True stealth aircraft designs take a great deal of care to make sure that the areas of interest (such as a nose-on aspect) have good shaping.
Balanced survivability fighter aircraft designs like the Typhoon, the Rafale and Super-Hornet try to use shape and radar absorbing material and skin where possible along with trying to hide the leading edge of jet engine components, to degrade the effects of the kinds of radars that are most likely to kill you, such as air-intercept-radar, radar in missile seekers and high-frequency surface-to-air missile radar ground guidance stations. The results have been reported as tactically useful, but they are not stealth aircraft.
Where are stealth aircraft and balanced survivability aircraft designs on this chart?
The "balanced" part comes in where in a terminal defensive situation, the use of on-board defensive jamming aids--combined with the enhancements mentioned above--help to further reduce the effects of enemy radar emitters. A towed decoy fused to the defensive system (for example, the ALE-50/55 on the Super Hornet) helps survivability in terminal enemy missile events even more.
While on-board defensive jamming may make your general location locatable, it makes it harder for the enemy to use a radar-homing missile against such aircraft in a defensive situation.
The survivability design of the F-35 is flawed. Badly. The F-35 has good nose-on shaping; just not so good anywhere else.
Welcome to "affordable", "export-friendly" stealth. That was the hope anyway. Or the hopes of what may be the greatest defense industry Ponzi scheme.
Ever.
The F-35 is neither balanced survivability nor a true stealth aircraft. The F-35 has no credible defensive jamming. Those selling the idea that the F-35's AESA radar as a defensive device against enemy terminal radar concerns aren't believable. Power output limits, thermal concerns along with the limited field of view and in-band frequency limits make the idea of the F-35 radar as a defensive solution of little value. It is only useful on a marketing PowerPoint slide to the clueless. And, unlike the designers of the F-22, the F-35 will not be in possession of true stealth, high-speed and high altitude to help degrade enemy no-escape-zone firing solutions of weapons. The thrust-vectoring on the F-22 is also an aid for quickly changing direction at Mach and not just sub-sonic speed.
The balanced survivability people have a workable solution, combined with, "man's got to know his limitations", (Dirty Harry; Magnum Force).
The F-22 designers also have a workable defensive solution: extreme performance regardless if the aircraft is or is not, naked due to degraded low observability event.
The F-35 design is not useful for future air combat survival. And, certainly, not at any price. Further, the numerous faults in the design--since it will be unable to face emerging threats and is too expensive to own and operate for anything else--point toward "balanced" survivability aircraft like the Typhoon, Rafale and Super Hornet, as providing more overall value to an air arm.
By 2020 (if there are no more delays), a seriously flawed F-35 may be ready to fight an air war 21 years earlier: ALLIED FORCE 1999.
Failure of the F-35 program--for a nation over $16T in the red--should be easy to define.
12 comments:
Where do super hornet and F-35 lie on your scale above?
How could a radar have enough power and cooling to act as a sensor but not as a jammer? A jammer by its nature outputs much less power than a sensor.
The principle of jamming is J/S; the received jamming signal must be greater than the received skin return. The skin return is attenuated by the F-35’s low RCS and to the fourth root of distance. The jamming signal is only attenuated by the so one root of distance. It just doesn't make sense that you assert the APG-81 will lack power to act as a jammer.
*read "so one" as "second". Ta.
"A jammer by its nature outputs much less power than a sensor."
Interesting. I am curious way thermal issues and power output have always been a concern of jamming aircraft, and for that matter, even self-defense jamming pods.
Because tradiontally they (jammers) have been self-contained in small low profile pods. When the radar is being used as the jammer then this is not a problem as the power and cooling available is already way more than required.
Define "way more than required" when this very feature ("AESA as electronic attack) over-sold on the show-room floor did not pan out for Australia's Block II Supers (which they otherwise like). The over-sell of AESA as an in-band, in field of view jammer also did not work out with the F-22 (sustained power vs. heat), yet somehow in a program that is way behind on software including watered-down software Block goals,...in an aircraft that already has significant thermal-shedding issues as-is, we are to believe that AESA will be able to provide electronic self-defense. Should be interesting to see how that promise pans out with all the other promises so far pushed out to a notional block or just reduced all together. Yes, this program has a track record of success.
