CUTAWAY: Gulfstream expands products but retains core identity

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gulfstream production family aircraft
 © Gulfstream
Four members of Gulfstream's new product line up introduced since 2002 (clockwise from top left): G650, G550, G450 and G250.
Then-Gulfstream president Bill Boisture shocked a sombre and anxious convention of the National Business Aviation Association in 2002, an event that coincided with the one-year anniversary of the 9/11 terrorist attacks on the USA.

It was a time of great uncertainty in the business jet market, yet Gulfstream boldly announced a dramatic shake-up.

A company that had been known until only a decade earlier as a strictly one-product business would field a family of seven aircraft, with its signature Roman-style product numbering surprisingly rebranded into a new series of three-digit categories.

Thus, the ultra-long-range (6,755nm/ 12,500km) GV-SP became the G550. The long-range (4,100nm) GIV-SP was renamed the G400. Two new aircraft with lesser performance filled in gaps around these products and were introduced as the (5,785nm-range) G500 and (3,565nm-range) G300.

Those four would be combined with Astra SP and Galaxy jets acquired by Gulfstream a year before the 2002 NBAA convention, and the 2,700nm-range renamed as the G100 and the 3,600nm, super-midsize called the G200. Gulfstream also introduced the development of the G150, a 2,700nm-range midsize aircraft with a 0.3m (1ft) taller cabin compared with the G100.

"We have decided to compete in every market segment above $10 million," Boisture explained at the 2002 convention.

It was a decision rooted in a strategic change that Gulfstream executives had detected in the marketplace. No longer would corporate customers be satisfied with selecting an aircraft based on a general preference for a particular brand. Business jet customers had become more sophisticated, defining their own transport requirements and searching for the aircraft that satisfied them.

gulfstream g650 production, gulfstream
 © Gulfstream

Even by 2002, Gulfstream had started to adapt to this new reality in the business jet market. One decade earlier, the introduction of the Gulfstream GIV-SP, an improved version of the GIV brand, marked the first time that the Savannah, Georgia-based company would produce two different models at the same time.

Since Grumman introduced the Gulfstream GI into service in 1959, each new Gulfstream aircraft superseded the previous model. Certain features remained the same, such as the Gulfstream signature oval windows. Other features changed, with propellers shifting to jets and a T-tail introduced on the GII.

The linear business strategy remained nearly intact through a succession of ownership changes, with Grumman, Chrysler and investor Allen Paulson in control of the company at different times until General Dynamics finally acquired Gulfstream in 1999.

Meanwhile, the template for building two different aircraft types at the same time was set with the introduction of the GV in 1996. The company had recruited McDonnell Douglas engineer and executive Pres Henne in 1994 to lead the GV intro production. "With the GV we made a decision to retain the GIV," Henne recalls. "Up to that point we kept walking away from market share."

That approach to the market changed for good when General Dynamics acquired the company. The purchase of the Galaxy aircraft added the G100 and G200. "That sort of filled in a third and fourth member of the product line," Henne says. "When we upgraded the GV and GIV into the G550 and G450, we also developed a second model of each of those into the G300 and G500. That was a fundamental shift from a one-model approach."

Eight years later, Gulfstream's decision to diversify its portfolio has been well rewarded. Finally, potential Gulfstream customers were offered an entry-level option with the G100. The existence of the G300 also allowed the company to compete for sales opportunities with a different price point than for a G450.

Conversely, customers with a need for a mixed fleet could start at the G550 level and move their way down the product line-up.

Since 2002, Gulfstream has continued to diversify and fill in gaps. Although the G300 has disappeared from the portfolio, the G350 has been introduced offering 3,800nm range for up to eight passengers. More recently, the company has unveiled the super-midsize G250 and the ultra-large, high-speed G650.

Across this expanded line-up, Gulfstream has remained true to its core design philosophy even as the manufacturer has adapted to the modern technologies.

If Gulfstream products are founded upon characteristics including a sturdy construction, conservative wing-sweep and advanced avionics, the company has been willing to slightly deviate from past practices as its product line-up and aviation technology evolve.

gulfstream family cutaway

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Nowhere has this flexibility been more important than in the development of the G650. Designed to deliver best-in-class speed at M0.925 - at least until Cessna responds with an improved version of the currently M0.92 Citation X jet - the G650 has several innovations for Gulfstream's manufacturing process.

The G650 design began with input from the company's "very strong" customer advisory board, says Henne, which recommended a wider, longer, taller and faster aircraft.

Increased speed means that Gulfstream would have to change its approach to wing design. A signature characteristic of the Gulfstream brand is a large, robust wing that would generate additional lift, especially in emergency engine-out conditions.

The all-new aerofoil for the G650 built by Spirit AeroSystems has 33° of wing sweep at the quarter-chord point. The compares with Gulfstream's normal wing-sweep of 27° and accounts for the G650's M0.055 speed advantage over the G550.

Henne says the company was careful not to trade the company's traditional robust wing structure for a speedier aerofoil. "Even though we had to make the airplane go faster it's still a robust Gulfstream design," Henne says.

While commercial airliners are driving new leaps in the ratio of composites to metal in airframe structure, Gulfstream remains committed to taking a more conservative approach. The G650, for example, represents the company's latest technology, but incorporates composites only in non-load bearing structures, such as flight-control surfaces.

"We're learning the same things others have," Henne says. "There is a significant potential in composites but the realisation of all the advantages of composites is a difficult challenge." Although composites are often primarily considered a weight-saving improvement, Henne believes their most important advantage is their ability to change the way structures are designed and manufactured.

"You have so much freedom in composite design when you're actually designing layers of the skin as opposed to the shape of the outside surface," Henne says. "The number of variables you're playing is at least an order of magnitude more."

Such variability is both a blessing and a curse, he adds. With the ability to design structures at the level of nanometres comes new and unknown kinds of risks. "Regulators have issues with composites," he says. "Variability is one of those issues. How do you know the bond is correct on each part you make?"

As conservative as Gulfstream's approach to aerodynamics and structures, the company has been almost as ambitious in avionics and flight controls. With fly-by-wire introduced in the mid-1980s with the GIV, the company has since experiment with fibre-optic ("fly-by-light") and Ethernet ("fly-by-wireless").

The G650 has a fibre-optic data channel on the enhanced vision system that links to the Honeywell PlaneView integrated cockpit. The flight controls actuators are connected to the pilot's controllers with fly-by-wire. The transition to fly-by-light may be imminent, however. "I think at some point you'll see some of that, but not the G650 and G250," Henne says.

Again, Gulfstream's view is that fly-by-wire's ability to reduce the weight of mechanical linkages is less important than the flexibility that such systems offer the aircraft designer. "The primary reason [to adopt fly-by-wire/light/wireless] is the ability for us to tailor the control function," Henne says. "You can do so much more with flight controls of the airplane."

He adds: "The fundamental philosophy is still the same. We want a very robust airplane. We want a very reliable airplane. We are doing more and more modelling. We're doing more and more simulation. We're doing more and more testing. We don't put technology on the airplane because we think we can. We put technology on the airplane because it offers the customer something."