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Subject: Scientists warned defence department against Joint Strike Fighter
french stratege    2/26/2010 1:30:12 PM
http://www.theaustralian.com.au/politics/scientists-warned-defence-department-against-joint-strike-fighter/story-e6frgczf-1225834053074 AN internal Defence study warned that the new Joint Strike Fighter would be a high-risk venture for Australia, admitting that the plane had weaknesses, including poor engine thrust that made it difficult to dodge missiles. The blunt criticisms of the warplane contained in the study by Defence scientists in 2000 have never been aired publicly by the government. But the Defence Science and Technology Organisation study, obtained by The Australian, was far more critical of the other fighter jet options available to Australia if it did not choose the JSF. The document uses highly undiplomatic language to trash the performance of the warplanes used by Australia's closest allies. The DSTO study, described as a "first-cut analysis" of Australia's future fighter needs, was written two years before the Howard government signed up to the US-led JSF program in 2002, abandoning the tender process and stunning aircraft manufacturers. Start of sidebar. Skip to end of sidebar. End of sidebar. Return to start of sidebar. Titled "A Preliminary Assessment of Inhabited Platforms for AIR6000" and written by the DSTO's Graeme Murray and David Carr, the study is significant because it is one of only a handful of studies that looked at alternatives to the JSF. The government plans to buy 100 JSFs for $16 billion in what will be the largest Australian defence purchase in history. The DSTO report, written at a time when the JSF existed only on paper, said that if Australia signed on to the JSF program, it would be doing so without knowing the plane's final capability and costs. "JSF has present serious shortfalls in engine performance and incomplete sensor-fusion capability," the DSTO said. "The aircraft lacks engine thrust in the baseline configuration due to the high weight, affecting the use of manoeuvrability to defeat missile attack." It also warned of hi-tech risks in the program because of tight schedule and cost targets, but it gave the plane strong marks for its stealth, range, payload and its "all weather, 24-hour lethality". It said the JSF would not be cheaper to acquire than other fighters, but would be cheaper to maintain and service. The study favours the JSF over other options and is blunt about the shortcomings of Australia's other fighter options. It describes the US F-16 used by the US Air Force as having a weak airframe and poor stealth. "Old airframe lacks agility to outmanoeuvre missiles and has a small internal fuel capacity," the DSTO said of the F-16. It said Europe's Typhoon fighter had limited strike capability and was unreliable. "Present (strike) capability is lacking due to limited sensors and weapons carrying capability," it said of the Typhoon. "Low reliability will mean high costs to operate." It said Sweden's Gripen fighter had poor stealth, an underdeveloped electronic warfare system and payload and range limitations. The DSTO found that the earlier version of the F/A-18E Super Hornet -- not the Block II version that has since been purchased by Australia -- was underpowered, lacked endurance and "risks being shot from behind with a radar-guided missile". The US F-15E lacked stealth while France's Rafale had an unreliable and weak engine. "The F-15E is good now, but not likely to be defensible in the expected electronic warfare environment in the 2010 timeframe," the DSTO said. "Rafale has short-term shortfalls in engine and radar performance." The DSTO said the F-22 fighter -- the production of which was recently cancelled by US Defence Secretary Robert Gates -- had limited strike capability and was very expensive. Despite these criticisms, the study recommended narrowing Australia's choice of a new fighter jet to only three: the JSF, the American F-15E and the French Rafale.
 
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french stratege       2/26/2010 1:35:01 PM
What is interesting is that:
While Australian goverment military equipement advisors point out that F15 is not stealth, they underline that France's Rafale had an unreliable and weak engine.
It was true since rafale was still a paper plane and only as prototypes and that its engine was short lived and its RBE2 not enough.
Since 2000  Rafale F3 exists now (since 2008), its engine has seen their service life increased by a magnitude, and its REBE2 radar is replaced by an AESA one with more than+ 40% range and new modes like submetric long range SAR sharpening.
 
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gf0012-aust       2/26/2010 3:35:04 PM
as has been painfully discussed on the australian board.  the assessment and the statements made by Stewart are a little distorted.

