Gulfstream Aerospace’s launch today of its new G500 and G600 large-cabin business jets was a well-kept secret, especially since the programs have been in the works for five years. During an event at its Savannah, Ga., headquarters, the company surprised guests by rolling out a prototype of the G500 under its own power.

Over the past 12 months, the U.S. airframer has seen rival Dassault Falcon refresh its product range with the launch of the new Falcon 5X and 8X models, but Gulfstream insists that its focus has been on boosting choice and the value proposition of its own family of aircraft rather than seeking to keep up with competitors The new aircraft build a bridge between the G450 and G550 models and the G650 flagship. According to Lor Izzard, Gulfstream’s director for sales support and technical marketing, the G500 and G600 will deliver unmatched high-speed range when they enter service, respectively in 2018 and 2019.

The G500 at its normal cruise speed of Mach 0.90 will deliver range of 3,800 nm, rising to 5,000 nm at Mach 0.85. Similarly, the G600 will have range of 4,800 nm at Mach 0.90 and 6,200 at Mach 0.85.

Pricing for the first 50 serial numbers has been set at $43.5 million for the G500 and $54.5 million for the G600. By comparison, the G650 is now priced at $66.5 million and the rates for the G450 and G550 are, respectively, “in the mid 30s and lower 50s,” according to Gulfstream.

The two new aircraft will feature a new, high-speed wing, based on that of the larger G650 and with the same 36-degree sweep. The G600 wing will be eight feet larger to accommodate 10,000 pounds of additional fuel capacity. They will have a new tail, again based on the G650 in terms of aerodynamic shape and systems, but using new composite materials. Both aircraft will carry less fuel than the G450 model, but will be able to fly farther and faster.

Extensive construction work over the past two years at Gulfstream Aerospace’s headquarters in Savannah, Ga., provided a visible clue that the manufacturer had something big brewing. One new building completed in September 2012 will be used to make the wings and tails for the new G500 and G600 models, and another facility opened last month will house fuselage manufacturing and final assembly.

Performance Versus Cabin

The airframer’s core challenge in product definition has been the classic trade-off between delivering a leap ahead in terms of aircraft performance, balanced against the desire to combine this with superior cabin comfort. The result is a pair of aircraft with a wider cabin cross-section than the G450 and G550, but not quite as wide as that of the G650. Nonetheless, the length of the passenger “living areas” equals that of the G650, and the new designs also boast the G650’s large windows, its 6.25-feet high main entrance door, its cabin altitude (4,850 feet at FL510 and 3,000 feet at FL410), as well as 100 percent fresh air.

“The aircraft are bigger in all dimensions to the G450 and 550,” said Izzard. “We didn’t want a cabin so large that it would be to the detriment of performance. This is the right cabin [size] for us to be able to produce the performance our customers want.” He added that the finished internal dimensions of the G500/600 cross-section will be bigger than that of the Falcon 7X.

There will be significant flexibility in cabin design options since the galley can be situated either in the forward or rear sections, and customers can choose from a variety of living-space options. It will also include a fully certified crew rest area and 175 cubic feet of baggage space.

Power by Pratt & Whitney Canada

Gulfstream has also made a significant shift in powerplant selection, opting for Pratt & Whitney Canada’s new PW800 turbofan series. The 15,144-pound-thrust PW814GA will power the G500, while the 15,680-pound-thurst PW815GA will be used for the G600.

The PW800 was selected for Cessna’s proposed Columbus jet, but this program was subsequently cancelled. The engine is understood to have been considered by Dassault for its new Falcon 5X, but the French airframer instead went for Snecma’s new Silvercrest engine. Gulfstream acknowledged that it considered several other powerplant proposals for the G500/600, and these likely would have included the Silvercrest, as well as GE Aviation’s new Passport and the Rolls-Royce BR725, already deployed on the G650.

Pratt & Whitney Canada is responsible for delivering a completely integrated powerplant system. This will feature an aluminum kevlar fan case and a nacelle developed by Nordam, which is aiming to deliver a thrust reverser that will be 50 percent more efficient than existing equipment.

The manufacturer has had nine engines involved in the development program, which has so far accounted for more than 1,720 operating hours, 2,786 cycles and 4,400 hours of core testing. As of last month, some 35 hours of flight-testing had been completed and Gulfstream pilots have participated in some of these tests. The PW800 should complete certification in the fourth quarter of this year.

