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kanban
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F-35 Structural Cracking Still Being Resolved

Tue Sep 06, 2011 6:20 pm

According to http://www.flightglobal.com/blogs/th...an-a-new-structural-crack-sug.html , one of the structural forgings is cracking at 1/10th the designed service life..

The bad news just keeps coming.. Even though they think they have a fix for the next production lot, replacing this forging will not be easy. Or we will have some very expensive museum show pieces.
 
GST
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RE: F-35 Structural Cracking Still Being Resolved

Tue Sep 06, 2011 7:26 pm

Quoting kanban (Thread starter):
Or we will have some very expensive museum show pieces.

This is a flight test program, the test aircraft are fully expected to be put through hell in the hunt for under performing parts and systems. All this story says is that the flight tests are succeeding in flushing out as many issues as possible to be fixed before EIS.
 
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kanban
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RE: F-35 Structural Cracking Still Being Resolved

Tue Sep 06, 2011 8:14 pm

Yes it was caught during the flight/structural test part of the program.. However, the disparity between design and actual is substantial and, like the 787, they are grinding more and more copies with the discrepancy.
 
ThePointblank
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 07, 2011 1:57 am

Quoting kanban (Reply 2):
Yes it was caught during the flight/structural test part of the program.. However, the disparity between design and actual is substantial and, like the 787, they are grinding more and more copies with the discrepancy.

They actually knew about the cracking issue well before the flight test program started, but they decided to press on because they wanted real world data for analysis. This issue only affects the A and B models, not the C model as the C model has a different wing, and beefier structure for carrier landings.

The new modified forward root rib design will be incorporated into production planes from the beginning of Low Rate Initial Production (LRIP) Lot 5 for both F-35A and B aircraft. A total of 64 F-35A and B's will need to be modified to fly for their full fatigue life. The modifications will be done during the Block 3 upgrade to reduce downtime, which is in any case a major scheduled overhaul period.

The Boeing 787 had a wing problem as did the Airbus A380; it's actually quite a common problem in aicraft testing. In fact if you are not running into problems when testing, it means that probably means you over designed and over built the airplane which is a bad thing in aviation. Inevitably the F-35 is going to have a few more problems show up in testing which of course is the reason why they test airplanes in the first place.
 
Oroka
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 07, 2011 5:28 am

BREAKING NEWS! EXTREMELY COMPLICATED FIFTH GENERATION STEALTH FIGHTER JET NEEDS DESIGN TWEAKS AFTER NOT BEING PERFECT ON FIRST TRY! LOCKHEED HIRES TELEPATHS AND PSYCHICS TO COMBAT NOT BEING ABLE TO SEE FUTURE EFFECTIVELY.

IN OTHER NEWS, CITY BANS DIHYDROGEN MONOXIDE BECAUSE IF INHALED IN QUANTITY, IT CAN CAUSE ASPHYXIA BY PREVENTING THE ABSORPTION OF O2 LEADING TO CEREBRAL HYPOXIA!


MORE AT 7!

[Edited 2011-09-06 22:32:05]
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 07, 2011 6:16 am

Quoting Oroka (Reply 4):

With the program being this many years late and over budget...nothing about the program is 'the first try' anymore. Since wings have been around as long as airplanes, one might assume that these 'psychics' perhaps should have stuck to structural engineering...or just pouring over the designs of some of the other hundreds of jet fighters to grasp a clue as to the strength of materials required for the proposed tasks.

Underdesign and overpromise...the miracle that is the F-35. Will it still be state of the art when it finally enters service? Remember back when wood was state of the art structural material...? Ah...those were the good old days.

I wonder if this metal stuff for structure in aircraft fad will ever catch on...
What the...?
 
ThePointblank
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 07, 2011 7:35 am

Quoting JoeCanuck (Reply 5):
With the program being this many years late and over budget...nothing about the program is 'the first try' anymore. Since wings have been around as long as airplanes, one might assume that these 'psychics' perhaps should have stuck to structural engineering...or just pouring over the designs of some of the other hundreds of jet fighters to grasp a clue as to the strength of materials required for the proposed tasks.

You cannot just lift designs off older aircraft for newer aircraft. Everytime you design an aircraft, you have to essentially start fresh. Every new aircraft design in recent memory has had design issues that cropped up during testing, the non-exhaustive list includes the A380's destructive wing test failure, the Boeing 787's software issues, the F-22's oxygen generator issues, the F/A-18's vertical stabilizer cracking, the F-16's fuel-control valve issues, the F-4's intake issues... may I go on?

