Stealth radar

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I remember when the Stealth bomber was the talk of the town. I remember hearing it used special materials to have the radar disposition of a bird. They said it was nearly undetectable.

Reading the Tomcat thread just revived the question (or observance) I had about the Stealth.......how did they not mention the bird on radar going 500+ knots throwing a red flag?
 
Stealth technology (shapes, coatings, etc) does *not* make an aircraft or other vehicle "invisible" to radar, it reduces the effective detection or tracking range.

The radar type/frequency also plays a role. My understanding is that over-the-horizon radars which operate at HF (short wave) frequencies are able to detect pretty much anything, and that current stealth technology is designed to protect against tactical radars operating at much higher frequencies.

If you saturate an area with enough radars, or fewer radars with higher power, then no, even a B2 will be detected.
 
There's a lot going on that we don't understand..

I'm not sure if your joking about a bird or not. (I am familiar with the saying, "reducing a radar signature to that of a bird.")

I couldn't see birds when I was sitting in front of an ASR-11
smile.gif


Nearly all radars I am familiar with (which isn't many) don't pick up birds.. They weren't designed for that. It sure is hard to have a radar reflection/signal bounce off a bird and come back.. But then again there are different types of radar these days..

Lest we forget the F-111 Nighthawk that was shot down. They were detectable by changing the frequency and modulation of the radar wave (longer).

I'm sure we've got some people here that can speak to physics and such better than I can.
 
Few points, from my limited knowledge as a civilian:

First of all, what AlaskaMike said is worth repeating: "stealth" doesn't mean invisible; it means hard to pick up and track.

When a stealth aircraft flies by you, you could see it if you were looking hard enough. It would just be a tiny blip for a fraction of a second, whereas a non-stealth aircraft would be a big blip that is easy to track consistently.

Could you track tiny blips with a good radar? Sure. But then you'd be tracking EVERYTHING in the sky for dozens or hundreds of miles around you that reflects such a tiny amount of radar signal -- birds, insects, random objects, etc. If your radar shows you that much clutter, it's useless, which is why they all have filters so that they show only the stuff that's not likely to be a bird.

If the stealth aircraft is REALLY close to your radar station (or infrared sensors, or eyeballs in a clear sky, or ears when all is quiet), then yeah, you'll pick it up. That's why a major piece of "stealth" is good mission planning (e.g. not flying right over top of things that could detect you).

The B-2 in particular also has the advantage of being able to fly at very, very high altitudes. Even if you could pick it up, it's that much less likely that your planes or missiles could ever get to it before it's out of range.

The SR-71 had a bigger radar signature than a B-2 and a MUCH larger heat signature, but flew even higher and MUCH faster, so the result was similar. Yeah, maybe you can detect it, but even if you can, there's nothing you can do about it.

The F-117 (not F-111) that was shot down had flown the same relatively predictable path at about the same time for a few consecutive nights. People had caught glimpses of it, so they knew what to look for and where to set up their sensors. Pretty sure this mistake hasn't been made since, not to mention that other stealth technologies have gotten MUCH better since then.
 
The physics is easy to understand.

How it applies, and what operational steps are taken in response, quickly becomes very highly classified...
 
Originally Posted By: Mr Nice
Would a B-2 be able to fly into North Korea, Iran or Russia undetected on a moonless night ?


The B-2 was built for that exact mission. It is an extremely capable airplane. I have no doubt that it can penetrate any air defense if the mission is properly planned and executed.
 
Originally Posted By: d00df00d
The SR-71 had a bigger radar signature than a B-2 and a MUCH larger heat signature, but flew even higher and MUCH faster, so the result was similar. Yeah, maybe you can detect it, but even if you can, there's nothing you can do about it.


Mig-31 Foxhound?
 
Yeah, that's as close as any interceptor ever came. But still, the SR-71 could cruise at speeds that the MiG-31 couldn't even reach without risking engine damage.
 
Originally Posted By: Astro14
The physics is easy to understand. How it applies, and what operational steps are taken in response, quickly becomes very highly classified...


It can be complicated. There are classified "helpers" and tricks. Thats all I'll say.
In summary, Russia/N.Korea/Iran/China don't stand a chance when the Air Force wants to reach out and touch somebody using sufficient tricks.

