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Subject: F-35 won't work well in hot climates?
reefdiver    4/13/2009 10:57:10 AM
from: link Not necessarily the best source but does bring up some points. Heat management, particulary in light of increasing electronics requirements, has always been a substantial issue for the F-35. excepts from the article: ....will not fly properly in hot weather ...early versions of the showpiece F-35 Lightning II Joint Strike Fighter are ?very limited? in the heat. ...In America, F-35s are only doing limited flying in hot weather while the makers try to fix the problem. ...(the F-35) jets will have limited range and may even have problems landing with weapons on board. That could mean pilots having to dump any bombs that have not been used. ...The F-35 risks overheating because designers want it to be ?stealthy? ? so it won?t show up on enemy radar. That means it can?t have the usual air scoops and vents to cool its engine, since they would show up as infra-red hotspots. So pilots need lots of fuel on board to keep the jet cool, restricting mission range. It is an even bigger headache for the British F-35B jump jet model, which already has less range than other versions because its big fan for hovering takes up a lot of fuel space. Defence Technology International editor-in-chief Bill Sweetman told us: ?JSF in its current form will be very limited in hot-weather performance and modifications intended to fix the problem won?t start to be tested until 2011 or 2012. ?But by that time the UK will be well down the road to building ships that can only operate JSFs.? The Ministry of Defence admits sorting the F-35 for hot weather is ?a demanding task? but insists they are on top of the problem and ?it is not a programme risk?.
 
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reefdiver    link...   4/13/2009 10:58:45 AM
h**p://www.dailystar.co.uk/news/view/76484/RAF-s-blunder-and-lightning/
 
 
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FJV    "Sources" and lazy reporters   4/13/2009 11:21:15 AM
It's those damn "sources" again.
 
Of course the real story is much more " mundane" and has been posted by Softwar:
Source:
"http://www.strategypage.com/militaryforums/6-55638.aspx"
 
F-35 May Need Design Changes for Thermal Management

Aviation Week & Space Technology Mar 30 , 2009 , p. 54

Upgrades to the Lockheed Martin F-35 Lightning II are being considered to improve the fighter?s ability to absorb heat from its powerful electronics and systems.

The aircraft is meeting the specification for thermal management, but the incoming Joint Strike Fighter program executive officer, U.S. Marine Corps Maj. Gen. (sel.) David Heinz, says he is asking contractors to assess the costs of changes to give it a bigger margin over the requirement.

The stealthy F-35 is designed to keep itself cool by dumping heat from the electronics and systems to its fuel. Under most conditions, that presents no challenge, but at the end of a mission the aircraft will have little fuel left to absorb the heat energy, says Tom Burbage, Lockheed Martin executive vice president for F-35 program integration. The toughest part of the specification is to distribute heat to the remaining fuel while operating in hot conditions.

?Thermal problems were first identified in hot-weather ground operations,? says a long-time Pentagon acquisition official. ?The problem was the fuel-air heat exchanger was not providing enough cooling. In the short term, at least, they?ll just limit hot-weather activity.?

As for the article's technical points:
This "huge problem" should be fixable.
 
 
 
 
 
 

 
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PierreLeGrand    Bill Sweetman is anythnig by lazy.   5/11/2009 9:56:48 AM
 
 He is also quiet advanced in terms of knowlegebase and credential.
 
  He highlighted one (more) of F-35 problems and wrote about it, this problem CAN be fixed but it is a weak point.
 
  Anythnig that relies on fuel for cooling increased vulnerability to adverse fire.
 
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DarthAmerica       5/11/2009 12:15:10 PM
This is an interesting trend. No other fighter has gone through development while under real time public scrutiny of this magnitude. No engineering project I've ever seen had gone flawlessly through development to production. This is not some insurmountable problem. Its simply one of many engineering challenges the F-35 and fighters like it face as testing reveals flaws in the original design. These designs are continuously revised and then things move until the product gets to a point where all of the shop stopping critical issues have been resolved and the trivial matters are waived as not serious enough to stop the program from meeting it's intent. People need to understand that and put these issues into context.

-DA 
 
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PierreLeGrand       5/11/2009 12:46:28 PM

This is an interesting trend. No other fighter has gone through development while under real time public scrutiny of this magnitude. No engineering project I've ever seen had gone flawlessly through development to production. This is not some insurmountable problem. Its simply one of many engineering challenges the F-35 and fighters like it face as testing reveals flaws in the original design. These designs are continuously revised and then things move until the product gets to a point where all of the shop stopping critical issues have been resolved and the trivial matters are waived as not serious enough to stop the program from meeting it's intent. People need to understand that and put these issues into context.




