5. Variable Speed Rotor System
Variable speed rotor systems disproved the conventional wisdom that helicopters had to run at a constant rotor RPM. This discovery lets the main rotor run effectively over a wider spectrum of speeds, therefore lowering power demand during cruise flight by up to 25%. The device lowers fuel consumption and noise by automatically changing rotor speed depending on flight circumstances, hence optimising performance. For long-range operations especially also for hybrid-electric propulsion systems, this invention has provided fresh opportunities.