Sikorsky reported successful flight tests for its 115-pound, battery-powered twin prop-rotor unmanned aircraft.

In fact, the X2 was not a standard helicopter, but a compound helicopter, with two coaxial counter-rotating main rotors and a prop rotor in the tail. This solution exploited the Advancing Blade ...

SHENZHEN -- The TD550D coaxial unmanned helicopter system has received its type certificate from the Civil Aviation ...

Although the helicopter, aptly named Ingenuity ... and each of the two coaxial rotors is just over 1.2 meters in diameter. Another way in which Ingenuity differs from terrestrial multicopters ...

The second variant is a helicopter with a combined powerplant, which comprises the main rotor and additional lateral propellers pulling the rotorcraft forward. The third scheme is a coaxial rotor ...

The TD550D coaxial unmanned helicopter system has received its type ... and verification across multiple areas, including the rotor system, power system, avionics and flight control.