-DA 

  Sorry to say but put these issues into context, i did time and time AGAIN...
 
   Untill i got tired of reading that L-M had overshot their weight target by 35%, then limited the aiframes structural loads to compensate then got the aerodynamic wrong and had the same problem with vertical fin structural fatigue than F-18 more than 25 yeares ago, had to fit less stealth material to their main beam, had to reduce steaslth by fitting thinner winf skin, still haven't resolved the aerodynamic issue, didn't meet the 9 g requierement for two versions out of 3, faced electric failures due to bad CATIA design managerment, had engine blade failures etc.
  Tell me, into contest how many protoptype you eared of had so many problems, cost so much even in the US and still failed to meet their requierements because just for the story, these have been lowered since the first major design review.
 
  BTW i can provide you with proper links to well documented articles and interviews on EVERY issue i mentioned and i'm sure i forgot a few...
 
  Regards, PlG
 
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DarthAmerica       5/11/2009 1:19:03 PM




This is an interesting trend. No other fighter has gone through development while under real time public scrutiny of this magnitude. No engineering project I've ever seen had gone flawlessly through development to production. This is not some insurmountable problem. Its simply one of many engineering challenges the F-35 and fighters like it face as testing reveals flaws in the original design. These designs are continuously revised and then things move until the product gets to a point where all of the shop stopping critical issues have been resolved and the trivial matters are waived as not serious enough to stop the program from meeting it's intent. People need to understand that and put these issues into context.










-DA 




  Sorry to say but put these issues into context, i did time and time AGAIN...

 

   Untill i got tired of reading that L-M had overshot their weight target by 35%, then limited the aiframes structural loads to compensate then got the aerodynamic wrong and had the same problem with vertical fin structural fatigue than F-18 more than 25 yeares ago, had to fit less stealth material to their main beam, had to reduce steaslth by fitting thinner winf skin, still haven't resolved the aerodynamic issue, didn't meet the 9 g requierement for two versions out of 3, faced electric failures due to bad CATIA design managerment, had engine blade failures etc.


  Tell me, into contest how many protoptype you eared of had so many problems, cost so much even in the US and still failed to meet their requierements because just for the story, these have been lowered since the first major design review.

 

  BTW i can provide you with proper links to well documented articles and interviews on EVERY issue i mentioned and i'm sure i forgot a few...

 

  Regards, PlG


Again, this is nothing particularly noteworthy with regard to meeting spec. This issue will be worked out, a new one will arise, the internet will run wild with peoples opinions, and sometime in early next decade the US and Allies will be flying around in the best all around fighter in the world. Again, context.

 

-DA
 
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PierreLeGrand    -DA   5/11/2009 1:33:37 PM
 "context".
 
  Sure but a very expensive and timely one, they didnt experienced this with the much more performant F-22.

 

 
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DarthAmerica       5/11/2009 1:42:33 PM

 "context".

 

  Sure but a very expensive and timely one, they didnt experienced this with the much more performant F-22.



Sure they did. Are you not familiar with the recent upgrades they have had to do with the 100+ F-22s that have already made it into the fleet? Things like this happen. Regression issues happen. Of course you try to prevent it. But it doesn't invalidate an entire program.  This is why we hire engineers. Considering the teething problems we've see in past platforms, INCLUDING falling out of the air, this is not something I'm too worried about. The testing done at this state is supposed to find issues like this. I'd be much more concerned about issues that make it through the development/LRIP phase and are only discovered through mishap after FOC.
-DA 

 




 
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PierreLeGrand       5/11/2009 1:48:25 PM




 "context".



 



  Sure but a very expensive and timely one, they didnt experienced this with the much more performant F-22.









Sure they did. Are you not familiar with the recent upgrades they have had to do with the 100+ F-22s that have already made it into the fleet? Things like this happen. Regression issues happen. Of course you try to prevent it. But it doesn't invalidate an entire program.  This is why we hire engineers. Considering the teething problems we've see in past platforms, INCLUDING falling out of the air, this is not something I'm too worried about. The testing done at this state is supposed to find issues like this. I'd be much more concerned about issues that make it through the development/LRIP phase and are only discovered through mishap after FOC.

-DA 





 












The design skill problem is global but with larger companies it is more accute...
 
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DarthAmerica       5/11/2009 1:53:49 PM
Well if you have some LM specific grievance by all means share. Otherwise, this is just another one of those things that happens with programs in development. The only difference is that we have much quicker access to the information. If you have been around long enough and followed other programs then this really isn't a surprise.

-DA 
 
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