The 480B Rolls Royce Turbine Engine... Quiet Confidence. Fast, powerful, and more fuel efficient than the competition With over 25,000 units produced and some 100 million flight hours logged, the Rolls-Royce 250 series engine has earned its position as the standard of the industry, with an outstanding record of reliability and low operating costs. The 420 SHP 250-C20W turbine is derated to 305 SHP (5 MIN) and 277 SHP (continuous). The substantial derating allows the delivery of full continuous power up to 13,000 ft or to 120° F. Take the 480B for a virtual spin! Click on the links on the left to hear a startup, idle, rotor engage, interior sound, and flyover.