Conformal fuel tank

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Conformal Fuel Tanks (CFTs) are additional fuel tanks, fitted closely to the profile of an aircraft, which extend either range of an aircraft or time on station with little aerodynamic penalties compared to the same capacity carried in external drop tanks.

There is of course a penalty; while external fuel tanks can be dropped when they are empty, conformal fuel tanks are "plumbed" into an aircraft and can only be removed on the ground. Conversely, when CFTs are empty the aircraft continues to suffer from the aerodynamic penalties with no benefit. However to use the Typhoon as an example, an aircraft could carry a full weapons load and two 1,500 litre CFTs; whereas a Typhoon without CFTs would have to sacrifice at least two weapons pylons to carry drop tanks, i.e. either range or weapons load must be reduced.

CFTs also have the advantage of not significantly increasing an aircraft's Radar cross section (RCS) and allow a higher maximum speed than drop tanks.

[edit] Examples

• F-15/F-15E
  F-15C entered service with CFT capability. Initially known as FAST packs (Fuel And Sensor Tactical), each unit carried an additional 849 gallons of fuel and were first tested on the F-15B in 1974. Today only Israeli F-15C/Ds regularly use CFT's. All F-15Es fitted with CFT's and require modification to fly without them. The FASTPack 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.
• F-16
  Export aircraft for Greece, Israel, Poland, Singapore and the UAE all plumbed for carriage of two CFTs, each capable of holding 450 gallons (2,271 litres)
• Rafale¹
  Two 1,150 litre CFTs were first tested by Dassault in April 2001.
• Typhoon¹
  Wind tunnel tested by BAE, two CFTs carrying 1,500 litres.
• Gripen¹

Notes 1: CFTs under development