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playloud wrote:

The Sidewinder would be considered a weapons system, wouldn't it?

Yes, the problem in dealing with the F-22 is getting it within launch parameters of your missile system. If the F-22 is fifth-teen to twenty thousand feet above you then the missile's range is cut by thirty to forty percent. A forty percent cut in range for an IR missile with an eleven mile range reduces the range down to six and a half miles!
The F-22's defensive display system shows symbology to the F-22 pilot how close he can allow an enemy pilot to get. As long as the F-22 pilot keeps opponents at least the distance indicated on the display the F-22 is safe!

mabie wrote:

just trying to reconcile his statement with what i read about the latest IR missile seekers being able to target aircraft based on heat signature generated by air friction on the fuselage, not to mention signature from the engine nozzle/exhaust. I know the AF and LM paid a lot of attention to reducing IR signature of the Raptor but surely it cannot be as cold as the surrounding air?

the latest IR seekers are sensitive enough to lock on a target based on fuselage friction with the air in w/c case it wouldn't even need to be directly behind the F-22.

A couple of things;
1) The F-22 'might' have an ionizing system like the B-2 bomber in the exhaust that helps defeat IR systems.
2) The F-22 was designed to emmit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

Adrian

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avon1944 wrote:

2) The F-22 was designed to emmit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

Could flares be made to emit IR in the same frequency ranges as the plane does, and how much more effective would that make the countermeasures?

playloud wrote:

avon1944 wrote:

2) The F-22 was designed to emmit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

Could flares be made to emit IR in the same frequency ranges as the plane does, and how much more effective would that make the countermeasures?

In line with what others have said--that I am not an engineer, I just play one on the Internet--my understanding is that IIR missiles do not home in on a signature but an image. Therefore, just emitting a random "signature" will have little to no effect on an IIR missile. AFAIK, probably the only reliable countermeasure against an IIR seeker is to go after the seeker head with a blinding laser beam, as is increasingly being utilized by helicopters, transport planes and such, most notably Air Force One.

Elite 2K Joined: Oct 20, 2005 Posts: 2103 Status: Offline

snypa777 wrote:

Just found this, supposedly Red flag 2007. Those Tornado's just don`t know it`s there!

From ACC´s public website (According to the original caption, the photo was taken from Coyote Summit, near the east side of the Nevada Test and Training Range.):

Elite 1K Joined: Aug 01, 2006 Posts: 1003 Status: Offline

Quote:

The F-22's defensive display system shows symbology to the F-22 pilot how close he can allow an enemy pilot to get. As long as the F-22 pilot keeps opponents at least the distance indicated on the display the F-22 is safe!

Actually, from what I have read it does more than that. From written accounts, the enemy indicator on the display supposedly shows a circle and a line from the enemy contact. The line indicates how far the computer "thinks" the enemy's weapon system can reach given the current tactical scenario and accounting altitude differences, speed, known weapon performance parameters and the like. The circle shows the detection range of the said target's sensors against the F-22. This presumably takes into account the F-22's RCS to that specific vector, the sensor types, wavelengths and the Ew environment etc. In short both indicators tell the pilot at a glance what an analyst can prepare in given all the collected info in a half an hour.

This I think is also the foundation of the F-35's combat system. And the goal is to allow the pilot to concentrate in making decisions and implementing strategies rather than being engrossed in technical details of flying, guessing and doing math. If the pilot can call time out during a flight to refer to enemy weapon/sensor performance intelligence, do some trigonometry, solve some differential equations, etc, I guess he could do the same thing -- assuming he paid attention in college. But he can't, so this kind of aid becomes invaluable.

avon1944 wrote:

2) The F-22 was designed to emit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

I find that amusing. What's your background in IR?

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Roscoe wrote:

avon1944 wrote:

2) The F-22 was designed to emit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

I find that amusing. What's your background in IR?

I knew the F-22 was full of high tech`, those F-119 engines must have been stolen from the USS Enterprise! Laughing

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Roscoe wrote:

avon1944 wrote:

2) The F-22 was designed to emit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

I find that amusing. What's your background in IR?

Instead of sharing your amusement, why dont you explain your specific disagreement and, even better, help us to understand the issue better. People from a wide range of backgrounds visit these forums, from engineering types, to folks in the military, to lay people with an interest in planes. Along with this diversity come a wide range and level of knowledge. You sound like an individual who has some very valuable technical insight. If you can deepen the level of discussion by sharing your knowledge, I know it would be much appreciated. I would prefer, however, that you not stiffle others by sniping at them without adding anything substantive.