It's better that we find about these issues NOW during testing, rather than later. For example, on the F-22, 101 F-22's have defective titanium forgings in the rear fuselage, which could lead to premature structural failure. They only found out about this until after those birds were built. On the F/A-18, they discovered well after production commenced that there was fatigue cracking on the vertical stabilizers, which was traced to excessive loads placed on the twin tails by the vortices streaming from the large wing leading-edge extensions. They fixed that by installing a cast-aluminum fence on the LEX to modify the vortex pattern and alleviate the stress on the tailplane, plus structural stiffening of the vertical stabilizers.
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 07, 2011 8:54 am

Quoting ThePointblank (Reply 6):
You cannot just lift designs off older aircraft for newer aircraft. Everytime you design an aircraft, you have to essentially start fresh. Every new aircraft design in recent memory has had design issues that cropped up during testing, the non-exhaustive list includes the A380's destructive wing test failure, the Boeing 787's software issues, the F-22's oxygen generator issues, the F/A-18's vertical stabilizer cracking, the F-16's fuel-control valve issues, the F-4's intake issues... may I go on?

Sure you can when it's been done on every plane since the Wright brothers. What failed was basic structures, using known materials on an aircraft where the stresses were also known and they failed in one fifth the design time...so they made it to 20% of the design goals. That's not a percent or two like the 380 wing, or fatigue after decades of hard service like the F-18.

This is a major cockup...one fifth of the stated design goal? Even the most rabid and enthusiastic F-35 apologist should at least be embarrassed by this.

When was the last time an aircraft program failed by 80%?
What the...?
 
ThePointblank
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 07, 2011 1:26 pm

Quoting JoeCanuck (Reply 7):
Sure you can when it's been done on every plane since the Wright brothers. What failed was basic structures, using known materials on an aircraft where the stresses were also known and they failed in one fifth the design time...so they made it to 20% of the design goals. That's not a percent or two like the 380 wing, or fatigue after decades of hard service like the F-18.

No you can't. Each design is totally unique and different. The structural loads are different from aircraft to aircraft. You don't want to overbuild aircraft because if you did, the engineer did something wrong, and cut into payload and range to do so. You are obviously not a structural or aviation engineer to understand this.

And the F/A-18 vertical stabilizer cracking? It happened right after IOC, and dogged the initial batches of the F/A-18, leading to a grounding of the type in the 1980's until they could figure out what was going on.
 
Oroka
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 07, 2011 6:35 pm

Quoting JoeCanuck (Reply 5):
With the program being this many years late and over budget...nothing about the program is 'the first try' anymore.

So exactly how many times have they reached the 1/10th fatigue life mark again? I would think this is probably one of the areas they shaved weight off of from the first batch of jets.

Better than finding say... defective stringers in say... F-15s 30 years after the fact.
 
wvsuperhornet
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 08, 2011 6:39 am

Quoting JoeCanuck (Reply 7):
When was the last time an aircraft program failed by 80%?

Dont laugh I wouldn't be suprised if it doesnt go higher with this never ending money pit.
 
jollo
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 08, 2011 10:06 am

Quoting Oroka (Reply 4):
IN OTHER NEWS, CITY BANS DIHYDROGEN MONOXIDE BECAUSE IF INHALED IN QUANTITY, IT CAN CAUSE ASPHYXIA BY PREVENTING THE ABSORPTION OF O2 LEADING TO CEREBRAL HYPOXIA!

Choked laughing too hard... I'll have to absorb some dihydrogen monoxide myself to restore ventilation! I'll report back if I survive this controversial procedure...

 
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Fri Sep 09, 2011 10:34 pm

Quoting ThePointblank (Reply 8):

No you can't. Each design is totally unique and different. The structural loads are different from aircraft to aircraft. You don't want to overbuild aircraft because if you did, the engineer did something wrong, and cut into payload and range to do so. You are obviously not a structural or aviation engineer to understand this.

No I'm not...but thanks for assuming that only aviation structural engineers could possibly understand these concepts. It seems, though, that the aviation engineers assigned to the F-35 are also having some trouble with the concepts.

Let's just go over what they did know, shall we?

