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F-35 Cancelled, then what ?

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F-35 Cancelled, then what ?

Old 9th May 2013, 15:17
  #2281 (permalink)  
 
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Originally Posted by JSFfan View Post
It hasn't changed....the f-35 is a low observable platform and is also an all aspect VLO plane that has exceeded it's 'stealth' KPP
A few years ago I gave a briefing to a general audience about RCS "numbers". I'm sure many folks on this forum are very familiar with this info, but for those that are new to the subject here are a few charts from the brief.








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Old 9th May 2013, 15:28
  #2282 (permalink)  
 
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Bevo,

Useful for those not familiar with the subject, Bevo, I'm sure. I would add, we're increasingling into circular polarization now too, which also has some compatibility with the others...


PhilipG,

Yes, if the redesign does not work, what happens? That's what I meant when I said you are right to ask the question - it's a good one for discussion, although you may now just get spot jamming from Australia in an attempt to stifle any chat. Sorry I didn't answer it - I wouldn't know how!!!

Regards,

Courtney

Last edited by Courtney Mil; 9th May 2013 at 15:54.
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Old 9th May 2013, 16:37
  #2283 (permalink)  
 
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HH, Courtney and others

Sorry to you if I wasn't clear - my comment was aimed those who inferred that LM had 'got the design all wrong' in terms of wheel to hook distance - they designed a hook system that met all the USN design guidelines and requirements (with the active involvement of the USN experts) but, as you correctly point out, it failed on initial tests.

My 'take' is that they will fix the issue with the point redesign and changes to the damper - but if those don't work, LM are on the 'hook' (sorry) to fix it. My guess for any next step would be some sort of extending hook system. that gets a greater wheel to hook point distance. The challenge they face is that there is not much structure back there to hang a hook from without getting it close under the end of the jetpipe.

Actually, the statement 'it's only a hook and we''ve been building them for years' might be a bit simplistic. First, this is an arresting hook system for use on board ships, not the simple emergency systems fitted to some jets - it's a complex and highly loaded piece of design, and the basic challenge is non-trivial. On top of that, this one has to be fully retractable inside a set of LO doors - that added another layer of challenges. Add in whipping wires and a very variable set of engagement conditions, and you have a complicated problem. As I've already sort of said, just because something looks simple doesn't mean it is.

Bottom line - LM will fix it because they have to. And the USN will make sure that they get it right.

Best Regards as ever to those who do the trapping

Engines
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Old 9th May 2013, 16:58
  #2284 (permalink)  
 
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Bevo - Good stuff.

Personally I have never been too sure where the line lies between "LO" and "VLO", let alone "ELO", which I dislike because it gets "Mr Blue Sky" stuck in my head for an hour.

I think LMT and other JSF fans like to give the impression that the F-35 is exactly like the F-22, which it most probably is not. (Exhausts for instance, not to mention the lumpy Rosie-O'Donnell-in-yoga-pants lower-aft view.) And neither is going to be like a flying wing with nary a single part that it smaller than a VHF wavelength.

Hooks and why it got that way: I wonder if there was a standard-minimum mainwheel-axle-to-hook-tip distance? Hooks are called "tailhooks" for a reason and were traditionally attached to the aftmost end of the load-bearing structure. This naturally gave you the right answer on a twin, with a keel between the engines, and (before JSF) the last Navy singles were the T-45 and A-7 - with the T-45 hook attached behind the ventral fin.

I suspect they'd have had problems with the A-12, had they got that far:



They have had problems with the X-47B, but tinkering with the hook point worked.

On the F-35C, the significance of two factors: the mainwheels far aft, and the last full-depth bulkhead far forward (because F-35B), seems to have been missed. After one try, they may be down to the last not-horribly-expensive solution.

The next step might be Engines' extensible hook, but I suspect at that point that the Rhino-Growler Mafia will grab the C's collar in one hand, and their Winchester in the other, and head for the back of the barn.
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Old 9th May 2013, 17:09
  #2285 (permalink)  
 
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"I think LMT and other JSF fans like to give the impression that the F-35 is exactly like the F-22, which it most probably is not."
no one I've seen said that..it's been the f-35 is second lowest LO to the f-22 being first...got a link to where LMT said it, or are you making it up through a vivid imagination?
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Old 9th May 2013, 17:14
  #2286 (permalink)  
 
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Originally Posted by LowObservable View Post
Personally I have never been too sure where the line lies between "LO" and "VLO", let alone "ELO", which I dislike because it gets "Mr Blue Sky" stuck in my head for an hour.
Agreed. Interestingly not too long ago (maybe still) it was considered classified to use the term ELO to describe a platform even though there was no open source definition of that term.

