# Stealth aircraft and radar

NateTG
Homework Helper
Originally posted by Tyro
Your equation assumes the plane flies in a straight line. Whether it works probably depends on the strategy the stealth aircraft is using; if the pilot thinks he hasn't been detected yet and is going slowly without evasive manoeuvers, then firing initially 'dumb' IR missiles in the general vicinity might take it down.

Not at all, it's simply the distance the plane can travel in the amount of time it takes the sound to reach the ground.

When you start figuring in for the heading of the plane, and the available targets, then you can predict the location better.

PS. From what you're describing, the radar on something like an AWACS should have little trouble picking up stealth planes.

Last edited:
russ_watters
Mentor
Originally posted by Tyro
I was actually joking about the Iraqi air defence Pardon my oblique sense of humour. Baghdad's air defence was in a terrible state after sanctions and the previous war. A better example of how a 'properly' equipped state would fair against stealth bombers would be the Kosovo conflict, where IIRC 3 Stealth bombers were downed. A quick Google search for old news turned up this website.
I'm hoping that link and the bit about the F-117 being shot down is more sarcasm. If not.... No. There was however a stealth fighter over Iraq that was locked onto and had a SAM fired at it because its bomb bay doors got stuck open.

I'm also skeptical of that Australian system. I heard the Australians were developing something that could detect it, but I don't think thats it. The article had several errors such as mixing up frequency and wavelength and the idea of detecting the stealth fighter from above is just plain wrong. No, it is not equally stealthy in all directions, but it IS very stealthy in all directions. A radar threat can come from any direction.

Nate, what I mean is that the equation gives the distance radially around which the plane could possibly be after it is detected with an acoustic system.

In your Hv/c equation, H/c is basically the time for the signal from the aircraft to reach the ground. Multiplied by v is thus the distance the plane could have travelled in that time. But the plane can change its heading and altitude, so very quickly, the possible space the plane can be shoots up.

Russ, I don't think I was joking that time . AFAIK the article about F-117's being shot down in Kosovo is true. Here is a more 'reputable' source:
http://news.bbc.co.uk/1/hi/world/europe/305973.stm

Apart from that, we risk getting into a debate on semantics with your "very" stealthy statement. "Very" is subjective.

I suppose that there is in effect, with respect to devices, that there military and secrets must be qualified with negative. Likely your 'opponent' knows your design before you do. I am not sure that a military secret, with respect to weapons, is in the national interest of any country. Isn't the ability to overwhealm the opponent the point? (Don't touch me or my 'big bad-assed fly swatter' will break your teeth if you do?) Doesn't 'one million' bombs beat ten stealth fighters?

russ_watters
Mentor
Originally posted by Tyro
Russ, I don't think I was joking that time . AFAIK the article about F-117's being shot down in Kosovo is true. Here is a more 'reputable' source:
http://news.bbc.co.uk/1/hi/world/europe/305973.stm
The bbc still isn't the source there. It says that right in the title: "Serbs say..." Without REALLY good evidence, there is no reason to believe that just as there was no reason to believe Bagdhad Bob when he said there were no American tanks in Bagdhad. The picture shown doesn't suffice for me (though a military expert could probably identify the markings). Also, it says they captured two crew members. An F-117 has a crew of ONE.

In wartime especially (or a report from a combatant in a war), it is essential to step back and consider the credibility of the sources - and the sources sources.
Apart from that, we risk getting into a debate on semantics with your "very" stealthy statement. "Very" is subjective.

Also, despite what the conspiracy theorists say, it is VERY difficult for the US military to hide losses.
I wasn't trying to be coy there. What I meant was it is stealthy enough at all aspects to evade radar. And that should be obvious: if it weren't, it would be of little use in an environment where a threat can come from any direction. One of the other errors in the article about the Australian radar for example was the part about detecting the stealth fighter from above by looking at the cockpit, engine intakes, etc. Thats false - those things are most certainly stealthy. Again, if they weren't the plane would be of limited utility. Those two things did however present major engineering problems - engine intakes are covered with grilles because otherwise you'd be able to see the engine itself. And the cockpit glass is coated because otherwise radar would be able to see the pilot's head.
A Radio signal is used, however it is not directed at the plane.
Use radar to "see" the wake left by a plane for example. Yeah ok, S, I've heard of that. But thats not "passive." And decoupling the transmitter and reciever is also not "passive." "Passive" means no transmistter at all, a la infrared.

Last edited:
Originally posted by S = k log w
Doesn't 'one million' bombs beat ten stealth fighters?

Unless the stealth fighter has a bomb with a nuclear warhead. Or is capable of carrying one. The value of a stealth fighter transcends its actual utility, it is like nuclear submarines. There could be one just outside the capital of a hostile country ready to reduce it to radioactive cinders.

Originally posted by russ_watters
The bbc still isn't the source there. It says that right in the title: "Serbs say..." Without REALLY good evidence, there is no reason to believe that just as there was no reason to believe Bagdhad Bob when he said there were no American tanks in Bagdhad. The picture shown doesn't suffice for me (though a military expert could probably identify the markings). Also, it says they captured two crew members. An F-117 has a crew of ONE.

It is not really my job to speculate on the competence of a news agency or its sources. I might add, neither is it yours. I respect your opinion, and your right to present it. So you think that the Serbs were exaggerating. That is OK - I respect that. Keep in mind that there are political reasons why the DoD might not want to admit its prized stealth aircraft got downed by hostile fire. But it also did admit to losing one plane during the conflict (possibly more later, because the report is dated).

In wartime especially (or a report from a combatant in a war), it is essential to step back and consider the credibility of the sources - and the sources sources. I wasn't trying to be coy there. What I meant was it is stealthy enough at all aspects to evade radar. And that should be obvious: if it weren't, it would be of little use in an environment where a threat can come from any direction. One of the other errors in the article about the Australian radar for example was the part about detecting the stealth fighter from above by looking at the cockpit, engine intakes, etc. Thats false - those things are most certainly stealthy. Again, if they weren't the plane would be of limited utility. Those two things did however present major engineering problems - engine intakes are covered with grilles because otherwise you'd be able to see the engine itself. And the cockpit glass is coated because otherwise radar would be able to see the pilot's head. Use radar to "see" the wake left by a plane for example. Yeah ok, S, I've heard of that. But thats not "passive." And decoupling the transmitter and reciever is also not "passive." "Passive" means no transmistter at all, a la infrared.

Of course, I am fully aware that truth is the first casualty of war. But don't forget it works both ways. I'm not saying the F-117 is crap, all I am saying is that it has its vulnerabilities.

As for "passive", I wish to draw your attention to the underlined & bold part of my post regarding the matter:

Originally posted by Tyro:
As for the suggestion on "passive radar", that is, partly, the idea behind one of the types of detection I mentioned, where you have a separate transmitter and receiver (in the developed case it was actually supposed to use mobile phone transmitters! Which, as you know, are scattered nicely across a country). Unexpected and unexplained changes in the 'background' signal suggest the presence of stealth aircraft.