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F-35 Cancelled, then what ?

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F-35 Cancelled, then what ?

Old 4th Sep 2014, 14:24
  #5141 (permalink)  
 
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The titanium issue has no direct connection to an engine fire that caused the F-35 fleet to be grounded this spring and miss a pair of major European aerospace shows. The fire, officials concluded, was caused by fan blades rubbing.
The part for which the titanium was used is called a fan-variable vane arm and had already been installed in more than 100 engines. The existing parts are to be replaced during regular maintenance at Pratt & Whitney's cost.

General Bogdan said the natural “flex” of the mishap engine under high-G conditions caused fan blades to “rub” and “dig too deep” in the rubber-like seal around the power plant.

Hmm, may take a little doing to stop the flexing of the engine inside the current flight envelope. Keep in mind the flight envelope has been reduced from what was originally expected and promised.
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Old 4th Sep 2014, 14:30
  #5142 (permalink)  
 
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What really galls me is the lack of proper kit for the UK pilots, surely the MoD can do better to properly outfit their crews, just look, no gloves, non-fire resistant coveralls, and the much hyped sensory helmet looks rather austere.

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Old 4th Sep 2014, 14:47
  #5143 (permalink)  
 
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Just as well it's a sidestick....


returning to the engine issue, won't any "pre-dug-in trench" reduce efficiency and so increase fuel burn?
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Old 4th Sep 2014, 14:50
  #5144 (permalink)  
 
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So much for Lone Ranger's screed - ha ha.
Indeed.

And just so I have it correct, according to Lone Ranger standards, then everyone in the UK is also "arrogant arsewipe" with the Typhoon on display? Or maybe everyone in Germany, Spain and Italy and the UK, since it is a multi-national program? Just curious.


Last edited by sandiego89; 4th Sep 2014 at 15:27.
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Old 4th Sep 2014, 15:00
  #5145 (permalink)  
 
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Apparently the Typhoon is a replica, but to me it looks like the real deal with the ribbons of the safety pins for the weapon systems and landing gear clearly visible, especially from the news footage. Can anybody confirm if it is indeed a replica or a real aircraft?

Second question: How would they get a real fixed wing aircraft in there? At 12 tonnes, I would have thought it's a bit too heavy for the Chinooks? Even if it wasn't, at ~£80 million a piece I'm surprised the RAF would allow that.
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Old 4th Sep 2014, 15:03
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Can anybody confirm if it is indeed a replica or a real aircraft?
If you look at some of the links previously posted in this thread you'll see the replica kit being assembled.

Second question: How would they get a real fixed wing aircraft in there?
They can't, it's a replica.
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Old 4th Sep 2014, 15:10
  #5147 (permalink)  
 
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Originally Posted by Lone_Ranger View Post
Par for the course innit..... It may be a NATO meeting, but only the U S of A has a model of a fighter jet parked on a golf course ..sorry but you really are a nation of arrogant arsewipes
That's pretty funny, considering the source. How about you get back on topic with the thread?

Interesting story on the titanium source and all that, but other than Pratt and Whitney doing the sort of thing that leads to why we require oversight of acquisition contracts, it doesn't seem to have moved the program any closer to being cancelled.

Perhaps its momentum has reached that critical value where nobody could stop it even if they tried.
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Old 4th Sep 2014, 15:26
  #5148 (permalink)  
 
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it doesn't seem to have moved the program any closer to being cancelled.

Perhaps its momentum has reached that critical value where nobody could stop it even if they tried.
I think the cancellation point is well past, with over a 100 now off the line. Remember this thread title started 4 years ago, when the entire program was much more in doubt, but has become the all things F-35 thread. Perhaps a thread retitling is past due, but it seems we have gotten used to it on this forum.
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Old 4th Sep 2014, 15:32
  #5149 (permalink)  
 
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Thanks, MM.
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Old 4th Sep 2014, 15:35
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returning to the engine issue, won't any "pre-dug-in trench" reduce efficiency and so increase fuel burn?
Probably, I think LO pointed out earlier, you could open up the tip clearances but sacrifice engine efficiency. The engine casings are the backbone of the engine. If the casings get too flimsy, backbone bending occurs. When that happens, things like third stage fan rotors (blisks) can rub. IMHO, increasing tip clearance is a Band-Aid, there is a more significant problem to be solved.
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Old 4th Sep 2014, 17:02
  #5151 (permalink)  
 
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What does this do to timelines and in year costs?