They knew the weight of the plane. They knew the characteristics of the materials. They knew the flight regimes and the contrary to your assertion, they actually do know the structural loads that would be imposed on the plane. The plane is specifically designed to withstand the maximum structural loads.

They knew all of this yet the components started cracking in one fifth the calculated time...ONE FIFTH. How is that not a failure?

Other planes failed so that makes it ok for the F-35 to fail? Talk about setting the bar low. They suck so we can suck too...great philosophy.

Sure...there have been other failures in other fighters...but these were designed 30 years ago...yet, it seems the folks doing the F-35 not only failed to achieve design goals by an amazingly large margin, (those amazing aircraft engineers again), using the absolutely most modern and highest tech available design and manufacturing techniques, they failed to learn from failures of the past.

Apparently pigs can fly...occasionally.
What the...?
 
ThePointblank
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 10, 2011 1:56 am

Quoting JoeCanuck (Reply 12):
They knew the weight of the plane. They knew the characteristics of the materials. They knew the flight regimes and the contrary to your assertion, they actually do know the structural loads that would be imposed on the plane. The plane is specifically designed to withstand the maximum structural loads.

The thing is that although you can make assumptions regarding load and structural strength, you can't be 100% certain. While today's technology and simulations can help engineers design structures, they are not perfect. Engineers have to walk a very fine line between sufficient structural strength and excessive weight. You don't overbuild aircraft beyond what is necessary because you cut into performance and capability. It is a very fine line to walk, and each instance is different.
 
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kanban
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 10, 2011 4:07 am

Interesting, a post on the Flightglobal site indicates this was suposed to be a titanium bulkhead, but because of weight problems they substituted aluminium.. can anybody verify that assertion..
 
GST
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 10, 2011 9:16 am

Quoting JoeCanuck (Reply 12):

They knew the weight of the plane. They knew the characteristics of the materials. They knew the flight regimes and the contrary to your assertion, they actually do know the structural loads that would be imposed on the plane. The plane is specifically designed to withstand the maximum structural loads.

In addition to ThePointblank's comments, it is very different task to design for ultimate loads, and by all accounts they suceeded at that, than it is to design for fatigue degredation.

We do have fancy computational fluid dynamics to ascertain what aerodynamic loads go onto the aircraft in different areas. The answer you get is always flawed because the computational power to carry out the accuracy of calculations that we would like so we have to simplify the calculations either by idealising variables or lowering the resolution of the solution. The same goes for the computerised tools used to analyse structures once we know what loads go into them. These are also relatively new tools and at the forefront of R&D, there is much we would like to do but cannot as of now, and somehow confirming that everything will work exactly as we plan or expect is one of them. This is why we have thorough testing of aircraft before EIS.
 
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 10, 2011 9:47 am

Quoting ThePointblank (Reply 8):
The structural loads are different from aircraft to aircraft. You don't want to overbuild aircraft because if you did, the engineer did something wrong, and cut into payload and range to do so. You are obviously not a structural or aviation engineer to understand this.

I am a structural engineer and if I missed my design target by 80% I'd be sacked. I know what you are saying about an over-design being as big a mistake as an under design, especially in Aviation but this shows that the model being used has some serious parameter errors.

Quoting kanban (Reply 14):
Interesting, a post on the Flightglobal site indicates this was suposed to be a titanium bulkhead, but because of weight problems they substituted aluminium.. can anybody verify that assertion..

If that is the case then its even worse. Titanium is all but fatigue proof for the design life of an airframe. Aluminium needs real attention to design in the fatigue case (think of the Comet). That would have been a big call by someone, Engineer or Project Manager?
 
Oroka
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 10, 2011 1:36 pm

Quoting spudh (Reply 16):
That would have been a big call by someone, Engineer or Project Manager?

Most likely someone that was replaced long ago in a shuffle. My guess is that this change was made as a stop gap measure to keep the program rolling and would be corrected at a later time.

Quoting JoeCanuck (Reply 12):
Sure...there have been other failures in other fighters...but these were designed 30 years ago...yet, it seems the folks doing the F-35 not only failed to achieve design goals by an amazingly large margin, (those amazing aircraft engineers again), using the absolutely most modern and highest tech available design and manufacturing techniques, they failed to learn from failures of the past.

