Abstract: An apparatus for stabilizing a shaft in an essentially horizontal position while an anchoring object at one end of the shaft is replaced without removal of an object at the opposite end of the shaft that would otherwise tend to destabilize the shaft from its essentially horizontal position includes a half-spool member configured to clamp above and around the shaft to resist torque around the rotor, under supports configured to attach to the half-spool member and clamp an underside of the shaft below the half-spool member, and a hydraulic or mechanical brake configured to resist torque on the shaft when the brake is engaged.

Abstract: A variable speed system for use in systems, such as, for example, wind turbines, is described. The system comprises a wound rotor induction generator, a torque controller and a proportional, integral derivative (PID) pitch controller. The torque controller controls generator torque using field oriented control, and the PID controller performs pitch regulation based on generator rotor speed.

Abstract: The terminal effectiveness of fin stabilized, subcaliber armor piercing projectiles depends primarily on the impact velocity at the target. The aerodynamic drag and related velocity decay experienced over the trajectory from the gun to target is reduced by shortening the length of the acceleration transfer interface between subcaliber projectile and discarding sabot. This applies for multiple annular grooves and helical grooves. Special groove configurations to reduce the pressure drag and related boundary layer shock wave interaction are disclosed. The reduction in length of the acceleration transmitting interface permits its location to a position aft of the point of boundary layer transition from laminar to turbulent flow and therewith to take advantage of the low frictional coefficient of the laminar boundary layer over a large portion of the subcaliber projectile. The resulting reduction in aerodynamic drag is particularly effective for mid caliber projectiles.