via Bloomberg
On-the-ground stress testing for the U.S. Marine Corps version of Lockheed Martin Corp.’s F-35 jet may be halted for as long as a year after cracks were found in the aircraft’s bulkheads, Pentagon officials said.Oh yeah.
Testing of the fighter’s durability was stopped in late September after inspections turned up cracks in three of six bulkheads on a plane used for ground testing, said Joe DellaVedova, spokesman for the F-35 program office.
The previously undisclosed suspension of the stress testing may increase scrutiny of the Marine Corps’ F-35B, the most complex of the three versions of the plane, during congressional hearings on the Defense Department’s fiscal 2015 budget. The department plans to request funds for 34 F-35s, eight fewer than the 42 originally planned, according to officials. Six of those planes would be for the Marines.
“We consider this significant but by no means catastrophic,” Frank Kendall, the Pentagon’s undersecretary for acquisition, said in an e-mailed statement. While the program office is still performing an assessment, “based on preliminary analysis, a redesign” of some F-35B structures will be required, said Kendall, who has a master’s degree in aerospace engineering.
Believe Elements of Power! Nothing to see here. This plane is golden!
Bullshit.
IOC in 2015? Only if you don't mind pilots flying a plane that my disintegrate around them.
Kill this turkey now. Buy Super Hornets, keep the Harrier in service with upgrades, start the 6th gen F/A-XX and a Harrier replacement and STOP THROWING GOOD MONEY AFTER BAD!
The Marines are confident that the structural issues will not effect IOC. Ditto with 2B software "gold" version. Seems somewhat optimistic, although the structural issues are not an immediate concern. As how they will impact weight margins and concurrency costs, that remains to be seen - and I would not be too optimistic about those effects.
ReplyDeleteremember my enthusiasm for the reborn MPC contest? well it got tempered by what i've been told and i'm trying to figure out how to do a post on it. long story short, the maintenance costs of this plane are coming in so high that the USMC is trying to shuffle procurement around again because that sweet spot they were hoping for that would occur once F-35 procurement was done and then we could start on the ACV is gone. just maintaining the F-35 will gobble up those funds.
Deleteadditionally the imbalance between air and ground is set to only grow and this is just a disingenuous bone being tossed that will see the MPC ending up being the future ACV.
Wait I red about this before check out this site:
Deletehttp://snafu-solomon.blogspot.com/2013/10/f-35-bulkhead-cracks.html
wrong answer. we knew what the problem was but had no idea about the extent.
Deletethey're talking about another redesign of an already chubby jet.
that's news.
As per Bloomberg: "To provide an extra margin of assurance, the Marine, Air Force and Navy versions of the F-35 are all required to undergo tests for the equivalent of 16,000 flight hours. The Marine version was supposed to complete its second 8,000 hours of testing by the end of this year.
ReplyDeleteThe ground testing aircraft had accumulated 9,480 hours “when testing was stopped to conduct root-cause analysis on discovered bulkhead cracks,” DellaVedova said. "
So, the B version has already passed the 8,000 hour mark, in fact it was 9,480 hours along when the cracks were discovered....
This is EXACTLY what this testing is supposed to find out. It would be an issue if these cracks showed up at anything less than 8,000 hours. The B had already passed it's baseline. It is supposed to last 8,000 hours and it did.
Is this a problem? Yes, but it didn't happen before the 8,000 hour mark, which would have been a big problem.
you can't down play this problem. the guy in the article states that this will PROBABLY require redesign.
Deleteadditionally, we're talking about strengthening the structure. thats short hand for additional weight. the airplane is already below design specs in performance, now you're adding additonal weight?
this bitch is a dog.
I agree Sol. Couple of things don't make sense, why the one year stoppage? That doesn't sound like a quick,easy fix. Maybe it's like that quick simple tail hook redesign that only added 137 lbs and took what, 2 years?!? The Aviation Week article mentions only a 2 pound weight gain for 1 bulk head crack, not sure about the other ones, which again makes one wonder about the tail hook 137 pound gain? Also will this carry over to the other versions, I'm wondering about the -C version in particular because of the extra stress of carrier operations. Have we heard anything about -C stress testing?
