The F-35 No Holds Barred topic

[Michel Van]

how was it in good old time ?

a 41 month program
30 June 1941 US NAVY signed contract for Grumman Prototype XF6F-1
30 July 1942 first prototype XF6F-3 flies
3 October 1942 first production aircraft off the line F6F-3s flew
February 1943 the F6F-3s reaching operational readiness with VF-9 on USS Essex
Grumman build 12275 F6F Hellcat until 1945 ( 454 per month !)

its the most successful aircraft in naval history, destroying enemies 5271 aircraft

of curse the F6F Hellcat is allot easier to build as a super complex VTOL F-35 Jet....

 

[yasotay]

of curse the F6F Hellcat is allot easier to build as a super complex VTOL F-35 Jet....

I would argue that for its day the Hellcat was plenty complex. Certainly no B-29, but still not a simple aircraft. I read a great article several years ago in VERTIFLITE magazine by a senior engineer who wondered why it took two years to develop the CH-47 and twenty two years for the V-22. His analysis pointed out (I am paraphrasing at this point) that on CH-47 there were three engineers and the remainder of the personnel where journeymen. The Boeing Company had to deal with three government agencies. With the V-22, all of the personnel were engineers and the Boeing-Bell team (a mandated marriage) had to deal with about thirteen government agencies. He also noted that the CH-47 was designed on paper, while the Osprey had much of the work done in CAD.

Moral of the story: An aircraft does not need a village to be made and the expectation that computers make everything right the first time causes over-expectation.

Even if I got everything wrong from the article; I still think my moral is correct. ;D

 

[Michel Van]

... it took two years to develop the CH-47 and twenty two years for the V-22. His analysis pointed out (I am paraphrasing at this point) that on CH-47 there were three engineers and the remainder of the personnel where journeymen. The Boeing Company had to deal with three government agencies. With the V-22, all of the personnel were engineers and the Boeing-Bell team (a mandated marriage) had to deal with about thirteen government agencies...

13 U.S. government agencies ? than its miracle that V-2 exist !!!
how many U.S. government agencies deal with F-35 ?

 

[Stargazer]

Moral of the story: An aircraft does not need a village to be made and the expectation that computers make everything right the first time causes over-expectation.

Even if I got everything wrong from the article; I still think my moral is correct. ;D

You got my point exactly: I sometimes wonder if doing things the ol-fashioned way wouldn't make it simpler and less costly. This is one of the reasons I admire Burt Rutan's free entrepreneuring spirit: by sending a ship to space for half the time and 10 times less the money, he shows a no-nonsense attitude that is all but lacking in the aerospace industry today.

 

[CFE]

Yawn! Here we go again - more F-35 bad, F-22 good garbage...

A bird in the hand is always worth two in the bush. At least the F-22's development costs had been sunk, and buying more could have been accomplished with a fixed-price contract. Development of a new weapons system is never a trivial undertaking, and it's always susceptible to requirements creep, cost and weight growth, and all sorts of unforseen factors which will eat away at performance while driving up cost.

A lot of congress-critters and DoD leaders (including Secretary Gates) have been living in a delusion where the F-35 will do it all and come in cheaper than the F-22. The reality is that F-35 is a compromise between STOVL, carrier-based and land-based requirements, and a compromise between the air-to-air and air-to-ground missions. Its stealth capabilities are a balance between affordability and survivability.

Eventually Congress, the DoD and allied partners in the F-35 program will wake up to extreme sticker-shock. That's not to say it's a bad program, but the expectations have been unrealistically high.

 

[GTX]

I asked it before and I'll ask it again - how many of the F-35 critics have ever actually worked in the industry and in this case actually have any real idea what is going on in the program? Being on the inside, it is quite amusing (and a little frustrating) to watch the un-informed rantings of enthusiasts.

Back top the point of my post: I am sick of ever week or so (and has been getting worse these last 12mths) a new thread appearing bashing the F-35 and usually saying how wonderful the F-22 would be. These are usually also heavily tinged with US political whining themes which have nothing to do with the ultimate purpose of this website. Posting new information on technical or similar aspects is fine, but simply coming out with threads saying thiings to the effect of "...it's getting more expensive...going to be cut...if only we had more F-22s..." add nothing.