Sounds like you think this is the future we were told about 30 years ago. I still dont have my flying car  

You can plan, calculate, test, rinse and repeat the numbers, but you still have to test the real thing in real world conditions. That is what flight test programs are for... designs are just ideas, that might not always work out. Nature has a way of making the best formulated plans land on their head.
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Sun Sep 11, 2011 2:46 am

Quoting Oroka (Reply 17):

Yes, I understand the concepts and limitations of designing and why they are tested before entering service. What we are talking about here are knowns, not anything to do with the exotic stealth areas or nifty engine design, bleeding edge communication and avionics or state of the art fly by wire....this is aluminum in an aircraft structure...failing at one fifth of its design life.

I understand why the nifty new stuff causes delays, (not accept them), but aluminum has been used in aircraft primary structures for the better part of a century. It's fatigue properties are quite well understood by now...or should be. So not only did they replace the designed for materials, they improperly designed the materials they used to replace them.

Somebody or a bunch of people, dropped the ball huge with this one. At some point, excuses have to stop being made for this project and the people running it. Why people are still apologising for the goofs running this project is beyone me. When is enough, enough?

Aluminum bulkheads have been state of the art for quite some time and have been used in thousands of aircraft...if they can screw this up, what next?

If aluminum is so hard to design for, why aren't planes falling out of the skies like hail? If anything commercial airlines have even more interest in getting as close to the perfect strength to weight ratio than the military since airlines have to buy their own gas, and they sure as hell go through a lot more flight cycles.
What the...?
 
connies4ever
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RE: F-35 Structural Cracking Still Being Resolved

Sun Sep 11, 2011 2:57 am

Quoting GST (Reply 15):
We do have fancy computational fluid dynamics to ascertain what aerodynamic loads go onto the aircraft in different areas. The answer you get is always flawed because the computational power to carry out the accuracy of calculations that we would like so we have to simplify the calculations either by idealising variables or lowering the resolution of the solution. The same goes for the computerised tools used to analyse structures once we know what loads go into them. These are also relatively new tools and at the forefront of R&D, there is much we would like to do but cannot as of now, and somehow confirming that everything will work exactly as we plan or expect is one of them. This is why we have thorough testing of aircraft before EIS.

I'd respectfully disagree with those statements. I work in the CFD field (one dimensional Navier-Stokes equation set) and our answers are extremely close to what the lab tests show, and are used in licensing nuclear reactors -- so accuracy is kind of important. Same goes for load calculating tools. Don't forget the Shuttle was designed using software tools basically developed in the 60s, and they seemed to get those values right.
Nostalgia isn't what it used to be.
 
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kanban
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RE: F-35 Structural Cracking Still Being Resolved

Sun Sep 11, 2011 3:12 am

Quoting GST (Reply 15):
We do have fancy computational fluid dynamics to ascertain what aerodynamic loads go onto the aircraft in different areas. The answer you get is always flawed because the computational power to carry out the accuracy of calculations that we would like so we have to simplify the calculations either by idealising variables or lowering the resolution of the solution. The same goes for the computerised tools used to analyse structures once we know what loads go into them.


My first thought was here is someone still dealing with punch cards.. Then I realized that it's someone trying to learn. Boeing/LM/etc. have computing capability beyond most schools. They have access to NASA computing as well. They can factor in all the variables very accurately predict the results. The problem is sometimes there is an error in the input that nobody catches because the results look so good and are within the rough estimate. It happens. That's why they recheck and recheck.
Now if we could substatiate that someone did a one for one material swap using the same molds and dies, they probably will have a short career. This wasn't an computing power problem it was an input problem.
 
connies4ever
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RE: F-35 Structural Cracking Still Being Resolved

Sun Sep 11, 2011 8:24 am

Quoting kanban (Reply 20):
The problem is sometimes there is an error in the input that nobody catches because the results look so good and are within the rough estimate. It happens. That's why they recheck and recheck.

That is exactly why I insist on an independent review of all input data for any given simulation: to eliminate as far as possible an input error. It's nice being the boss.  
Nostalgia isn't what it used to be.
 
Oroka
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RE: F-35 Structural Cracking Still Being Resolved

Sun Sep 11, 2011 8:06 pm

Quoting JoeCanuck (Reply 18):
Aluminum bulkheads have been state of the art for quite some time and have been used in thousands of aircraft...if they can screw this up, what next?

