F-35 Cancelled, then what ?
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So the hook don't work because the USN gave LM duff gen?! And what about the problems they're now encountering with the nose gear, is that the Navy's fault too?
-RP
-RP
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Who is designing the F35?
If one is to believe GK121 the problems with the F35C hook are all down to the USN, this implies that LM are pure contract assemblers of the plane, relying on the USAF, USMC, USN, RN etc etc to instruct them what to build.
I thought that to begin with there was a competition between design teams as to who was to build the JSF, or did I miss a trick? If LM are just contract assemblers of the intellectual property of others, they are getting a very good profit contribution.....
I thought that to begin with there was a competition between design teams as to who was to build the JSF, or did I miss a trick? If LM are just contract assemblers of the intellectual property of others, they are getting a very good profit contribution.....
Last edited by PhilipG; 26th Apr 2014 at 08:46. Reason: Typo
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IF 'LO' can make wild guesses (incorrectly IMHO - see previous page) I feel free to proffer my own - so bear that in mind. Perhaps the modified CF-3 nose gear needs further mods for the sake of testing? As has been pointed out earlier - testing at PaxRiver is rigourous and every part of the aircraft needs to be at best possible state. Stats, that follow the quote below, probably point to why the USN - in particular - is meticulous & cautious about their preparations.
F-35 Joint Strike Fighter (JSF) DOTE Jan 2014
http://www.dote.osd.mil/pub/reports/...nualReport.pdf (48Mb)
______________________
Admiral: China Will Likely Learn Carrier Ropes Faster than U.S. USNI News Editor
Published: May 16, 2013 Updated: March 6, 2014
Admiral: China Will Likely Learn Carrier Ropes Faster than U.S. | USNI News
F-35 Joint Strike Fighter (JSF) DOTE Jan 2014
http://www.dote.osd.mil/pub/reports/...nualReport.pdf (48Mb)
"...F-35C Flight Sciences
Flight Test Activity with CF-1, CF-2, and CF-3 Test Aircraft
• F-35C flight sciences focused on:...
...-- Carrier suitability testing in preparation for the first set of ship trials scheduled for mid-CY14. The program configured aircraft CF-3 with a modified and instrumented nose landing gear system to begin initial catapult testing in August 2013. The test team modified CF-3 with the new arresting hook system and began on-aircraft testing with rolling engagements in late CY13...."
Flight Test Activity with CF-1, CF-2, and CF-3 Test Aircraft
• F-35C flight sciences focused on:...
...-- Carrier suitability testing in preparation for the first set of ship trials scheduled for mid-CY14. The program configured aircraft CF-3 with a modified and instrumented nose landing gear system to begin initial catapult testing in August 2013. The test team modified CF-3 with the new arresting hook system and began on-aircraft testing with rolling engagements in late CY13...."
Admiral: China Will Likely Learn Carrier Ropes Faster than U.S. USNI News Editor
Published: May 16, 2013 Updated: March 6, 2014
Admiral: China Will Likely Learn Carrier Ropes Faster than U.S. | USNI News
"...The U.S. Navy’s education in carrier aviation came at a high price. From 1949 to 1988, “the Navy and Marine Corps lost almost twelve thousand airplanes of all types (helicopters, trainers, and patrol planes, in addition to jets) and over 8,500 aircrew,” according a section of the book “One Hundred Years of U.S. Navy Airpower” by Robert C. Rubel."
Thank you GreenKnight121, I was unaware - GIGO, and yes RP, the knock-on effect of the nosewheel is still down to the duff data.
My apologies to the LM landing gear design team. It isn't an easy job, I know; I had a colleague once who had been on the Concorde landing gear design team
My apologies to the LM landing gear design team. It isn't an easy job, I know; I had a colleague once who had been on the Concorde landing gear design team
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Sorry but, I'm just not buying the argument that the problems with the hook design is entirely down to wonky data supplied by the USN... I'll use very rough and ready analogy, If I want a builder to build me an extension on my house, and I supply him with the 'data' he needs in order to build it, the very least I'd expect, is for him to check my figures/measurements to make sure they are correct! The USN provide the specs, LM provide the design solution (apparently). If the specs are wrong, fair enough, but surely any significant error in the data should be found long before it gets to this stage of development?
As always, I'm more than happy to be proved wrong, after all, everyday is a school day!
-RP
As always, I'm more than happy to be proved wrong, after all, everyday is a school day!
-RP
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I'm unable recall the last aircraft that didn't encounter an issue in the design, development or fielded phase of its usable life.
Probably because such an aircraft has never existed!
