Atlantic GlobalFlyer Specifications
Wing span................... 114 ft
Wing Aspect Ratio......... 32.5
Length, overall .......... 44.1 ft
Height, overal............ 13.3 ft
Tail plane, total.... 24.8 ft
Wheel track............ 29.75 ft
Passenger door: Ht. ..... ~2.5 ft
Width ................. ~3.0 ft
Wings, gross ................ 400 sqft
Flaps ....................... none
Spoilers ..................... none
Drag chutes (2 )............. ? sqft
Fin (total)............... 76 sqft
Rudder (total) .............. 52 sqft
Tail plane (total) ........... 49 sqft
Elevators (total) ............ 13.5 sqft
Weights and Loadings
Empty Weight................ 3,700 lbs
Max T-O Wt ................. 22,000 lbs
Max 0-fuel wt ............... 3,700 lbs
Max Ramp wt ................ 22,100 lbs
Max Landing wt. ............ 16,000 lbs
Max Wing loading ... ........... 55 lb/sqft
Max power loading ............ 9.56 lbs/lb st
Williams J44-3 ATW.......... 2,300 lb st
(at Max T-O wt)
Best Rate of Climb (dirty) ..... 100 kts
Best Rate of Climb (clean) ..... 130 kts
Max speed (flutter) .... ... 70 kts
Cruising speed (true) ..... 250 kts (287 mph)
Service ceiling .............. 51,000 ft
Max cruising alt............ 45,000 ft
Range with max fuel (zero wind): 19,000 nm
Sixty-seven hours and one minute. The amount of time required to fly solo around the world, non-stop and non-refueled. Steve Fossett accomplished this feat departing from Salina,
Kansas on February 28, and returning to this departure point March 3, 2005. There has been substantial coverage about the flight and the setting of three world records - Speed around the world non-stop, non-refueled, distance between declared points, and distance for a jet powered aircraft non-stop, non-refueled. What we haven't seen is much about the unique aircraft that made all of this possible. Let's take a more detailed look at the Virgin Atlantic
When Steve Fossett and Richard Branson set out to capture one of the last remaining significant flight achievements they turned to the leading innovative aircraft designers of our time - Burt Rutan. His selection was based not only on his innovative designs, but because he better than most others clearly understood the challenges involved and had the unique experience of having accomplished this task before with
Voyager. Drawing on knowledge learned in building and the flight itself, Rutan initiated Scaled Composite's development of Model 311 that would become the
Some Design Requirements
- Ability to fly above most weather
- Ability to fly high enough for "jet stream" assist
- Speed sufficient to make a solo attempt practical
The GlobalFlyer is a single engine, turbofan powered trimaran type aircraft consisting of two "booms" that hold the main landing gear, rudders, elevators, and 5,454 pounds of fuel contained in three tanks per side. The remaining 7194 pounds of fuel is contained in six integral wing tanks and a center pod header tank. In addition to the header fuel tank, the center pod contains the pressurized pilot's cabin and a single pylon mounted Williams turbofan engine mounted above. Construction materials are all graphite/epoxy composites with carbon-carbon used in the wings with skins being a sandwich of graphite/epoxy and Aramid honeycomb. The pilot's cockpit is a pressurized design capable of maintaining a 10,000 foot cabin altitude at the typical cruise altitude of 45,000 feet. Though the engine is certified to 51,000 feet, cruising altitude will be limited to 45,000 feet to assure pilot survivability in the case of loss of cabin pressurization. Even this is marginal due to the high glide ratio (approximately 37:1) of the
GlobalFlyer and available emergency oxygen on board.
In order to achieve a design configuration optimized for range and fuel efficiency, the engineers at Scaled Composites made extensive use of computational fluid dynamics which allowed them to refine the aircraft's shape and helped predict the effectiveness of the control surfaces. The resulting aircraft is so aerodynamically efficient that it achieves glider like performance with a lift to drag ratio of 37 to 1. In fact the plane glides so well
| that at light weights and engine at idle, it will not descend. In order to achieve reasonable descent rates, the plane is equipped with two drag chutes and with gear extended can fly a standard three degree glide path. These chutes are not detachable once deployed though there is sufficient power to allow the aircraft to climb with them deployed.
The GlobalFlyer is not equipped with deicing or anti-icing capabilities. Because of its design and long slender wings the plane does not handle turbulence very well. This is particularly true when heavily fuel loaded, creating lower structural margins. These limitations played heavily on the selection of Salina, KS for the departure point on the world record attempt.
The cockpit of the GlobalFlyer is approximately seven feet in length. Entrance is through a single port on the left side that is not large enough to simply step into. This necessitates some technique for ingress and egress. The cockpit door is attached just prior to takeoff. The plug-type door has an opening that can be used for fresh air ventilation when the cabin is not pressurized or fitted with a plug when pressurized.