Mike

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The listed Ir ranges are pretty much the standard on what you can expect from an aircaraft and even a ship. They would more or less be radiant or reflected heat from the surfaces and the exhaust/engines. Ir missiles look for both ranges to increase chances of hitting a target. Depending on the model, the seekers can "squint" or reduce the FOV to counter flares and other devices.

What I can tell that LM did with the 117, 22, and 35 is that the exhausts look shrouded in some way. Compared to say a Vipers exhaust that a missile could easily "see", these shrouded exhausts would be more difficult to "see".

Elite 1K Joined: Aug 01, 2006 Posts: 1003 Status: Offline

As far as IR measures go, I believe that it is done on two fronts -- airframe and engine.

On the airframe department, the idea may very well be to minimize specific hot spots like the nose, leading edges, etc by using coatings that reflect the heat inwards back towards the metal or composite structure rather than allow it to leave the airframe at those areas. Reflected heat is conducted away to the rest of the airframe through regular thermal conductance and leaves the aircraft over a larger area. By doing so, you do not change to total amount of heat signature, but you minimize contrast. You also changed the wavelength of the IR radiation emitted because the temperature of the majority of the emission is now lower.

On the engine front the idea is to insulate the exhaust nozzle and engine housing such that very little "hot metal" can be seen by IR devices. The F-35 for instance uses a new kind of material for the feathers of the convergent/divergent nozzle. It is black and probably insulating. There is very little you can do about the plume exiting the aircraft in fighters like the F-22 and F-35. In the F-117, the plume is spread horizontally to minimize its intensity and exists above the aircraft such that the hottest part of it is shielded from the ground by the airframe.

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avon1944 wrote:

1) The F-22 'might' have an ionizing system like the B-2 bomber in the exhaust that helps defeat IR systems.
2) The F-22 was designed to emmit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

Adrian

Yeah...and it can also go warp 9 and fire photon torpedoes!

Elite 1K Joined: Jul 26, 2005 Posts: 1455 Status: Offline

IR seekers are very good at distinguishing between different IR wavelengths, filtering out sunlight, reflected IR and background IR. The best way to reduce IR emissions is to try to cool everything down. The F-22 does that by using actively cooled wing leading edges, surface coatings to control reflected IR energy. Shrouded nozzles may be used to make the heat signature less visible from certain aspects/angles.Probably a whole host of other measures that we don`t know about.

The F-22 designers would probably have had a whole team dedicated to JUST reducing IR signature and emissions.
Don`t know what they did with the huge exhaust plume you get behind a jet!

The IR signature is dependent on temperature, these newer engines run much hotter than older designs, a turbofan exhaust is cooler because of cooler bypass air mixing with the exhaust, in comparison to a turbo-jet for example. Use of afterburners increases temperature and emissions. F-22 is at an advantage with supercruise capability, afterburner use could be quite frugal....

Atmospheric conditions affect IR energy propagation immensely. Absorption, scattering and scintillation. Absorption by moisture, C02, scattering by moisture, again. I am talking about moisture in clouds for example, not rain droplets which affect IR energy differently. Scintillation by refraction. If you want to avoid an IR missile, jump into the nearest cloud! This is just from articles I have read and is not my field. Cool

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checksixx wrote:

avon1944 wrote:

1) The F-22 'might' have an ionizing system like the B-2 bomber in the exhaust that helps defeat IR systems.
2) The F-22 was designed to emmit IR in two specific frequency ranges, the 3-5 and 8-12 micron ranges. These particular frequency ranges are difficult to detect and propagate over distance poorly.

Adrian

Yeah...and it can also go warp 9 and fire photon torpedoes!

No that would be the PAK-FA with the Plasma Stealth Laughing

playloud wrote:

Could flares be made to emit IR in the same frequency ranges as the plane does, and how much more effective would that make the countermeasures?

If I remember correctly, flares don't trick the missiles into following them, they blind the missile and make it lose track of the airplane.

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For a lot of F-22A Red Flag 07-2 shots, taken by Karl Drage, please check out the latest pages of our F-22 Photo Gallery!

<a href="http://www.f-16.net/gallery_item15059_page32.html">F-22 Photo Gallery - Page 32</a>
<a href="http://www.f-16.net/gallery_item15059_page33.html">F-22 Photo Gallery - Page 33</a>
<a href="http://www.f-16.net/gallery_item15059_page34.html">F-22 Photo Gallery - Page 34</a>

Just a few teasers:

USAF F-22A block 20 no. 04-4082 from the 94th FS is seen landing at Nellis AFB during Red Flag 07-2 on February 14th, 2007.

A pair of F-22As from the 94th FS are seen overhead at at Nellis AFB during Red Flag 07-2 on February 15th, 2007.

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