Introducing the OS Engines Speed 91HZ-R 3D Helicopter Engine, designed specifically for thrilling 3D flights. Engineered with a cutting-edge DRS (Demand Regulator System), it ensures a consistent fuel supply, essential for the rapid attitude changes typical of 3D flying. Its advanced 61G carburettor features twin needles, allowing precise adjustments for idling/hovering and high-speed mixtures independently. Plus, you can enhance stability further by installing the BPS-1 cover plate mounting sensor when utilising the governor function with a Futaba gyro. With the governor function activated, your flights become even smoother and more controlled.