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                                  Helicopters                

Thomas Edison said in the early 20’s:
The airplane won’t amount to a damn until they get a machine that will act like a hummingbird:
go straight up, go straight down and alight like   a humming bird.(translation at the botton of this page)

At Edison's time there weren’t  helicopters yet.( see  the Harrier page too). Nevertheless the idea was as old as the dream of flying. It was found a drawing by Leonardo Da Vinci with sketches of what should be a helicopter. It was a machine with a big screw shaped propeller which rotation should elevate the machine in the air. But there were no engines at Leonardo’s time and the machine never became practical. Besides that, today we know it would never work, but the idea in principle was correct just like many other Leonardo's ideas who was centuries ahead of his time. Only in the 20th Century engineers began to study the problem of Vertical Flight.  Many systems were tried and left behind after terrible accidents. They were researching in a non-mapped territory. Some tried to use a balloon with two propellers pointing up but it was really difficult, almost impossible in fact, to control such gadget. In modern helicopters the lift is controlled by varying the attack angle of the rotors instead of varying the speed of them as it was done in earlier models. Varying the attack angle is much more effective than varying the speed due to the inertia of the rotors. The machine body tends to rotate in the opposite direction of the rotor rotation because they are moved by the engine which is fixed to the machine body. This is neutralized by the tail rotor that has a variable pitch giving the pilot control on the side movement. In the early 30’s, a German aeronautical engineer called Anton Flettner started studying the problem of vertical flight. In the early 40’s he designed and constructed the FL-282 Kolibri. The first models operated successfully from boats and land, with a top speed of 93 mph (about 150 Km/h).Around 1931, Igor Sikorsky began to design helicopters with the configuration of a main rotor and a tail rotor. His R4 model was the first helicopter to be produced in substantial numbers. It had side-to-side seats for two pilots and was used for pilot training, as well as people transportation.Helicopters development was stopped during World War II and only in 1945 the first crossing of the English Channel was done by a German built FA 223 machine, originally built in 1940 by the Fokke-Achelis group. In the same year the FA 223 achieved the record height of 23,924 feet (about 7800 meters).After 1946 helicopter design progressed slowly but today there are several models and types for almost any need we can think about.There are small helicopters used for private service, many medium models used by radio and TV reporters and giant helicopters with two big rotors able to carry more than 10,000 kilos. And don’t forget military machines with enhanced performance to work as war weapons. Helicopters are now very sophisticated machines with all the electronic resources you can imagine, and even some you can’t.In big cities like São Paulo, Rio, New York, Tokyo and so on, people are so used to helicopters crossing the sky that they not even look up when they listen to one of them.Pay attention in your daily routine. You’ll see many helicopters flying everyday.

To read more about helicopters go to http://www.helis.com
pagina sugerida por R.M.B ex-aluno e piloto

Please answer the questions with "True or "False" according to the text.
After click on "Answer" to check. Try to answer BEFORE looking at the answers,ok?

1- Leonardo Da Vinci designed the first helicopter able to fly.
Answer FALSE

2- Modern helicopters control elevation by changing rotor's attack angle.
Answer TRUE

3- Igor Sikorsky built the first helicopter produced in great number.
Answer TRUE

4- English Channel was crossed by a helicopter during World War II.
Answer FALSE

5- It's part of our daily routine to see helicopters over big cities.
Answer TRUE

6- After 1946 helicopter design progressed very fast.
Answer FALSE

7- Today helicopters are complex and useful machines.
Answer TRUE

A frase dita por Thomas Edison foi:
O avião não valerá droga nenhuma até conseguirem uma maquina que se comporte como um beija-flôr:
que vá direto para cima,direto para baixo e pouse como um beija-flôr.