Fuel fraction

{{About|flight vehicles|the topic in combustion physics|fuel mass fraction}}

File:GlobalFlyer at KSC before launch.jpg could carry 5 times its weight in fuel.]]

In aerospace engineering, an aircraft's fuel fraction, fuel weight fraction,{{cite book | last = Brandt | first = Steven | title = Introduction to Aeronautics: a Design Perspective | publisher = AIAA (American Institute of Aeronautics & Ast) | page = 359 | year = 2004 | isbn = 1-56347-701-7 }} 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):{{cite book | last = Vinh | first = Nguyen | title = Flight Mechanics of High-Performance Aircraft | url = https://archive.org/details/flightmechanicsh00vinh | url-access = limited | publisher = Cambridge University Press | location = Cambridge | page = [https://archive.org/details/flightmechanicsh00vinh/page/n153 139]| year = 1993 | isbn = 0-521-47852-9 }}

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

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.{{cite book

|title=Flight Performance of Fixed and Rotary Wing Aircraft

|author=Filippone, Antonio

|year=2006

|publisher=Elsevier

|page=426

|isbn=0-7506-6817-2}}

In this context, the Breguet range is proportional to -\ln(1-\ \zeta)

Fighter aircraft

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,[https://web.archive.org/web/20050908090849/http://www.af.mil/factsheets/factsheet.asp?fsID=199 8200/27900 = 0.29] 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.[http://www.pogo.org/p/defense/do-000812-f22.htm The F-22 Program FACT VERSUS FICTION] {{webarchive|url=https://web.archive.org/web/20070421194617/http://www.pogo.org/p/defense/do-000812-f22.htm |date=2007-04-21 }} by Everest E. Riccioni, Col. USAF, Ret. The Panavia Tornado had a relatively low internal fuel fraction of 26 percent, and frequently carried drop tanks.{{cite book | last = Spick | first = Mike | title = Brassey's Modern Fighters | publisher = Potomac Books | location = Washington | year = 2002 | pages = 51–53 | isbn = 1-57488-462-X }}

Civilian Aircraft

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

class="wikitable sortable"
Model{{abbr|MTOW|maximum take-off weight}} (t){{abbr|OEW|operational empty weigh}} (t)OEW
Fraction
Fuel
capacity (t)
Fuel
fraction
Payload
Max. (t)
Payload
fraction
Airbus A380{{cite web |url= http://www.airbus.com/fileadmin/media_gallery/files/tech_data/AC/AC_A380_20161201.pdf |title= A380 Aircraft Characteristics – Airport and Maintenance Planning |publisher=Airbus |date= December 2016 }}575.0

| {{#expr:369-84}}.0

{{#expr:285/575*100round1}}%

| 254.0

{{#expr:254/575*100round1}}%

| 84.0

{{#expr:84/575*100round1}}%
Boeing 777-300ER351.5

| 167.8

{{#expr:167.8/351.5*100round1}}%

| 145.5

{{#expr:145.5/351.5*100round1}}%

| 69.9

{{#expr:69.9/351.5*100round1}}%
Boeing 777F

|347.8

|144.4

|41.5%

|145.5

|41.8%

|102.9

|29.6%

Boeing 777-200LR{{cite tech report |url= http://www.boeing.com/assets/pdf/commercial/airports/acaps/777_2lr3er.pdf |title= 777-200LR/-300ER/-Freighter Airplane Characteristics for Airport Planning |publisher=Boeing |date= May 2015 }}347.5

| 145.2

{{#expr:145.2/347.5*100round1}}%

| 145.5

{{#expr:145.5/347.5*100round1}}%

| 64.0

{{#expr:64.0/347.5*100round1}}%
Boeing 767-300F

|186.9

|86.1

|46.1%

|73.4

|39.3%

|54.0

|28.9%

Airbus A350-1000322.0

| 155.0

48.1%

| 124.7

38.7%

| 67.3

20.9%
Airbus A350-900{{cite web |url= http://www.airbus.com/fileadmin/media_gallery/files/tech_data/AC/Airbus-AC_A350-900-1000-Nov16.pdf |title= A350 Aircraft Characteristics – Airport and Maintenance Planning |publisher= Airbus |date= November 2016 |url-status= dead |archiveurl= https://web.archive.org/web/20161128050613/http://www.airbus.com/fileadmin/media_gallery/files/tech_data/AC/Airbus-AC_A350-900-1000-Nov16.pdf |archivedate= 2016-11-28 }}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{{cite web |url= http://www.boeing.com/assets/pdf/commercial/airports/acaps/787.pdf |title= 787 Airplane Characteristics for Airport Planning |publisher=Boeing |date= December 2015 }}254.7

