The Hidden Troubles of the F-35 [DefenseNews]

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spazsinbad

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Unread post25 Apr 2020, 11:54

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lukfi

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Unread post25 Apr 2020, 13:27

So the Navy doesn't consider supersonic flight very important, they are content with not fixing the issue and actually haven't been able to replicate it a second time. Why did they file it as a Category 1 deficiency in the first place?
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geforcerfx

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Unread post25 Apr 2020, 15:41

lukfi wrote:So the Navy doesn't consider supersonic flight very important, they are content with not fixing the issue and actually haven't been able to replicate it a second time. Why did they file it as a Category 1 deficiency in the first place?


The Navy didn't, the JPO did.
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Unread post25 Apr 2020, 16:00

Dragon029 wrote:
commisar wrote:Anyone heard anything regarding this:

It's talked about in the original article that this thread is based on; a single F-35B and a single F-35C, back in somewhere around 2013 or so, in a single flight each, experienced damage to the skin of their tails when using their afterburners for extended periods in order to fly at supersonic speeds and high altitudes, near the edge of their flight envelope. The test team tried to replicate this issue, but to date no other F-35 has ever received that damage.

Because Lockheed and the JPO don't know exactly why the damage occurred (but didn't occur in later tests), they can't guarantee it won't ever happen again, and so it was made into a pair of Category 1 deficiencies (one for the B, one for the C) and a time limit on afterburner usage above certain Mach speeds has been put into place for pilots to abide by when combat doesn't necessitate it (there's no software limited preventing pilots from exceeding time limits if they feel it's necessary). F-35s have also since (back in like 2014 or 2015) received an upgrade to their stealth coating on those tail surfaces that face the afterburner plume, but again, they can't guarantee that this

Neither Lockheed nor the JPO are aware of any materials available today that would meet the stealth and thermal requirements needed to sufficiently guarantee that no harm would come from extended afterburner use, and so ultimately they've decided that it's not worth spending potentially hundreds of millions, or possibly billions of dollars on a wild goose chase for a material that might not yet be feasible.



Thanks for this

Of course this kind of useful information is helpfully OMITTED from most of the junk tier reporting on the F-35.

Unlike here 8)
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Unread post25 Apr 2020, 18:44

I’ve met Bryan. He’s a very bright guy. But he knows as much about fighting jets as I know about fighting submarines.

Those who want to understand more should go back to the beginning of the thread and start with the reporting on ‘hidden troubles’ last summer.
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Unread post25 Apr 2020, 19:01

quicksilver wrote:I’ve met Bryan. He’s a very bright guy. But he knows as much about fighting jets as I know about fighting submarines.

Those who want to understand more should go back to the beginning of the thread and start with the reporting on ‘hidden troubles’ last summer.


Clark’s comments are distinct from the journalist who wrote the article. He is not just another mouthpiece reciting a list of “hidden troubles”. His comments specifically address the importance or otherwise of supersonic speeds to the effectiveness of how the F-35 will typically operate. Smart guys, particularly defense analysts, who don’t know anything about a topic should talk to those that do and form opinions accordingly. It isn’t who he is that is the issue but what he is saying. Is he wrong? If so why is he wrong?
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Unread post25 Apr 2020, 19:07

lukfi wrote:So the Navy doesn't consider supersonic flight very important, they are content with not fixing the issue and actually haven't been able to replicate it a second time. Why did they file it as a Category 1 deficiency in the first place?


Here’s generally how it goes — some years ago, DT pilot flies jet (in pursuit of some kind of supersonic test point(s)). Jet returns with damage to horizontal stab(s). Pilot writes test report for the flight, noting said damage. Confers w multi-discipline engineering team, they review the data, put into motion an EI (engineering investigation) to determine root cause and corrective action. Somewhere in this there is collective agreement that the problem and potential consequences are worthy of Cat 1 kind of problem.

At some point — after years of engineering work by some of the brightest and most experienced materials and aero guys in the world — they determined that the juice was not worth the cost of the squeeze. They’ve apparently chosen operational workarounds, the exact nature of which we do not know.
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Unread post25 Apr 2020, 19:11

aussiebloke wrote:
quicksilver wrote:I’ve met Bryan. He’s a very bright guy. But he knows as much about fighting jets as I know about fighting submarines.

Those who want to understand more should go back to the beginning of the thread and start with the reporting on ‘hidden troubles’ last summer.


Clark’s comments are distinct from the journalist who wrote the article. He is not just another mouthpiece reciting a list of “hidden troubles”. His comments specifically address the importance or otherwise of supersonic speeds to the effectiveness of how the F-35 will typically operate. Smart guys, particularly defense analysts, who don’t know anything about a topic should talk to those that do and form opinions accordingly. It isn’t who he is that is the issue but what he is saying. Is he wrong? If so why is he wrong?


Without getting into tactics, characterization of supersonic flight as a ‘break glass...’ capability is wrong. Else why would it be so important to F-22 — which is also ‘stealthy.’
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Unread post25 Apr 2020, 19:30

Ref ‘operational workarounds’ — sometimes problems that were ‘deficiencies’ in flight test, become ‘caution’ or ‘warning’ or limitation entries NATOPS. We don’t know and aren’t likely to find out.
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geforcerfx

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Unread post25 Apr 2020, 20:13

quicksilver wrote:
Without getting into tactics, characterization of supersonic flight as a ‘break glass...’ capability is wrong. Else why would it be so important to F-22 — which is also ‘stealthy.’


Couldn't one argue that the F-35 and F-22 were designed with different main mission focus in mind, F-35 affordable strike fighter, F-22 top performance air supremacy aircraft?

