Present helicopters are limited by aerodynamics considerations and the need for fuel efficiency to top cruising speeds of about 185 miles per hour, NewScientist.com reports.
"Helicopters don't fly fast, managing only about half the speed of an airplane. That's a severe limitation," Gordon Leishman, a helicopter aerodynamics specialist at the University of Maryland, says.
Experimental prototypes by Sikorsky Aircraft in the United States and Eurocopter in Germany have propellers in addition to their rotors for additional thrust, a technology that could help commercial chopper speeds increase by 60 percent within five years.
This could be particularly helpful in the medical air ambulance field, so injured people could be plucked by a hovering helicopter at an accident scene and flown to a hospital quicker.
"While the helicopter's hovering ability makes it extremely useful, its lack of speed often means people cannot be treated in what medical teams call the 'golden hour', where the ability to save life is strongest," says Leishman.
Eurocopter's X3 model has made just one test flight to date, but engineers are hoping it will eventually crack 250 mph.
Sikorsky's competing X2 has already reached a top speed of 290 mph.