Forum: General F-22A Raptor forum

What percentage of the F22 will be visible to radar? Or is it all 100% stealth.

Thanks.........

Shev

F-16.net Sponsor

If you can reduce the Radar Cross Signature (RCS), by 34%, you've reduced the "reflectivity" of the aircraft by the size of a bird on radar. Thats pretty darn good. Nobody knows the RCS of the F/A-22.

Lockheed "Stealth" by: Bill Sweetman

Wouldn't the RCS be largest when there's a large plate to reflect against? Does anybody know how RCS is actually measured (other than in a special facility where magic elves pull a random number out)? I would imagine the largest radar signature of the Raptor would be looking straight down on it. The would give you the wings and spine of the aircraft to see. I don't know much about aircraft yet, but I do know about EM. I can thank my physics class for knowing that. I'm not sure about the exactness of this idea, but I believe I've heard it before. In order to reflect an EM wave, distrubances in the surface must be less than 1/8th the height of the wave apart.

The reason why Im asking is because some people have said that you cant hit what you cant see.True. But if there still is a small chance for you to see the 22, than it can be brought down with a good missile. Or no?

Shev

I'm sure the F-22 can be seen and hit. The likelihood is that the detection range is low enough to cause some problems for the enemy. They would probably have a missile on them before they could get a good lock on the 22. A dual seeking warhead, IR and radar with link to a larger detecting station, would be the most likely thing to hit the Raptor. Remember, the US will often enjoy saying all sorts of stuff about its fighters, but it never fully tips its hand. If anything the US will say the Raptor is far worse than it is. This is a little bit of bluffing to make opponents get a little cocky and fly a little stupid. Anyway, back to what I was saying, tracking will be a function of the other aircrafts sensors and the orientation of the two planes. A Raptor flying at a sensor suite aircraft like an AWACS will get detected before say a SU27 would see it. It's not really probablities with detections, it's returns. If you made the sensor suite sensitive enough you could pick the Raptor up at 120 nm, but you'd also pick up clouds and anything else you wanted in the air. Your sensors would confuse themselves and pick up radar from space or something. I'll end on this, if other countries practiced truly net centric warfare like the US does then the Raptor could run into a few problems, but since other coutries don't or can't it's more or less safe for now.

allenperos wrote:

Nobody knows the RCS of the F/A-22.

I'm sure somebody does Wink

Sorry to crash the party here guys, but this has been asked or implied in several other threads. Those of us who know weren't allowed to divulge the info in those threads, and we still can't. Let's just say that it's d@mn low, and if you say you saw it on your radar screen, then you've either defeated several laws of physics or you're lying.

Some folks ask the same question you've just asked AC, and it IS a very good question, as to whether there is a dim chance it could be briefly spotted and if so, could it be shot down. I can only answer by saying that there's a dim chance the San Diego Padres could win the World Series this year, but...

Refer to the last sentence of my first paragraph. What little bit could theoretically be seen shows up as something that couldn't be recognized as an airplane.

Tack on a very fast speed with supercruise (and an even faster speed in full blower), and it will either a) be miles down the highway, or b) the enemy will be strumming his harp by then.

Sorry to tap dance around the question, but even though I'm no longer with LM, I'm still not allowed to discuss what I learned.

Beers and MiGs were made to be pounded!

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can't. Let's just say that it's d@mn low, and if you say you saw it on your radar screen, then you've either defeated several laws of physics or you're lying

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Some folks ask the same question you've just asked AC, and it IS a very good question, as to whether there is a dim chance it could be briefly spotted and if so, could it be shot down. I can only answer by saying that there's a dim chance the San Diego Padres could win the World Series this year, but...

Pretty good TC. Jump in anytime, the water is warm.

I've been talking to many guys at work about this quistion for quite some time. It's all very complicated. But most of them know how avionics, radars work. Im only a novice at avionics. And many of them think that in the next 5-10 years the Stealth of the F-22 will not be a "huge" factor. Sounds pretty crazy.Their bassicly saying that the F-22 can be, and will be tracked. If there is a chance than the technology can be built to great lenghts to counter that stealth jet. Again its only their, and my professional work related opinion. And by having a small understanding of how radars work, I would certainly agree. But, someone knows quite a bit more.

Shev

Why I am sure someone knows the RCS of the F/A-22 Roscoe, you do!! Anyone can PM about the mathematics involved in "stealth".

