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-   -   F-35 Cancelled, then what ? (https://www.pprune.org/military-aviation/424953-f-35-cancelled-then-what.html)

kbrockman 30th Mar 2013 09:52


With the advances in Avionics technology I seem to recall that the GR7 to GR9 upgrade actually lightened the aircraft whilst increasing the capability. Which was handy when the requirement to carry Sniper, a Terma pod and a useful weapon load was essential. Weight growth over the lifetime of an airframe is not a given, but more thrust is always good.
More thrust is indeed always good provided it doesn't mean less reliability and substantial higher fuel consumption, the F135 is probably scoring positive on all these fronts.
However the F35 airframe-strrength is already pretty much stretched as far as it can go for now, more power will probably mean more structural integraty needed.

Also for a 60000-70000 lbs it is very doubtfull that substantial weightloss can be achieved in the avionics department like in your GR7-9 example, certainly not looking at the complexity of the F35 in this department.

As an example it might be best to look at its predecessors, the F16 for one was specifically conceived with the idea that weightgain would have to be minimal over its complete lifetime.
It had intentionally very little empty room left in the beginning ,,2cu ft in comparison the F15 had about 15 cu ft of empty space in the beginning.
As a general rule fighters gain about a pound per day due to added complexity and added capabilities, the F16 scored pretty favorably on that point , the weightgain was limited to about 0.5lbs per day over its lifetime but even than it still managed to grow from a block 10 15600 pound fighter to a 19200pound block 50 fighter.

There is absolutely no foundation to believe that the F35 will not gain substantial weight over its lifetime.
A more powerful engine will inevitably mean some weightgain even further degrading the performance of the F35, wingloading is pretty terible at the beginning of its life and will further degrade when it becomes inevitably heavier.
Maybe the NAVY's proposal of going for the C iso A for the USAF wasn't such a bad idea at all, the larger wings will accomodate more fuel negating the need for something like CFT's in an already very bulky and draggy F35A.

Substantial weightloss for the Air Force C version could still be made by using a lighter landing gear , lighter arrestor hook+reinforcements needed to cope with carrier ops and using a boom-refuel point iso a heavier and more complex hose refuel system, also they could redo the gun and go for the lighter 27mm mauser single barrel iso the heavier 25mm gatling the A has now.
Less ammo would be needed also.

Easy Street 30th Mar 2013 10:42


sorry guys, I'm not in a hole..it seems you can't accept that the f-35 goes M1.2 in dry
Sigh... yes it can, but it will be decelerating [slowly] and will continue to decelerate until subsonic, because it cannot supercruise. The LM spin machine is using the apparent fact that it takes 150nm to decelerate to subsonic speeds to hoodwink casual observers into believing this equates to supercruise - with apparent success.

Read Lt Col Griffiths' quotes carefully - it needs reheat to get supersonic, and will not stay there in dry power!

ORAC 30th Mar 2013 16:32

Wired: If the Military’s Future Stealth Jet Fails, the Navy’s Got a Backup Plan

HalloweenJack 30th Mar 2013 16:53

wouldn't this be a moot point anyway? as on day 2 the wing tabs are pulled off and the F35 would have as much stores as she could slapped on ; and IIRC the typhoon can carry more anyway?


anyway - canapés at FL 600 @ M2 supercrusing vs any mil aircraft thank you ;)

Stuffy 30th Mar 2013 17:24

McDonnell Douglas A-12 Avenger II - Wikipedia, the free encyclopedia

LowObservable 30th Mar 2013 22:18

The definition of supercruise varies a lot - according to which bunch of LM shills has the floor. One argument is that the JSF can't supercruise, but neither can anything else except the F-22 because the "definition" of supercruise is M>1.5 sustained without A/B. The other is that that the JSF can supercruise based on second-hand misinterpreted statements about persistence at M=1.2 at "minimal" burner.

A bit of history: The Marines may have been involved in Tripartite Kestrel/XV-6 but the lead service in the US was the Army. All that work was winding down inconclusively as the Tarawa-class (basis of Wasp and America) was designed. When the contract was let, the USMC was only at the beginning of its renewed Harrier acquisition, which had started in Sept 1968 with an informal visit to HSA at Farnborough.

So it is entirely correct to say that the ships are primarily amphibs and that their design does not provide the fuel volume &c that is optimal for fast jets. Hence the kludged design of LHA-6/7 (America and Tripoli).

As for the landing environment: The current contracts for the construction of heat-resistant landing pads are based on Navy engineers' data, which show that a single F-35B VL on standard concrete may cause spalling (that is, near-explosive breakup due to subsurface moisture turning to steam). This data appeared in late 2010, IIRC, and was pooh-poohed by LockMart (and its cheerleaders) on the grounds that tests had shown the ground environment to be no worse than Harrier. Despite this, the same NavFac specs are still in force and the pizza-oven concrete is still specified in construction contracts. And I have yet to see a land VL performed on anything other than AM-2-shielded concrete or the specially built pads.

