Forum: General F-35 Forum

If the F-35C can't make carrier landings as designed then the ideal thing to do is shove all the F-35 hardware and avonics into a carrier specfic airframe. Hopefully we won't have to do that.

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Last edited by hb_pencil on Dec 15, 2011 - 01:38 AM; edited 3 times in total

arkadyrenko wrote:

hb_pencil

The point I raised about weight is that they have to hit targets that are tougher than the previous F-18 and F-22 programs, in terms of weight margins. This is going to be tricky, particularly as they already have a solid number of targets to hit.

But they've met them, and have really been able to keep it under the limits year after year since SWAT was enacted.

arkadyrenko wrote:

Next, about the F-35C and the USN. I would actually disagree with you, I stand by my statement that the Navy is the most prepared service to drop the F-35. The Navy, unlike the USAF, is continuing to purchase F-18E/F. This means that they have the easiest route to bailing on the JSF program, they can just continue F-18s. That the Navy hasn't purchased those upgrades for the F-18 isn't surprising, as those would only be purchased if the Navy decided to bail on the JSF program (No need to buy them now as you still plan to buy the JSF). However, the fact that Boeing is suggesting the F-18 upgrades, when only the USN operates that airplane in significant numbers, hints to me that they suspect a favorable ear in the Navy. Add to that the fact that Boeing brings up the F/A-XX for the Navy more than its F-XX for the USAF and it seems to me like Boeing thinks Navy's dedication is wavering. For those two reasons, I still believe that the Navy will be the most likely to bail on the JSF program.

I'm sorry, but that is your conjecture and not backed up by Navy thinking. The EPE upgrade in particular was something envisaged for quite some time (since 2000), but the Navy funded it. The Navy decided to purchase more Super Hornets for two needs: First to fill the gap in capability due to F-35 delays and the exhaustion of some Legacy hornet squadrons. Second, to purchase more Growlers to expand the number of SEAD squadrons by four. This isn't my view; its that of NAVAIR personnel. The Navy desperately wants a low observable plane, its been their single greatest desire since 1990. The F/A-18E isn't it.

Also: Boeing brings up the F/A-XX because it has nothing between now and 2025.

arkadyrenko wrote:

But, I'll add another one. The USN has been far superior to the USAF when it comes to managing the aircraft fleet. USN is pushing the boundaries with the UCAV, USN has modernized its AEW&C with the E-2D, and the USN has a brand new patrol aircraft, the P-8. Not to mention that the USN has continued to purchase the F-18 while it appears that the USAF couldn't care less if the F-15 line shut down. Thus, I trust that the USN will bail from a sinking program faster than the USAF.

No, they have to be because they operate aircraft in the most demanding environment. The dynamics of carrier landing means that instead of the 30+ year lifespans that USAF fighters often have, Navy fighters tend to have 20~25 years in service. Furthermore it is far more costly to undertake SLEPs for these aircraft due to their environment. If you look at the F-16.net front page, you'll note that most F-16s are still in service... even Block-30s from the early 1980s. That's certainly not the case for F/A-18As from that time period.... while many of the Cs are already near retirement because they are reaching the end of their service life.

Even the patrol aircraft have shorter life spans: they fly at lower altitudes in inclement weather. The P-3s from the 1970s and 80s are simply wearing out and the P-8 is its replacement. .

So the Navy is more concerned with aircraft replacement simply because they do it far more often. Many of the reliability metrics for the F-35 development were set by the Navy to meet their stringent requirements.

arkadyrenko wrote:

On concurrency and the JSF, what I suspect they mean by concurrency is keep building the thing, as in don't shut the line down, but do not accelerate production. That side of concurrency, accelerating production as a precursor to full production is now done, LRIP will continue to be low because there are so many mistakes and potential mistakes.

Sure, but Congress has been undertaking cuts now for the past two lots... so it was going to happen.

arkadyrenko wrote:

If I can recall correctly, the plane is experiencing higher than expected buffering, but it doesnt' clearly state if its the same as comparative fighters or greater. It says words like "same level" but over a wider flight envelop? That portends either an aerodynamic fix or a reduced maneuverable fighter. As for the night vision, how is it possible that the 5th gen fighter has less night ability than 4th gen fighters?