The thread title is, 'F-35 cancelled, then what?'. 217 pages and [nearly] 4 years later and the F-35 still isn't cancelled; it's still going strong as a matter of fact. Meanwhile, this thread has morphed into a soapbox for haters and uninformed critics, some of whom purport to be objective. The F-35 isn't perfect (see my initial point) but I'm confident it will be bloody brilliant and a workhorse of our future air forces; long after Typhoon OSD I'd wager.
Probably because such an aircraft has never existed!
The thread title is, 'F-35 cancelled, then what?'. 217 pages and [nearly] 4 years later and the F-35 still isn't cancelled; it's still going strong as a matter of fact. Meanwhile, this thread has morphed into a soapbox for haters and uninformed critics, some of whom purport to be objective. The F-35 isn't perfect (see my initial point) but I'm confident it will be bloody brilliant and a workhorse of our future air forces; long after Typhoon OSD I'd wager.
Maybe I should modify one of my previous posts...
Perhaps the 'C' will be as big a Turkey as the 'B' LOL
I don't buy the blaming the hook problems entirely on the USN either...One has to cross check all the design criteria if designing a system...it has all been done before - the basic design pitfalls should all be fairly well known !
Trouble is many people do not learn from history and historically designing a Jack of all trades a/c is extremely difficult (esp trying to make one version stovl).
Good job the USN have the FA/18 to fall back on - whereas the brits will have a carrier incapable of operating anything else...except maybe some third hand Harriers !!
Perhaps the 'C' will be as big a Turkey as the 'B' LOL
I don't buy the blaming the hook problems entirely on the USN either...One has to cross check all the design criteria if designing a system...it has all been done before - the basic design pitfalls should all be fairly well known !
Trouble is many people do not learn from history and historically designing a Jack of all trades a/c is extremely difficult (esp trying to make one version stovl).
Good job the USN have the FA/18 to fall back on - whereas the brits will have a carrier incapable of operating anything else...except maybe some third hand Harriers !!
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Originally Posted by Fox3
Basic physics ...
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Hmm, interesting pic there CS. My understanding of the engine was that the augmentor (i.e. AB) is inhibited in converted mode with the engine nozzle at a position away from straight aft. If that is the case - and I sincerely hope someone on here can confirm - there might be a bit of Photoshop in that there pic!
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I'm gonna say photoshop, given the MV-22 can fly at ordinary fixed wing aircraft speeds, why on earth would you choose to refuel this way?! The use of afterburner at the speed these would be flying in the pic is BS too I suspect. The MV-22 has done tests, last August, with an F/A-18 and that was done in normal wing-borne flight...
-RP
-RP
The argument has been made that the Navy's data on the wire's behavior - specifically, its recovery after being trampled by the main gear - was faulty and a contributor to F-35 problems.
Up to a point, perhaps. But the Navy data had never been tested by such a configuration in terms of short axle-to-hook distances. It was the designers' responsibility to recognize that they had an outlier configuration.
Up to a point, perhaps. But the Navy data had never been tested by such a configuration in terms of short axle-to-hook distances. It was the designers' responsibility to recognize that they had an outlier configuration.
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Coff, someone has been clever on Photoshop for that one I would suggest!
The Pax jets usually tank from a KC-130 but have tested both KC-10 and KC-135.
As for the issue with CF-3, the aircraft at Pax are considerably more instrumented than test jets in the past. Better to find problems and deal with them early than have nose gear oleo failures after 50 traps or so in service.
The Pax jets usually tank from a KC-130 but have tested both KC-10 and KC-135.
As for the issue with CF-3, the aircraft at Pax are considerably more instrumented than test jets in the past. Better to find problems and deal with them early than have nose gear oleo failures after 50 traps or so in service.
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Didn't a similar problem crop up with the F/A-18A? If I remember the story correctly Hornet number 3 performed an almost flawless series of carrier suitability tests on USS America and then embarrised itself by collapsing one of it's main gear on return to Pax River? That problem was found and fixed very quickly.
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Rhino power & longer ron - the data provided by the USN was for how the wire interacted with aircraft wheels during landing.
Simplistically put, it was the amount of time after the aircraft wheels rolled over the wire (and pushed it to the deck) before the wire had lifted back up to, and remained at, a height where the hook would reliably and consistently "catch" the wire.
LM and NG (and Boeing with the X-32) then did the simple math task of dividing aircraft landing speed by the "lift time", and got a "minimum wheel>hook distance". They then designed the aircraft accordingly.
The only way they could have verified the USN data would be for them to take an aircraft to the USN's land-test facility for arresting gear and duplicate the tests themselves at significant expense (in part because it would interrupt any testing the USN was doing).
This would have had to be done "off-contract" (at LM/NG/Boeing's expense), as the whole reason the USN gave them the data in the first place was to eliminate the need for the contractors to do the tests themselves, and the USN would certainly not pay for them to repeat the tests.
