F-22/F-35 vulnerability to IR detection?

Originally posted by planeman
With the best will in the world, jet engines kick out a lot of hot air out the tail end.

In many low-observable designs an attempt to reduce the intensity of this is made by:
1. Not using afterburners (yes the F-22 follows this concept)
2. Having a long narrow exhaust to even out exhaust and reduce “hot spot”, usually with an elongated jet pipe.
3. Mixing the exhaust with cold air before it exits the aircraft.
4. Masking by tail etc.

But the F-22 and F-35 do not do #2 and probably not #3. Both of those features reduce the thrust which is negative to performance.

The square exhausts and worse round exhaust of the F-35 is likely to produce a hot spot much like conventional fighters. And that is before airframe heating.


How susceptible to IR/visual detection are these jets?

Given that they are already quite vulnerable to radar detection I suppose IR would be a fine supplemental tool.

Mod Edit: Image Size – Please Review This Link.

[edit on 11/5/2006 by Mirthful Me]

Given that they are already quite vulnerable to radar detection I suppose IR would be a fine supplemental tool.

Uh the F/A 22 is designed to avoid detection by radar i don't know what you're talking about. Besides that's a pic of the F/A 22 in full afterburner the flames aren't that big.

Originally posted by urmomma158

Given that they are already quite vulnerable to radar detection I suppose IR would be a fine supplemental tool.

Uh the F/A 22 is designed to avoid detection by radar i don't know what you're talking about. Besides that's a pic of the F/A 22 in full afterburner the flames aren't that big.

You wouldn't know what I am talking about and that's not your fault. As for the flames, it's not the size that counts, its how you use it.

I don't know that much about the F-22's heat signature. I've always wondered about that myself. After all, how embarrassing would it be to loose a "stealth fighter" to a heat seeking missile? I suspect that the Raptor probably has some tricks up it sleeve to deal with IR missiles. Surely Lockheed and the Air Force thought about that at some point. The good old flares still work. Almost 40 years after Viet Nam and you can still loose a $70'000 missile with a 50 Cent flare, Imagion that!

Wouldn't it be Ironic if the F-22 uses flares like the F-4 and F-15 before it?

Tim

I have no doubt that the F-22 uses flares, but their usefulness would be degraded against imaging infrared (IIR) seekers. The F-22 also has to know the IR missile is coming to fire the flares.

The question isn't "has the F-22 been designed with IR stealth in mind?" - the answer is obviously "yes". The ereal question is "how susceptible to IR attack is it and given the problems with using radar guided weapons against it, is IR a logical alturnative?"

well, the f35/22 have stealth concepts in their desing, but not to make them invisible, but to increase the efeciveness of the counter-measures, both are some kind of f15s with faceted surfaces, btw, the exhaust shape main reason is the TVC, not stealth, actually these small exhaust area and the change of the geometry of the flow increase the IR signature of the plane , also the team design already have problems of overheating in the rear area of the plane, the f23 ones were "truely" stealth exhaust, but really if a stealth plane sucks in dogfight, then is money wasted

[edit on 8-5-2006 by grunt2]

Ghost,

>>
Wouldn't it be Ironic if the F-22 uses flares like the F-4 and F-15 before it?
>>

Not ironic, just sad.

www.f22-raptor.com...

photos.joyandjon.com...


As I recall, there are four covered wells, two each top and bottom, covering internal EXCM 'buckets numbering 16 in all. Given that flares are actually rather large, you're still only looking at 8-12 mechanicals in each so the above 'panic attack demonstration' is actually probably one of about 4-5 total salvo-releases that could be counted upon IF there are no residual chaff or active jammer payload requirements.

Such is what IRCM has come down to. You can't beat the individual seekerhead with a single flare, you have to create /such a mess/ (each flare is outgassing huge 'prismatic sprays' of IR particulates) as to fuzz the entire area around the target.

Of course, every time you do this, everyone and their glaucoma'd grandmother are going to see it happen.

While the notion that the F-22 is going to be taking IR-off-the-deck shots is ridiculous for a 10-mile-hi cruising altitude airframe unless you are talking something similar to a modified Kub (SA-6) which fires as the plane passes overhead and then is CG'd into range for the scabon seeker.

The reality of life remains:

1. If I can blow your skull out the back of your afterburner from beyond the point at which YOUR MISSILES can home on me, independently, conventional signature IR attack from an A2A perspective is worthless. Because I will simply leave the predictor volume down which your precious R-27ET are chugging. While you can never leave my (and my offboards) equivalent sensor volume so that a digital-tether missile can fry you even if I'm no longer nose-on looking.

2. If you want to truly 'beat the arrow, not the indian' it's likely you need to use the AAR-56 or AAS-37 to cue a TADIRCM turret to kill the threat seeker, inbound. Some say that the APG-77/81 can also do this as a long-dwell HPM/HERO type effect (electronics kills behind the FPA) but I would feel better if all-aspect systems could be scabbed on to give the IR equivalent of Jaffing via CLIRCM-onto-flare.

CONCLUSION:
Only an utter ass plays 'Schwarz' games with an enemy when the sum of his systems superiorities 'cap at equality' based on his own limited biologic capabilities relative to the other guy's WVR HOBS MISSILE.

Under such a scenario, there is no reason not to assume that a 150km AIM-120D can out range the detection threshold for any optics aperture not specifically advantaged by top-aspect lookdown (as SATWACS). Simple attenuation and anaprop through high level winds, atmospheric pollutants and water vapor should be more than enough to make the F-22 invulnerable (untouchable for pole if nothing else) at these distances as well as by S2A lookup optics.