I do agree with you that the BASICS of the physics is easy to understand. I tell people: Shine a flashlight in a dark room at a faceted (F-117) or rounded (B-2) black object. Note how the light reflects. The faceted object glints at you occasionally as you rotated it, and the rounded object almost always reflects a small point back at you. Both mean reduced radar visibility.

And don't forget the special iron-filings paint. Absorbs some radar energy.
 
Stealth means basically two things:

1. the radar "cross-section" appearing on radar screens is reduced significantly by a number of methods,

2. EW or "electronic warfare" methods helps to "blind" any EM detection.


The methods and equipment used are highly classified.
 
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Originally Posted By: Astro14
Originally Posted By: Mr Nice
Would a B-2 be able to fly into North Korea, Iran or Russia undetected on a moonless night ?


The B-2 was built for that exact mission. It is an extremely capable airplane. I have no doubt that it can penetrate any air defense if the mission is properly planned and executed.


In my line of work, I have direct experience with B2 mission planning/training/execution and I can concur without a doubt that it is still capable of performing ANYTHING asked of it to perfection within the scope of its design and intent.
 
Slightly off topic, but my transponder failed on my Cessna 177. I was in TN and heading through mil controlled airspace at about 7500 feet.

Not only did they have a "primary return" on my aircraft, they knew my altitude and speed. We confirmed it verbally, and that was good enough for them to allow me to transition their airspace! As normally, a mode C, altitude reporting transponder would be required.

What I found interesting is that they knew my altitude and speed exactly.
 
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so, those old mig-17 and 19 (or chinese variants) without radar or missiles that Kim has are at no disadvantage against a B-2.. that must be why he keeps them around...
 
Originally Posted By: Cujet
Slightly off topic, but my transponder failed on my Cessna 177. I was in TN and heading through mil controlled airspace at about 7500 feet.

Not only did they have a "primary return" on my aircraft, they knew my altitude and speed. We confirmed it verbally, and that was good enough for them to allow me to transition their airspace! As normally, a mode C, altitude reporting transponder would be required.

What I found interesting is that they knew my altitude and speed exactly.


Depending on how close to a primary radar site you were, the primary returns are pretty substantial. In the enroute environment, they're pretty weak until we physically tag a primary and tell it to track as a primary target and the return becomes substantial. It the I'm scratching my head about the altitude unless they assumed you hadn't changed altitude when your transponder failed or it was coordinated to them by a previous controller. The ASR radar feeds from mil RAPCONs controls are virtually identical to FAA TRACONS. The speed is a computer average of your distance traveled over the last 5 radar updates. ASR's complete a rotation every 6 seconds so in 30 seconds of tracking they have your speed. I've yet to have a Class C TRACON deny a primary target lander or overflight as long as we are tracking them. Class B is more like 50/50 depending on their workload.
 
Is there a certain range and accuracy of radar?

Like within ten miles below FL10 they can determine the HxWxL of your aircraft. But at twenty five miles in a rainstorm at FL 30, you are either a hummingbird or the GoodYear blimp?
 
Originally Posted By: zuluplus30
Originally Posted By: Cujet
Slightly off topic, but my transponder failed on my Cessna 177. I was in TN and heading through mil controlled airspace at about 7500 feet.

Not only did they have a "primary return" on my aircraft, they knew my altitude and speed. We confirmed it verbally, and that was good enough for them to allow me to transition their airspace! As normally, a mode C, altitude reporting transponder would be required.

What I found interesting is that they knew my altitude and speed exactly.


Depending on how close to a primary radar site you were, the primary returns are pretty substantial. In the enroute environment, they're pretty weak until we physically tag a primary and tell it to track as a primary target and the return becomes substantial. It the I'm scratching my head about the altitude unless they assumed you hadn't changed altitude when your transponder failed or it was coordinated to them by a previous controller. The ASR radar feeds from mil RAPCONs controls are virtually identical to FAA TRACONS. The speed is a computer average of your distance traveled over the last 5 radar updates. ASR's complete a rotation every 6 seconds so in 30 seconds of tracking they have your speed. I've yet to have a Class C TRACON deny a primary target lander or overflight as long as we are tracking them. Class B is more like 50/50 depending on their workload.


My transponder failed in Florida, upon departure. So I was not talking with anyone for about 4 hours. So the fact that they had my altitude and speed really "piqued" my interest. They verified my position with me verbally, via visible landmarks.

I made the assumption that it was military radar and not civilian. I simply wanted to transition their mil airspace, so I called them with the request.
 
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