I'm sure I'll cop the usual attacks now, but still I stand by my opinion.

Greg

 

[overscan (PaulMM)]

Agreed, Greg.

While I can see possible technical and economic issues with F-35 development, like any complex weapons system, I cannot understand the incessant bashing of this program online. I would appreciate it if we tried to keep the politics to a minimum.

 

[Woody]

From the BBC this morning.

Pentagon chief fires head of F-35 aircraft programme

US Defence Secretary Robert Gates has sacked the marine general overseeing a $40bn (£25bn) project to build the next generation strike fighter jet.

Mr Gates said the F-35 programme had been plagued by problems and failed to hit performance targets.

He also said Lockheed Martin, the US corporation responsible for building the jet, would not be awarded $614m in performance-related payouts.

"The progress and performance of the F-35 over the past two years has not been what it should," Mr Gates told a news conference on the Pentagon's proposed budget.

He added that "a number of key goals and benchmarks were not met".

Despite all the issues I'd like to see this aeroplane finished - if only to replace the Harrier. Perhaps this might be the 'incentive' they need.

Cheers, Woody

PS: Didn't now where to put this as there are so many JSF/F-35 threads - time to rationalise?

 

[Steve Pace]

Why is the F-35C anchored down? It rolled out months ago.

 

[F-14D]

Why is the F-35C anchored down? It rolled out months ago.

I think the bigger question is why in all of 2009 the F-35 program only managed to do 16 of its scheduled test flights

 

[Matej]

Might be of interest

 

[Sundog]

Why is the F-35C anchored down? It rolled out months ago.

I've read (At the Ares blogs?) that the F-35C wings may need to be strengthened as it may not be strong enough to handle cats and traps. I know it uses the same spar as the B and C, which is why with the added wingtips it actually has a lower max G load capability. But the only thing I can figure out is the spar was so optimized, that the weight growth caused the spar to exceed the limits or they just screwed it up royally. That's just my opinion based on what I've read. It may just be they're actually still waiting for "flight ready" parts. Whatever the case, LM has created a huge clusterf*ck with the F-35 program. I really think more heads need to roll on this program, than what happened a week or two ago.

 

[Ian33]

Sundog,
I read an article that said that it was some structure in the mid-body that wasn't up to catapult and arrester strains and needed an over haul on the 'C' variant.

Which ever it is, its one unholy cluster f#ck if it is true.

 

[Sundog]

Thanks for the info Ian. Now go read this. "Abrupt Stall Problems?"

F-35 Trouble Aviation Week Article

Do you think maybe Boeing knew this was coming and that's why they've been working on their F/A-XX? Because I'm beginning to wonder if the F-35C will even fly.

 

[Ian33]

Thanks for the info Ian. Now go read this. "Abrupt Stall Problems?"

F-35 Trouble Aviation Week Article

Do you think maybe Boeing knew this was coming and that's why they've been working on their F/A-XX? Because I'm beginning to wonder if the F-35C will even fly.

After reading about the F-35C I am not too sure that it will to be honest. The F-35 from its very first days has been one unholy mess - weight, hover, time line slipping: in short, everything it wasn't supposed to be. Oh and lets not forget the issue of cost. F-22 was canned at 183 and its starting to look like possibly the costliest mistake the USAF has suffered in some time.

As for Boeing? yes I certainly can see why they have started their in house efforts. To be honest it is what i would of done had I been in charge at Boeing and watching this mini disaster epic unfold.

 

[Ian33]

http://www.bloomberg.com/apps/news?pid=20601087&sid=a6gq84TiIFcA&pos=9

F-35C not strong enough for catapult stresses. What a joke.

Jan. 29 (Bloomberg) -- Lockheed Martin Corp. is fixing a structural weakness in the Navy version of the F-35 Joint Strike Fighter that limits the jet’s ability to launch from aircraft carriers, according to a company spokesman.

Engineers in July discovered a “strength shortfall” in an aluminum structure in the aircraft’s center fuselage that helps absorb stresses during a catapult takeoff, Lockheed spokesman John Kent said today in an e-mailed statement.

“U.S. Navy and program office engineers were apprised immediately and have been directly involved in approving design updates,” Kent said. “A modification is already approved and ready to incorporate early this year prior to any catapult testing planned for 2011.”

