Patent ID: 8083173

Claim:
A rotary-wing vehicle comprising an airframe establishing a longitudinal axis, a first set of rotor blades coupled to the airframe and configured to rotate in a first direction about the longitudinal axis, and a second set of rotor blades coupled to the airframe to lie in spaced-apart relation to the first set of rotor blades to define a space therebetween and configured to rotate in a second, opposite direction about the longitudinal axis, and wherein a center of gravity of the airframe is located in the space provided between the first and second sets of rotor blades a first power source module configured to provide power of the first set of rotor blades and wherein the first power source module is coupled to the airframe and the first set of rotor blades is located between the center of gravity and the first power source module, a second power source module configured to provide power to the second set of rotor blades and wherein the second power source module is coupled to the airframe and the second set of rotor blades is located between the center of gravity and the second power source module.