GVFlyer
Well-known member
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- Feb 22, 2002
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The following data are based on 8 passengers, ISA, NBAA Reserves.
Gulfstream G550 / Bombardier Global Express XRS
Long Range Cruise / Range: M 0.80 - 6,750 nm. / 6,395 nm.
Intermediate Cruise: M 0.83 - 6,500 nm. / NA
Normal Cruise: M 0.85 - 6,000 nm. / 6,045 nm.
High Speed Cruise: M 0.87 - 5,000 nm. / Not a part of Bombardier range guarantee
Thrust (ea.): BR 710C4-11 - 15,385 lbs. thrust / BR710A2-20 – 14,750 lbs. thrust
T/O, MGTOW: 5,910 ft. / 6,190 ft.
Ldg. Dist, MLW: 2,770 / 2,700 ft.
Max Ramp Wt: 91,400 lbs. / 98,250 lbs.
Max Fuel: 41,300 lbs. (all in the wings) / 44,975 in multiple tanks
Max Payload: 6,200 lbs. / 4,500 lbs.
Max Payload Full Fuel: 1,800 lbs. / 1,775 lbs.
Cabin: 42'11"x 6'2" x 7'4" / 43’2”x6’2”x8’2” (10 inches wider)
Length: 96 ‘5” / 99’5”
Wingspan: 93'6" / 94’0”
Wing Area: 1,136.5 sq. ft. / 1,022 sq. ft.
Wing Loading: 80 lbs. sq. ft. / 96.135 lbs. Sq. ft.
Baggage Area: 226 cu. ft. / 200 cu. ft
Cabin Alt: 5,960 at 51,000 ft. / 4,500 ft. at 45,000 ft.
Avionics: Honeywell Planeview Avionics with 14.1 in. Full Color 3D LCD Displays / Honeywell Primus 2000xp avionics with 8" displays
Direct Cost Per Hour: $2,285 / $2,525
Price (millions): $46.67 / $47.75
While in the military I flew the CL 601-3A on a modified close- loop handling qualities evaluation for service source selection. It was an underpowered, buffet limited aircraft. We chose the G-IV. It's significant to note that in every military competition the Gulfstream has won the fly-off. First for the G-III against all comers, then the G-IV, the GV and finally the G550 against the Global Express and the Boeing Business Jet.
The G550 wing, as produced by Northrop Grumman in Dallas, is a beautiful thing, designed with CAD, CATEA and Computational Fluid Dynamics on the same computer that designed the Boeing 777, it's an all lifting device with no washed out or washed-in regions, no stalled regions, even the radius going to the winglet is lifting. It is the first usage of Micro Boundary Layer Energizers on any wing. The wing was designed to use them to increase wing camber, reduce structure, and increase interior volume while generating only a fraction of the drag normally created by a VG. The winglet is set on such an angle as to provide a forward thrust vector - much like a sailboat tacking into the wind. It is the only application of a supercritical winglet on any aircraft.
Gulfstream has flown the GV from 72 knots to 1.07 mach with no adverse effects. The wing is U-2 long and exceptionally wide producing 1136.6 square feet of wing supporting 91,000 pounds of jet for a wing loading of just 80 pounds per square foot. The Global wing is 1022 square feet for a wing loading of 96 pounds per square foot. This makes the Global another buffet limited airplane. I've done 45 degree bank turns at 51,000 feet in the GV/G550. This would be a suicide attempt in the Global Express XRS.
The design philosophy for the Global wing concerns me. The Global Express wing is swept 35 degrees. As sweep increases longitudinal stability decreases, adverse Dutch Roll characteristics increase and tip stall speed becomes lower. My guess is they dramatically swept the wing to reduce drag on a draggy wing.
The wing is a supercritical design. Supercritical wing usage in most applications is used to achieve a lower local mach number on the wing upper surface than on a laminar flow wing and to cause the termination of supersonic flow once Mcrit is exceeded through gradual deceleration thereby avoiding a shock wave and it's associated drag. This is not the case for the Global.
Bombardier used this design to reduce drag on a wing made thick in an attempt to contain as much fuel as possible. With a supercritical design you can either reduce thickness over cord (T/C ratio) to reduce drag or thicken the wing and maintain equivalent drag. In an effort to put all of the fuel in the wings, Bombardier came up with a wing that was 12% T/C, about the theoretical aerodynamic limit as to how thick a wing can be (the GV wing is 8.4% T/C). Something had to be done. The radical sweep and the supercritical wing are a series of kluges to compensate for what I view to be a poorly designed Japanese wing.
The Global Express wing was designed and is manufactured by Mitsubishi Heavy Industries in Nagoya, Japan. The wing and mid-fuselage section containing the spar carrythrough structure is built in Japan and subsequently shipped to Canada for final assembly.
The airplane is a hand-full in a crosswind; even the factory pilots drug a wingtip during development
I fault the use of radical sweep on a wing because of the aerodynamic penalties paid for the minimal gain. As I stated before, as sweep increases longitudinal stability decreases, low speed handling becomes more difficult, Dutch Roll characteristics become worse, tip stall speeds decrease, and the wing aspect ratio decreases causing more induced drag. This later characteristic is particularly dangerous during take-off and landing. There have been two recent fatality accidents in Challengers involving loss of control during takeoff. In part, I fault the design. I knew one of the pilots that died on runway 19 at Mid Continent and had worked with the flight test engineer on board before he went to work at Bombardier. They were competent professionals.
The beauty of the G550 wing is that they were able to get better high altitude maneuverability, achieving in unaccelerated flight at 51,000 feet a window of over a 100 knots between compressibility and stall, and great hot and high and short field capabilities without resorting to excessive wing sweep or leading edge devices. The upper surface of the G550 wing is a single piece of extruded aluminum. This is new technology used by Gulfstream to achieve the cleanest low drag wing possible. The wing is clean top and bottom. There are no "canoes" hanging down for the slotted Fowler flaps.
I know the Global Express is severely buffet limited by looking at it's MMO numbers above 38,000 feet. Far 25.335 requires that you reduce VC/MC .07 mach below the point at which you encounter mach/compressibilty effects. Looking at the height velocity curve you will see a steady MMO decrease from 38,000 feet to 51,000 feet tracing the edge of buffet.
Late in the program Bombardier found that they were unable to tune the airflow between the wing and the nacelle to reduce drag and increase lift as Gulfstream had done because engine placement is much farther aft of the wing on the Global. Also, strong shockwaves were forming in the engine nacelle, pylon/fuselage area. This required recontouring of the fuselage to produce a waisted shape for application of the area-rule concept to minimize drag. You can see this after the fact modification in the coke bottling of the fuselage in the vicinity of the engines. . The area rule design on the Global, while a good idea on fighters, is a design emergency procedure on a transport category jet to reduce excessive drag as it diminishes interior volume.
The Global Express has severe CG limitations, you must buy it with a forward galley so as not to exceed the aft cg limit. The more aft the cg, the more unstable the aircraft.
The Global Express has a 2000 pound fiberglass fuel cell within the secondary burst radius of the engine. The vent lines from the wings to this fuel cell run through the pressure vessel.
In an effort to save weight, the Global has no air to air heat exchangers. They use exotic materials to send extremely hot customer discharge air forward through the pressure vessel. If there was a bleed air leak in the GV/G550 (this has never occurred) you could find he leak by the noise; in the Global Express all you would have to do is locate the flaming passenger.
In the flight controls, the G550 offers full manual reversion. If you have a complete hydraulic failure in the Global, you will die.
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