The cabin has a 32cm wide bubble canopy blown from polycarbonate that is too small for standard military type flight helmets. In order to facilitate better head motion pilots tend to wear 1940's style cloth helmet, oxygen mask and goggles. In addition to the bubble canopy, the cockpit has two small windows on each side. View from the bubble is good forward and upward. With an upright posture and craning of neck it is possible to see down to about 30 degrees below the horizon. The side windows view are similar to that of an airliner - good but not panoramic.
The flight control system consists of a side stick on the right - selected to provide freer movement about the cabin. A trim switch for pitch and roll control is located on the top of the stick. Trim is by spring force. Conventional rudder pedals actuate the rudder and independently pivot for differential braking. The throttle lever is located on the left side. Cabin differential pressure is maintained at 8 psi through an outflow valve. A second valve set at a slightly higher pressure serves as a back up. This arrangement produces a cabin altitude of 10,000 feet at a 45,000 foot cruising altitude.
The single seat is hinged to allow it to fold down flat. Upright for normal flying the seat incorporates a custom fitted cushion that elevates the pilot to permit viewing out of the bubble canopy for takeoff and landing. During normal cruise at altitude the pilot may choose to remove the cushion for a more comfortable sitting position in the cabin.
The GlobalFlyer's wings are of carbon fiber spanning 114 ft (35m) and comprising 400 square feet of plan form area. This results in an aspect ratio of 32.5 that is similar to high performance gliders. The wings have mechanically actuated ailerons, but no spoilers, flaps or high lift devices. Roll control is achieved through conventional ailerons. Roll rate is leisurely with high roll forces and sluggish response due to high roll inertia and damping. Adverse yaw due to aileron drag effects are moderate - similar to older sailplanes - but easily corrected with rudder. Dihedral effect is positive but low at light weights. Effective dihedral increases with weight due to increased wing bend.
The tail units located on the aft end of the outriggers pods are conventional in design. Initial observation might lead to the conclusion they are a little small, but due to their aft location they are quite effective. Pitch control is light and effective. Yaw control is also light, though yaw inertia is high.
The landing gear is a standard tricycle configuration with the mains located in the outrigger pods and the nose in front of the cabin in the center fuselage. The dual nose wheels are free castering incorporating a live axle to eliminate the need for a shimmy damper. In order to facilitate ground handling, the mains can turn to any angle and are locked into the fore/aft position prior to flight. Ground steering is accomplished through differential braking using the main gear hydraulic disk brakes. The plane steers well, especially at light weights. There is a noticeable increase in yaw inertia as fuel load increases. Gear retraction is quick with no pitch change during the process. The retraction system is driven by a dry air pressure system. Gear extension is gravity free-fall.
The GlobalFlyer is powered by a specially designed Williams International FJ44-3 ATW jet turbofan. The engine is a derivative of the FJ44-3 that can be found on executive jets such as the
CitationJet. The FJ44-3 ATW is de-rated from the standard 3,000 pound static thrust to produce 2,300 pounds static. The engine has unique fan and compressor sections developed by Williams over the past 30 years incorporating integrally bladed fans and compressors
(blisks). Other characteristics of the engine include uncooled, high-pressure turbine, an effusion-cooled combustor, and a high-work, two-stage LP turbine. This axial flow turbo fan is 48 inches long with a diameter of 23 inches. The engine operates on a special low-freezing point JP-4 fuel.
Though having an unusual design, the GlobalFlyer actually handles surprisingly well. Initial climb speed is 100 knots prior to gear retraction and 130 knots after. Cruise speed for best range is about 250 knots (true).
Descents are typically made at idle thrust and with the gear up resulting in a shallow glide angle. Deploying the gear increases the descent rate which can be further increased by deploying one or both of the drag chutes. Yaw asymmetry with only one chute deployed is minor and easily controlled with only small rudder deflection. Emergency descents are performed with everything hung out - gear and chutes. This produces descent angles that are similar to small general aviation aircraft.
Landing approach speeds are relatively low producing good perceived maneuverability. One-chute landings require more planning and technique due to the reduced descent angle. No-chute landings are difficult, requiring precise speed control and approach setup with the additional requirement of a long runway having no obstacles. Approach to landing is generally flown at 1.2 time stall speed for the aircraft weight.
Record Flight Facts
In all, Steve and the GlobalFlyer set three official FAI World Records. These records are:
(1) Absolute speed record around the world, unrefueled, non-stop of 341.93 mph.(aided with an average tailwind component of approximately 55 mph.)
(2) Jet Category distance without refueling of 22,915 miles.
(3) Jet Category closed circuit record of the same distance.
The FAI does not recognize records for solo flight. The absolute distance record is still held by Dick Rutan and Jeena Yeager in Voyager at 24,987 miles.
If we run the run performance numbers, we find that for this flight the
GlobalFlyer averaged an estimated 10 mpg. Assuming the same average tailwind component,
GlobalFlyer would have a maximum range of around 27,600 miles. More than sufficient to grab the absolute distance record. So who knows? Maybe we’ll see additional record setting flights by
GlobalFlyer prior to its retirement to an aviation museum.
photos courtesy of Virgin Atlantic GlobalFlyer. For additional
information, go to www.virginatlanticglobalflyer.com