helis.com/howflies/rotconf.php>.

Image Citations

Copyrighted images of helicopters from "Microsoft Office Online" <http://office.microsoft.com/clipart/default.aspx?lc=en-us&cag=1> (October-March, 2004-2005). Clip art available only to licensed users for non-commercial purposes.