Fuel fraction

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The GlobalFlyer had a fuel fraction near 85% — it could carry five times its weight in fuel.
The GlobalFlyer had a fuel fraction near 85% — it could carry five times its weight in fuel.
This article is about flight vehicles. For the topic in combustion physics, see fuel mass fraction.

An aircraft's fuel fraction, or fuel weight fraction,[1] is the weight of the fuel divided by the take-off weight of the aircraft (including fuel):[2]

\ \zeta = \frac{\Delta W}{W_1}

For aircraft with external drop tanks, the term internal fuel fraction is used to exclude the weight of external tanks and fuel. 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] Fuel fraction is a key parameter in determining an aircraft's range, the distance it can fly without refueling.

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 estimated at between 29 and 31 percent, similar to those of the subcruising F-4 Phantom II, F-15 Eagle and the Russian Mikoyan MiG-29 "Fulcrum". The Russian medium range supersonic interceptor, the Mikoyan MiG-31 "Foxhound", has a fuel fraction of over 45 percent.[4] The Panavia Tornado had a relatively low internal fuel fraction of 26 percent, and frequently carried drop tanks.[5]

Airliners typically have a fuel fraction between 25 to 45 percent, so less than half their takeoff weight is fuel. The Boeing 777-200-IGW very long range airliner has a fuel fraction of 47 percent.[6] The Rutan Voyager took off on its 1986 around-the-world flight at 72 percent, the highest figure ever at the time.[7] Steve Fossett's Virgin Atlantic GlobalFlyer could attain a fuel fraction of nearly 85 percent, meaning that it carried more than five times its weight in fuel.[8]

[edit] See also

[edit] References

  1. ^ Brandt, Steven (2004). Introduction to Aeronautics: a Design Perspective. AIAA (American Institute of Aeronautics & Ast, p. 359. ISBN 1563477017. 
  2. ^ Vinh, Nguyen (1993). Flight Mechanics of High-Performance Aircraft. Cambridge: Cambridge University Press, p. 139. ISBN 0521478529. 
  3. ^ Filippone, Antonio (2006). Flight Performance of Fixed and Rotary Wing Aircraft. Elsevier, 426. ISBN 0750668172. 
  4. ^ The F-22 Program FACT VERSUS FICTION by Everest E. Riccioni, Col. USAF, Ret.
  5. ^ Spick, Mike (2002). Brassey's Modern Fighters. Washington: Potomac Books. ISBN 157488462X. 
  6. ^ The Sonic Cruiser – A Concept Analysis by Dr. Martin Hepperle
  7. ^ Noland, David (February 2005). "Burt Rutan and the Ultimate Solo". Popular Mechanics. 
  8. ^ Schneider, Mike. "Adventurer Set for Record-Setting Flight", Associated Press, Space.com, 2006-02-06. Retrieved on March 18, 2007. “At takeoff, fuel is expected to account for almost 85 percent of the graphite-made aircraft's weight.”
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