From what I read, this part was originally titanium. Someone fudged with the switch up, probably trying to save weight.
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Sun Sep 11, 2011 11:22 pm

Quoting Oroka (Reply 22):
From what I read, this part was originally titanium. Someone fudged with the switch up, probably trying to save weight.

I'm not sure if that makes it better or worse. One cockup after another...does it really matter who actually screwed up at this point?
What the...?
 
Oroka
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RE: F-35 Structural Cracking Still Being Resolved

Sun Sep 11, 2011 11:46 pm

It just says at some point someone made the decision to swap the titanium for aluminum, probably fully knowing the aluminum would not hold up, but by doing so, helped remove the weight that was need to get the program moving. The test frames will be retired after testing is done, so were never needed to have a full life. It has been stated that Lockheed has know about this problem for quite a while, and in fact, the aluminum held up longer than expected.

What is really going on here is the public has just learned of this, and is something for the anti F-35 people to dump on.

Everyone will get the F-35, over budget and late, but they will still get it.
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Mon Sep 12, 2011 3:36 am

Quoting Oroka (Reply 24):

Sadly, you are probably right.
What the...?
 
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Dreadnought
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RE: F-35 Structural Cracking Still Being Resolved

Mon Sep 12, 2011 9:31 pm

I just wanted to point out that the P-51, arguably the greatest fighter of it's era, took 178 days from concept through design, construction and first flight.

Now i know that planes are a bit more complicated now. But 20 freakin' years???

The last privately funded fighter design that I can think of was the Northrop F-20 Tigershark. It took only 2 years from concept to first flight, but then ran into the BS at the DoD and Congress that ended up killing the program, in spite of the F-20 being a superb little fighter.

It seems to me that the biggest problem seems to be the Federal procurement process, which does not give the manufacturer any incentive to do the job quickly and effectively. If Boeing or Lockheed had to build an F-35 or F-22 type plane from scratch, and on their own dime, I highly doubt it would take so long.
Forget dogs and cats - Spay and neuter your liberals.
 
Oroka
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RE: F-35 Structural Cracking Still Being Resolved

Tue Sep 13, 2011 1:16 am

Roll in stealth, ever increasing demands for lighter jets, greater range, super cruise, thrust vectoring, not to mention AESA, advanced inter-communications, new engines...

Modern jets are like comparing a old Volkswagen Beetle to a McLaren MP4-12C, in 1940. There was very little new technology in the P-51, some new shapes... it wasnt even that effective until the introduction of the Meriln 60 engine where it became the fighter we remember now.
 
redflyer
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RE: F-35 Structural Cracking Still Being Resolved

Tue Sep 13, 2011 9:41 pm

Quoting Dreadnought (Reply 26):
The last privately funded fighter design that I can think of was the Northrop F-20 Tigershark. It took only 2 years from concept to first flight, but then ran into the BS at the DoD and Congress that ended up killing the program, in spite of the F-20 being a superb little fighter.

I think the F-20 was based on an existing design, the F-5, which would account for the relatively short development cycle time. Nonetheless, your point about the excruciating long development time at the hands of the Feds is well taken. While I think it would take more than 2 years to privately develop a superiority fighter, only the government can stretch such a program out to 20 years. In comparison, it took us less than a decade to develop the technology get to the Moon (ironically, that was a government controlled program!).
My other home is in the sky inside my Piper Cherokee 180.
 
connies4ever
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RE: F-35 Structural Cracking Still Being Resolved

Tue Sep 13, 2011 11:06 pm

Quoting redflyer (Reply 28):
I think the F-20 was based on an existing design, the F-5, which would account for the relatively short development cycle time. Nonetheless, your point about the excruciating long development time at the hands of the Feds is well taken. While I think it would take more than 2 years to privately develop a superiority fighter, only the government can stretch such a program out to 20 years. In comparison, it took us less than a decade to develop the technology get to the Moon (ironically, that was a government controlled program!).

It only took 4 years, more or less, to develop the atomic bomb.

It only took 2 years, more or less, to plan, develop and deliver the required equipment and personnel, and actually implement the largest seaborne invasion of all time: D-Day.

Ironically, both were government programs.

I find it passing strange that so many Americans (and increasing numbers of Canadians, to be fair) have formed this idea, which is patently wrong, that governments are incapable of anything.