All-new Flight Deck

There is to be even greater innovation in the cockpit of the fly-by-wire G500 and G600, which will be the first Gulfstreams to feature active sidestick controls. According to Mark Kohler, Gulfstream vice president for advanced aircraft programs, the airframer was unwilling to make the shift to a sidestick control until BAE Systems adapted technology originally developed for fighter aircraft for civil use. “The system’s active force feedback provides a classic airplane feel, and it simulates the feel of mechanically linked sticks,” explained Izzard. In addition to BAE Systems, Thales, Parker Aerospace and Moog are contributing to the flight control/fly-by-wire systems for the new models.

The flight deck is based on Honeywell’s Primus Epic suite and is being branded as Gulfstream Symmetry. The avionics manufacturer’s PlaneView system is used on existing Gulfstream aircraft. For the G500 and G600 it is also providing the APU, the environmental control system, cabin pressure system and most of the touchscreen control panels for all cabin systems.

The new Gulfstreams feature no fewer than 10 integrated touchscreen control panels in the cockpit. Since pilots can easily switch the functions for which these are used, the aircraft will be able to be dispatched with just three of the screens functioning. Backup flight displays will be provided by L-3. Esterline group subsidiary Korry is contributing the three overhead displays.

An enhanced vision system (featuring higher resolution and an increased field of view) and synthetic vision for the primary flight display will be standard equipment for the new aircraft. Both will feature the same Rockwell Collins head-up display as the G650.

The cockpits will feature an all-new crew seat, with a full seat pan thanks to the absence of a control wheel and column. This will make it easier for the pilots to move in and out of their seats (as will new handles on the headrests). They will also benefit from Ventimesh materials that make the seat area cooler.

GE Aviation is supplying the electrical power distribution system, as well as the aircraft health and trend monitoring system, and data concentration network. For the latter, engineers have devised a way to break down the usual radio rack into separate elements, in the process reducing the amount of wiring and weight, while also improving the network’s reliability. This change has also gained some space for additional cabin volume.

Gulfstream has selected UTC Aerospace to provide the air data system, landing gear and various electrical power systems for the new models. Parker Aerospace is supplying the hydraulic actuation system for the fly by wire controls. Moog is responsible for the rudder pedals and flap actuation system.

Overall, the G500/600 program will result in a 50 percent reduction on LRUs compared with the G650. For instance, the flight controls will require just eight control units (compared with the G650’s 16).

The maintenance interval between major inspections will be 750 flight hours. Gulfstream has used 3-D virtual reality technology to optimize access to systems for maintenance, which will follow the MSG-3 task-orientated programs. The new aircraft will have a high degree of systems commonality with the G650.

Skunk Works, Savannah-style

Working under extraordinary levels of secrecy out of its expanded research and development facilities in Savannah, Gulfstream and its program partners have made great progress in testing and evaluating systems and airframe structures. All wind tunnel testing for the G500 and G600 is now complete, and engineers are now embarked on iron bird testing of the airframe and cockpit systems integration.

The first flight-test aircraft are already under construction with a view to achieving a first flight for the G500 in 2015 and for the G600 in 2017. Critical design review for the G500 is already complete and this stage should be reached for the G600 by the end of 2014.

The two models will have a common basis for flight certification and five test aircraft will be used for the G500 development program and four for the G600. One of these will be used entirely for evaluating cabin design and systems.

Two full-size static test articles (including all flight controls) are being used for structural tests that will include ultimate limit-load testing. The new test laboratory can process some 15,500 channels of data.

Much thought is already being given to devising a more efficient manufacturing process for the new models. It will use new autoclave technology that is able to produce large composite airframe sections, mobile robotic platforms for drilling, multi-panel assembly cell equipment for attaching skin panels and laser radar for high-speed contour mapping of the wing, as well as greater use of standard parts and various lean manufacturing techniques.

The G500 and G600 will have increased composite content compared with existing Gulfstream models. Composites will be featured in the winglets, nose radome, horizontal stabilizer, elevator and rudder, engine cowling, floor boards, landing gear doors, wing-to-body fairings, spoilers, pylons, dorsal fin and rear pressure bulkhead.

Potential Customers Buy Into Design

Gulfstream has closely involved prospective buyers in helping to define key characteristics of the new models through its Advanced Technology Customer Advisory Team. This consultation has resulted in more than 200 design changes, including improved cockpit functionality and comfort, additional storage space, cabin layout revisions, a commitment to common type ratings for G500 and G600 pilots, as well as overall performance goals.

Gulfstream senior sales and marketing vice president Scott Neal insisted that recent product developments at major rivals have not been a significant driver of its latest plans. “We listen to the customer base and determine what to build,” he told AIN. “We have always led the market with our products and our behavior is not changed by what competitors are doing.”

Neal also stressed that Gulfstream remains committed to production of the G450 and G550 models. Part of the company’s thinking on market segmentation is that existing customers of the smaller G280 model will be more inclined to upsize to these existing types.