Like you said earlier though we don't know the full restrictions is this a limited afterburner above 40,000ft thing like where the incidents happened? Or is this a anytime the Jets are above Mach 1.2 they are limited to 60 seconds of burner no matter the altitude. If it's the high altitude limitation I agree it's impact on the vast majority of the F-35 B & Can missions is insanely small. Also with it only affected the B & C that means 75% of the fleet still has no restrictions. I guess without knowing the full details of the limitations we will never know how gimped the time limit is. But looking at the F-35B which only has enough fuel for around 15min at full burner with Max internal a 60 second limit at altitude doesn't seem as limiting.
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Unread post25 Apr 2020, 20:22

“We don’t know and aren’t likely to find out.“
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lukfi

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Unread post25 Apr 2020, 21:41

geforcerfx wrote:Couldn't one argue that the F-35 and F-22 were designed with different main mission focus in mind, F-35 affordable strike fighter, F-22 top performance air supremacy aircraft?

In the past, the Navy had its own air superiority fighters, namely F-4 and F-14. I doubt they would just give up that ability. They may not always be backed up by F-22s from a nearby ground base.
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Unread post25 Apr 2020, 22:12

lukfi wrote:
geforcerfx wrote:Couldn't one argue that the F-35 and F-22 were designed with different main mission focus in mind, F-35 affordable strike fighter, F-22 top performance air supremacy aircraft?

In the past, the Navy had its own air superiority fighters, namely F-4 and F-14. I doubt they would just give up that ability. They may not always be backed up by F-22s from a nearby ground base.

They haven't had a dedicated fighter ever since the F-14 was retired...
If the F-18 is good enough for the job, so is the F-35. End of story.
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Unread post25 Apr 2020, 22:27

DefNews RECYCLE their shite news all the time with some retorters notorious for doing so. An example from the past:

viewtopic.php?f=22&t=55673&p=421722&hilit=extremely#p421722
________________________________________________________

ASLO (yes I know) go here: viewtopic.php?f=22&t=55673&p=421684&hilit=comments#p421684
wot references:
Lockheed Martin Comments on Defense News Reporting 12 Jun 2019 LM PR
https://www.f35.com/news/detail/lockhee ... -reporting
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Unread post26 Apr 2020, 09:02

The lemon is squeezed to turn molehills into mountains and it ain't finished yet the mountain has to come to whomever.
Five F-35 issues have been downgraded, but they remain unsolved
24 Apr 2020 Aaron Mehta, Valerie Insinna, and David B. Larter

"WASHINGTON — The F-35 Joint Program Office has put in place stopgap fixes for five key technical flaws plaguing America’s top-end fighter jet, but the problems have not been completely eliminated. Last June, Defense News reported exclusive details about 13 major technical issues, known as category 1 deficiencies, impacting the F-35. The JPO has since quietly downgraded five of those issues to the lesser category 2....

...Aside from a few basic statements on which projects were downgraded to CAT 2, a JPO spokesperson said the office “cannot disclose any information about how these deficiencies were resolved or downgraded due to their security classification.”… [then some lahdedah about some of 'em]

The F-35B and F-35C experienced incongruous lateral and longitudinal control response above a 20-degree angle of attack.
One of the most eye-opening issues identified in the initial report was that the F-35B and F-35C models used by the Marine Corps and Navy become difficult to control when operating above a 20-degree angle of attack — which would be seen in the extreme maneuvers a pilot might use in a dogfight or while avoiding a missile. Pilots reported the aircraft experiencing unpredictable changes in pitch, as well as erratic yaw and rolling motions when coming in at that angle of attack..

“It has random oscillations, pitch and yaw issues above [its] 20-[degree angle of attack]," a longtime naval aviator told Defense News last year. "[So] if I had to perform the aircraft — if I had to maneuver to defeat a missile, maneuver to fight another aircraft, the plane could have issues moving. And if I turn around aggressively and get away from these guys and use the afterburner, [the horizontal tail and tail boom] start to melt or have issues.”

The issue was important enough that it accounted for two CAT 1 issues, one each for the two variants impacted by the design issue. However, the JPO downgraded this issue to a CAT 2 on May 28, 2019, for the F-35C and on July 8, 2019, for the F-35B. The solution involves “improvements in flying qualities that were implemented in software. The improvements provide pilots with an intuitive reference indication for AOA [angle of attack], which allows pilots to more quickly optimize lateral maneuvering during air-to-air maneuvering. These software improvements have been released to all F-35 operators.”

There were unanticipated thrust limits in jetborne flight on hot days. [earlier story 12 Jun 2019: https://www.defensenews.com/air/2019/06 ... ironments/ ]
This particular issue only occurred once, but was so significant that it was identified in the original document as the “No. 1 priority” for the Marine Corps. The issue was identified aboard the amphibious assault ship Essex, where a Marine pilot performed what is known as a “mode four” [STOVL] operation.

The engine — working hard on a day [the little engine that could - I think I can I think I can I think I can] that temperatures cracked 90 degrees Fahrenheit while trying to lift a plane that was heavier than most returning to base — wouldn’t generate the needed thrust for a safe, ideal landing. The pilot managed to land, but the issue set off alarm bells in the Marine aviation community.

The JPO initially expected a fix for this issue to be out sometime in 2019, but it wasn’t until March 2020 that a mix of nondescript “software updates and procedural adjustments” brought the “propulsion system performance back to original specified performance levels.” [phew]

Source: https://www.defensenews.com/smr/hidden- ... -unsolved/
Last edited by spazsinbad on 26 Apr 2020, 09:23, edited 1 time in total.
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