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F-35 Cancelled, then what ?

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F-35 Cancelled, then what ?

Old 14th May 2013, 21:51
  #2381 (permalink)  
 
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Originally Posted by JSFfan View Post
Bevo,
re B2, they have said the f-35 has a lower RCS but they haven't said in all or what bands.
I was not referring to the RCS levels. The discussion was the repair of OML materials. The point I was making is that because the B-2 has a much broader band signature reduction its material stack is more complex than the F-35.
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Old 14th May 2013, 22:03
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Bevo, your point was well understood, mostly. JSFf won't get it if it's not on the internet, so don't be concerned.

There is an unfortunate truth in your post, however. The B-2 does have a very broad, but undisclosed, LO bandwidth, but the problem is that if the F-35 is to go alone and unafraid over sausage side as a four-ship with no support, it should probably require the same LO spectrum. And it clearly doesn't. And that isn't, or isn't planned to be in the VSIM evaluation for some reason.

Thank you, APG63 for your point.

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Old 15th May 2013, 00:58
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Maybe something more exotic?

Just a thought on the original question:

U.S. Navy's X-47B 'stealth drone' launches from an aircraft carrier for the first time - as critics warn it heralds the rise of 'killer robots' | Mail Online

Although we'd have to get rid of the ski ramp first . . . .
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Old 15th May 2013, 02:16
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Curved EMALS Ski Jumped

OR... Youse could put an EMALS (curved to fit) up the ski jumperoonie? The arrestor wires would mess up the deck park plans but....
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Old 15th May 2013, 10:25
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Essentially the ASTOBAR configuration looked at in the concept phase. Less of an emb8ggerance for safe parking area than STOBAR, but still risky from PoV of nose gear loading and EM catapult development.
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Old 15th May 2013, 13:04
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Bevo there hasn't been much said about any RP composites on the B2 but Schwartz said when talking about the B2 replacement come 2025..
"While the 20 B-2s in service are capable aircraft, their stealth technology is “80s vintage“ The reality is that the B-2 over time will become less survivable in contested airspace,

Do you think that the Chinese have established one of the world’s best air defense environments in their eastern provinces just to invest their national treasure — or, for that matter, that the Iranians have established integrated air defenses around certain locations in their country?”
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Old 15th May 2013, 22:08
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Originally Posted by JSFfan View Post
Bevo there hasn't been much said about any RP composites on the B2 but Schwartz said when talking about the B2 replacement come 2025..
"While the 20 B-2s in service are capable aircraft, their stealth technology is “80s vintage“ The reality is that the B-2 over time will become less survivable in contested airspace,

Do you think that the Chinese have established one of the world’s best air defense environments in their eastern provinces just to invest their national treasure — or, for that matter, that the Iranians have established integrated air defenses around certain locations in their country?”
And your point is?? The B-2 still has one of the best broad-band low signatures in existence. The F-35 is pretty much a high frequency only design, and then mostly from the front hemisphere. And yes the Chinese have a very capable IADS which will make it very difficult for an F-35 with its narrow band reduced signature to get anywhere close to Chinese targets. The best the US will have until the next generation bomber comes along will be the B-2.
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Old 15th May 2013, 23:44
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well thank you for your opinion. I'll take onboard that you think it's "very difficult for an F-35 with its narrow band reduced signature to get anywhere close to Chinese targets."
Would you like to validiate it with a link?

As I said earlier it is reported that the f-35 has the second lowest RCS, although it doesn't state in all bands

"We’ve taken it to a different level," O’Bryan said. The stealth of the production F-35—verified in radar cross section tests performed on classified western test ranges—is better than that of any aircraft other than the F-22.

Last edited by JSFfan; 16th May 2013 at 08:03.
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Old 16th May 2013, 10:01
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Perhaps I can help, Bevo. Global Security and Air Power Australia made the point between them quite well in that the F-35 has a frontal RCS in the region of 0.0015m2,which is comparable to the B-2A. However, the RCS increases away from the head aspect - largely due to the aircraft shape, a problem not shared by the B-2A. F-35 LO design is optimized in the X and S-bands while Russian (post-Soviet) and Chinese designed IADS have been moving into L-band, UHF and VHF. The F-35 design strategy is consistent with defeating mobile battlefield short range point defence SAM and AAA systems such as -8 Gecko, SA-9, Chapparel, Crotale, Roland, SA-15, SA-19 and SA-22.