The internet, satellites, programmable computers, and on and on. All government. Go figure...
Nostalgia isn't what it used to be.
 
bennett123
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 14, 2011 9:14 am

I think that suggesting that the F20 is a modified F5 is off the mark.
 
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Dreadnought
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 14, 2011 12:05 pm

Quoting connies4ever (Reply 29):
Ironically, both were government programs.

I find it passing strange that so many Americans (and increasing numbers of Canadians, to be fair) have formed this idea, which is patently wrong, that governments are incapable of anything.

We are talking about the Federal procurement program since the late 60s/70s. I guess the last fighter planes that were accepted into service that had a somewhat reasonable gestation period were the F14 and F16, which both took well under a decade.
Forget dogs and cats - Spay and neuter your liberals.
 
Oroka
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 14, 2011 3:09 pm

Quoting Dreadnought (Reply 31):
I guess the last fighter planes that were accepted into service that had a somewhat reasonable gestation period were the F14 and F16, which both took well under a decade.

While true, they were also developed during the cold war, there was an urgency there. The F-22 and F-35 are having a hard time being justified being built at all. Also, consider what was being asked of these fifth gen jets. They were meant to completely outclass EVERYTHING in the world, with new technology AND stealth. The F-14, F-16, F-16, F/A-18 were only intended to be somewhat superior. Anyone who though it would be anywhere close to being relativity affordable is a fool.
 
baroque
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RE: F-35 Structural Cracking Still Being Resolved

Wed Sep 14, 2011 10:08 pm

Quoting connies4ever (Reply 29):
I find it passing strange that so many Americans (and increasing numbers of Canadians, to be fair) have formed this idea, which is patently wrong, that governments are incapable of anything.

   That is enough to raise me from my overwork and manga mousse induced torpor in Porto!! Most of the reason for gubmints not doing anything very splendid of late is the "private industry does it better, quicker and cheaper" model. If you do not like the F-35 try any of the PPP partnerships in Aus building roads. One of them might not have gone bankrupt after getting incredibly favourable conditions such as closing alternative roads.

The SE5 held its own in its day. Perhaps the private constructors need a bit of real competition instead of a nice duopoly.
 
bennett123
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 7:58 am

There are those who suggest building more F22, rather than the F35.

However, with the final F22 being built in 2012, this option will soon be gone.
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 1:25 pm

Quoting connies4ever (Reply 29):
I find it passing strange that so many Americans (and increasing numbers of Canadians, to be fair) have formed this idea, which is patently wrong, that governments are incapable of anything.

What they are incapable of doing, (in recent years at least), is funding a program which is completed anything close to on time or on budget...or on spec...until they work out the bugs in service...if they ever do.

I don't understand why they even bother with a bidding process. Contracts mean nothing and government does nothing to protect the taxpayer from cost overruns.

What we get are excuses from government, contractors and the military...and, of course, higher taxes to pay for the privilege.

I find it strange that more people don't protest these blatant wastes of their money. Accountability...? nah..that's something we tell the suckers who pay the taxes.
What the...?
 
connies4ever
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 1:48 pm

Quoting JoeCanuck (Reply 35):
What we get are excuses from government, contractors and the military...and, of course, higher taxes to pay for the privilege.

I find it strange that more people don't protest these blatant wastes of their money. Accountability...? nah..that's something we tell the suckers who pay the taxes.

At least you're not bitter ...  Wow!
Nostalgia isn't what it used to be.
 
redflyer
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 3:24 pm

Quoting connies4ever (Reply 29):
It only took 4 years, more or less, to develop the atomic bomb.

It only took 2 years, more or less, to plan, develop and deliver the required equipment and personnel, and actually implement the largest seaborne invasion of all time: D-Day.

Ironically, both were government programs.
Quoting connies4ever (Reply 29):
The internet, satellites, programmable computers, and on and on. All government.

Interesting observation - and all of it correct. What is even more interesting is that all of those were borne out of a need of necessity in the midst of war (including the Cold War). Only governments fight wars and that is the one realm in which a government is efficient at.  
My other home is in the sky inside my Piper Cherokee 180.
 
474218
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 3:47 pm

So cracking was found, that is why they test aircraft!

A lot of people on a.net love the C-17, but they must have forgot, or never knew, that the C-17 wing failed the static test and during the redesign the program ran way over budget was very close to being cancelled!
 