DeleteIt is a big deal because it is failing so close to it's original design of 8000 hours. All US fighters are being used way beyond their original life and F35 I am sure will be flown beyond 8000 so finding already problems at 9480 hours isn't good.
The fragile aluminum F-35B wing carry-through bulkhead has also failed before. There is a long history of aluminum bulkhead cracking beginning after 1,500 hours during F-35B durability testing in 2010, causing a 16-month breakin durability testing, restarting in January 2012.
DeleteThere are six of these fragile aluminum bulkheads, imposed on the B in 2004 as a part of the 3,000 pound weight reduction. Now three of them have failed. See the F-35 bulkheads here.
The CTOL and CV have titanium bulkheads. Titanium has the highest strength-to-weight ratio of any metal. Aluminum works fine on soda cans and lawn chairs.
Is it too late to go with the boeing X32?
ReplyDeleteThree years ago SecDef Gates said: Testing of the F-35B has uncovered issues that “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,” Gates said. Because of the problems uncovered by the testing so far and the risks involved with redesigning the F-35B, Gates said he is “placing the STOVL variant on the equivalent of a two-year probation.. . .If we cannot fix this variant during this time frame and get it back on track in terms of performance, cost and schedule, then I believe it should be cancelled,” Gates said.
ReplyDeleteOne of the reasons for the probation was in the 2010 test report: "A major fatigue crack was found in the STOVL test article at approximately 1,500 flight hours. Failure of the bulkhead in flight would have safety of flight consequences."
The F-35B probation was lifted by SecDef Panetta a year later, but the bulkhead problem has never been fixed. Now the acquisition chief Frank Kendall says: "Root cause analysis is still ongoing, however based on preliminary analysis a redesign of the affected F-35B structural members will be required."
This is as serious as the Navy tailhook problem, another problem like many others that has not been solved by Lockheed and the JSF program Office.
The two subsequent SecDefs were/are career politicians susceptible to the charms of LM lobbyists and sympathetic to jobs programs in home districts. Gates was a career bureaucrat whose POV is more focused on performance. One thing is for certain: LM's political engineering was/is near perfect.
DeleteThe UK Defence Minister Hammond is late with his F-35B order, for fourteen faulty fighters. DM Philip Hammond recently said the F-35B was an expensive plane, but one with an "incredible capability".
ReplyDeletein·cred·i·ble, adjective
--: difficult or impossible to believe, too extraordinary and improbable to be believed
If Hammond is reading the newspapers he may get the point.
riddle me this. how does Amos have the moral authority to put this plane into service with all the problems that its suffering?
Deletei contend that he doesn't.
a CMC that is accused of misconduct? universally despised by the Marine Corps family? add all that to issues with this airplane and i would think questions about its RISING cost to retrofit all the airplanes that have already been delivered and i can't imagine that he won't be over ruled.
additionally SOMETHING is going on with the Brits because the buy of 14 is WAAAAAAy late (good catch).
this thing is already dead. the brain just doesn't realize it yet.
Generals (mostly) get to be generals (except for Zinni, Shoup, and a few others) by adhering to the program, especially a joint program when the decision authority of the service chiefs is mostly moot.
DeleteAdmiral Greenert is doing okay -- talking the talk but acting otherwise. Smart guy, unusual for a flag officer.
It's late night -- time to reminisce about Peter "Perfect" Pace. General Peter Pace, CJSC, once visited West Point and spoke with the cadets. General Pace told the cadets to look out for themselves and use their subordinates for the dangerous work. According to General Pace, the worst thing a new lieutenant in combat can do "is get yourself killed." He said getting killed "is the easiest thing to do" in combat. "As a leader, you will have to decide who does what in life-and-death situations," he said. "It's easier to do it yourself than to send one of your soldiers out and watch him get killed doing what you told them to do," Pace said. "But you've got to worry about more than one soldier and all of your soldiers are looking to you for leadership. They will do whatever you tell them to do," he continued. "They do not want you to do it for them. They need to have you, lieutenant, on the radio calling in the fire support, giving the direction, telling them what to do. They'll go do it. They understand the risks."
