Helicopters have been built every year since about 1940
The cheapest way to build a helicopter is to build a LOT of them. This way you get economies of scale.
That depends on what level your talking about in the level of Cat woman you will have to build it and in other levels you either have to build it or build a thing you have to push and get the helicopter out of a shed or something.
Igor never flew a helicopter, but he did build one though.
He didn't have or build an actual helicopter. It was just a sketch.
yes it i they build it in the 1945 it was one of the first navy helicopters to be in army
Metal and wood and a little hard work.
Igor Sikorski invented helicopter in the year 1906.
The first practical helicopter was invented about 1942
there as 61 helicopter crashes
Can you build the transmission and rotor hub, that's the real point
You need a design for a helicopter. That design will tell you what materials you need...because every heli has different materials in it. The things you need to build a Robinson R-22 are different from the things you need to build a Sikorsky CH-53E.
Many very complex tools.