The Gulfstream GIV (also known as the G-IV or G4) and its successor, the Gulfstream G450, represent two distinct generations of business aviation excellence from one of the world’s most prestigious aircraft manufacturers. While they share a common lineage, the differences between them are significant and worth exploring for anyone considering these remarkable machines.

The Gulfstream GIV: A Legend Is Born

The Gulfstream GIV first took to the skies on September 19, 1985, entering service in 1987. It was developed in collaboration with Grumman as a re-engined, stretched-fuselage derivative of the Gulfstream III.

Design and Engineering

The GIV featured a new wing design that reduced weight and improved aerodynamic performance, lowering drag and increasing range. Upon delivery, it became the first business jet to feature an entirely “glass cockpit” with an advanced EFIS avionics suite and six color CRT displays.

Cabin and Capacity

The GIV offers a spacious stand-up cabin measuring approximately 45.1 feet in length, 7.3 feet in width, and 6.1 feet in height. In its standard executive configuration, it typically seats 14 passengers, with the flexibility to accommodate up to 19 passengers in high-density layouts.

Performance

• Range: The GIV offers an NBAA IFR range of approximately 4,100 nautical miles (7,593 km)
• Cruise Speed: Approximately 480 knots (889 km/h)
• Engine: Two Rolls-Royce Tay turbofans
• Service Ceiling: 45,000 feet

Production History

Over its production run, more than 900 units of the GIV, GIV-SP, and related variants were built. The aircraft set more than 50 world records for round-the-world flights, establishing Gulfstream’s reputation for long-range capability.

The Gulfstream G450: Evolution of Excellence

The Gulfstream G450 (originally designated GIV-X) represents a significant evolution of the GIV platform. Production began in October 2004, with the last G450 delivered on January 19, 2018, after 365 deliveries over 12 years.

The Upgrade Story

The G450 retains the basic GIV airframe, but incorporates technologies from the G550/GV, including automated electrical and pressurization systems. The entire nose section of the G550 was grafted onto the aircraft, giving the crew a 12-inch stretch in the cockpit and creating a 30 percent larger cockpit.

Design Changes

Key structural differences include:

• The fuselage is 12 inches longer than the GIV
• The cabin entry door has been moved three feet to the right
• Re-contoured canopy for improved aerodynamics
• Sleeker engine nacelles and improved engine pylons
• New composite, fixed-nozzle thrust reversers

Performance

• Range (Mach 0.80): 4,350 nautical miles – 500 nautical miles farther than the GIV/GIV-SP
• Range (Mach 0.85): 3,500 nautical miles – 500 nautical miles farther than the GIV at the same speed
• Normal Cruise Speed: 476 knots (Mach 0.80)
• Maximum Operating Speed: Mach 0.88
• Takeoff Distance: 5,450 feet (MTOW)
• Landing Distance: 3,190 feet (MLW)
• Service Ceiling: 45,000 feet

Cockpit and Avionics (The Game Changer)

The G450 features the PlaneView cockpit with four large Honeywell Primus Epic LCD displays. The system includes:

• Cursor control device in the outboard armrests, making it intuitive to operate
• Kollsman Enhanced Vision System (EVS) as standard equipment, using a forward-looking infrared camera and military-style head-up display (HUD) – turning night into day and allowing pilots to see runway lights even in the worst weather
• Gulfstream PlaneBook electronic flight bag for a paperless cockpit

Cabin

• Length: 45 feet 1 inch (13.7 meters)
• Height: 6 feet 2 inches (1.88 meters)
• Width: 7 feet 4 inches (2.24 meters)
• Typical Passengers: 12 to 16
• Maximum Passengers: 19
• Baggage Capacity: 169 cubic feet (4.8 cubic meters)

Improved Reliability and Maintenance

The G450’s Rolls-Royce Tay engines have been updated with more durable components, allowing for an astonishing 12,000 hours of recommended time between overhauls – far exceeding the GIV. Overall maintenance costs are claimed to be as much as 20 percent lower than for a GIV.

Gulfstream GIV vs G450: Side-by-Side Comparison

The G450’s Advantage: What You Get for the Upgrade

1. Superior Range

At Mach 0.80, the G450 flies 500 nautical miles farther than the GIV. This means routes like New York to London can be completed with more reserve fuel, or New York to Moscow becomes achievable without the range anxiety.

2. Advanced Avionics

The PlaneView cockpit with LCD displays, cursor control, and standard EVS with HUD is a generational leap forward in pilot situational awareness and safety.

3. Quieter and More Capable

The G450 has a larger capacity APU with revised intake and exhaust ducting that greatly reduces external noise. The thrust reversers also improve braking performance (3,190-foot landing distance).

4. Enhanced Passenger Experience

The cabin is slightly longer and wider, with the same generous baggage capacity of 169 cubic feet – enough for 15 standard suitcases.

5. Lower Operating Costs

With 12,000-hour TBO on the engines and 20% lower overall maintenance costs, the G450 offers better economics over the long term.

Which One Should You Consider?

Choose the Gulfstream GIV if:

• You have a lower acquisition budget – pre-owned GIVs are significantly more affordable
• Your typical missions are under 3,800 nautical miles
• You are comfortable with older avionics (though many have been upgraded)
• You appreciate the historical significance of a true business aviation icon

Choose the Gulfstream G450 if:

• You need greater range – 4,350 nautical miles at Mach 0.80
• You want modern avionics with HUD, EVS, and LCD displays
• You value lower maintenance costs – up to 20% less than the GIV
• You prefer better performance – 500 nautical miles more range at Mach 0.85
• You appreciate the larger cockpit (30% bigger) and improved crew comfort

Final Thoughts

The Gulfstream G450 is, in many ways, the GIV reimagined with 21st-century technology. While the GIV established Gulfstream’s reputation for long-range business aviation and remains a capable aircraft, the G450 represents the culmination of that legacy – incorporating the best of the G550 into a slightly smaller, more efficient package.

With over 900 GIV-family aircraft produced across all variants and the last G450 delivered in 2018, both models remain highly sought after in the pre-owned market. The G450, with its modernized systems, improved range, and lower operating costs, offers exceptional value for those seeking a large-cabin, long-range business jet.