Here's the Sikorsky X2, a prototype helicopter with three blades that is set to fly at the end of the year at 287mph. That's 240 knots versus the usual 170kt of conventional choppers. We saw the idea a while ago and, after some cancellations of the program by the military, Sikorsky is now building it on their own. To keep the costs down enough for Batman to buy a dozen and paint them black, they are building them using already existing components for the most part.
Sikorsky X2 heralds the DIY helicopter [Flight Global]