How unstealthy is a f-35 with external stores of aim-9

[spikef22]

I'm just talking with 2 sidewinders 1 on each wing how badly would that effect the stealthyness of the aircraft

[sprstdlyscottsmn]

Well, I remember seeing something about how an AIM-9X has the same frontal RCS of around 0.001m^2. So ignoring the pylons that means no less than 0.003 right? Someone on the boards here has said that due to complicated surface reflections external stores make RCS go up by an order of magnitude, so 0.01-0.03? I am inclined to believe that the reason for the unique pylon design is RCS based. 0.005-0.007? We are still talking about 17 to 100 times smaller than a clean Super Hornet and 5-30 times larger than baseline. In the ballpark of the F-117 from the front depending on source, but the overall plot will be VERY different as the return spikes of a missile are very different than a purpose built VLO aircraft.

[spikef22]

Thanks so what's the big deal with the s-300/400 the Russians say it can detect low radar cross section aircraft well a stealth plane is not really compleatly stealth. I've read that low frequency radar or something like that can actually detect stealth but is very screwey. So about the f-117 that was shot down I'm thinking that maybe the ground crew knew were the aircraft was and fired when the bay's were open so stores could be problematic. I also have a theory that the f-117 was banking and because the f-117 uses irregular shapes to deflect radar and RAM maybe the shapes deflected enough energy in the direction of the radar reciver. Sorry for bad punctuation I'm on IOS and it's really a pain

[sprstdlyscottsmn]

There has been great review of the F-117 shootdown on this site. The radar commander knew where the F-117 was going to be (same routes and times used day after day) so he positioned his radar in place. He detected the F-117 ~25km away (on a radar that claims 100+km detection on fighter aircraft) and was able to fire once the F-117 was ~15km away. Low frequency sees stealth further than high frequency, but it is still directly relative to the RCS of the aircraft in the first place.

[neurotech]

Well, I remember seeing something about how an AIM-9X has the same frontal RCS of around 0.001m^2. So ignoring the pylons that means no less than 0.003 right? Someone on the boards here has said that due to complicated surface reflections external stores make RCS go up by an order of magnitude, so 0.01-0.03? I am inclined to believe that the reason for the unique pylon design is RCS based. 0.005-0.007? We are still talking about 17 to 100 times smaller than a clean Super Hornet and 5-30 times larger than baseline. In the ballpark of the F-117 from the front depending on source, but the overall plot will be VERY different as the return spikes of a missile are very different than a purpose built VLO aircraft.

Actually, a "clean" Super Hornet (only AIM-9Xs on the wingtips) is practically stealth (frontal RCS reduced) to older aircraft at BVR range. There is publicly known RCS figures around.

When the Super Hornet first entered the fleet, they were still using the same pylons as the legacy Hornet, that have a much larger frontal RCS. The later pylons had RAM in certain areas, and other enhancements to allow for a reduced frontal RCS with certain stores like external tanks. They still use legacy pylons on the SuperBug sometimes for cost and availability reasons.

[MD]

There has been great review of the F-117 shootdown on this site. The radar commander knew where the F-117 was going to be (same routes and times used day after day) so he positioned his radar in place. He detected the F-117 ~25km away (on a radar that claims 100+km detection on fighter aircraft) and was able to fire once the F-117 was ~15km away. Low frequency sees stealth further than high frequency, but it is still directly relative to the RCS of the aircraft in the first place.

We learned nothing from the first few nights of Linebacker II, regarding routes and not changing it up. Kind of easy to connect the dots when an F-117 departs its base.....it isn't going to up for pattern work......and targets get hit later. Not difficult to draw at least a basic corridor of where to cue EW and TT radars, which the Serbs did.

The 117 can be seen, by certain radars more than others, albeit its signature is miniscule, however its still there. A good operator can work his gain and adjust his scope enough (pending he knows where to look), and be able to interperet a basic idea of where the jet is.

Didn't help that the 117 had no RWR of any kind, and there was the official as well as unofficial reasoning for that. Zelko was lucky he was able to visually acquire the SAMs coming up his way, as they were fired in the small quadrant of good visibility, in the sea of bad visibility the canopy of that jet provides. Otherwise he may have been taken down by a hit her personally might not have survived.