Strength shortfall - If it wasn't so tragic it would be funny.

 

[ubiquitous08]

Can't wait for opvals. Should be REAL interesting

 

[Ian33]

Can't wait for opvals. Should be REAL interesting

If it keeps going at snails pace its on now... 2018 time?

 

[elmayerle]

http://www.bloomberg.com/apps/news?pid=20601087&sid=a6gq84TiIFcA&pos=9

F-35C not strong enough for catapult stresses. What a joke.

Jan. 29 (Bloomberg) -- Lockheed Martin Corp. is fixing a structural weakness in the Navy version of the F-35 Joint Strike Fighter that limits the jet’s ability to launch from aircraft carriers, according to a company spokesman.

Engineers in July discovered a “strength shortfall” in an aluminum structure in the aircraft’s center fuselage that helps absorb stresses during a catapult takeoff, Lockheed spokesman John Kent said today in an e-mailed statement.

“U.S. Navy and program office engineers were apprised immediately and have been directly involved in approving design updates,” Kent said. “A modification is already approved and ready to incorporate early this year prior to any catapult testing planned for 2011.”

Strength shortfall - If it wasn't so tragic it would be funny.

Hmm, I'm wondering if that's in the NGC section or the BAE section? If it's in the lower center section, it most definitely is not an area designed by LM-Aero.

Actually, the flgiht test series I'm looking forward to is BF-4, the first aircraft with most of the mission avionics fitted (not all-yet; some just wasn't ready and even there they had some unwelcome surprises (without going any farther, I'd ask who'd expect an electrical connector on the outside of an avionics box to be the cause of a qual test failure?). I rather suspect that getting more aircraft into the air is as much a function of getting qualified hardware from suppliers as anything LM-Aero proper is responsible for.

 

[Colonial-Marine]

When did everything start going so horribly wrong? Besides for weight issues at an earlier stage, things seemed to be going as well as expected in such a large and complex program.

The result of trying to make one airframe do everything?

 

[shedofdread]

Don't sell the Harriers yet...

S

PS I was going to bang on about unforgivable errors etc etc but frankly I couldn't be bothered - I've just come to expect it.

PPS Does anyone know what percentage of carryover from the Yak 41 there is? Or am I not supposed to mention that?

 

[sferrin]

Don't sell the Harriers yet...

S

PS I was going to bang on about unforgivable errors etc etc but frankly I couldn't be bothered - I've just come to expect it.

PPS Does anyone know what percentage of carryover from the Yak 41 there is? Or am I not supposed to mention that?

We need more posts like this. :

 

[sublight]

If you have read the Pentagon Paradox, you will highly suspect that the F-35 will ever enter into service with the Navy....

 

[Sundog]

Hmm, I'm wondering if that's in the NGC section or the BAE section? If it's in the lower center section, it most definitely is not an area designed by LM-Aero.

Actually, the flight test series I'm looking forward to is BF-4, the first aircraft with most of the mission avionics fitted (not all-yet; some just wasn't ready and even there they had some unwelcome surprises (without going any farther, I'd ask who'd expect an electrical connector on the outside of an avionics box to be the cause of a qual test failure?). I rather suspect that getting more aircraft into the air is as much a function of getting qualified hardware from suppliers as anything LM-Aero proper is responsible for.

What about the sudden stall problem at high alpha, have you heard anything about that as mentioned in the article I posted above? From the article;

One source suggests that JSF may be running into high-angle-of-attack handling problems including “abrupt stall.” Lockheed Martin says that tests have allowed the designers to prevent such a problem “by incorporating design elements and developing fallback options, should the phenomenon appear during flight testing.”

Of course, as long as they can fix it, I guess that's OK if it doesn't compromise anything else. Why would it take them so long to discover this? Is it that high alpha simulation is just that far back in the research end of development?

With regard to the electrical connector, who decides it can or can't fly like that? The government/military or the contractor?

 

[mz]

When did everything start going so horribly wrong?

"The good old times weren't" - don't remember by who, maybe Henry Spencer. There have been so many problems in history as well.
Ok, just trying to lighten up a little as the bashing gets a bit heavy at times. I don't have that much expertise myself to judge how big this is.

