The three principal JSF variants, although they will bear the same service designation, are quite different aircraft, with different capabilities and characteristics.

Details were revealed in a briefing at the show by Maj Gen John Hudson, director of the US Department of Defense JSF programme.

The basic aircraft, usually known as the CTOL (Conventional Take-Off and Landing) variant, will be the major type for the USAF and for most export customers. The first Lockheed Martin JSF prototype tested this configuration (Configuration 220A) under the designation X-35A.

The CTOL aircraft has a 590nm (1,100km) combat radius, and a 93% mission reliability rate, and the equipment needed to support it – its logistics footprint – would fill eight C-17s.

The aircraft is fitted with a standard USAF-style refuelling receptacle in the upper fuselage, whereas the other versions each feature a retractable inflight refuelling probe. Hudson gave the average unit flyaway cost of the CTOL version as $37 million in 2002 dollars.

The US Marine Corps will use the STOVL version, with a swivelling engine nozzle and the Collier Trophy-winning Rolls-Royce/Allison lift fan mounted in the fuselage, behind the cockpit. This gives the aircraft smaller internal weapons bays and necessitates a shorter canopy and a bulged fuselage spine. The first JSF prototype was converted to STOVL configuration (Configuration 220B) after completing CTOL testing, and was redesignated X-35B in its new guise.

The aircraft has a lower fuel capacity than the baseline aircraft and its radius is thus only 450nm. The aircraft has an impressive vertical landing bringback capability, being able to land while carrying two 1,000lb JDAMs and a pair of AMRAAMs. The aircraft has a 95% mission reliability rate and a logistics footprint about 15% smaller than that of the USAF aircraft. Its cost is given as $46 million.

The largest of the JSF sub-types is the US Navy's carrierborne CV version. The second prototype flew in this form as the X-35C.

It has wingtip and chord extensions, giving a significant increase in area, and incorporates full-span trailing edge flaperons and increased-chord inboard leading-edge flaps.

Together these improvements give a useful reduction in approach speed, allowing the aircraft to achieve the maximum approach speed requirement of 145kt (268km/h). The wing folds for carrier stowage.

The aircraft is fully stressed for catapult launch and arrested recovery, and incorporates a conventional arrester hook and a revised landing gear incorporating a catapult holdback and attachment points. The CV version has a radius of 600nm, and costs $48 million.

Source: Flight Daily News