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kanban
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 3:52 pm

Quoting 474218 (Reply 38):
So cracking was found, that is why they test aircraft!


It's not the cracking itself that's the worry, it's how early in the designed life it occurred. What else will fail in under 20% of the design requirement?
 
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 4:04 pm

Quoting kanban (Reply 39):
It's not the cracking itself that's the worry, it's how early in the designed life it occurred. What else will fail in under 20% of the design requirement?

Since we know nothing more than a bulkhead failed. What we don't know is why it failed.

Was there an inclusion in the forging, Was there a swarf cut left from machining? Was the a miss drilled hole or a hole that didn't get cold worked properly?
 
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 9:42 pm

Quoting 474218 (Reply 40):
Was there an inclusion in the forging, Was there a swarf cut left from machining? Was the a miss drilled hole or a hole that didn't get cold worked properly?

Wouldn't those be just as egregious as a failure to properly design the part? These are production aircraft and everything about the construction process has to be just as precise as the design itself. To imply that the design is sound but that something in the production cycle caused the problem is not really diminishing the extent of the problem.

I'm just saying...
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RE: F-35 Structural Cracking Still Being Resolved

Thu Sep 15, 2011 10:14 pm

Quoting redflyer (Reply 41):
Wouldn't those be just as egregious as a failure to properly design the part?

No because those are one off errors that effect one part, a real design fault effects the entire fleet!
 
JoeCanuck
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RE: F-35 Structural Cracking Still Being Resolved

Fri Sep 16, 2011 2:43 am

Quoting connies4ever (Reply 36):
At least you're not bitter

When my taxes are going into money pit programs like this, I think I have every right to demand some accountability...if you're ok with it, that's your right.

So I'm wondering when Canada will get its 65 aircraft with production held to 32 aircraft for the next 4 years.

Quoting 474218 (Reply 42):
No because those are one off errors that effect one part, a real design fault effects the entire fleet!

Actually, the latest cracks are different than the ones discovered last year. So what we are seeing is repeated early failures of the aluminum components...not one off failures.

With only a few aircraft actually produced, if they were manufacturing errors, then there are serious issues with quality control...either way, it's a significant failure.

The the blame for the failures is either poor design, poor choice of materials, (which was caused by poor original design which turned out to be overweight), poor manufacturing techniques or poor quality control.

...but it's ok since other military programs have also gone over schedule and over budget. So instead of learning lessons, they insist on repeating them.

Fantastic...
What the...?
 
ThePointblank
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 17, 2011 7:13 am

Quoting JoeCanuck (Reply 43):
Actually, the latest cracks are different than the ones discovered last year. So what we are seeing is repeated early failures of the aluminum components...not one off failures.

With only a few aircraft actually produced, if they were manufacturing errors, then there are serious issues with quality control...either way, it's a significant failure.

The the blame for the failures is either poor design, poor choice of materials, (which was caused by poor original design which turned out to be overweight), poor manufacturing techniques or poor quality control.

...but it's ok since other military programs have also gone over schedule and over budget. So instead of learning lessons, they insist on repeating them.

Fantastic...

There is a significant learning curve for these new 5th generation aircraft. I will point to this RAND study that compares the development of the F/A-18E/F and the F-22. Its argues that the learning curve for the F/A-18E is flat because it shared significant commonality with the legacy Hornet. They noted the development costs of the avionics and engines were very low because because they were either the same components used in the legacy Hornet or applied low risk derivatives of its technology. Simply put, the learning curve for the F/A-18E/F was very minimal as there is almost nothing new to learn.

The F-22 offers a very different case. The RAND article notes that there was a significant learning curve for F-22 as there were significant design challenges in the airframe arising out of the stealth requirements, the integrated avionics suite, and, finally, the new propulsion system. When you purse revolutionary technology and try to develop new systems from scratch, you greatly increase the chance of increased costs and delays.
 
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 17, 2011 8:20 am

Quoting ThePointblank (Reply 44):
Simply put, the learning curve for the F/A-18E/F was very minimal as there is almost nothing new to learn.