Please research the development history of the F-14, F/A-18A the F-15 and F-22. you will find report after report on buffeting issues, even at moderate angles of attack. NASA and the DoD have studied this issue for the better part of 40 years and have suggested different fixes, or simply just ignored the issue and called for better monitoring to monitor their possible effects.

arkadyrenko wrote:

Finally, about the classified element. Its placed under the critical section, and if we look at the other ones, EODAS, fuel dump, tail-hook, IPP, this classified issue can be rightly judged to be a pretty sizable problem.

Absolutely, it probably is. However if it was really that bad, then they probably wouldn't allow concurrency production to occur.

arkadyrenko wrote:

PS. - What do people say to the critics of concurrency, test and buy, etc. now? Sadly, the basic program criticism of the JSF, too ambitious to meet its price point or its IOC date, is thoroughly justified by this report. The problems cover the whole gamut of the aircraft subsystems and the unknowns are pretty large.

I really think its just an example of a project in the first 20% of its development cycle. Its tough to do a quantitative comparison of these issues with other programs, but qualitatively there seems to be a few more issues, but not many.

On concurrency I was of two minds. Really I saw it as a big freebee for Canada: it dropped the potential costs of our early buys when you ate up the concurrency costs. Yet I wasn't a huge fan of concurrency... partly because it contravenes the GAO's best practices scheme. Certainly it wasn't a good idea in hindsight. Then again its not been a major disaster either because it has been curtailed severely upon sign of trouble.

*double post*

Last edited by cxxtxx on Dec 15, 2011 - 01:48 AM; edited 1 time in total

But it’s not just the difference of 2.3 linear feet between the A-4 and F-35 C, (not to mention the extra five to eight tons slamming down on the deck,) it’s the actual geometry of the arresting gear. The attachment point of the F-35C arresting gear is significantly higher off the deck than the A-4, AND it’s 2.3 linear feet shorter behind the landing gear, therefore the downward angle of the arresting gear has to be much steeper. Just from looking at it, I can't see how it’s ever going to work on an operational flight deck. I just don’t see it.

As arresting gear is an absolutely FUNDAMENTAL design consideration for naval aircraft, Lockheed Martin's apparent engineering incompetence in this regard creates a total lack of confidence for the entire F-35 program. For God's sake, what were they thinking?

I’m not trying to be a jerk, I just want our military to have the best and I am far from convinced that the F-35 A/B/C is the best that we can do...

Chad

alloycowboy - exactly, if the F-35C cannot make the tail hook work, they'll probably build a new airframe. Also, the new air frame could be better optimized for Pacific warfare. Hence, why I think that USN is going to be the most likely service to drop the F-35 program and do something else.

As for the tail hook issue, I will gladly apologize about the A-4 issue if it was brought up as possible speculation. The thread seemed to me, though, to have an air of seeking, maybe desperately?, for a way out of the F-35's problem. The aircraft weights, as showed on the previous page, put the the whole problem, and the comparison with the A-4, into a difficult light.

I would like to hear someone else's comments about airframe weights and the tail hook problem. That to me seems to be the killer.

hb_pencil - About the weight: the strict weight limits are going to exact a continuing cost on the airframe development, as each upgrade / change needs to fit the tightest margins. That is the problem, the JSF program can achieve its weight targets, but it'll be expensive and time consuming. Put in other words, the JSF cannot trade weight for expense and time.

About the F-18: If the F-18 upgrades were offered at the same time as the JSF program, than I can see why the Navy did not follow through with them. As the JSF was supposed to hit IOC in 2011 - 2013 ish, there wouldn't be much gain for the Navy to upgrade its fighters. In the early 2000s, the USN planned to have its fleet of stealthy strike fighters so upgrading the F-18's may have been seen as unnecessary. I think that the Navy will only go for those "silent hornet" upgrades if it pulls out of the F-35 program, and perhaps not even then, depending on the speed of the F-35C's replacement.