Historically fighter radars had much less peak power output than podded jammers. With AESA this can change when the jammers use AESA modules, as peak power output of an AESA-based radar or AESA-based jammer is a function of module count.
In case anyone is interested:
http://151.100.120.244/nanoelettronica/Presentations_29_10/Peroni.pdf
"Way more than required":
Assume the APG-81 is trying to jam a radar 20km away (transitioning from BVR to WVR). Assume the F-35 RCS is -10dbSM (conservative?).
Assume the technique being employed requires an effective J/S of 0dB (typical).
Assume line of sight propogation (valid at all altitudes besides low level). Assume a 10GHZ radar (valid for fighter antenna size limitation and tracking resolution requirements for weapons employment). This means over 20km there is 138dB loss (4pi^2*d^2/wavelength^2)
J = Power of jammer + Gain of APG81 - LOS attenuation (138) + Gain of TGT
S = Power of radar + Gain of TGT - LOS attenuation (138) + F-35 RCS (-10) - LOS attenuation (138) + Gain of TGT
= Power of radar + 2*GainTGT - 286
J/S (dB) = Power of Jammer - Power of Radar + GainAPG81 - GainTGT - 148
Assume Gain of APG-81 and TGT’s radar antennae are similar
J/S = Power of Jammer - Power of Radar - 148 = 0
148 = Power of Jammer - Power of Radar
148dB is a factor of 6x10^14.
This means that the APG-81 can be 600,000,000,000,000x less powerful than the target radar and be effective at the merge. Even I am surprised by this, ifsomeonecan spot an error in my logic, please point it out.
Think I forgot to account for the gain patterns of the antennas.. back to the books. But you get the idea.
Gripen A/B reportedly has 0.1 m2 of equivalent radar cross section, and it is something that has been worked on for the subsequent iterations.
And thermal as well ... will not the JSF be a bit of a blowtorch?
http://www.network54.com/Forum/211833/thread/1270841564/1270841564/Signature+reduction+Gripen+%28pics%29
A self-defence jammer has to distort the echo, not the original radar emission. The echo has only a tiny amount of the energy of the original emission.
Stand-off jammers are a different story.
Some historical self-defence jammers were IIRC frontal aspect-only jammers, so the ~110° restriction of AESA radars is probably acceptable.
The bigger problem is probably the home-on-jam threat and with the band restriction is most likely the biggest problem.
To: FkDahl,
The Gripen is a credible and highly respectable economical contemporary jet fighter.
With respect to Gripen's RCS, that ratio would of course be relative to whichever actual stores said Gripen was hauling along for the ride.
For example, how many Air-air missiles is that Gripen deciding to take with to the air. And is that Gripen taking to the air with drop tanks, etc.
RCS will always be relative and influenced by the actual configuration (including any additional ECM-enabling equipment) a particular operator is actually taking it's platform into the air.
Thanks for those remarks S.O.
Well taken for the record.
I'll further wish to add to that thought though and add to it my personal view, that frontal sphere jamming alone is not sufficient in the next-generation of air-combat. That is, what happens if the jet you are flying in actually wants to take a hard turn as part of the counter-measure to evade an incoming shot? (Hoping to trash the shot?)
Frontal-sphere jamming however will of course most likely be essential in next-gen air-combat to get 2 opposing fighters into a NEZ launch profile.
And after NEZ launch, it will then be up to the actual seeker-head(s) type and abilities and be up to the computing power of the missile and ability of assets in the area to guide said missile via effective data-linking capabilities.
Although, the concept of a dedicated next-generation support jammer (with air-air functions) flying within a package would still seem to be viable. As does a concept of a dedicated 'multi-sphere' self-protection jammer capability.
Bottom line: a fighter in say around, 2016, would not want to be fully reliant on AMRAAM alone as it's medium range air missile.
Post a Comment