Helicopter speeds have traditionally been limited by a phenomenon called “retreating blade stall,” which describes what happens to the main rotor at high speed. The relative wind on the retreating ...

Here’s What You Need to Know: Lockheed-Sikorsky-Boeing engineers, builders and weapons developers of the DEFIANT X have found a way to massively decrease or even remove what’s called “Retreating Blade ...

A team of US Army, Navy and NASA researchers has successfully tested a helicopter rotor blade with a variable-droop leading edge (VDLE) that could dramatically expand the operational envelope of ...