Thats what they thought maybe, except that they failed at the fundamental design point of getting the aerodynamics of the wing right resulting in degraded performance. The superbug is better example of 'we're too far in to fail now, just get it finished' than 'lets take all that we've learned and make sure we get it right'
 
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RE: F-35 Structural Cracking Still Being Resolved

Sat Sep 17, 2011 8:47 am

Quoting ThePointblank (Reply 44):

This isn't state of the art avionics, radar, exotic stealth coatings, engines, systems or communications systems...it's aluminum bulkheads...failing at one fifth of their design life. They aren't any more revolutionary than Big Macs.

Sure...I can see miscalculating by some margin but 80%...? It's aluminum airframe structure...the same stuff that's been used in that very same application forever.

Whatever...I'm sure it will be a lovely piece of kit when we finally get it, which should be in the next 10 years. Whether or not it will still be state of the art by then will depend on how much everyone else has caught up in the meantime.
What the...?
 
ThePointblank
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RE: F-35 Structural Cracking Still Being Resolved

Fri Oct 07, 2011 2:45 am

Quoting JoeCanuck (Reply 46):

This isn't state of the art avionics, radar, exotic stealth coatings, engines, systems or communications systems...it's aluminum bulkheads...failing at one fifth of their design life. They aren't any more revolutionary than Big Macs.

Sure...I can see miscalculating by some margin but 80%...? It's aluminum airframe structure...the same stuff that's been used in that very same application forever.

Whatever...I'm sure it will be a lovely piece of kit when we finally get it, which should be in the next 10 years. Whether or not it will still be state of the art by then will depend on how much everyone else has caught up in the meantime.

Speaking of development difficulties... guess the airplane...

- A static wing test wing failed 22% below requirements – both wings were totally destroyed. The wing was redesigned, and still failed 5% short of the design requirement. It was only through paper re-certification did the wing pass.
- In current dollars it cost about $250 million to totally redesign the wing.
- The aircraft project was many years late and far over budget. Congress tried repeatedly to kill it.
- The LRIP aircraft did not meet weight, fuel burn, payload and range specifications, and had numerous defects related to airworthiness.
- There were technical problems with mission software and landing gear.
- A GAO report revealed that while the original budget was $X billion for 210 aircraft, the 120 aircraft already ordered at that point had already cost almost $X billion, almost doubling the original unit cost.

This aircraft is now a very successful aircraft that many of you love for its versatility and capabilities, and has found export success.

Still don't have a clue? It is the C-17 Globemaster III. So when you read all the F-35 bad press and hear all the fear mongering from critics and opposition members, remember that vested interests are at play. Crap happens when you build complex technological systems; it all doesn't go right the first time out of the box. And yet the C-17 is a superb aircraft today after getting all of the issues and bugs worked out.
 
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RE: F-35 Structural Cracking Still Being Resolved

Fri Oct 07, 2011 5:23 am

Quoting ThePointblank (Reply 47):
Still don't have a clue? It is the C-17 Globemaster III. So when you read all the F-35 bad press and hear all the fear mongering from critics and opposition members, remember that vested interests are at play. Crap happens when you build complex technological systems; it all doesn't go right the first time out of the box. And yet the C-17 is a superb aircraft today after getting all of the issues and bugs worked out.

Basing success as a comparison of other programs that were significantly later and more expensive than the contracted company said, does little to encourage confidence in a program.

We all know that the plane will work eventually but when...and for what price...?

Why have a bidding process if contractors can make anything up they like and get away with it?

Besides, there actually is a fallout. As with the c-17, or f-22 or Typhoon or A400 or v-22 or a myriad of other programs, the fallout was the taxpayers, (the schmucks footing the bill), end up with substandard equipment upon delivery, (we'll fix it later), get fewer models than they ordered and at a significantly higher price.

The bugs should have been worked out when the contractor first said they would be. I don't think the bids were based on the 'superb eventually and much more expensively' principle...yet that's the basis on which they'll be delivered.
What the...?
 
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RE: F-35 Structural Cracking Still Being Resolved

Fri Oct 07, 2011 2:40 pm

Quoting JoeCanuck (Reply 48):
Why have a bidding process if contractors can make anything up they like and get away with it?

I could ask the same question only in reverse.

Lockheed (Later to become Lockheed Martin) won the contract to build over 800 F-22's. After the contract was signed the DOD (against the USAF's wishes) cut the number of aircraft they would buy to 300. They later cut the 300 down to 180 examples.

LM based all their cost estimates on the original contracted number (800+) when the number of orders decreases (180+) the unit cost increases. It is simple math!!!

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