DSTO never had access to any of the meaningful JSF data in 2000
In 2000 JSF was also a relative paper plane because none of the systems data was available for in depth review
Stealth (FFS!!) was of minimal interest.

Stewart has this tendency to ignore actual material.  eg he was given a briefing by the Dept on some specfor issues and still managed to c0ck it up when he went to print.  to such an extent that the staffer who briefed him publicly canned the article and had the cheek to publicly point out that Stewart had been provided with citable material but had abused the content to suit his own purposes.

in Defence circles Stewart has had zero credibility for the last 2 years. 

as for Rafale, the french tried pushing that barrow again in australia 3 years later.  no sale. 

and not to put too fine a point on it, DSTO are currently involved with JSF development for australian e-reqs (funnier when you factor in all the hype that the US won't provide "source code" and yet we (and the danes and the norwegians) are happily developing national specific "systems" with the full blessing of the US.....)

go figure.

who would have thought that an incomplete 10 year old assessment sans access to actual US briefs would get a run on SP..... :-) 

 
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Phaid       2/26/2010 4:44:55 PM
Saw this on Ares or DEW Line a few days ago.  When I read "risks being shot from behind with a radar-guided missile" as a criticism, I figured it was either a joke or something written by a grade-school student.  Leave it to the village idiot to trot it out as "evidence" of something.
 
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french stratege       2/26/2010 9:27:46 PM
The journalist has probably zero credibility (especially when he makes such comment like "risks being shot from behind with a radar-guided missile" - and most of journalists are idiots on tech matters BTW)  but is the Australian Defence Science and Technology Organisation a joke gf0012?
In 2000 main specifications of JSF and its concept were already known.
And I guess as you pointed out, that collaboration between Oz and USA allows some exchanges on data.
"The aircraft lacks engine thrust in the baseline configuration due to the high weight, affecting the use of manoeuvrability to defeat missile attack."
This is not new since F35 T/W ratio is closer to a F4E Phantom than a F16C.
Just funny, but still valid in a great extent since any competent aircraft designer knows weaknesses of F35.
 
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gf0012-aust       2/27/2010 12:16:02 AM

The journalist has probably zero credibility (especially when he makes such comment like "risks being shot from behind with a radar-guided missile" - and most of journalists are idiots on tech matters BTW)  but is the Australian Defence Science and Technology Organisation a joke gf0012?

the alarm bells should have gone off for you straight away when you saw the comment about thrust and missile evasion.
 
that means that the item is either completely out of context, or that its missing significant detail around that comment.
 
it smacks of the same silliness that came out of RAND. - out of context and incomplete.
 
blind freddy can see that this is not the kind of material that gets presented and shared with the likes of NAVSEA, DARPA, DERA/Quinetic etc....
 
if you can't see the holes in this article and still assume that its a literal presentation around that timeframe - then there's not much else I can say to point out why the alarm bells should be going off.
 
 
 
 
 
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sinoflex    Thrust to Weight   2/27/2010 5:31:41 AM
The criticism of F-35 TW ratio is often disingenuous especially when it is based on a full internal fuel load since a good portion of the the weight in fuel would have been burned off to reach combat station.  A F-35 with 18,500 lbs of internal fuel has a similar range to a F-16 with 7,160 lbs of internal fuel and 8,000 lbs of external fuel in 2 6,000 gal tanks.
 
If one considers a simplistic scenario of a mission to the edge of intercept radius  and assuming a F-35 with 43,000 of AB thrust / ( empty weight of 28,000lbs + half expended fuel load of 9,250 lbs ) and a F-16C with 29,000 of AB thrust / ( empty weight of 18,270lbs + 7,160 lbs of internal fuel ) the F-35 has a slightly higher TW ratio of 1.15 vs 1.14.   So in actuality with realistic combat and fuel loads the TW ratios are similar throughout the mission profile. 
 
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sinoflex    Typo   2/27/2010 5:35:35 AM
My mistake, the 6,000 gal external tanks should be 600 gal tanks.
 
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StobieWan       2/27/2010 10:22:10 AM
Not sure why you had to turn this into yet another Rafale vs everything thread but what's the T/W ratio of a Rafale with the same fuel load as an F35?
 
