The Gulfstream 450’s Rolls-Royce Tay Mk 611-8C engines are built around the high-pressure engine core of the SpeyRB.183-555, which has successfully documented thousands of hours of flight time in various other commercial and private jets. The Rolls-RoyceTay engine, however, gets 2,600 pounds more thrust on takeoff than the Spey. The Tay engines produce 13,850 pounds of thrust each, allowing a sea-level takeoff in 5,450 feet. At an altitude of 5,000 feet, the runway requirement is 8,030 feet.