| 128.8

50.6%

| 101.5

39.9%

| 52.6

{{#expr:52.6/254*100round1}}%
Airbus A330-300{{cite web |url= http://www.airbus.com/fileadmin/media_gallery/files/tech_data/AC/Airbus-AC_A330-Dec16.pdf |title= A330 Aircraft Characteristics – Airport and Maintenance Planning |publisher= Airbus |date= December 2016 }}242.0

| 129.4

53.5%

| 109.2

{{#expr:109.2/242*100round1}}%

| 45.6

18.8%
Airbus A330-200242

| 120.6

49.8%

| 109.2

{{#expr:109.2/242*100round1}}%

| 49.4

20.4%
Airbus A330-200F

|233

|109.4

|47.0%

|109.2

|46.9%

|68.6

|29.4%

Boeing 787-8227.9

| 120.0

{{#expr:120/227.9*100round1}}%

| 101.3

{{#expr:101.3/227.9*100round1}}%

| 41.1

18.0%
Airbus A320ceo{{cite web |url= http://www.airbus.com/fileadmin/media_gallery/files/tech_data/AC/Airbus_AC_A320_Jun16.pdf |title= A320 Aircraft Characteristics – Airport and Maintenance Planning |publisher= Airbus |date= June 2016 }}79

| {{#expr:64.3-20}}

{{#expr:44.3/79*100round1}}%

| 23.3

{{#expr:23.3/79*100round1}}%

| 20

{{#expr:20/79*100round1}}%
Boeing 737-800{{cite web |url= http://www.boeing.com/assets/pdf/commercial/airports/acaps/737.pdf |title= 737 Airplane Characteristics for Airport Planning |publisher=Boeing |date= September 2013 }}79

| 41.4

{{#expr:41.4/79*100round1}}%

| 20.9

{{#expr:20.9/79*100round1}}%

| 21.3

{{#expr:21.3/79*100round1}}%
Bombardier CS300{{cite web |url= http://commercialaircraft.bombardier.com/content/dam/Websites/bca/literature/cseries/Bombardier-Commercial-Aircraft-CSeries-Brochure-en.pdf.pdf |title= CSeries brochure |publisher= Bombardier |date= June 2015 |access-date= 2017-10-22 |archive-url= https://web.archive.org/web/20150908154642/http://commercialaircraft.bombardier.com/content/dam/Websites/bca/literature/cseries/Bombardier-Commercial-Aircraft-CSeries-Brochure-en.pdf.pdf |archive-date= 2015-09-08 |url-status= dead }}70.9

| 37.1

52.3%

| 17.3

24.4%

| 18.7

26.4%
Bombardier CS10063.1

| 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{{Cite web |title=Concorde Airframe |url=https://www.heritageconcorde.com/airframe-weights-and-loadings |access-date=2024-03-17 |website=heritage-concorde |language=en}}

|185.1

|78.7

|42.5%

|95.7

|51.7%

|12.7

|6.9%

Virgin Atlantic Globalflyer{{Cite web |title=Virgin Atlantic Global Flyer {{!}} National Air and Space Museum |url=https://airandspace.si.edu/collection-objects/virgin-atlantic-global-flyer/nasm_A20070018000 |access-date=2024-03-17 |website=airandspace.si.edu |language=en}}

|10.1

|1.6

|16.1%

|8.4

|82.9%

|0.1

|1.0%

General aviation

The Rutan Voyager took off on its 1986 around-the-world flight at 72 percent, the highest figure ever at the time.{{cite journal

|journal = Popular Mechanics

|title = Burt Rutan and the Ultimate Solo

|author = Noland, David

|date = February 2005

|url = http://www.popularmechanics.com/science/air_space/1262012.html?page=3

|url-status = dead

|archiveurl = https://web.archive.org/web/20061211202755/http://www.popularmechanics.com/science/air_space/1262012.html?page=3

|archivedate = 2006-12-11

}} 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.

See also

References