SpazSinbad 30th Mar 2013 22:41

F-35B AM-2 Matting on Asphalt NAS Patuxent River
 
'LowObservable' said: "...And I have yet to see a land VL performed on anything other than AM-2-shielded concrete or the specially built pads."

However photos show F-35Bs VLing on AM-2 matting laid on asphalt, testing the AM-2 matting (indicated on previous pages). Video shows the X-35B more than a dozen years ago now vertical landing at the same site. PhotoBucket scrunches the original .MP4 video down to 2.7Mb (click on 2nd image below).

http://i98.photobucket.com/albums/l2...t.jpg:original

http://i98.photobucket.com/albums/l2...erHiQmusic.jpg

JSFfan 30th Mar 2013 23:18

LO, it seems that you are the one misrepresenting what was said
It seems some are really upset that the f-35 can "cruise" with min AB and "maintain Mach 1.2" without AB

glad rag 30th Mar 2013 23:21

Once again, play the ball, not the player JSFF.


although the eu would class it as such
Really. Tedious.com

But no longer.

JSFfan 30th Mar 2013 23:33

what are you on about? the US call supercruise M1.5+, EU calls supercruise M1+

servodyne 31st Mar 2013 01:31

I think the essential point is missed, it does not matter what the definition of Supercruise is be it M1.5 or greater than M 1.0 the aircraft quoted (F-22 or typhoon) can MAINTAIN those speeds and therefore Cruise. The F-35 continues to decelerate and thus does not CRUISE without afterburner 'nuff said.

Foghorn Leghorn 31st Mar 2013 01:55

Are all these figures people quote on here open source?

JSFfan 31st Mar 2013 01:59

yes, both cruise with min AB and maintains M1.2 without AB is open source
http://www.airforce-magazine.com/Mag...112fighter.pdf

although the spec for f-35ac is 700kt speed limited to M1.6, it's been reported that the f-35a does 750kt and speed limited to M1.6, so the alt is important too and there is no mention of it in any statement

further to that, Hog who said it cruises with min AB. also on f-16net is said to say when asked, the f-35A does M1.25 without AB

SpazSinbad 31st Mar 2013 05:34

Cool Concrete Under F-35B Similar Harrier Sim
 
VIDEO: History of the F-35 by Skunk Works inventor (3 parts)
By Stephen Trimble on March 22, 2010

VIDEO: History of the F-35 by Skunk Works inventor (3 parts) - The DEW Line

"The DEW Line is pleased to offer a three-part video showing a fascinating (albeit poorly-lit), 1hr lecture on the F-35 Joint Strike Fighter, presented last week by Skunk Works engineer Paul Bevilaqua at Johns Hopkins University's applied physics laboratory in Laurel, Maryland.

Bevilaqua is credited with the invention of Lockheed Martin's shaft-driven lift-fan, the core technology allowing the short-takeoff-vertical-landing (STOVL) F-35B...."

39 second VIDEO snippet (5.3Mb) at PhotoBucket shows the 'cool' temperature during an F-35B VL simulation. Otherwise go to the webpage above to view 3 videos which make up the presentation. Quote approximation: "concrete spalls at 1,000 deg F whilst concrete temp under F-35B exhaust is 600 deg F".
_____________

Additional text added here to explain video.

'LowObservable' said on page 75 of this thread [ http://www.pprune.org/military-aircr...ml#post7767529 ]

"...WhiteOvies - Wheeler raises a perfectly valid point. As you note, the VL pad at Pax is AM-2 mat, but laid over concrete as a heat-shield rather than as a structural surface over dirt or cr@ppy asphalt. The VL pads at Yuma and Beaufort are made of heat-resistant concrete. There's some notion of a "creeping vertical" landing but there is no word as to when that will be demonstrated at all, let alone on the equivalent of a 3,000-foot-somewhere-ending-in-stan runway...."

'LowObservable' said on page 77 of this thread [ http://www.pprune.org/military-aircr...ml#post7769356 ]

"...As for the landing environment: The current contracts for the construction of heat-resistant landing pads are based on Navy engineers' data, which show that a single F-35B VL on standard concrete may cause spalling (that is, near-explosive breakup due to subsurface moisture turning to steam). This data appeared in late 2010, IIRC, and was pooh-poohed by LockMart (and its cheerleaders) on the grounds that tests had shown the ground environment to be no worse than Harrier. Despite this, the same NavFac specs are still in force and the pizza-oven concrete is still specified in construction contracts. And I have yet to see a land VL performed on anything other than AM-2-shielded concrete or the specially built pads."
______________

Reference recent photo of AM-2 matting on asphalt at NAS Patuxent River (+ old video of the same site) here (2 places):

http://www.pprune.org/military-aircr...ml#post7769396 & http://www.pprune.org/military-aircr...ml#post7767601

Best hear the video clip to understand the 'cool' 600 degree F temp on concrete during a VL - similar to Harrier. Similarly USS Wasp and tests at NAS Patuxent River on the AM-2 matting during F-35B VLs confirm the environment is similar to the Harrier. Click second graphic for video - first graphic is a screenshot showing 600 degree F concrete temperature during VL.

http://i98.photobucket.com/albums/l2...m.png:original


http://i98.photobucket.com/albums/l2...reteSimHiQ.jpg

Shackleton Mark 3 31st Mar 2013 10:26

F-35 Cancelled?
 
