STEPHEN TRIMBLE / WASHINGTON DC
Lockheed Martin to realign major milestones as weight and performance problems continue to dog F-35 development
Lockheed Martin is backing away from an ambitious plan to develop and field the first short take-off and vertical landing (STOVL) Joint Strike Fighter (JSF) unit for the US Marine Corps near the end of 2010, yielding to projected airframe weight and performance shortfalls.
Senior Lockheed Martin officials say the company is proposing to restructure the original timetable, but not abandon it. The goal remains to complete the programme's $33 billion system development and demonstration (SDD) phase on schedule by 2012, while realigning major milestones for the JSF's three variants - the STOVL F-35B, the conventional take-off and landing (CTOL) F-35A and the F-35C carrier variant (CV).
A weight problem continues to dog development of the F-35B, the most complicated of the variants. Engineers believe they can rescue the STOVL variant with more time to mature propulsion and airframe design, but the development schedule runs against them. For example, the F-35B will in 2006 become the second variant to begin flight testing - following the CTOL aircraft by a few months, but will be first by almost a year to reach initial operational capability.
The company is seeking to introduce a more streamlined development plan. "There's a lot of jumping around from one version to the other" on the SDD calendar, says a Lockheed Martin official. A better approach may be an "alignment of these variants into more of a flow to where you almost had CTOL, CV [and then] STOVL".
The programme has passed the fourth of five bottom-up weight reviews set before the final airframe design is locked in by April. The excess weight of the F-35B means it is in danger of failing to meet its performance requirements.
A Lockheed Martin official says slipping the development schedule for the F-35B, which has been selected for the USMC and the UK, offers two advantages. First, the delay offers the programme more time to find ways to compensate by improving the propulsion system.
Second, it increases the programme's early focus on the simpler design of the US Air Force's F-35A, which is to start flight tests by late October 2005. The tests may offer clues to airframe or propulsion improvements. The official says the X-35's powerplant stunned designers by offering about 2,500shp (1,900kW) more than projected. A similar margin could largely resolve the F-35B's performance shortfall.
Source: Flight International
