The helicopter is, together with the airplane, the most important invention of the 20th century's aeronautical industry. People have fantasized flying for millennia now. As early as Leonardo da Vinci, the genius who drew a sketch of a manually piloted helicopter, the concept was around. The first modern helicopter was built much later though, in the late 30s.



The differences between the two main types of aircraft, the plane and the helicopter, are many. The former has to execute a forward motion in order to be able to move. The wings generate a force that neutralizes the gravity force when they wings are moving in the air, which is actually what makes the plane fly.

The helicopter is a much different story though. It has the ability to hover into the air without even moving, and this is caused by the continuous motion of the blades. This has a main factor, like in the case of airplane wings, the air resistance force.

The force generated by the rotating blades is equal to the weight of the helicopter when the helicopter hovers. When the pilot wishes to take the helicopter to a bigger height, the blades' positioning angle must be modified. The pilot has the ability to do this simultaneously with all the helicopter's blades.

The helicopter has only one engine, and this engine is used to spin the rotor. Although most helicopters have a single main rotor, there are some who have two. They are meant to offer a greater stability for the helicopter by spinning in different directions.

But most helicopters have a single main rotor though and a smaller one which produces a horizontal force at the tail of the helicopter. If, by any chance, the engine fails in mid-air, the main rotor's spin will be significantly reduced. This means that the rotor won't be able to provide the necessary ascending force for the helicopter to fly.

However, even in this desperate situation, a helicopter can still land safely, especially if there's an experienced pilot on board. This can be done through a method called auto-rotation. This is also one of the main advantages of the helicopter, the fact that even in the most difficult conditions it can bring a pilot safely to the ground.

Helicopters have many uses, from warfare to saving lives or as a transportation means. The most technologically advanced ones are a menace on any battlefield, due to their sheer maneuverability and stealth. There are also big helicopters used to carry military equipment from place to place. Also, rich people can afford helicopters which are able to get them from place to place very quickly.

Then, helicopters are also used in rescuing people from difficult situations, in places where nothing else could reach. For example, countless persons have been saved from remote mountain tops or from rough seas. This could have never been possible otherwise, and this is maybe the biggest utility of a helicopter.