Gulfstream IV - Design and Development

Design and Development

Gulfstream, in collaboration with Grumman began work on the Gulfstream IV in March 1983 as a re-engined,stretched fuselage derivative of the Gulfstream III. A decision to redesign the wing structure for weight reduction presented an opportunity for an aerodynamic redesign of the wing to reduce cruise drag and increase range. Wing contour modifications had to be restricted to the forward 65% of wing chord so that no redesign of the control surfaces would be necessary. Modification of the inboard wing would have entailed a redesign of the fuselage floor structure, consequently this region of the wing was not modified. Outboard wing modifications were aimed at reducing the peak subcritical pressure coefficient and moving it aft in an effort to reduce shock strength and increase shock sweep. The Gulfstream IV wing has a weaker, more swept outboard shock resulting in a lower cruise drag. Other benefits arising from this design are a lower root bending moment due to the more inboard center of pressure, a lower stall speed due to washout and a larger fuel volume due to increased chord. These aerodynamic improvements result in an increase in range of over 300 nautical miles.

The first GIV made its maiden flight on September 19, 1985. The model received type certification from the FAA in April 1987. The G-IV entered into service with serial number 1000 in 1987 and was upgraded to the special purpose GIV-SP version at serial number 1214 in 1993. It was later redesignated G400 at serial number 1500.

A shorter range variant was created based on the GIV and given the G300 designation in 2002. The G400 has a large cabin, long range of 4,350 nautical miles (8,060 km) and the same comfort and design that characterize the G series. Typical cruise height and speed are 45,000 ft and Mach 0.88. Earlier models were fitted with Honeywell's SPZ 8000 Avionics package. The SPZ 8400 Avionics Package was an option, becoming standard on later models. It costs about $15 million at 2009 prices.

In 2001 Gulfstream began work on an improved version of the GIV-SP, originally designated GIV-X. It was later renamed G450. The G450 is lengthened 1 ft (0.305 m) over the G400 and shares the forward fuselage and larger cockpit of the G550. Production of the G450 began in October 2004, replacing the G400. The G450 has better performance and comes with the PlaneView cockpit with four 14 in (355 mm) liquid crystal displays and a Head up display (HUD). The shorter range G350 version of the G450 was developed and received certification in 2004.