In aerospace engineering, an aircraft's fuel fraction, fuel weight fraction,[1] or a spacecraft's propellant fraction, is the weight of the fuel or propellant divided by the gross take-off weight of the craft (including propellant):[2]

With a fuel fraction of nearly 85%, the GlobalFlyer could carry 5 times its weight in fuel.

The fractional result of this mathematical division is often expressed as a percent. For aircraft with external drop tanks, the term internal fuel fraction is used to exclude the weight of external tanks and fuel.

Fuel fraction is a key parameter in determining an aircraft's range, the distance it can fly without refueling. Breguet’s aircraft range equation describes the relationship of range with airspeed, lift-to-drag ratio, specific fuel consumption, and the part of the total fuel fraction available for cruise, also known as the cruise fuel fraction, or cruise fuel weight fraction.[3]

In this context, the Breguet range is proportional to

Fighter aircraft

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At today’s state of the art for jet fighter aircraft, fuel fractions of 29 percent and below typically yield subcruisers; 33 percent provides a quasi–supercruiser; and 35 percent and above are needed for useful supercruising missions. The U.S. F-22 Raptor’s fuel fraction is 29 percent,[4] Eurofighter is 31 percent, both similar to those of the subcruising F-4 Phantom II, F-15 Eagle and the Russian Mikoyan MiG-29 "Fulcrum". The Russian supersonic interceptor, the Mikoyan MiG-31 "Foxhound", has a fuel fraction of over 45 percent.[5] The Panavia Tornado had a relatively low internal fuel fraction of 26 percent, and frequently carried drop tanks.[6]

Civilian Aircraft

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Airliners have a fuel fraction of less than half their takeoff weight, between 26% for medium-haul to 45% for long-haul.

Model MTOW (t) OEW (t) OEW
Fraction
Fuel
capacity (t)
Fuel
fraction
Payload
Max. (t)
Payload
fraction
Airbus A380[7] 575.0 285.0 49.6% 254.0 44.2% 84.0 14.6%
Boeing 777-300ER[8] 351.5 167.8 47.7% 145.5 41.4% 69.9 19.9%
Boeing 777F 347.8 144.4 41.5% 145.5 41.8% 102.9 29.6%
Boeing 777-200LR[8] 347.5 145.2 41.8% 145.5 41.9% 64.0 18.4%
Boeing 767-300F 186.9 86.1 46.1% 73.4 39.3% 54.0 28.9%
Airbus A350-1000[9] 322.0 155.0 48.1% 124.7 38.7% 67.3 20.9%
Airbus A350-900[9] 283.0 142.4 50.3% 110.5 39.0% 53.3 18.8%
Airbus A350F 319.0 131.7 41.3% 131.7 41.3% 111.0 34.8%
Boeing 787-9[10] 254.7 128.8 50.6% 101.5 39.9% 52.6 20.7%
Airbus A330-300[11] 242.0 129.4 53.5% 109.2 45.1% 45.6 18.8%
Airbus A330-200[11] 242 120.6 49.8% 109.2 45.1% 49.4 20.4%
Airbus A330-200F 233 109.4 47.0% 109.2 46.9% 68.6 29.4%
Boeing 787-8[10] 227.9 120.0 52.7% 101.3 44.4% 41.1 18.0%
Airbus A320ceo[12] 79 44.3 56.1% 23.3 29.5% 20 25.3%
Boeing 737-800[13] 79 41.4 52.4% 20.9 26.5% 21.3 27%
Bombardier CS300[14] 70.9 37.1 52.3% 17.3 24.4% 18.7 26.4%
Bombardier CS100[14] 63.1 35.2 55.3% 17.5 27.7% 15.1 23.9%
McDonnell Douglas MD-11F 286.0 112.7 39.4% 117.4 41.0% 92.0 32.2%
Ilyushin IL-76TD-90VD 195.0 92.5 47.4% 90.0 46.2% 50.0 25.6%
Boeing 747-8F 447.7 197.1 44.0% 181.6 40.6% 132.6 29.6%
Concorde[15] 185.1 78.7 42.5% 95.7 51.7% 12.7 6.9%
Virgin Atlantic Globalflyer[16] 10.1 1.6 16.1% 8.4 82.9% 0.1 1.0%

General aviation

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The Rutan Voyager took off on its 1986 around-the-world flight at 72 percent, the highest figure ever at the time.[17] Steve Fossett's Virgin Atlantic GlobalFlyer could attain a fuel fraction of nearly 83 percent, meaning that it carried more than five times its empty weight in fuel.[16]

See also

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References

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  1. ^ Brandt, Steven (2004). Introduction to Aeronautics: a Design Perspective. AIAA (American Institute of Aeronautics & Ast). p. 359. ISBN 1-56347-701-7.
  2. ^ Vinh, Nguyen (1993). Flight Mechanics of High-Performance Aircraft. Cambridge: Cambridge University Press. p. 139. ISBN 0-521-47852-9.
  3. ^ Filippone, Antonio (2006). Flight Performance of Fixed and Rotary Wing Aircraft. Elsevier. p. 426. ISBN 0-7506-6817-2.
  4. ^ 8200/27900 = 0.29
  5. ^ The F-22 Program FACT VERSUS FICTION Archived 2007-04-21 at the Wayback Machine by Everest E. Riccioni, Col. USAF, Ret.
  6. ^ Spick, Mike (2002). Brassey's Modern Fighters. Washington: Potomac Books. pp. 51–53. ISBN 1-57488-462-X.
  7. ^ "A380 Aircraft Characteristics – Airport and Maintenance Planning" (PDF). Airbus. December 2016.
  8. ^ a b 777-200LR/-300ER/-Freighter Airplane Characteristics for Airport Planning (PDF) (Technical report). Boeing. May 2015.
  9. ^ a b "A350 Aircraft Characteristics – Airport and Maintenance Planning" (PDF). Airbus. November 2016. Archived from the original (PDF) on 2016-11-28.
  10. ^ a b "787 Airplane Characteristics for Airport Planning" (PDF). Boeing. December 2015.
  11. ^ a b "A330 Aircraft Characteristics – Airport and Maintenance Planning" (PDF). Airbus. December 2016.
  12. ^ "A320 Aircraft Characteristics – Airport and Maintenance Planning" (PDF). Airbus. June 2016.
  13. ^ "737 Airplane Characteristics for Airport Planning" (PDF). Boeing. September 2013.
  14. ^ a b "CSeries brochure" (PDF). Bombardier. June 2015. Archived from the original (PDF) on 2015-09-08. Retrieved 2017-10-22.
  15. ^ "Concorde Airframe". heritage-concorde. Retrieved 2024-03-17.
  16. ^ a b "Virgin Atlantic Global Flyer | National Air and Space Museum". airandspace.si.edu. Retrieved 2024-03-17.
  17. ^ Noland, David (February 2005). "Burt Rutan and the Ultimate Solo". Popular Mechanics. Archived from the original on 2006-12-11.