I understand that the F-18 was purchased as a gap filler and that the Navy desperately wants a LO fighter, my point was that the Navy has continued to purchase gap filler aircraft . This puts them in a much better position than the USAF, as the Navy has maintained aircraft productions and is best positioned to continue them. The gap filler could become a different form of gap filler.

And, for the issue of airframe replacements, at least the Navy replaces its fighters before they fall apart in midair. The USAF is now forced to do expensive SLEP programs to keep some fraction of its fighter force flying, when they could have been doing a low level purchases to replace the oldest fighters, keeping overall force age down, the production lines open, and lowering maintenance costs.

About the F/A-XX: Boeing is desperately seeking for a job, we all understand that, but I am of the opinion that they're selling to Navy because Boeing thinks that the Navy is most likely to request a new airplane first. With the F-35C's tail hook problems, Boeing may get its contract sooner than it anticipated (which I think is an unambiguously good event for the US fighter industrial base).

On buffeting, you're probably correct, we'll have to see how that problem continues. It could just be that they haven't pushed the envelope far enough.

Chad, can you provide scale drawings or figures for this claim please? Tah. "The attachment point of the F-35C arresting gear is significantly higher off the deck than the A-4". Interested of OzLand.

Last edited by spazsinbad on Dec 16, 2011 - 11:21 PM; edited 2 times in total

'arkadyrenko' said: "The aircraft weights, as showed on the previous page, put the the whole problem, and the comparison with the A-4, into a difficult light." Perhaps - however the maximum arrested landing weight would be more relevant to compare. Look at the photos on the other link to see what the Hornet nosewheel does to a wire momentarily. [Now reproduced below]

For one thing I'm surprised the hook malfunction was not tested earlier - to be discovered earlier - as people rightly point out this is a basic requirement for any carrier aircraft. Speculation that this problem cannot be fixed is just that. Already a solution has been designed to be tested. But I guess the sky is really falling when it is only raining eh.

http://www.f-16.net/f-16_forum_viewtopi ... rt-45.html

[edit] Have found the new InstaPinch site [via the Tommy H. Thomason website] with this info here: Cross Deck Pendant – Redux December 12th, 2009
http://instapinch.com/?p=456

InstaPinch says [from old now no longer available webpage]: "...What you are seeing is the instantaneous deformation of the CDP by the nose gear of a Hornet as it lands and passes over the wire at 135knots...."

http://attach.high-g.net/attachments/in ... es_111.gif

@arkadyrenko.... The speculation about the A4 tailhook was just kicking the ball around trying to figure what Lockheed Martin is upto with the F-35C. Given the level of CAD and virtual reality that Lockheed Martin employed I just can't see the tailhook not working. You have to remeber these are the guys that got the F-117 to fly. If anyone can do it is Skunk Works. If Skunk Works can't get it to work then it can't be done!

cxxtxx wrote:

a calm, neutral, reassuring, well-reasoned axe murder attack in preparation for the quiet mercy killing... LETHAL to the entire F-35 program. Look at that page, it's a dagger thrust into the heart of the entire F-35 program.

A sure sign of someone who simply hasn't got a case to make at all on the actual evidence or logic: creationist-style dramaticism about the nature of the debate.

arkadyrenko wrote:

Notice that the distance increases for the larger aircraft... Clearly, past aviation designs have increased that length for heavier aircraft.

What are you saying the connection/relationship is?

If it takes a serious redesign to get the C to trap then they'll have to do it. Designing carrier aircraft is challenging. From memory the last time LM did so was the S-3 in the 1960's and they brought in LTV to help.

delvo - look at the figures I presented. The relationship is: heavier weight --> longer distance from the real wheels to the tail hook. The F-35 is not only an outlier in terms of the tail hook length, its an outlier in terms of the weight too. The aircraft around it have much lower dry weights than it.

lb - I think its more likely that the USN just cancels their participation.

arkayrenko will have to find out the maximum landing weights of any carrier aircraft to begin to make his point. I can help and I'll look briefly for other aircraft but I'm not sure his argument is worth pursuing. The F-35C Hook Designers think they have a solution and it would be interesting to know more about why it is so. Perhaps there are clues in that report.