 

[Evil Flower]

This might be a stupid question, but why are they redesigning so much from the X-35? What's the point of producing a flying prototype if you're going to build a completely different production machine?

 

[Matej]

Probably because if you are creating fundamentally new product, you simply don't know how to do everything best from the beginning. You have some ideas, you test them and after that you use them. Than you will find something better and use it too. There can be a lot of similar questions - for example why we have Gripen A/B and C/D and not directly machines like Gripen DEMO? Why the GD built the YF-16 and not directly F-16E/F Block 60 airframe with conformal fuel tanks and such a things...

 

[Evil Flower]

Well I mean it seemed to go into production a whole lot quicker back in the day. Now it's all supposed to be perfect before delivery or something?

 

[Matej]

Seems so. Combine it with the complexity of the current fighters and requirements that they are forced to fulfill and you will be close to the answer.

 

[Spring]

Wonder if this kind of testbed competitions are not rushing the design/manufacturing industries to put in to the sky a plane that could suit and actually win a demonstrator competition but not a operative aircraft competition.

What are the main differences between the ATF/JSF programs and the F-16/17 programs? i think , for example, radar and basic electronics were ready, and the testbed planes were more mature for the service, but i don't recall well.

I'm confused with this stall issue, was it tested in a real aircraft, or are simulations, i think other programs had similar issues, the F15,14,16 had engine stalling issues

Edit: seems the stall is the aerodynamic issue, not the engine's one

 

[Stuka]

What about the sudden stall problem at high alpha, have you heard anything about that as mentioned in the article I posted above? From the article;

Quote
One source suggests that JSF may be running into high-angle-of-attack handling problems including “abrupt stall.” Lockheed Martin says that tests have allowed the designers to prevent such a problem “by incorporating design elements and developing fallback options, should the phenomenon appear during flight testing.”

Early F-35Cs will have spoilers on the outboard wing panels as risk mitigation during flight testing. F-18E/F and T-45 both experienced wing drop during flight testing and both platforms were subsequently fixed. If no problems are found in flight testing then the spoilers will be removed for production. This has nothing to do with F-35A or B.

http://www.flightglobal.com/articles/2009/08/05/330590/lockheed-martin-develops-wing-spoiler-for-f-35c-flight.html

This might be a stupid question, but why are they redesigning so much from the X-35? What's the point of producing a flying prototype if you're going to build a completely different production machine?

X-35 was a technology demonstrator not a prototype. The prototype would have been YF-35.

F-35C not strong enough for catapult stresses. What a joke.

In general, airplane design is an iterative process. You never get it right the first time. When parts are designed, assumptions are made about the loads that the parts need to take. The most structurally efficient design will be just strong enough to meet those assumptions. Later, because of requirements creep or during flight testing, the actual loads may be found to be higher than the assumed loads. Then your just strong enough part becomes not strong enough. In such cases the parts are either swapped, reinforced, or life limited or flight envelope restrictions are put on the airplane. Parts get redesigned to a newer, more accurate set of assumptions and get incorporated into future birds. This is not unusual. In happens in every program.

If a brand new airplane design completes flight testing and no structural mods were needed then someone did their job wrong. That would indicate that there is extra weight that could be removed from the design.

 

[SOC]

Is it me, or is this thing turning out to be the spiritual successor to the F-111?

 

[sferrin]

What about the sudden stall problem at high alpha, have you heard anything about that as mentioned in the article I posted above? From the article;

Quote
One source suggests that JSF may be running into high-angle-of-attack handling problems including “abrupt stall.” Lockheed Martin says that tests have allowed the designers to prevent such a problem “by incorporating design elements and developing fallback options, should the phenomenon appear during flight testing.”

Early F-35Cs will have spoilers on the outboard wing panels as risk mitigation during flight testing. F-18E/F and T-45 both experienced wing drop during flight testing and both platforms were subsequently fixed. If no problems are found in flight testing then the spoilers will be removed for production. This has nothing to do with F-35A or B.

http://www.flightglobal.com/articles/2009/08/05/330590/lockheed-martin-develops-wing-spoiler-for-f-35c-flight.html

This might be a stupid question, but why are they redesigning so much from the X-35? What's the point of producing a flying prototype if you're going to build a completely different production machine?

