Gulfstream Launches New Large-Cabin, Long-Range Jets
Aviation Week & Space Technology
BY FRED GEORGE
For its latest large-cabin, long-range business jets, the G500 and G600,
Gulfstream has moved away from its long-time engine supplier, Rolls-Royce,
and left behind its original fuselage cross-section, as it did for the
flagship ultra-long-range G650. The new aircraft were unveiled ahead of the
industry-showcase National Business Aviation Association convention this
week in Orlando, Florida.
The G500 and G600 are launch applications for Pratt & Whitney Canada’s
(P&WC) PW800 turbofan and fit into Gulfstream’s product line-up above the
Rolls-Royce-powered G450 and G550, which are to stay in production as long
as demand continues. In addition to a larger fuselage cross-section, the
new jets share with the G650 wing aerodynamics, fly-by-wire controls and
systems.
The new aircraft not only have longer and larger cabins than the G450 and
G550 but also will fly higher, faster, quieter and farther on less fuel.
High-speed cruise for both aircraft is Mach 0.9. At Mach 0.85 long-range
cruise speed, the $54.5 million G600 has a range of 6,200 nm, compared with
the G550’s 6,000 nm, while the $43.5 million G500 has 5,000-nm range,
compared with the G450’s 4,220 nm at Mach 0.8.
“We have a very long-term development strategy,” says Scott Neal,
Gulfstream’s senior vice president of sales and marketing. “Cabin volume,
range and speed were the design drivers, [and that combination] will be
matched by no other aircraft.”
In the works since 2008 under Gulfstream’s project P42, the G500 rolled out
in Savannah, Georgia, Oct. 14. With 1,800 hr. of wind-tunnel work
completed, the G500’s first flight is planned for 2015, leading to expected
certification in 2017 and entry into service in 2018. Five aircraft will be
used in a two-year, 3,000-hr. flight-test program. The G600’s design, which
includes a longer fuselage and increased span, will be frozen by year-end,
aiming for a first flight in 2016 and service entry in 2019.
The new models’ enhanced performance is due to the new engines and a wing
with G650 high-speed aerodynamics, including supercritical airfoil, 36-deg.
quarter-chord sweep and increased span—10 ft. more than the G450, in the
case of the G500. Gulfstream says the P&WC engines are lighter and more
fuel-efficient than current 16,000-lb.-thrust-class engines. The G500 is
powered by two 15,144-lb.-thrust PW814GAs, the G600 by 15,680-lb.-thrust
PW816GAs.
Operators told Gulfstream they wanted a bigger fuselage but better fuel
economy, and the company briefly evaluated using the G650 fuselage
cross-section for the G500 and G600. But the weight and drag imposed
unacceptable performance penalties. Instead, the aircraft have a new
fuselage shape that is 7 in. narrower and less tall than the G650’s but
provides 2 in. more headroom, 7 in. more cabin width and 8 in. more floor
width than the G450 and G550. Used in the G650, the four-radii fuselage
shape provides more head and shoulder room than a circular cross-section.
The floor sits proportionately lower in the fuselage than in the G650, and
headroom is only 1 in. less than in the flagship Gulfstream.
The new aircraft have the same cabin windows as the G650, 16% larger in
area and positioned 3.4 in. higher than those in the G450 and G550. With a
cabin 2.5 ft. longer than the G450’s, the G500 has six windows per side and
three seating areas. The G600 cabin, 1.6 ft. longer than the G550’s, has
seven windows per side and room for 3.5 seating areas—the extra length
accommodates an optional crew-rest compartment. The 10.7-psi pressurization
system provides a 3,000-ft. cabin altitude at 41,000 ft. and 4,850 ft. at
the aircraft’s 51,000-ft. maximum ceiling, the lowest cabin altitude in
their classes.
The digital fly-by-wire system is based on that in the G650, with a pair of
dual-channel Thales flight-control computers and Parker electronic
power-control actuators. But new to the G500 and G600—and a first for civil
aviation—are the active-inceptor sidestick controls supplied by BAE
Systems. These are electrically back-driven, so they appear to be
mechanically linked side to side: When one sidestick is moved, the other
moves with it. The sidesticks also move in response to autopilot inputs,
providing the pilots with tactile and visual feedback.