[hornetfinn]

There has been a study about RCS of an air-to-air missile conducted in Brazil using MAA-1 Piranha missile, which is very comparable in size and layout to AIM-9 missile before X-variant.

http://www.jatm.com.br/papers/vol3_n3/JATMv3n3_p287-294_Numerical_evaluation_of_an_air_to_air_missile_rcs_signature_at_x_band.pdf

http://www.jatm.com.br/papers/vol3_n1/JATMv3n1_p73-78_Measurements_in_an_outdoor_facility_and_numerical_simulation_of_the_radar_cross_section_of_targets_at_10_GHz.pdf

Basically MAA-1 missile has RCS of about -10 to -22 dB (0.1 to 0.006 m^2) in most aspects but about 0 dB directly behind and about 17 dB (50 m^2) directly perpendicular. Using some RAM they discovered about 6-15 dB reduction in all (0 to about -28 dB or 1 to 0.0015 m^2).

AIM-9X has much better layout of fins and wings compared to MAA-1 when RCS is considered. MAA-1 has serious corner reflectors due to wing and fin installation and AIM-9X does not have these. So the perpendicular RCS should be a lot smaller. Also having imaging seeker, it likely has quite a bit lower RCS frontally. I think frontally AIM-9X might have lower than 0.001 m^2 RCS and it's likely less than 0.1 m^2 perpendicularly, possibly significantly so depending on materials used.

[sprstdlyscottsmn]

And then there is the very unique double canted and kinked pylon.

[hornetfinn]

Very true. I think we'll see quite a lot of photos of F-35s carrying external AIM-9Xs when they get to combat exercises or actual combat. Especially so if the aircraft is tasked for air to air.

[Gums]

Salute!

Good comments so far. Not worried about most of the the "security" stuff as lots of the "stealth" technology is now out there and it comes down to your production precision and such to get the really low RCS. I was amazed back in the late 70's when numbers like .01 square meters were being bandied about. Then soon it was .001 square meter. Chrissakes, we're talking about a hummingbird!!! We would have given rights to our firstborn to have that RCS over Hanoi in the 60's and early 70's.

Secondly, physics of radar show that some freqs can see you but others can not. So what kind of radar do you wish to defeat?

I would imagine that a spray can of RAM could be applied to a 'winder and reduce its RCS by a lot.

I saw RAM on Viper and Hornet pylons back around the time of Desert Storm. What? twenty-five years ago? Hmmmm.

Gums opines....

[neurotech]

Salute!

Good comments so far. Not worried about most of the the "security" stuff as lots of the "stealth" technology is now out there and it comes down to your production precision and such to get the really low RCS. I was amazed back in the late 70's when numbers like .01 square meters were being bandied about. Then soon it was .001 square meter. Chrissakes, we're talking about a hummingbird!!! We would have given rights to our firstborn to have that RCS over Hanoi in the 60's and early 70's.

Secondly, physics of radar show that some freqs can see you but others can not. So what kind of radar do you wish to defeat?

I would imagine that a spray can of RAM could be applied to a 'winder and reduce its RCS by a lot.

I saw RAM on Viper and Hornet pylons back around the time of Desert Storm. What? twenty-five years ago? Hmmmm.

Gums opines....

I suspect the use of RAM on Viper and Hornets were to avoid reflections between the wings and pylons, causing a major increase in radar return. While it was an improvement with just RAM coatings, but the SuperBug and "Have Glass" F-16 upgrades are a huge improvement in RCS.

One thing a lot of "experts" forget is that these jets can fly at insanely low level. Flying 150 ft, through trees and even between buildings has been done before, and will be done again. Even with 5th Gen F-35s, the pilots will still fly low and fast through heavily defended airspace. There is also IR guided MANPADs to avoid.

Its also probable that F-35s carrying missiles and weapons externally, are also supported by other "clean" F-35s that are not detected by radar. There has been a few cases of non-friendly aircraft harassing US 4th gen fighters, and suddenly realizing there is a F-22 behind them, then running for home.

[Gums]

Salute!