I realize that you have a compulsive need to vilify LockMart, and cannot believe anything that proves they aren't incompetent and stupid, but in this case reality differs from your obsession.
Simplistically put, it was the amount of time after the aircraft wheels rolled over the wire (and pushed it to the deck) before the wire had lifted back up to, and remained at, a height where the hook would reliably and consistently "catch" the wire.
LM and NG (and Boeing with the X-32) then did the simple math task of dividing aircraft landing speed by the "lift time", and got a "minimum wheel>hook distance". They then designed the aircraft accordingly.
The only way they could have verified the USN data would be for them to take an aircraft to the USN's land-test facility for arresting gear and duplicate the tests themselves at significant expense (in part because it would interrupt any testing the USN was doing).
This would have had to be done "off-contract" (at LM/NG/Boeing's expense), as the whole reason the USN gave them the data in the first place was to eliminate the need for the contractors to do the tests themselves, and the USN would certainly not pay for them to repeat the tests.
I realize that you have a compulsive need to vilify LockMart, and cannot believe anything that proves they aren't incompetent and stupid, but in this case reality differs from your obsession.
I am not obsessed by anything GK
But if I were designing a tailhook system - I would be looking at other aircraft and wondering why they have a larger wheel to hook distance...it aint rocket science - it has all been done before,reinventing wheels is ok if one uses some common sense !
LM have fallen into the old trap of trying to make a jack of all trades aircraft out of one airframe - this concept has failed on many occasions in the past !
rgds LR
But if I were designing a tailhook system - I would be looking at other aircraft and wondering why they have a larger wheel to hook distance...it aint rocket science - it has all been done before,reinventing wheels is ok if one uses some common sense !
LM have fallen into the old trap of trying to make a jack of all trades aircraft out of one airframe - this concept has failed on many occasions in the past !
rgds LR
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Guys,
I did get some insight into the arresting hook design during my time on the F-35 programme, and I might be able to help the thread along.
First off - designing combat aircraft is hard. Designing combat aircraft to go to the deck is even harder. Designing a family of aircraft to include a deck landing and a STOVL aircraft - well, it's a big ask. But it wasn't LM's idea- it was the US DoD's strategy for an affordable tactical aircraft programme. LM, NG and Boeing all had to respond to that.
That's a decision that is open to comment and the most robust criticism - that's one of the things about open democracies. And the F-35 programme is one of the most openly reported there's ever been. That's a good thing, but it does lead to what I would respectfully call 'slightly less informed speculation'. In my posts, I try to add information as much as I can. So here goes.
The locations available for the arresting hook were driven by a number of factors, mainly the single engine design, which drives the hook lower down and further forward than on a twin engined aircraft. Modern aircraft have their C of Gs further aft than traditional designs, and going for stealth involves weapons bays - these two factors can drive the main gears aft.
The LM team knew that had a challenge with the arresting gear, and sought not only specifications but also active advice from the USN specialists. There were plenty of risk areas identified in the aircraft by the USN, but the hook system was not high up on the list in the early days.
The prosaic truth is that getting a fast moving aircraft to reliably and safely land by snagging a thin wire on top of a moving deck is one if the harder things to do in aviation. It often takes redesigns and repeated test, and this programme has had to do that. It looks as if thy are on the right track now.
Best regards as ever to all those trying to trap,
Engines
I did get some insight into the arresting hook design during my time on the F-35 programme, and I might be able to help the thread along.
First off - designing combat aircraft is hard. Designing combat aircraft to go to the deck is even harder. Designing a family of aircraft to include a deck landing and a STOVL aircraft - well, it's a big ask. But it wasn't LM's idea- it was the US DoD's strategy for an affordable tactical aircraft programme. LM, NG and Boeing all had to respond to that.
That's a decision that is open to comment and the most robust criticism - that's one of the things about open democracies. And the F-35 programme is one of the most openly reported there's ever been. That's a good thing, but it does lead to what I would respectfully call 'slightly less informed speculation'. In my posts, I try to add information as much as I can. So here goes.
The locations available for the arresting hook were driven by a number of factors, mainly the single engine design, which drives the hook lower down and further forward than on a twin engined aircraft. Modern aircraft have their C of Gs further aft than traditional designs, and going for stealth involves weapons bays - these two factors can drive the main gears aft.
The LM team knew that had a challenge with the arresting gear, and sought not only specifications but also active advice from the USN specialists. There were plenty of risk areas identified in the aircraft by the USN, but the hook system was not high up on the list in the early days.
The prosaic truth is that getting a fast moving aircraft to reliably and safely land by snagging a thin wire on top of a moving deck is one if the harder things to do in aviation. It often takes redesigns and repeated test, and this programme has had to do that. It looks as if thy are on the right track now.
Best regards as ever to all those trying to trap,
Engines