X-35 was a technology demonstrator not a prototype. The prototype would have been YF-35.

F-35C not strong enough for catapult stresses. What a joke.

In general, airplane design is an iterative process. You never get it right the first time. When parts are designed, assumptions are made about the loads that the parts need to take. The most structurally efficient design will be just strong enough to meet those assumptions. Later, because of requirements creep or during flight testing, the actual loads may be found to be higher than the assumed loads. Then your just strong enough part becomes not strong enough. In such cases the parts are either swapped, reinforced, or life limited or flight envelope restrictions are put on the airplane. Parts get redesigned to a newer, more accurate set of assumptions and get incorporated into future birds. This is not unusual. In happens in every program.

If a brand new airplane design completes flight testing and no structural mods were needed then someone did their job wrong. That would indicate that there is extra weight that could be removed from the design.

You keep bringing common sense into this discussion and the Bill Sweetman fan club is going to lynch you.

 

[Sundog]

Early F-35Cs will have spoilers on the outboard wing panels as risk mitigation during flight testing. F-18E/F and T-45 both experienced wing drop during flight testing and both platforms were subsequently fixed. If no problems are found in flight testing then the spoilers will be removed for production. This has nothing to do with F-35A or B.

http://www.flightglobal.com/articles/2009/08/05/330590/lockheed-martin-develops-wing-spoiler-for-f-35c-flight.html

Thanks, the Aviation Week article never specified that it just affected the F-35C, which is funny, because I had mentioned to a friend that it reminded me of the Super Hornet wing drop problem.

 

[Stuka]

Thanks, the Aviation Week article never specified that it just affected the F-35C, which is funny, because I had mentioned to a friend that it reminded me of the Super Hornet wing drop problem.

Bill's article was very vague but I believe this is the issue he was referring to. If not, maybe he should provide more info. Are you reading this Bill?

You keep bringing common sense into this discussion and the Bill Sweetman fan club is going to lynch you.

It's funny. The people who complained about weight before SWAT are the same people complaining about mods after SWAT. It's a sliding scale. You can't have both. The program office decided to be aggressive on weight because of STOVL.

 

[Sundog]

It's funny. The people who complained about weight before SWAT are the same people complaining about mods after SWAT. It's a sliding scale. You can't have both. The program office decided to be aggressive on weight because of STOVL.

Are you saying that the F-35C's strength problem in the center of the fuselage is the outgrowth of the weight savings program? It makes sense to me, but I'm just checking if I'm understanding you correctly.

 

[GTX]

If you have read the Pentagon Paradox, you will highly suspect that the F-35 will ever enter into service with the Navy....

The USN is an interesting situation since they already have the F/A-18E/F and were always the third priority when it comes to the F-35. Depending how things progress, they could even conceivably skip the F-35 and go straight to UCAVs though I doubt it. As for the others, it WILL ENTER SERVICE if only because so many other countries (and their industries) have a lot invested in it.

Regards,

Greg

 

[sferrin]

If you have read the Pentagon Paradox, you will highly suspect that the F-35 will ever enter into service with the Navy....

The USN is an interesting situation since they already have the F/A-18E/F and were always the third priority when it comes to the F-35. Depending how things progress, they could even conceivably skip the F-35 and go straight to UCAVs though I doubt it. As for the others, it WILL ENTER SERVICE if only because som many other countries (and their industries) have a lot invested in it.

Regards,

Greg

UCAVs are worth ----all in air to air missions, where the Super Hornet is already weak.

 

[GTX]

UCAVs are worth ----all in air to air missions, where the Super Hornet is already weak.

Current ones maybe - but there is no reason why they couldn't be adapted to the role quite easily. If the USN chose to skip the whole F-35 and go to a UCAV + F/A-18E/F mix it would probably be in the 2018-2020+ timeframe.

Regards,

Greg

 

[Stuka]

Are you saying that the F-35C's strength problem in the center of the fuselage is the outgrowth of the weight savings program? It makes sense to me, but I'm just checking if I'm understanding you correctly.

I don't know any more than you do. I'm just saying that the more aggressively you attack weight, the less padding is left for unforeseen loads increases.