Last edited by Pat1 on Aug 08, 2005 - 04:00 PM; edited 1 time in total

Hi LordOfBunnies,

I’m not sure what you know, but RCS must be measured at some standard condition (fixed distance, orientation, and radar settings [power, frequency, sensitivity, etc...]) and is only useful to qualitatively asses two airplanes. As far as clouds go, I would imagine no radar in the world emits at ~2.45GHz (the TV dinner freq.), unless you are a meteorologist.

Somebody else in this forum has said it before; when somebody says that the RCS of an airplane is the same as a bee, it doesn’t mean anything. If this RCS was constant, then an enemy wouldn’t loose any sleep. How many bees fly at 40,000 ft @ M1.5? If this were the case, simple code on the radar’s computer software could discriminate among threats and non-threats.

As for the F-22, I’m sure if you place any radar a few cm. away, you could detect it, lock it and shoot it. But this implies careless tactics by the Raptor pilot? If anybody knows the limitations it would be the pilot, and I assure you he would not put the plane at risk. That’s the advantage of stealth and the most advanced sensor suite; choosing to engage or leaving it for another day.

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In order to reflect an EM wave, distrubances in the surface must be less than 1/8th the height of the wave apart.

It’s been a while since I’ve done anything with EM. Could you elaborate? Allenperos?

EDIT: I have been corrected on this post by members of this forum. Better explantions are provided further on. I have also misphrased "If this RCS was constant..." and is misleading

EM, you got me Pat, I understand wave length and the application of it to "reflectivity". For one thing, I did not know that there were avionics involved in counter-measuring refelectivity, the only things I truly know about stealth is airframe/composite, geometry and radar absorbing material respectively, avionics is not my strong point.

I will research this and post as soon as I can.

I have access to geometrical material application with stealth airframes, but I don't dare state the methodology on the web, as I have warned by the Professor who gave me the literature not to show anyone as it has been copywrited. I may add, materials are really not that important, it's the method they are arranged. Case in point a popular stealth aircraft is made entirely of aluminum alloy as would any other aircraft with the exception of the leading edge of the wings. If you present a perpendicular surface to the radar, you will get a return wave. I hope this helps. The idea is to send the return elsewhere than back to the radar screen.

Hi allenperos,

Thanks for the additional info, but don't waste time researching my previous question, LordOfBunnies is fresh on the subject and will probably help me. Very Happy

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I understand wave length and the application of it to "reflectivity".

I think what he meant has either to do with this or wave transformations (signal processing). I'll await his response to satisfy my curiosity for the subject. Very Happy

Thanks in advance

There are dozens of computer programs that are used to predict the TOTAL RCS of an object. You just input data like the dimentions of the object, shape, materials, radar frequencies used......etc. Again, there is no substitute for real testing.

Simply stick a plane in front of a radar, present the aircraft in every orientation imaginable, measure the results. You repeat the tests using different frequencies and radar types. You use all proposed aircraft mission configurations. You can even simulate battle damage to see what effect it has on the RCS.This method can be used to give a "TOTAL" RCS of any object or aircraft....

Stealhy-ness depends on a whole host of factors, as mentioned in above replies. Aircraft shape, density, materials, aircraft size, component angles, you want to scatter radar away from the emitter,skin composition etc......For example, steel and aluminum are great reflectors, certain composites are not.

The USAF uses mobile test rigs like the one pictured to determine The total RCS of aircraft, using bistatic and monostatic testing.(Bistatic, this is using two test rigs, one an emitter, one a receiver. Mono`, just one rig to transmit/receive).

Lordofbunnies, you could be right, the radar returns of an object can change drastically depending at which surface a radar is looking at......ie, from the front, above or below.
The point is that the RCS of the F-22 could be TINY from all aspects, some slightly better than others.

Most published RCS figures from aircraft are from the frontal aspect, where the figures are the best. No-one publishes Total RCS figures, for obvious reasons. If an enemy knew the RCS of the F-22, it would be invaluable, they would know what to tune their systems to look for, that`s why it must remain classified.

TOAN has published a pretty exhaustive list on RCS data from most of the current next gen` fighters on another thread....It is from the frontal aspect though.

.

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

I think I saw this posted somewhere else on this board, but here is an excellent primer on what RCS means.

http://www.aerospaceweb.org/question/electronics/q0168.shtml

Thanks for the website post - GuySmiley, I found more than I needed and then some, thanks again.

Forum: General F-22A Raptor forum

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