Two 61.6kN (13,850lb) Rolls-Royce Tay Mk.6118 turbofans.
G-IV - Normal cruising speed 850km/h (460kt). Initial rate of climb 4000ft/min. Range with max payload and reserves 6732km (3633nm), range with eight passengers and reserves 7815km (4220nm).
G-IV-SP - Max cruising speed 936km/h (505kt), normal cruising speed 850km/h (460kt). Initial rate of climb 4122ft/min. Range with max payload and reserves 6182km (3338nm), range with eight passengers and reserves 7815km (4220nm).
G-IV - Empty 16,102kg (35,500lb), max takeoff 33,203kg (73,200lb).
G-IV-SP - Empty same, max takeoff 33,838kg (74,600lb).
Flightcrew of two. Main cabin seating for between 14 and 19, plus flight attendant.
SRA-4 special missions version can also be configured for freight work.
Approximately 340 Gulfstream IVs and IV-SPs delivered by late 1998. Military C-20s built for the US Air Force, Navy, Marines and Army, other military customers include Sweden and Japan.
Long range large corporate transport
The Gulfstream IV is a significantly improved, larger, longer ranging and advanced development of the earlier II and III.
The most significant improvement with the G-IV over the earlier Gulfstream models are the Rolls-Royce Tay turbofans, which bring significant fuel burn and noise emission improvements despite their higher thrust output than the II and III's Speys (the IV continues a Gulfstream and Rolls-Royce association that dates back to the original Dart powered Gulfstream I). Other changes include a stretched fuselage and aerodynamically and structurally improved wing with 30% fewer parts, greater fuel capacity and range, increased span tailplane and an advanced EFIS avionics suite with six colour CRT displays.
Design work on the IV began in early 1983, with the first of four production prototypes making the type's first flight on September 19 1985. FAA certification was awarded on April 22 1987. The improved Gulfstream IV-SP (SP = Special Performance), with higher payload and landing weights and improved payload range performance, replaced the IV from September 1992.
A third development is the special mission SRA-4. Designed primarily for military roles (such as maritime patrol and electronic surveillance, depending on equipment fit) it is also offered as a freighter for priority cargo transport (the US Navy has ordered four and the Marines one as C-20G operations support aircraft capable of accommodating 26 passengers or three freight pallets).
Both the Gulfstream IV and IV-SP have set a number of records. A Gulfstream IV flew west around the world over 36,800km (19,890nm) in June 1987 in a time of 45hr 25min, setting 22 class world records, another flew east around the world in February 1988, setting 11 class world records. More recently a IV-SP set new world speed and distance records on a routine business flight from Tokyo to Alberquerque in the USA in March 1993.