I think LMT and other JSF fans like to give the impression that the F-35 is exactly like the F-22, which it most probably is not. (Exhausts for instance, not to mention the lumpy Rosie-O'Donnell-in-yoga-pants lower-aft view.) And neither is going to be like a flying wing with nary a single part that it smaller than a VHF wavelength.
You are correct. The F-35 all-aspect numbers are not as good as the F-22.
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Old 9th May 2013, 17:15
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Engines,

Yes, I'm with all that. My comment about building hooks was aimed at 'proper hooks' like the F-4 etc. I remember my disappointment when I saw what they'd glued onto the back end of the F3. Mind you, the weak point there wasn't the hook, it was the rear fuselage, a point you make well in this context.

Courtney
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Old 9th May 2013, 17:18
  #2288 (permalink)  
 
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Originally Posted by Bevo
You are correct. The F-35 all-aspect numbers are not as good as the F-22.
Quite, and we won't know completely how much different until the mods are complete (F-35C hook for example as well as internals) and someone can jack the final thing up in an anechoic chamber to measure it.

Last edited by Courtney Mil; 9th May 2013 at 17:19.
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Old 9th May 2013, 19:36
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jack the final thing up in an anechoic chamber to measure it.
Which probably won't be done. And if it was, would be an inconclusive exercise.
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Old 9th May 2013, 19:43
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Yes, you may well be right. But it would be mainly too late.
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Old 9th May 2013, 19:52
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'PhillipG' & 'Courtney Mil' it does seem odd that thus far you both have chosen to ignore the success of the interim redesign tests of the F-35C hook, as outlined in this thread. Yes the redesigned damper needs to be tested WITH the redesigned successful hook. However success is success. Here is another snippet...

LM F-35 Fast Facts 31 May 2012 (unpublished)
“CF-3 performed a total of 18 success-ful roll-in arrestments [MK-7 (6 with risers & 4 with no risers) & E-28 (8 arrestments)] at Lakehurst from 80 to 100 knots ground speed....” (risers in this context would be the gizmos wot keep the wire off the deck/ground so in four MK-7 cases the wire was flat on the ground)

Last edited by SpazSinbad; 9th May 2013 at 19:53. Reason: for to four
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Old 9th May 2013, 19:53
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Courtney,

Excellent point well made - there is a whole world of difference between the F-4's hook system (stressed and designed for repeated engagements in a wide variety of attitudes, and able to be repeatedly raised and lowered) and the F3's emergency 'one time only' design. You also make the excellent point that you need a fair bit of structure in the aft fuselage to react all those hook loads back into the airframe.

LO, the aft frame location on the F-35 wasn't driven by the F-35B variant. It was driven by the need to develop a single common airframe layout for all three variants, at the lowest possible weight. The main aft frame also carries landing gear loads as well as engine thrust loads, plus taking the rear wing spar. That's a common arrangement these days.

No, there wasn't a standard-minimum wheel to hook distance. And tail hooks are attached to end of a load bearing structure that is specifically designed to take tail hook loads. That structure only exists to take the hook loads, and it's usually massive. F-35C is no exception, with many hundreds of pounds of extra metal down aft for that very reason. The keel between the engines on twin engined designs like F-18 was only there to take the hook loads - that's why Courtney's point about the F3 is well made - the F3 really didn't have much of a 'keel' because it didn't need one.

By the way, as massive as the structure is to handle the hook loads, it's as nothing compared to the tons of metal needed to handle catapult loads - but's that's another story....

I was involved with the T-45, and I can tell you that the additional longerons needed to handle the hook loads were very, very substantial. BAE couldn't use a single keel beam because of the engine removal panel.

The point I'm trying to get across is that this deck landing business is hard, and the systems and solutions needed to do it reliably and safely are hard to design. No, really hard. LM very clearly did not get this hook system right first time - but my bet is that they'll fix it.

Hope this helps

Engines
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Old 9th May 2013, 20:04
  #2293 (permalink)  
 
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F-35C Hook Redesign Success (Only Part Update Tested Success Thus Far)

F-35 JSF Testers Report Progress, Problems By Guy Norris, Graham Warwick — With Amy Butler & Bill Sweetman in Washington; Source: Aviation Week & Space Technology; January 21, 2013

F-35 JSF Testers Report Progress, Problems

"...A new tailhook for the CV will undergo its critical design review within a month and is scheduled to be installed in test aircraft at Pax River by yearend. After the F-35C had problems catching the arrester cables, the hook point, shank and dampers were redesigned. The concept was demonstrated last August [2012] at NAS Lakehurst, N.J., when aircraft CF-3 made five successful engagements, McFarlan says....

...Ground and flights tests have demonstrated that the stealthy F-35’s radar signature is meeting design requirements, says McFarlan. “We have shown that if the aircraft passes the test in the [anechoic] chamber, it will pass in flight,” he says. “We are now in the mode of showing we can maintain the [low-observable] characteristics after a year in flight.”...