And then there's David Shoup, and also James Otis, two ends of the spectrum, the latter reminding me of Peter Pace, the former not.
correction -- make that James Amos not James Otis (the patriot).
Deleteok. i was a bit confused on that one!
DeleteHere's a good look at the failing bulkheads, a vital part of the plane.
ReplyDeleteFor reference, aluminum is roughly half the weight of titanium, while titanium is roughly twice as strong, in terms of tensile strength. Titanium is about 5x as expensive as aluminum. Which leads to the question why did they choose aluminum over titanium? Cost perhaps?
Deletewell it really doesn't matter why they chose aluminum now. its going to end up being a poor choice. once you factor in the engineering change, the cost of retrofitting that change and then the cost to machine the titanium then you're looking at even more cost than you are now.
DeleteWhy? weight
Deletesee my comment above
Friday, February 21, 2014 8:38:00 PM
Here's (pdf) the letter of Senators McCain and Levin to SecDef Panetta Feb 6, 2012 in response to Panetta's lifting the F-35B probation a year early and before structural (and propulsion) problems were demonstrably solved.
ReplyDeleteextracts:
We similarly understand that engineering solutions to known problems with the F-35B's structure and propulsion have been identified. However, in the intervening time since probation was imposed, more problems with the F-35B's structure and propulsion, potentially as serious as those that were originally identified a year ago, have been found. This is salient where the F-35B has completed only 20% of its developmental test plan to date. Your decision, therefore, appears at least premature,
The Department's hastily-prepared report on the F-35B, intended to fulfill the statutory requirement of section 148, was provided to the Committee only after you announced your decision. It purports to justify your decision by explaining that based on a "holistic view" of this weapon system "sufficient progress in F-35B development, test and production [has been made] such that no uniquely distinguishing issues require more scrutiny than the other variants of the F-35". Notably, this standard was never originally defined or articulated as the exit criteria determining the F-35B's removal from probation. It is, rather, now being offered as an after-the-fact rationalization of a decision already made.
Probably Senator McCain will not be heard from again.
ReplyDeleteDec 2013 -- In 2014, Luke Air Force Base, Ariz., will begin receiving the first of its 72 F-35As, the first of which came off the production line Dec. 13. The base will be the F-35A training center and home to 144 jets.
Here's (pdf) the 2004 self-congratulating Lockheed report on STOVL weight reduction.
ReplyDelete"...Program leadership was soon faced with the grim reality that the short takeoff/vertical landing (STOVL) variant would need to lose as much as 3,000 pounds to meet performance requirements. This was a sobering development, and there were more than a few who said that a" fix was either impossible or too expensive and time-consuming. . "
Here's a pdf photo of STOVL bulkhead forging and finished part. (possible slow loading)
ReplyDeleteIt's not small.
For those mechanically inclined you might be interested in how to patch cracked and fractured airplane parts like bulkheads -- google "Chapter 4: Aircraft Metal Structural Repair - FAA" -- then scroll down to about page 103.
ReplyDeleteThe JPO has spoken of "blending" and "doublers" to correct the bulkhead faults. I don't know, I assume the blending involves the application of heat, which is probably a short term effort. It isn't covered by the FAA document. Doublers, or what we have called fishplates, are pieces (patches) of the same (aluminum) material riveted in place over the fault and are covered by the FAA.
Faults are caused by increased stress at the failure point, resulting either from poor design, or a crack or some other stress-raiser. The holes drilled for the rivets to hold the patches also have the potential of being stress-raisers. The patch itself might concentrate stresses at a new location, and of course the patches add weight. When one bulkhead fails it transfers increased stress to the next bulkhead which then might fail, and so on.
"This is EXACTLY what this testing is supposed to find out." -- that this airplane after twelve years in development still has MAJOR issues.