Forum: General F-22A Raptor forum

Elite 1K Joined: May 26, 2005 - 08:39 PM Posts: 1496

http://www.youtube.com/watch?v=58N6Plr17GU&feature=player_embedded

I love at about 1:00 when the pilot puts the spurs to her and the thrust vectoring really kicks in it blooms out the camera sensor a little.

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Awesome! Thanks.

I notice at the time of 43-sec. to 54-sec., the bottom of half of the F-22 appeared hotter than the top! I would have expected just the opposit.
Thanx for the video.

avon1944 wrote:

I notice at the time of 43-sec. to 54-sec., the bottom of half of the F-22 appeared hotter than the top! I would have expected just the opposit.
Thanx for the video.

Yeah, there's bare metal at the bottom, like an F-15. Makes me worry about IR signature...

At least you can tell that afterburner crazy increases the signature, making it obvious why supercruise is such a big deal.

Notice it was cold overall until it lit the afterburner. The F-22 won't need an afterburner most of the time.

If Raptors have some triks to reduce IR signature or make cooler the body, probably they don't activate it on airshows (in the same way they carry RCS enhancer).
They were also showed at relatively short distances. At thoose ranges they probably appear on radar screen too.

Neno wrote:

If Raptors have some triks to reduce IR signature or make cooler the body, probably they don't activate it on airshows (in the same way they carry RCS enhancer).
They were also showed at relatively short distances. At thoose ranges they probably appear on radar screen too.

I'd figure that it would be harder to "deactivate" IR signature reduction than radar, unless maybe the F-22 shuts off the circulation of fuel through the airframe.

Perhaps the temperature distribution is the result of performing supermaneuverability, ie, the bottom is going to see a lot of air and bring it close to stagnation, raising the temperature. This would heat the bottom as most maneuvers are + AoA. That's just a guess though.

Neno wrote:

If Raptors have some triks to reduce IR signature or make cooler the body, probably they don't activate it on airshows (in the same way they carry RCS enhancer).

Gosh, I hadn't thought of that but, it makes perfect sense. Even the old SR-71 had IR reduction measures.

I'd concur with Prinz's seemingly no-brainer comment: the value of super-cruise. That tactical (and arguably strategic) advantage needs no further explanation, imho.

Below are comparative stills of fairly equivalent F-22 and Typhoon images in IR, while in after-burner (no IR reduction treatments here folks, sorry) and taken from the same airshow and from same FLIR. Roughly 70k lbf total thrust vs 40k total lbf.

Interesting to note is the F-22's apparent FLIR-neutral canopy... You wonder if they could bottle and spray some kind of whatever-that-canopy-effect-is-treatment over the standard RAM treatment?

Just another Two Cents

Maybe the F-22/EF/F-35 use materials/coatings that emit mostly in certain parts of the spectrum. Certain frequencies are completely absorbed by water, CO2, etc. in the atmosphere, as seen below (from Wikipedia). Don't know the specs for the sensor used in the display, but as some have noted, perhaps it's of use only at the close ranges during the show.

Weird sh*t?

Funny how you put all your money in one basket to avoid radar, and something else still see’s ya?

Glass material typically doesn't let IR emissions through. If you've ever watched the home thermal imaging guys they show heat escaping around windows rapidly. Surprisingly the window glass isn't losing heat by their images. In reality the glass is, even triple panes, nowhere near the r-value of an insulated wall.

Elite 1K Joined: May 26, 2005 - 08:39 PM Posts: 1496

The thing is VarkVet, IR is a shorter ranged sensor than radar that can't search a large volume of space quickly (not to mention being at the mercy of meteorological conditions) and even with a state of the art IRST you can't get range data accurately. I'd assume once you're close enough to be spotted by an IIR sensor you're probably close enough to be detected on radar regardless of stealthy RCS.

Video showing the Typhoon and Viper as well as F-22 in IR.

http://www.youtube.com/watch?v=PLzD1SCk__g

Could the darkened canopy area in the F-22 IR photo just simply be from the cooling of the cockpit from the environmental control systems?

Forum: General F-22A Raptor forum

We've all see Raptor demos before. But ever seen one in IR?