You're only hope then being to go in and bag the _subsonic_ platforms which cannot exit the volume at the same 15 miles per minute as the Raptor does. And that means having a cheap suicide-sled force that can be literally thrown away as they sweep down range, more readily than the enemy can fire AMRAAM to knock them down.

STEALTH ON MISSILE then becoming the true determinator of reaching a point where seeker functionality starts to drive the engagement.

You wouldn't know what I am talking about and that's not your fault. As for the flames, it's not the size that counts, its how you use it.

that's not what i was referring to(size of the flame) the pic that's provided is the Raptor in afterburning mode. Why do you think they're susceptible to raar detection????

It should be well noted mach 1.7 is good for getting around short range sams such as ir sams. The only part that is vulnerable is the back. Considerbale work has been made to eliminat IR on the sides and front. IR detection has its own weaknesses such as weather(there's ways to manipulate the weather to your desire).

what ? again the fantastic M1.7??, lol

"The only part that is vulnerable is the back"

lol actually the back is the only vulnerable IR part of all planes, but still can be detected from all angles

"Not ironic, just sad."

not sad, the problem is that ppl love to overrate some things, the f22 wasnt designed to be stealth, even a blind man can see that, but mostly to increase the effectiveness of their counter measures

what ? again the fantastic M1.7??, lol

"The only part that is vulnerable is the back"

lol actually the back is the only vulnerable IR part of all planes, but still can be detected from all angles

"Not ironic, just sad."

not sad, the problem is that ppl love to overrate some things, the f22 wasnt designed to be stealth, even a blind man can see that, but mostly to increase the effectiveness of their counter measures

The Raptor can go mach 1.7

One tactic for the F-22s will be to approach a wave of cruise missiles head-on, get in a first shot and then turn at Mach 1.7 supercruise speed for a second and third shot from behind.

Link

www.f22-raptor.com...

Mod Edit: Fixed Link.

[edit on 11/5/2006 by Mirthful Me]

that 1.7 number was in a test and ppl take as nominal, also dont explain if is the pre production-post production plane, the service raptor have a nominal supercruiser of M1.4, was decreased from the nominal close to 1.6M of the YF, thats coz the increase of aspect in the wing -increasing the drag- (by supossely the lack of subsonic maneoverability)

anyway that was already discussed, if you thing that the nominal speed will be increased increasing the wing aspect , you have the right to believe whatever stuff....

[edit on 8-5-2006 by grunt2]

Originally posted by grunt2
that 1.7 number was in a test and ppl take as nominal, also dont explain if is the pre production-post production plane, the service raptor have a nominal supercruiser of M1.4, was decreased from the nominal close to 1.6M of the YF, thats coz the increase of aspect in the wing -increasing the drag- (by supossely the lack of subsonic maneoverability)

anyway that was already discussed, if you thing that the nominal speed will be increased increasing the wing aspect

, you have the right to believe whatever stuff....

[edit on 8-5-2006 by grunt2]

It's been achieved multiple times though I don't see why it can't do it.

Originally posted by WestPoint23
Don't be too sure, maybe for current stealth technology. Like I told you in another post, when radar tech was getting very precise at tracking normal aircraft stealth technology was developed. If stealth becomes obsolete then naturally a new technology will emerge. However currently the F-22 still gets the job done.

There is not an aircraft design in the world that can hide its wake - especially low aspect ratio fighter designs.

If the radar is not tracking the aircraft, but the aircraft's wake - there is pretty much nothing you can do.


Unless you'd like a U2 as a A2A combat aircraft?

here is not an aircraft design in the world that can hide its wake - especially low aspect ratio fighter designs.

If the radar is not tracking the aircraft, but the aircraft's wake - there is pretty much nothing you can do.


Unless you'd like a U2 as a A2A combat aircraft?

And you're assuming stealth aircraft will always fly at the same altitude. The next batch will fly at extremely high altitudes and very high speeds. You're assuming tech advances on one side.

Originally posted by urmomma158
And you're assuming stealth aircraft will always fly at the same altitude. The next batch will fly at extremely high altitudes and very high speeds. You're assuming tech advances on one side.

Oh, you mean the ones that will have an IR signature like the sun?

Yeah, they'll be real hard to detect them.


The laws of physics are the laws of physics and cannot be avoided.




The only way to avoid this problem would be full on space flight.

^^^^ Who say's it won't obey the laws of physics. I was simply stating that as radars get better at detecting wakes planes will minimize wakes by flying at higher and higher altitudes. Not to mention there will also be hypersonic planes.



[edit on 12-5-2006 by urmomma158]

Originally posted by urmomma158
^^^^ Who say's it won't obey the laws of physics. I was simply stating that as radars get better at detecting wakes planes will minimize wakes by flying at higher and higher altitudes. Not to mention there will also be hypersonic planes.



[edit on 12-5-2006 by urmomma158]

They already fly at massive altitude. F-22 runs around at 50,000 ft


Getting above this kind of altitude leads you out of turbofan areas and into RAM/SCRAMjet territory. I'd think the military would just go the full hog and spaceflight if they were at that stage.

^^^^ I was referring to future UAV's/UCAVS. Scramjet tech is already feasible and being applied on a bunch of projects such as project HyFly.Plus I never said anytime soon,I was referring to the future like in 10-20 years not anytime soon.

Originally posted by kilcoo316

They already fly at massive altitude. F-22 runs around at 50,000 ft

Massive altitude? 50'000 ft is standard ceiling for most military aircraft! U-2's Fly at 75'000ft. and the SR-71 blackbird could reach 100'000ft. according to some reports. I'm not sure how you figured that 50'000 is so high in the overall sceme of things.

Tim