Why The F-35B Is In Trouble

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Why The F-35B Is In Trouble​

Defense Secretary Gates announced last week that the F-35B short take-off, vertical landing fighter was "on probation". Coupled with the release of a short summary of actions that follow new program manager VAdm Dave Venlet's review of the program, it points to a challenging couple of years.

The change to the F-35B plan is major. All but three of the FY11/Lot 5 B-models are cancelled, and another 27 aircraft in FY12 and FY13. Production is being drawn down to the minimum leveel necessary to preserve a restart option.

Gates said that solving the unspecified technical issues now afflicting the aircraft "could" add cost and weight; the program office says that it "will", and that it will take two years to "engineer solutions.. and assess their impact."

This action has been in the works for some time, foreshadowed by comments in September from Lockheed Martin CEO Robert Stevens.

Gates hit the issue on the nose when he stated that changes could "add yet more weight and more cost to an aircraft that has little capacity to absorb more of either." The current situation has been in the making since the start of the systems development and demonstration program and has to do directly with the basics of a STOVL aircraft.

Vertical landing is a nonvariable requirement. The required airspeed is zero and can't be adjusted by a few knots to compensate for extra weight. The JSF key performance parameter for bring-back load - corresponding to two 1,000-pound JDAMs and two AMRAAMs - was set early on at a minimal level.

One reason that Lockheed Martin's shaft-driven lift fan (SDLF) concept was a winner in 1996 and 2001 was that it seemed to offer thrust margin for vertical landing. At the start of SDD, the F-35B was projected to have an empty weight of 29,700 pounds - not a bad place to be in with (then) almost 40,000 pounds of vertical thrust. But, in the weight crisis of 2004, engineers found that the jet had ballooned to a far higher figure (never actually published) at which it could not land vertically with normal fuel reserves, let alone weapons.

The subsequent redesign clawed back some of the growth, to a goal weight that has since floated up and down around the 32,200-pound mark - at the cost of many detail changes, including smaller horizontal tails and a change in some bulkheads from titanium to aluminum. A little more thrust was coaxed out of the engine, fuel reserves were renegotiated and the F-35B once again met Marine KPPs.

However, the margin was so tight that the Royal Navy felt it necessary to look at shipboard rolling vertical landing (SRVL) techniques to boost landing weight - a controversial measure that we have been reporting on for almost four years.

But the redesign left a fundamental problem: the bring-back load (around 3,000 pounds) was only eight per cent of the landing weight. The result is that the F-35B couldn't tolerate any OEW growth or thrust shortfall. The engine and transmission are maxed: that's the issue underlying the repeated delays in powered-lift testing, chronicled here and here.

(Interesting analogy: Concorde, which, in its production version, was designed to cross the Atlantic with a payload that was under ten per cent of its fuel load. Consequently, even a marginal shortfall in cruise efficiency would obliterate its payload, which nearly happened in 1972-74 and was averted only by difficult and expensive refinements to the air inlets.)

So whatever the F-35B propulsion and structural problems are, they have to be solved without adding weight. At the same time, changing materials and redesigning components will further reduce commonality between the B and the other two versions, putting upward pressure on costs for what is already the most expensive version.

The sharp brake that Gates has put on production does not speak to a high level of faith that it can be done. It suggests that the decision to put the STOVL jet on probation, rather than sending it directly to meet Old Sparky, may have been driven by concern that killing both the F-35B and the Expeditionary Fighting Vehicle was a political impossibility, and by a desire to minimize political impact on the entire JSF program.

The next developments to look for: the outcome of the review of Marine force structure, and the scale and type of resources that will be made available to fix the F-35B.


Why The F-35B Is In Trouble

 

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Australia Welcomes F-35 JSF Restructure​

The Acting Minister for Defence Jason Clare today welcomed the restructure of the Joint Strike Fighter (JSF) Program by US Defense Secretary Robert Gates.


The restructure follows a detailed six month Technical Baseline Review of the JSF Program’s progress by the US Department of Defense to examine the remaining development tasks and the resources and time required to complete them.


The restructure will see an extension of the System Design and Development phase and a reduction in the production rate in the earlier batches of aircraft. The US will fund costs associated with extended design and test activity.

The JSF Program involves the development of three different types of aircraft:​

the F-35A Conventional Take Off and Landing (CTOL) variant;
the F-35B Short Take Off and Vertical Landing (STOVL) variant; and
the F-35C Carrier Variant (CV).



Australia is purchasing the CTOL variant. The US Air Force is also purchasing this variant. Secretary Gates confirmed today that this variant was on schedule and proceeding satisfactorily. In 2010 it exceeded its test flight targets.



Secretary Gates advised that the STOVL variant being developed for the US Marines is experiencing significant testing problems and has now been placed at the back of the overall JSF production sequence.
Mr Clare welcomed the news that the development of the aircraft Australia is purchasing is on schedule and proceeding satisfactorily.
"It is less expensive and less complex than the other variants. The restructure announced by Secretary Gates means it is now at the front of the production queue", Mr Clare said.



Defence has advised that the restructure of the US JSF Program will reduce overall program risk to Australia and should not affect Australia's planned introduction date for the JSF.



The Australian Government approved the acquisition of the first 14 aircraft in November 2009. The first two aircraft will be delivered in 2014. The first 10 aircraft will initially remain in the United States for pilot and maintainer training. The remaining four aircraft are planned to arrive in Australia in 2017 for operational test and evaluation activities with other ADF equipment to achieve an initial operational capability in Australia from 2018.



Defence has also advised it is confident Australia has adequate buffers in place to withstand any changes to the cost and schedule.
“Australia has always adopted a conservative approach to JSF cost estimates and has explicitly included contingency funds and buffers to the schedule,” Mr Clare said.



“While there is no need to change our cost and schedule estimates, Defence will continue to assess options to ensure that cost and schedule buffers remain adequate.”



A recent agreement between Lockheed Martin and the US Department of Defense to move to fixed price contract agreements – at a lower price than independent estimates – has enhanced confidence in the costs for future JSF production.



In December last year Mr Clare met with senior US Defense officials in Washington and inspected the Lockheed Martin JSF production line in Fort Worth Texas.


http://www.****************/australia-welcomes-f-35-jsf-restructure-31164/

 

[casual]

can the whole thing and get more f22s

 

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Lockheed: One F-35B Problem Fixed​

F-35B maker Lockheed Martin says it has a solution to at least one of the problems that has put the vertical-takeoff variant of the Joint Strike Fighter on a fix-it-or-die deadline.

The company says it has finished redesigning an aluminum bulkhead located where the aircraft's main landing gear attaches to the airframe.

Cracks had been found in the bulkhead after ground tests.

"A redesign of the bulkhead is completed and an implementation plan has been developed. No cracking was found in any of the flight test aircraft, and flight testing has not been affected. Other locations of similar design are also being assessed," a company spokesman John Kent said in an e-mailed statement Jan. 11.

On Jan. 6, U.S. Defense Secretary Robert Gates said the F-35B was "experiencing significant testing problems," and that the program had two years to "get it right" or face cancellation.

"These issues may lead to a redesign of the aircraft's structure and propulsion, changes that could add yet more weight and more cost to an aircraft that has little capacity to absorb more of either," he said.


Lockheed: One F-35B Problem Fixed - Defense News