Gulfstream IV airplane model. As the fourth installation in the Gulfstream family line, the GIV offers new advancements that the former aircraft lacked. One of the most significant improvements is the change of engines from the Rolls-Royce Spey to the Rolls-Royce Tay Mk 611-8, used in later jets including the G300 and 400. The successful intercontinental-range business jet has been a prototype for later Gulfstream models.
Two Rolls-Royce Mk 611-8 engines provide 13,850 lbs of thrust each. Inspection interval is 8,000 hours. The Roll-Royce upgraded engine is responsible for 15% improved fuel consumption and decreased noise levels.