Helicopters started to be manufactured in the 1940's, and continued improvements were made through about 1986, when the bottom fell out of the aviation market.
Since then, some small improvements have been made, with most of them coming in the electronics/ avionics packages that include computer power.
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According to NASA, future helicopters may be probably made of shape-changing materials.
Heinkel made the first for Nazi Germany, but now Boeing and Sikorsky are well-known companies for building helicopters
nobody knows
dura alminium
By chicken wings
Made in America - 2003 Sikorsky Helicopters - 1.10 was released on: USA: 2004
Made in America - 2003 Sikorsky Helicopters 1-10 was released on: USA: 2004
Helicopters are made with sophisticated specialized engines and heavy materials which is fueled with special gas. They are also made of steel which makes it really heay.
There have been hundreds of helicopters made in the US
Because it made transport easier.
Because they can do many things that winged aircraft can not do