The massive increase in power output of engagement radars means agreater ability to track LO platforms off the head aspect in the X and S-bands.

Paraphrased assessment:

JSF can provide genuinely good stealth performance only in a fairly narrow ~29° sector about the aircraft’s nose, where the shaping of the nose, engine inlets, panel edge serrations, and alignment of the leading and trailing edges of the wings and stabilators results in the absence of major spikes in the radar signature. The ±14.5° angular limit is constrained by the principal reflecting lobe of the leading and trailing edges of the wings and stabilators. The signature degrades rapidly due to the influence of the lower centre fuselage as the angle swings past ±45° off the nose.

The beam aspect RCS is especially problematic, due to the presence of multiple specular reflecting shapes, specifically due to singly and doubly curved lower fuselage surface feature shaping. The Joint Strike Fighter has a complex lower fuselage shape as well as a wing and fuselage lower join shape, unlike any other aircraft designed with stealth in mind. The result of this design is that the beam aspect RCS will be closer in magnitude to a conventional fighter flown clean than a classical stealth aircraft. This is an inevitable result of clustering no less than nine unique convex specular scattering shapes in the lower hemisphere of the aircraft.

The aft sector RCS is also problematic, as a result of the use of an axisymmetric nozzle design. While the aft fuselage and tailboom shaping qualify as stealthy across the upper bands, the nozzle presents as a specular reflector in bands where the wavelength is comparable or exceeds the dimensions of the nozzle segments.

These are from unclassified sources doing analysis on highly classified issues.

A picture paints a thousand words. Here are 4,000 words for you.


Last edited by Courtney Mil; 16th May 2013 at 10:33.
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Old 16th May 2013, 13:03
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Quite a useful piece, CMil. It chimes with the Israeli report on F-35 that raised three main concerns,the first of which was:
A low radar signature in the X-band and Ka/K/Ku-band, the frequencies used in most current threats. This low signature is effective especially in a forward sector, but less so in other sectors. Its level of stealth is much lower against radar using lower frequencies (and the Russians are already developing such systems).
I would place the B-2's RCS at around 0.0001 m2 or -40dBm2 (head aspect so that we compare like with like compared to CMil's figure for the F-35). It appears that everyone here is using the US band designations, but to talk numbers, I would say that F-35 stealth optimization is in the 1.5 to (say) 10 GHz. There is a big difference between that region and large radars operating below 1 GHz, even down to 100MHz which would be classed as metric radar.

So, I would say that Bevo's comment regarding the difference between the secret RCSs of two very different aircraft would be difficult to dismiss, especially in the lower wavebands.
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Old 16th May 2013, 13:25
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If you give the opposition 15 years notice of what the damn plane look like it's no wonder they have time to develope countermeasures............
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Old 16th May 2013, 13:41
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Goodness JSFfan - If you can't base an RCS calculation from "Internet photos" (which are of lower quality than regular photos, exactly how?) how come, back in the day, you'd find yourself assuming the position at the wrong end of an M-16 if you tried to get within telephoto range of TTR?

Believe me, sonny, back in those days the GRU would have killed for images like we have on the web today. Literally.

In our modern day, photos beget a wireframe and the wireframe begets a pretty good physical-optics estimate, and while there are other bits and pieces involved, PO is the Big Kahuna once the wavelength is shorter than most of the shape features on the aircraft.

And in PO terms (think optical glint) the F-35 is a step back from the F-22, because if you filled in all the valleys and flattened the hills you'd have worse weight and drag than you already do.

The relationship between wavelength and feature size, plus the need for all-round stealth, is why the B-2 is a big flying wing, because the P-14 Tall King ran in VHF (meter class) frequencies where fins and tails and such like get resonant. And it is why UCAVs (which can't dodge or shoot back) share the same kind of manta-ray look.

Meanwhile, openly available software can solve Maxwell's equations for complex shapes (which is what stumped all low-RCS aircraft efforts until the mid-1970s). So in fact there is no reason that APA should not have the numbers as close as you can reasonably get. And that's why the trolls have no counter except posting silly pictures.

HH - You're right of course. Except that by the time JSF is in service and able to do something useful, it will be nearly 25 years since the RCS objective was obvious.

