Lockheed Martin has revealed new details of the forthcoming F-35 Joint Strike Fighter (JSF) flight-test programme as the first flight of the conventional take-off and landing (CTOL) F-35A variant approaches in late 2006.
The programme will include nine flight-test and seven ground-test aircraft, as well as the modified Boeing 737-300 JSF Cooperative Avionics Test Bed (CATB), which will be used to evaluate F-35 systems, particularly the Northrop Grumman APG-81 active-array radar.
Test flights using the 737, which will be modified with F-35 structure and flight surfaces to replicate the relative positions of the infrared and electro-optical sensor suite, are around “one year away” said Lockheed F-35 chief test pilot Jon Beesley, speaking at a Society of Experimental Test Pilots meeting in California.
The flight-control laws for the first CTOL test aircraft, A-1, will be evaluated for the final time on a motion simulator at NASA Ames in October and November. The tests will also take a “brief look” at the approach and landing flight-control laws for the F-35 carrier version (CV), as well as some further development work on the short take-off and vertical landing (STOVL) control laws, which were evaluated in August 2005.
The initial CTOL aircraft, A-1, is “non-optimised” in that it does not incorporate the revised structure developed for the short take-off and vertical landing F-35B, which removed the equivalent of more than 1,360kg (3,000lb) from the configuration. Many of these changes translate to the F-35A and F-35C variants, and will feature in the follow-on CTOL test aircraft A-2 and A-6.
The A-1 airframe will, however, be used for systems and propulsion risk-reduction work as well as environmental systems and aerodynamic evaluation into areas such as tail buffet.
Flutter, flying qualities and other handling tests are scheduled to be undertaken by the A-2/6 aircraft, the latter being an additional aircraft placed into the test effort as part of the weight-reduction effort. The optimised CTOLs will join the test effort in the first quarter of 2008, just after the first of four F-35B STOVL test aircraft begin flight tests from the third quarter of 2007.
Two CV variants will join the flight-test programme from the first quarter of 2009.
GUY NORRIS/LOS ANGELES
Source: Flight International