Anyway a later model A-4E/F/G had a 14,500lb max landing weight (which includes arrest). However as always there is an exception when ashore when higher approach airspeed can be used to 'flare' before mainwheel touchdown but then any weight / airspeed limitation of any ashore arrestor gear will apply if arrest intended. Often the ashore gear has very high landing airspeed/weight limits because they are also usually bi-directional to cater for long field arrest for any aborted takeoffs. [Long field gear for takeoff is the short field gear for landing on same runway.]

Perhaps surprsingly or not (considering the purpose of the aircraft) the T-45C can land / arrest with full fuel load (no other stores such as practice bombs or blivets though) and two pilots but likely one because who wants to carrier land for the first time with a student in front! Rolling Eyes

The F-35C max. landing weight is mentioned on another thread. I'll go find it. The other current or recently former max. landing weights could be found in NATOPS (USN Pilot Flying Notes). Scroll down to end of this page:

F-35 Approach AOA
http://www.f-16.net/f-16_forum_viewtopic-t-13450.html

"...Knowles says the aircraft approached at 135 kt., compared with 155 kt. for the smaller-winged F-35A and B variants at the same 40,000-lb. gross weight. Takeoff rotation speed was 15-20 kt. slower, he says...." [http://alturl.com/fnsk]
http://www.aviationweek.com/aw/generic/ ... ht%20Goals
&
on page 2 of same thread at end again:
http://www.f-16.net/f-16_forum_viewtopi ... rt-15.html

F-35C carrier approach info: VX-23 'Salty Dogs' Joint Strike Fighter Update -LCDR Ken “Stubby” Sterbenz VX-23 Ship Suitability Department Head in Paddles Monthly - Sept 2010

http://www.hrana.org/documents/PaddlesM ... er2010.pdf (1.3Mb)

"The F-35C is 51.5 ft long and has a wingspan of 43 ft and 668 ft2 of wing area (7 ft longer wingspan and 208ft2 more wing area than the Air force or Marine versions.) It also carries 19,800 lbs of internal fuel - 1000 pounds more gas then the Air Force version. It is powered by a Pratt and Whitney F135 engine that produces 28k lbs and 43k lb of thrust in MIL and AB respectively. The max trap weight will be around 46k lbs, with an empty weight of about 35k lbs. It will fly an on-speed AOA of 12.3° at 135-140 KCAS [Optimum Angle of Attack or Donut]. Due to the fact that flap scheduling is completely automatic, the cockpit was designed without a flaps switch. Additionally, the tail hook retracts into the fuselage and is covered by hook doors that have an as-yet-to-be-determined airspeed limitation..." LT. Dan "Butters" Radocaj - VX-23 Ship Suitability"

I got 42,900 lb for the F-18E/F

http://www.uscost.net/aircraftcharacter ... fa18ef.htm

Last edited by spazsinbad on Dec 15, 2011 - 07:49 AM; edited 1 time in total

arkadyrenko (if stats reliable) there is a list of other aircraft top right [oops left - I'm dyslexic) hand side of that page. Note FIELD landing max. weight is 7,900lbs higher but with restrictions about stores carried and how aircraft is landed one would presume. NATOPS will tell all. There is a link to a Super Hornet NATOPS on this forum....

Hornet / Super Hornet NATOPS on this page:

http://publicintelligence.net/u-s-navy- ... t-manuals/

I'm still pro F-35. There is no way Congress would fund multiple new fighter programs. IMHO these politicians would rather have three aircraft with (rather limited) airframe commonality in one program, as opposed to two or three different programs that could still share common avionics, engines, and other components.

Yet this news certainly has me concerned. Why wouldn't Lockheed Martin have gone with the more "tried and true" location of the tailhook? How serious is this classified issue? What ever happened to the weight savings from SWAT? What ate that up? The F-22 is Mach 2+ capable so why would the F-35's stealth coatings be damaged by Mach 1.1+ speeds as some claim? The F-35's stealth coating is supposed to be more durable and maintenance friendly.

Forum: General F-35 Forum

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