The helicopter is one of the most versatile machines in existence. They use rotating blades for lift, propulsion, thrust and steering.
Helicopters are used for many purposes in today’s world, including forest fire fighting, air taxis, farming and crop dusting, traffic surveillance, life flight ambulances, and many military uses.
The helicopter is unlike any other mode of transportation. To understand the complexity of them, let’s compare them to other vehicles. A train can travel in two directions, forward and reverse, it has no steering. A car can travel forward and reverse as well as left and right steering. An airplane can fly up, down, left, and right. A helicopter, in addition to all of these directions and unlike any other machine, can fly in reverse, hover, and turn on its axis while hovering without any forward motion.
The unique design of the helicopter’s method of lift is what enables it to accomplish all of these abilities. To understand this better, you need to understand lift and thrust. On an airplane, the wing provides lift and the engines provide thrust. The wing’s shape, curved on the top and flat on the bottom, causes a low-pressure condition on the top of the wing and a high-pressure condition on the bottom of the wing, causing lift.
The helicopter’s lift and thrust come from its rotor blades. Each rotor blade is shaped like a wing on an airplane. They are driven by a transmission that is driven by the engine. Their rotation causes the high and low pressures required to create lift. They are adjustable as a whole, to provide thrust, and they are independently adjustable to provide lateral movement.
When the helicopter leaves the ground, the transmission will drive the engine and additionally the helicopter body in the opposite direction. To prevent this there is an intermediate driveshaft and gearbox connected to a tail rotor. The tail rotor provides the necessary resistance to prevent the helicopter from rotating. The tail rotor has the same characteristics as the main rotor blades do.
They provide lift and thrust in the same fashion. They are also adjustable in flight, controlled by pedals at the pilot’s feet, so he is able to control lateral direction (left and right) on the helicopter’s axis, much like the rudder and rudder pedals in an airplane, however, the helicopter can turn an entire 360 degrees. The helicopter is controlled by three main flight controls.
The rudder pedals as previously discussed, the cyclic control and the collective. The cyclic control also controls lateral movement, including left, right, forward and backward motions. The cyclic is usually a stick that is located between the pilot’s legs. The collective controls the up and down movement of the helicopter.
It usually has the throttle on it as well. It is located on the left side of the pilot’s seat and is pulled up or pushed down to control the up and down movement. The throttle is usually turned much like a motorcycle throttle by the pilot’s wrist movement, controlling engine speed. The flexibility that a helicopter gives us is incredible.
But with these amazing capabilities comes a very complex machine that requires a great deal of training and skill to operate and maintain. The pilot must think and control the helicopter in three dimensions using both his feet and hands together to accomplish the desired reaction from the helicopter.
Used for so many beneficial things in our society, the helicopter is truly one of the world-changing inventions of the twentieth century. The first successful flights were in 1907, and more successfully in 1939 when Igor Sikorsky flew his VS-300.