In addition to the active sidesticks, the new Symmetry flight deck for the
aircraft introduces touchscreen displays and other features that
distinguish it from the PlaneView cockpits of current-production
Gulfstreams. Based on Honeywell integrated avionics, Symmetry provides four
large-format, landscape-orientation flight displays, their associated
cursor-control devices relocated from the sidewall armrests to the center
console to make room for the sidestick controls.
Three large, software-driven touchscreens on the overhead panel control
virtually all airframe systems. Four smaller touchscreens, two outside the
main displays and two in the center console, provide flight management
system, radio and avionics/display controls. There are no conventional
multi-function control display units. Wider-screen standby flight
instruments are installed in the glareshield. All this provides
unprecedented redundancy. Gulfstream’s goal is to allow dispatch with one
overhead, one lower touchscreen and one standby flight display inoperative.
The new aircraft are equipped with a standard head-up display and
third-generation Elbit Kollsman EVS III infrared enhanced-vision system
camera with four times the image resolution, an integrated exterior window
and digital interface to the avionics suite.
Several systems are carried over from the G650. The electric system has
left and right engine-driven 40-kVA generators, a 40-kVA generator driven
by the auxiliary power unit and a 15-kVA ram air turbine. The dual
3,000-psi hydraulic systems, with phosphate ester fluid, are powered by
high-capacity, left and right engine-driven pumps, plus a left-side
electrically powered auxiliary pump and left-to-right power transfer
system. There is no need for a hydraulically powered motor generator.
Also shared with the G650 are the digital air data computers, secondary
power distribution system, satellite communications and cabin management
system (with improvements). The oxygen, cabin pressurization, landing-gear
control and aircraft health and trend monitoring systems are adapted from
the G650, but are more fully integrated with the avionics system.
The PW800, meanwhile, shares its eight-stage high-pressure compressor,
low-emissions combustor and two-stage high-pressure turbine with Pratt &
Whitney’s PW1000G geared turbofan. But the engine has a 50-in.-dia.
direct-drive fan with 20 titanium blades, a three-stage low-pressure
compressor and three-stage low-pressure turbine. Bypass ratio is
approximately 5.5:1. P&WC says the engine will have “double-digit” margins
to current International Civil Aviation Organization Chapter 4 noise and
proposed CAEP/8 emissions limits.
Working with Nordam, P&WC is developing a nacelle system that improves
inlet and exhaust flow efficiency, particularly when the thrust reverser is
stowed. A prime design goal for the propulsion system is 40% lower
scheduled maintenance cost and 20% fewer maintenance inspections. Initial
time between overhauls will be 10,000 hr.
Parent company General Dynamics is investing heavily in new facilities in
Savannah as Gulfstream moves to more vertically integrated manufacturing to
improve quality and reduce production costs. The G500 and G600 wings will
be built in-house, a first for Gulfstream. This has required investment in
computer-controlled milling machines and other automated manufacturing
processes, along with an autoclave for creep-age-forming of wing skins.
More pre-flight development work is being done than for any previous
Gulfstream models. The objective is to streamline flight testing by doing
development work on the ground and then flying mainly to verify and
validate the design. The goal is to deliver mission-ready aircraft on entry
into service.
As it did with the G650, Gulfstream has built both an integrated test
facility and an iron-bird rig to evaluate most airframe systems, including
electrical, hydraulic, power control actuators and environmental system
components. The company also has an integrated cockpit and cabin mock-up
with the actual equipment to be used on production aircraft. The goal is to
wring out bugs before the first production aircraft, particularly in the
cabin management system.
Designed to appeal to G450 and G550 operators looking to upgrade, the G500
also will compete with the Dassault Falcon 900LX and upcoming Falcon 5X in
cabin size, range and price, while the G600 will vie against the new Falcon
8X. The new Gulfstreams also compare favorably with Bombardier’s existing
Global 5000 and 6000.
Industry sources long have speculated that Gulfstream was developing
successors to its G450 and G550. Neal says the new aircraft are not
replacements but additional models to help fill gaps between the G450/G550
and flagship G650. Gulfstream says the G450 and G550 “are selling well,”
but their market appeal could suffer as prospective customers learn more
about the capabilities of the new models.
These aircraft also set new standards for speed. Operators can expect to
slow down to Mach 0.85 only when necessary to achieve maximum range.
Gulfstream boasts Mach 0.9 is the new “normal cruise” for business aircraft
travel. Compared to today’s Mach 0.8, that speed can slash an hour or more
off the flight time between continents.