Dunno about the "beneath the radar tactic any more". Ask my Israeli studs from 1980 about the Yom Kippur experience with the SA-6.

I successfully avoided some SA-6 sites at Red Flag because I flew behind hills that destroyed the line-of-sight of the tracking radar. But you can't count on that everywhere. Vietnam was a real bear.

I want a RCS to defeat SAM systems and I'll take my chances with the long range radar systems ( jamming and such really helps).

My view is the Stub will do just fine with a few 'winders on pylons if in a strike "package" I also feel the RAM and such will keep the RCS to a very low level.

Gums sends...

[quicksilver]

...the SuperBug and "Have Glass" F-16 upgrades are a huge improvement in RCS.

Perhaps, but they dont begin to approach the RCS reduction in jets designed to be LO. And, that's before you put drop tanks and weapons on SH and Viper.

...One thing a lot of "experts" forget is that these jets can fly at insanely low level. Flying 150 ft, through trees and even between buildings has been done before, and will be done again. Even with 5th Gen F-35s, the pilots will still fly low and fast through heavily defended airspace. There is also IR guided MANPADs to avoid.

In addition to what Gums is gently saying, exactly what threat is going to drive F-35 into low altitude in "heavily defended airspace"? F-35 was designed to access those kinds of environments autonomously -- the specs were based on that requirement. Doesn't mean they'll go to war that way (F-35s alone) but that's the environment the specs were written to. Also, study a little history and you'll come to a different understanding of the virtues of flying low. Ask the RAF Tornado guys about the opening days of DS. Can you spell "small arms," "AAA," and "barrage fire"?

Its also probable that F-35s carrying missiles and weapons externally, are also supported by other "clean" F-35s that are not detected by radar. There has been a few cases of non-friendly aircraft harassing US 4th gen fighters, and suddenly realizing there is a F-22 behind them, then running for home.

Now that F-35 Fleet operators have been exposed to some more aero envelope with 2B jets, they have come to understand how nice it is to fly slick jets. F-35 ain't a Raptor but it goes fast much more easily than a combat configured Hornet, SH, or Viper. Let the 4th Gen guys be bomb trucks.

[neurotech]

Salute!

Dunno about the "beneath the radar tactic any more". Ask my Israeli studs from 1980 about the Yom Kippur experience with the SA-6.

I successfully avoided some SA-6 sites at Red Flag because I flew behind hills that destroyed the line-of-sight of the tracking radar. But you can't count on that everywhere. Vietnam was a real bear.

I want a RCS to defeat SAM systems and I'll take my chances with the long range radar systems ( jamming and such really helps).

My view is the Stub will do just fine with a few 'winders on pylons if in a strike "package" I also feel the RAM and such will keep the RCS to a very low level.

Gums sends...

Thanks Gums.

IMHO Its more a case of having low RCS to defeat SAMs, and flying low are both options. The goal would be to avoid situations where a F-35 becomes vulnerable to AAA and MANPADs, similar to the F-117 shootdown incident.

Incidentally, weren't these Israeli studs the same F-16 pilots who flew Operation Opera? I'm not going to disagree that Yon Kippur experience shaped various Israeli tactics with regard to SAMs. Didn't Israeli F-16s avoid flying near Iraqi Air Defenses, as well as flying 150 ft off the desert?

The experience of the US Navy EA-18G pilots over Libya was that they were detecting more threats than they had missiles to engage. The SuperBugs fired missiles (& JSOWs) to engage the threats for the EA-18Gs. Even though the F-22A was available for limited A/G strikes, Sec. Gates was adamant that taking out their Air Defenses was required.

Quicksilver: I realize the Tornado pilots were engaged and a few times shot down by AAAs and small arms fire over Iraq. The 4.5th and 5th gen battlefield is going to be a lot different than previous wars. According to legend, various strike pilots over Iraq in DS 91 were flying low enough they had to "pop-up" because the AAAs were on relative high ground, and they flew in between, below the AAA elevation.

Its my understanding that in DS 91, the Navy didn't have MALD type decoys, that result in AAAs and "barrage fire" being located and engaged or avoided by a strike package. They also didn't have MQ-1s flying in 91.

[quicksilver]

And so, what threat is going to push F-35s into the weeds?