Last edited by LowObservable; 16th May 2013 at 13:44.
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Old 16th May 2013, 14:42
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Originally Posted by JSFfan
well thank you for your opinion. I'll take onboard that you think it's "very difficult for an F-35 with its narrow band reduced signature to get anywhere close to Chinese targets."
Would you like to validiate it with a link?
You just don't get it, do you?
Everyone with 101 radio knowledge knows the size matters in respect to wavelength and RCS.
Why?
Because, (an)isotropy of a radio return (and scatter) depends on the size of the antenna (reflector), which are aircraft features in this case (wings, fins, intake mouth, etc.)
There's no fighter sized aircraft in this world, stealthy against low freq. radars, although the F117's geometry made the most progress in the class.
So yes, F35 is probably the stealthiest NATO manned aircraft after the F22, but it doesn't mean, EVEN BY A LONG SHOT, it can penetrate enemy airspace unobserved.
Read this link to get a clue what are strategic radars capable of doing today (some are even mobile!).
WILKENING-EUROPEANMISSILEDEF.PDF - download now for free. File sharing. Software file sharing. Free file hosting. File upload. FileFactory.com

About APA's figures...they conditioned their calculations with generic RAM, so actual material may produce differences in the final result.
Finally, about your claim one can't calculate RCS from a 3D model...
How do you think LM came up with the initial layout for the F35, in the first place?
I suppose you believe they built and scrapped actual plane after plane, until radar showed KPP values, right?

Last edited by NITRO104; 16th May 2013 at 15:03.
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Old 16th May 2013, 15:17
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A perfect illustration of why a troll shouldn't turn up in front of a load of people who know their business and start spouting off like an expert, trying to be clever and generally behaving with a complete lack of respect.

JSFfan, you clearly have no understanding of this subject, so why not refrain from embarrassing yourself further?
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Old 16th May 2013, 15:18
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Well said.


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Last edited by Mach Two; 16th May 2013 at 15:19.
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Old 16th May 2013, 15:54
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So much for stealth ...
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Old 16th May 2013, 18:55
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...or is it? We still don't know how the wonder jet is going to go over the badlands without support and survive day one of the war. Whatever war that might be. We haven't discussed who's going to do air defence of the fleet for the Royal Navy and, far more important, how we're going to explain it away to the Bearded One when it doesn't work. Do we admit to yet another RAF conspiracy now or wait until it happens?

Last edited by Courtney Mil; 16th May 2013 at 18:56.
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Old 16th May 2013, 19:06
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Courtney, I was thinking, as I posted that, of the matter of system integration. The comments preceding it indicate certain RF spectra and aspect where the F-35 appears to be more difficult to detect, and others where it isn't as difficult. Most IAD systems have more than one sensor.

Sensor fusion, such as the CORT refit for the USN's FFG-7 class frigates (IIRC, Ingraham was the lead ship to get that refit) took the same basic sensors that got the frigates dubbed "Helen Keller" (deaf and blind) and by fusing the sensor suites (and using better computing equipment) made it a viable player in the NTDS link, in terms of track quality and confidence in tracking, particularly in the AAW/Air Defense role. That was going on 20 years ago.

It's not much of a leap to believe that other services in other nations try their hands at sensorand network data fusion to get rid of potential blind spots created by RF spectrum issues, lobes, scatter, and a dozen other detractors to RF signals getting the gain needed to separate valid from invalid returns.
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Old 16th May 2013, 19:25
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You are spot on. And linking sensors brings another benefit in synthetic apature technology, which doesn't just offer amazing resolution, it also exploits the LO hotspots of targets. Mix that with radars of different frequencies, polarizations and PRFs and you have a system that is far greater than the sum of its parts. The Russians have been working in this area for decades and the Chinese have been 'researching' their technology too.

Just an example...

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Old 16th May 2013, 19:40
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Originally Posted by Courtney Mil View Post
You are spot on. And linking sensors brings another benefit in synthetic apature technology, which doesn't just offer amazing resolution, it also exploits the LO hotspots of targets. Mix that with radars of different frequencies, polarizations and PRFs and you have a system that is far greater than the sum of its parts. The Russians have been working in this area for decades and the Chinese have been 'researching' their technology too.
Absolutely correct. This is why it now takes a combination of EMC/com jamming, low signature aircraft, and cruise missiles to take out the fixed/less mobile radars, in order to have any chance of penetrating a modern IADS. Fortunately there aren’t too many IADS that match either the Chinese or Russian’s in their level of sophistication.
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