Some nice thoughts here but please don't be under any illusion that the F-35 aircraft programme might yet be cancelled by the DoD or that the UK might yet dump its committment to buy the F-35B. That isn't going to happen - not under the this Coalition, a potential Labour Coalition or even if we end up with a one party government post the next General Election. This programme is sacrosanct on both sides of the 'pond' even if numbers of aircraft remain open to question.

Like many of you I would also love to see a new British designed and British built replacement aircraft for Harrier but it just isn't going to happen. We do not have the political, financial or industrial capability to achieve this but worse is that in a risk averse world driven by short term thinking neither do we have the will. Rest assured though that for good or bad, for better or worse F-35B will come and despite the prospect of even more damage to UK defence as a likely result of SDSR 2015 I believe that we will retain both new aircraft carriers. For now, my fear is that we might see a further drive towards base and personnel cuts in the Royal Air Force and merging of additional Royal Air Force and Royal Navy operational capacity and support services.

As to a future 'new' maritime capability committment - best put that dream back its box.

glad rag 31st Mar 2013 10:55

Nice video, everybody nod your heads together.

LowObservable 31st Mar 2013 13:08

Bevilacqua has not been part of the JSF program for some years and most of the graphical material included in that presentation is old. Note that the video shows the pre-2004 split-top fan doors.

Below, Navy engineers from 2010.


For landing, VL (or VTOL) pads will be used. This pads will be exposed to 1700ºF and high velocity (Mach #1) exhaust. This exhaust will melt the top surface of asphalt pavements, and is likely to spall the surface of standard airfield concrete pavements on the first VL.
Therefore high heat resistant materials are required for the pavement and for the joint sealants. At the present time there are no identified sealants that can survive a significant number of VLs, and the pads shall be constructed
using continuously reinforced concrete (CRC)... with continuous reinforcement in both directions to insure that all cracks and
joints remain closed.
High heat resistant materials for the pavement have been identified but are still being tested.


http://www.wbdg.org/ccb/NAVFAC/INTCRIT/fy10_01.pdf

Those specs still appear to be current, the main change having been that a suitable concrete has been selected. This is from last September, almost three years after the LockMart spokesmen and USMC commander were assuring everyone that the ground environment was Harrier-like:

Navy prepares more contracts for work related to F-35 | Beaufort News | The Island Packet

Made from an advanced, high-temperature concrete that can withstand the heat from the new jets' engines, the surface will be used by pilots to practice taking off from and landing on the deck of an aircraft carrier using the plane's short takeoff and vertical-landing capabilities.

Maybe "creeping vertical" can alleviate some of these effects. However, I'm not aware of any schedule for testing F-35B on low-quality surfaces, nor is it a KPP to my knowledge.

Also, as for "asphalt" and "concrete" we should not get tied up in terminology:

https://en.wikipedia.org/wiki/Asphalt_concrete

AM-2, by the way, is not solid so it will have a heat-shield effect on either standard or asphalt concrete. The JSF's ability to land on an unprotected surface has nothing to do with AM-2-shielded demos.

Stuffy 31st Mar 2013 16:43

Shackleton Mk 3,

Nothing is certain in politics, in this case history seems to be repeating itself.
Cameron and Osbourne remind me of Heath and Barber in 1973/74.

Osbourne's sub-prime Ponzi scheme a la Fanny Mae and Freddie Mac, is bound to end in tears. Assuming they last until 2015? A date they claim is set in stone.

The bottom of this recession/depression will be 2014/15 approximately.

The F-35 is too expensive for what it does.

A navalised Typhoon will only need an arrester wire. It's power allows it to take off with the aid of a ski ramp. As the Sukhois do on the Russian carrier Admiral Kuznetzov.

2014/15, and the UK will not be able to afford the F-35.

The political scene could also be very different then.

Your analysis may well be correct, I just don't see where the money is coming from?

I would also like to see the argument that the F-35 has no equal? I don't see the point of STOVL ?

Milo Minderbinder 31st Mar 2013 17:07

Stuffy
Have you seen a photo of an aircraft launching from the Kuznetzov ski ramp actually carrying any payload?

Stuffy 31st Mar 2013 17:45

Kilo,

Good point. It is unlikely the Russians or Chinese would waste their time if it were not possible?

Perhaps this thread should be called 'The Dog's Dinner'.

As ever, time will tell.

The Coalition spent £700 million to find out that we couldn't have the F-35C.

Perhaps - 'The Expensive Dog's Dinner' ?

President Eisenhower warned about the 'Military Industrial Complex'.



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