Conformal fuel tank

An F-15E Strike Eagle fitted with conformal fuel tanks under the wing roots.

Ground crew handling the CFT of an F-15E.

Conformal fuel tanks (CFTs) are additional fuel tanks fitted closely to the profile of an aircraft which extend either the range or "time on station" of the aircraft, with a reduced aerodynamic penalty compared to external drop tanks.

Conformal fuel tanks have the disadvantage that, unlike drop tanks, they cannot be discarded in flight. This is because conformal tanks are plumbed into the aircraft, and can only be removed on the ground. Thus, when the CFTs are empty, the aircraft continues to suffer the same aerodynamic penalty, with no benefit. However, to use the Eurofighter Typhoon as an example, an aircraft with CFTs can carry a full weapons load and two 1,500 litre CFTs, whereas a Typhoon without CFTs has to sacrifice at least two weapons pylons to carry drop tanks, reducing either range or weapons load.

CFTs also have the advantages of not significantly increasing an aircraft's radar cross-section, and allowing a higher maximum speed than drop tanks.

Examples

Conformal fuel tanks

• F-15C Eagle/F-15E Strike Eagle

F-15C entered service with CFT capability.^[1] Initially known as FAST packs (Fuel And Sensor Tactical),^[1] each unit carried an additional 849 US gallons (3,213.8 L) of fuel and were first tested on the F-15B in 1974. Today only Israeli F-15C/Ds regularly use CFT's.^[1] All U.S. F-15Es, and Strike Eagle export variants such as the IAF and Singapore models, are fitted with CFT's and require modification to fly without them.^[2] The FAST pack was originally intended to carry a navigational and targeting infrared sensor system (thus "Fuel And Sensor"); however, the F-15 simply began carrying LANTIRN pods for ground-attack missions instead.^[1]

Israeli F-16I Sufa, based on the F-16D Block 50/52+, with 2 attached CFTs.

• F-16C/D Block 50/52+, F-16E/F Block 60 and F-16I Sufa

Export aircraft for Greece, Israel, Poland, Turkey, Singapore,Morocco and the UAE all plumbed for carriage of two CFTs, each capable of holding 450 US gallons (1,703.4 L)

• Dassault Rafale

Two 1,150 litres (300 USgal) CFTs were first tested by Dassault in April 2001.^[3]

• Eurofighter Typhoon

Wind tunnel tested by BAE, two CFTs with 1,500 litres (400 USgal) capacity.^[4]

• AIDC F-CK-1 Ching-kuo

The F-CK-1D prototype ("Brave Hawk") and the F-CK-1C single-seater prototype are equipped with the new CFTs.

Distended internal tanks

• English Electric Lightning^[5]
• Gloster Javelin^[6]
• Gloster Meteor^[7]
• Shenyang J-6^[8]
• Q-5 Fantan^[9]

References

Notes

1. ^ ^{a b c d} Joe, Baugher (20 February 2000). "McDonnell F-15C Eagle". JoeBaugher.Com. http://www.joebaugher.com/usaf_fighters/f15_8.html. Retrieved 21 September 2010. 
2. ^ Joe, Baugher (9 May 2004). "McDonnell F-15E Eagle". JoeBaugher.Com. http://www.joebaugher.com/usaf_fighters/f15_10.html. Retrieved 21 September 2010. 
3. ^ "Rafale B Fitted with Conformal Fuel Tanks". Airforce-technology.com. http://www.airforce-technology.com/projects/rafale/rafale9.html. Retrieved 2010-11-09. 
4. ^ Robert, Wall (18 August 2009). "U.K. Pushes On Typhoon Upgrades". United Kingdom: AviationWeek.Com. http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/TYPHOON081809A.xml. Retrieved 21 September 2010. 
5. ^ "Thunder & Lightnings - English Electric Lightning - Pictures - Profiles". Thunder-and-lightnings.co.uk. 2009-08-11. http://www.thunder-and-lightnings.co.uk/lightning/pictures.php. Retrieved 2010-11-09. 
6. ^ http://www.thunder-and-lightnings.co.uk/javelin/full/xh712.jpg
7. ^ "Meteor2". Aviationmuseum.com.au. 2008-07-19. http://www.aviationmuseum.com.au/aircraft/Meteor2.cfm. Retrieved 2010-11-09. 
8. ^ http://www.xairforces.com/images/country/pakistan/f-6a_pakaf_924.jpg
9. ^ "Image". SinoDefence.com. http://www.sinodefence.com/airforce/groundattack/showimage.asp?imagename=q5_09large. Retrieved 2010-11-09.