When people think of aircraft, they often imagine sleek planes flying through the sky at breakneck speeds. The bulky, oddly-shaped helicopter, however, is rarely thought of as a means of transportation. Yet this versatile aerial vehicle performs a variety of vital tasks for both civilian and military purposes. In this Wonder of the Day, we’ll take a closer look at how a helicopter works!
Airplanes use wings to lift them into the air, but helicopters have spinning blades called rotors on top instead. These rotors provide the same force of lift that airplanes do, but they do so vertically rather than horizontally. In addition to their role in transporting people, helicopters can drop food packets and supplies to remote locations or carry wounded soldiers to hospitals more quickly than a car on the road.
Leonardo da Vinci had an idea for a helicopter back in 1490, but it would be hundreds of years before anyone actually built one that could fly. Several inventors had some minor successes in the 1920s and 1930s, including the Breguet brothers and Henrich Focke, but it wasn’t until 1940 that a man named Igor Sikorsky designed a practical helicopter.
Helicopters are so useful because they can carry heavy loads and people over long distances, which is why you’ll see them in the sky carrying food, water, medicine, medical supplies and other emergency supplies to disaster areas. They can also be used in military operations, dropping bombs or transporting troops to places where roads are impassable.
The helicopter’s rotor blades rotate in order to generate lift, but they can also spin at different speeds and have a different direction of rotation. The combination of these factors makes it essential that a pilot is able to control the helicopter’s speed and direction of rotation. Pilots do this by using a lever or collective, which is located on the left side of the cockpit. Increasing the collective increases the angle of attack on the rotor blades, which increases the lift. But if the blades turn too fast, they will stall and lose lift. This is why it’s important that helicopters have a cyclic pitch control system to prevent the blades from turning too fast or stalling.
Another issue a helicopter pilot must deal with is a phenomenon known as ground effect, where a cushion of air forms beneath the vehicle when it hovers. This air can cause the helicopter to descend too slowly or even roll over. To counter this, pilots must learn to land their helicopters on grass rather than asphalt or tarmac, where the air tends to dissipate and lessen the ground effect.
Helicopters are also useful in police and other law enforcement operations, where they can be used to pursue suspects or patrol the skies. They can be loaded with lights and heat-sensing equipment for night pursuits and used to locate objects or people in the dark. In addition, police departments use helicopters to carry prisoners to prison or take them to hospital when they’re injured.