...Recent test highlights include hovering the F-35B for 10 min. “It was record, hovering at max performance with more than 5,000 pounds of fuel before doing a vertical landing,” he says. “We have done a lot of night flying to understand the helmet and DAS [distributed aperture system], and done night hovering as well.”..."
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Old 9th May 2013, 20:21
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Talking Stealth: USAF Pushes for 5th to 4th 'Gateway' 09 May 2013 Amy Butler

Talking Stealth: USAF Pushes for 5th to 4th 'Gateway'

"USAF officials are preparing by year’s end to begin flight testing of a communications gateway technology designed to solve the vexing problem of allowing stealthy aircraft to communicate with legacy fighters, though they operate using different protocols....

...Because the gateway aircraft will host all of the 5th to 4th components, engineers do not envision having to add equipment onto fighter aircraft. This was a primary goal , as adding any antennas onto the F-22 or F-35 without compromising their radar evading qualities could prove troublesome and costly...."

http://www.aviationweek.com/Portals/...To4th-USAF.jpg

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Old 9th May 2013, 20:35
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The point I'm trying to get across is that this deck landing business is hard, and the systems and solutions needed to do it reliably and safely are hard to design. No, really hard. LM very clearly did not get this hook system right first time - but my bet is that they'll fix it.
Absolutely, Engines. I agree.
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Old 10th May 2013, 00:54
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SRVL? Will be interesting to read the NAO report on this issue

Navy carrier jets 'can't land in hot weather' 10 May 2013 Nick Hopkins

Navy carrier jets 'can't land in hot weather' | UK news | The Guardian

"Report warns of problems with Joint Strike Fighter and exposes costs of MoD U-turns.

The hi-tech jets that will be flown from the Royal Navy's two new aircraft carriers cannot land on the ships in "hot, humid and low pressure weather conditions", a report warns today.

The version of the Joint Strike Fighter (JSF) that has been bought for the £5.5bn carriers is still in development but currently cannot land vertically – as its predecessor the Harrier jump jet could – in warm climates without jettisoning heavy payloads, the National Audit Office says.

Though the Ministry of Defence insists the problem will be overcome by the time the first carrier is ready for service in 2020, it is one of a number of concerns pointed out by the NAO over a project that has been bedevilled by delays and cost increases....

...Other hurdles must also be overcome, the NAO states, including the landing difficulties. "The STOVL is unable to land vertically on to a carrier in hot, humid and low pressure weather conditions without having to jettison heavy loads. The department advised decision makers of this risk but stated the solution it is developing will be ready by 2020."..."
_________________

UK Watchdog: Faulty Data Drove F-35 Choices for New Carriers 09 May 2012 ANDREW CHUTER

UK Watchdog: Faulty Data Drove F-35 Choices for New Carriers | Defense News | defensenews.com
_____________________________

Carrier Strike: The 2012 reversion decision 10 May 2013
The MOD acted promptly to revert to the decision to buy the vertical take-off version of the Joint Strike Fighter but will have to manage significant risks

Carrier Strike: The 2012 reversion decision | National Audit Office

Downloads:
• Executive Summary (pdf - 117KB)
http://www.nao.org.uk/wp-content/upl...ve-summary.pdf

• Full Report (pdf - 332KB)
http://www.nao.org.uk/wp-content/upl...ull-report.pdf

Last edited by SpazSinbad; 10th May 2013 at 01:17. Reason: Another URL edit + NAO LINK add
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Old 10th May 2013, 07:39
  #2297 (permalink)  
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As I was saying concerning the issue of linking the F-35 to other types, and the ground, see the link below. You might squeeze it into MASC, but the LOS won't be great and there will be weight issues when MIDS/JTRS is added. The other options of a Global Hawk or new type compound the costs.

Talking Stealth: USAF Pushes for 5th to 4th 'Gateway

Last edited by ORAC; 10th May 2013 at 07:40.
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Old 10th May 2013, 07:59
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'ORAC': Same info with a pic no less BTM of previous page:

http://www.pprune.org/military-aircr...ml#post7834762
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Old 10th May 2013, 08:03
  #2299 (permalink)  
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I'll leave my post as the comment stands. What, when and how much? Can you take the F-35 into a mixed type/SAW environment until it can crosstalk?
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Old 10th May 2013, 08:05
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Spaz,

Goodness, you're quick off the mark with the news! Fortunately for the programme, the NAO, IMHO, is good at stating the bleedin' obvious when it's all way too late. At least the report brings more of the issues we've seen being discussed here out into the open and more in the public eye.

In response, the MoD here have stated that they do not support the timelines in the report and that they will have it all operational by the end of the decade, or something along those lines.
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