As I think many of us feel a solution to the engine problem has yet to be engineered and tested, that is if the real cause of the problem is known. I have read that P&W are going to repair all of the engines that are in existence at the moment, as has been stated well over 100 of them, quite an operation when the solution has yet to be found and the kits to implement the fix designed, produced and distributed prior to installation.

I assume that the Fort Worth production line is at best just making engine less planes, what this does to the in year cost of these LRIP aircraft could be interesting.

With the Marines wanting to declare IOC next year I assume that for this to happen they will have to have their initial squadron aircraft updated, is this really possible?

The carrier trials that the USN have planned for the F35C I suppose could be interesting and slightly prolonged if the engines have to be checked every three hours.

There are of course many other test points that may not be achievable with an aircraft limited as to what it can do.

Another year or so's delay in realistic IOC in my view, it transpires that it was a good move to delay the UK Aircraft Carriers for financial reasons some years ago.
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Old 4th Sep 2014, 17:14
  #5152 (permalink)  
 
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It only counts as a good move if it was done for that reason, which it wasn't. It was a fortuitous move.

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Old 4th Sep 2014, 17:31
  #5153 (permalink)  
 
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Agreed, delaying the entry to service of the QEC Aircraft Carriers due to cash flow considerations now with the benefit of some hindsight looks to have been fortuitous....
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Old 4th Sep 2014, 22:01
  #5154 (permalink)  
 
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What really galls me is the lack of proper kit for the UK pilots
And the skirt is way to long, makes it restrictive when maneuvering during unusual maneuvers.
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Old 5th Sep 2014, 00:07
  #5155 (permalink)  
 
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This seems like a bit of deja vu, all over again .


On the JT9D on the 747 and 767, we had problems with engine bending and compressor case distortion causing excessive tip rub, efficiency loss, and engine surge.


Again on the 747 and 767, the PW4000/94" had problems with compressor case distortion causing excessive tip rub, efficiency loss, and engine surge (it got so bad on the PW4000 that the FAA issued an AD, forcing Pratt to redesign the compressor and retrofit over 2000 engines with new compressors at a cost of several billion dollars).


So, now, on the F135 we have a problem with engine bending and case distortion causing excessive tip rub. Hum, I wonder what the common thread might be


BTW, I like the implication that wasn't that bad because it wasn't the engine that caught fire, it was the ruptured fuel tank. Yea, that makes me feel much better...
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Old 5th Sep 2014, 02:07
  #5156 (permalink)  
 
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Had a scan but couldn't see this posted
The microcracks in the third stage of the integrally bladed rotor that caused a catastrophic F135 engine fire in an F-35A on June 23 began forming three weeks earlier when a pilot conducted a fairly benign maneuver with a unique combination of yaw, roll and g stresses
F-35 Blade Microcracking Began Three Weeks Prior To Engine Fire | Defense content from Aviation Week
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Old 5th Sep 2014, 13:18
  #5157 (permalink)  
 
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Had a scan but couldn't see this posted
Think it's contained in ORAC's post #5143 from yesterday.
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Old 5th Sep 2014, 18:09
  #5158 (permalink)  
 
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Evening all.

F-35 Fire: In Search Of A Solution | Technology content from Aviation Week
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Old 5th Sep 2014, 19:19
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Ooh, now LO, I'm sure someone will come along and patronizingly, pompously, assert that everything is rosy up the '35's ass.
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Old 5th Sep 2014, 19:53
  #5160 (permalink)  
 
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P&W has its say too:

Pratt & Whitney Offers Some F135 Explaining | Defense content from Aviation Week

Makes an interesting compare-and-contrast with their propaganda four-to-five years ago.
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