The helicopter is a type of aircraft which is lifted and propelled by one or more sets of horizontally revolving overhead rotors.  It has two rotors that spin several blades. A blade is a tilted airfoil, just like an airplane wing. As it speeds through the air, each blade generates …

Hypersonic refers to aircraft, missiles, rockets, and spacecraft that can reach atmospheric speeds in excess of Mach 5, which is almost 4,000 miles per hour or 6,125 kilometers per hour or more. Hypersonic flight is flight through the atmosphere below about 90 km at speeds greater than Mach 5, a …