Oh, wait, to carry that extra fuel, there's practically nothing left over to carry any weapons for the Rafale? Plus all that drag from the external tanks of course. And you're not very stealthy. Or in fact, at all.

Ian
 

This is not new since F35 T/W ratio is closer to a F4E Phantom than a F16C.

Just funny, but still valid in a great extent since any competent aircraft designer knows weaknesses of F35.


 
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french stratege       2/27/2010 1:03:02 PM

The criticism of F-35 TW ratio is often disingenuous especially when it is based on a full internal fuel load since a good portion of the the weight in fuel would have been burned off to reach combat station.  A F-35 with 18,500 lbs of internal fuel has a similar range to a F-16 with 7,160 lbs of internal fuel and 8,000 lbs of external fuel in 2 6,000 gal tanks.

If one considers a simplistic scenario of a mission to the edge of intercept radius  and assuming a F-35 with 43,000 of AB thrust / ( empty weight of 28,000lbs + half expended fuel load of 9,250 lbs ) and a F-16C with 29,000 of AB thrust / ( empty weight of 18,270lbs + 7,160 lbs of internal fuel ) the F-35 has a slightly higher TW ratio of 1.15 vs 1.14.   So in actuality with realistic combat and fuel loads the TW ratios are similar throughout the mission profile. 
Range is proportional to log of fuel ratio divided by specific consumption*drag
On pure fuel ratio if we assume a F16 with 60% fuel and 4 AMRAAM we have
60% of 7,160 lbs = 1,95 tons of remaining fuel,
empty F16+4 AMRAAM and pylons=8,99 tons so
Fuel ratio= (1,95+8,99/8,99)=1,21 and T/W=1,203
 
F35 empty weight of 29 300 lb so 13,3 tons plus 4 AMRAAM about 14 tons
So with similar 1,21 Fuel ratio it is 16,94 tons so a T/W ratio of 1,15
Not so bad on paper  if we don't forgot that frontal drag is massive and wing loading bad.
F35 is a step backward.
Whatever you may think, internal bay makes empty weight higher of 40% for a similar performance.
Compare to a Rafale if you want which would have 10 tons empty with 4 mica, 12,1 tons with same 1,21 fuel ratio, 15 tons thrust today so 1,24 T/W ratio today, and 1,48 with tomorrow 2*9 tons engine.
Difference is massive.
F35 is a massive aircraft in fact.Heavier than a F15 with at least, similar operating costs.
 
 
 
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Phaid       2/27/2010 4:56:55 PM
LOL at the idea that you can simply compare the frontal cross section of two fighters with entirely different design philosophies, wing geometries, number of engines, and stores configurations, and conclude that one is overall draggier than the other.
 
First off, that sort of pronouncement completely ignores wave drag (which increases with speed) and induced drag (which increases as speed decreases), both of which are influenced more by wing design than anything else.
 
Then you have the various components of parasitic drag: skin friction drag, form drag, interference drag.  It's eminently clear the F-35 does not have a problem with skin friction drag.  Then you have form drag, which is affected by the wings, control surfaces, external stores, pylons, etc, not just the fuselage.  And then you have interference drag, which further adds to the drag penalty of external stores, and from which the F-35 will suffer much less than any 4th gen fighter.
 
But, back to the initial assumption, namely that the F-35 somehow has a disproportionately large frontal cross-section:
 
http://img174.imageshack.us/img174/3733/rafalevsf35aey6.jpg" />
http://img174.imageshack.us/img174/7995/f18vsf35et6.jpg" width="622" height="375" />
 
http://img224.imageshack.us/img224/7897/f15f35xy6.jpg" />
 
As we see above, the notion that internal carriage automatically brings about a humongous penalty in frontal area cross-section is simply nonsense.  The fact is that in the F-35's case, frontal cross-section is used more efficiently since it has a single engine instead of two, and therefore is able to incorporate weapons bays without a significant increase in size.  Couple that with a highly blended fuselage / wing / canopy layout, a skin almost completely free of protrusions, no added form drag and interference drag from pylons or external stores, and it's pretty obvious that this is, at worst, a non-issue.
 
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