sorry fellas for hijacking the thread!
Methods of making an aircraft stealth
- Thread starter Oqaab
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Back to detecting stealth aircraft....
Australia's Jindalee system spotted F117s flying over Baghdad during Desert Storm. At that stage, the Jindalee portion was the only part of the JORN OTH system in operation. The publicly disclosed range of JORN is about nine million square kilometres. The system is now fully operational.
Our agreement with the Americans under which we give them all our intelligence from JORN is called Project Dundee.
Australia's Jindalee system spotted F117s flying over Baghdad during Desert Storm. At that stage, the Jindalee portion was the only part of the JORN OTH system in operation. The publicly disclosed range of JORN is about nine million square kilometres. The system is now fully operational.
Our agreement with the Americans under which we give them all our intelligence from JORN is called Project Dundee.
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Aussie Digger
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Gf, I've read comments about the future of Australia's FA -18A/B fleet that future phases of the HUG program will include modifications to reduce the radar signature of the Hornets. What do you think this will involve? Structural modifications along with avionics changes (to LPI equipment) and perhaps a radar absorbent type "paint job"? Or are these comments just hubris to impress uninformed types like myself?
Aussie Digger said:
There are certainly ways to bring the RCS down, but I would question whether its worth the effort. As soon as the aircraft flies "dirty" ie, with external weapons mounted, you have just advertised your presence.
The F117 is consistently stated to have the RCS of a steel ball bearing, the B2 is supposed to have the RCS of a golf ball, the B1 an RCS of a tennis ball. All of those aircraft have clean bodies and internal weapons bays.
The Hornet, SU27, Mig 29, SU32 etc are not designs that can be reconfigured to be "stealthy". You can do it, BUT, once the racks are full, your ID is up for every radar system to see.
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Aussie Digger
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Yeah I've heard that but maybe it will allow our rather short legged Hornets to get close enough to fire our new (promised, not yet delivered) standoff missile before they're shot down?
a couple of my more informed colleagues have not expressed any concern about this. They are of the firm belief that the future force mix will be the most long range capable in the region. I can only assume that other goodies are in the shopping trolley yet to go through "checkout".
They've done sims on all the existing and projected russian and french aircraft with the future capability profile (and I'm assuming that there are some undeclared items in the list) and haven't blinked.
"dunno" again
They've done sims on all the existing and projected russian and french aircraft with the future capability profile (and I'm assuming that there are some undeclared items in the list) and haven't blinked.
"dunno" again
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Aussie Digger
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Well, if we are going to remain "long range capable" than some things will have to happen. 1. Fitting Hornets with conformal tanks. I don't know if this is possible but it would certainly help and go a long way to resolving the problems with the lack of hard points on the FA-18 for weapons. 2. Additional air to air refuellers, although this creates additional problems with the requirement for escorts etc, not to mention cost... 3. Additional use of AP -3C and/or transport aircraft as "missile shooters" again this has the problem of requiring escorts, and survivability issues from the large slow unprotected aircraft being used in a role it wasn't designed for. Except for the conformal fuel tanks, I don't see that either of the other options will provide greater capability than what we have now. I think the only way to improve this and rid ourselves of the F-111 would be to acquire the F15E or maybe the Super Hornet. The Government and the RAAF seem deadset against that though.
True on the interim, but the US wants to redefine the JSF deliverables again, which will blow out our acceptance by another year. If the pigs are pulled within 2-6 years, then I think we will end up with F15E's.
My personal preference is for an F15 rather than an '18e/F.
Better plane, longer legs, better missile truck, better bomb truck, and a better anti-shipping platform.
The AP-3C's will end up with stand-offs in the end. and yep, we do need more AAR. Minimum of 7, preference for 9. 3@ fleet west, 3@ fleet east and as a backup for micronesia and NZ, 3@ the top end.
My personal preference is for an F15 rather than an '18e/F.
Better plane, longer legs, better missile truck, better bomb truck, and a better anti-shipping platform.
The AP-3C's will end up with stand-offs in the end. and yep, we do need more AAR. Minimum of 7, preference for 9. 3@ fleet west, 3@ fleet east and as a backup for micronesia and NZ, 3@ the top end.
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Aussie Digger
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Yes, a purchase or lease of 50 or so F 15E's would mean that we could retire our pigs and a goodly number of our oldest (n airframe terms) FA-18's and still keep our air defence and strike levels at the standard it's at now both in numbers and quality and perhaps even improve our capability. We might even save some money doing it as well, with money saved from upgrades and maintenance of the F111's and FA-18's. It would at least provide us with unsurpassed capability within our own region and provide a valuable capability for Coalition operations.
Its more likely that we will end up with some of Canadas airframes, unless they do a very rapid 180, they will end up like NZ.
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Aussie Digger
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Yeah I've read that they've already retired 19 non upgraded Hornets which would benefit our fleet in the event of an early withdrawal of our F-111's. They would have to be upgraded unless you want to experience the F-111G problems all over again...
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Aussie Digger
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Not that it really matters, it'll happen or it won't but I'm not convinced that equipping AP -3C's with standoff weapons is the right way to go. If they are used in a high intensity conflict, the missile better have an unbelievable range or the firing platform will be in trouble. A PC-9 armed with a 0.50 calibre gunpod could shoot one down. If it's to be used in low intensity warfare, why are mega-expensive standoff weapons being used in such a scenario anyway?
Aussie Digger said:
Well, they are long range, capable of loitering, ideal for LR anti-shipping and if push comes to shove can throw things at ground targets. Didn't the Kiwis have mavericks on theirs? Plus they can look after themselves. If they went into somewhere hot they can be railed with Sidewinders. Plus I imagine in a hot theatre they would be part of a box of tricks including AWACs, AAR and CAP.
/back to thread topic.
they aren't very stealthy though...
elkaboingo
New Member
gf0012 said:Back to detecting stealth aircraft....
Australia's Jindalee system spotted F117s flying over Baghdad during Desert Storm. At that stage, the Jindalee portion was the only part of the JORN OTH system in operation. The publicly disclosed range of JORN is about nine million square kilometres. The system is now fully operational.
Our agreement with the Americans under which we give them all our intelligence from JORN is called Project Dundee.
jeez, thats all i've been hearing, russians deteced f-117, old british destroyer detected f-117, austrailians detected f-117, so and so detected f-117, commercial airliner weather radar detects f-117 200km out, whats wrong with this plane? or are radars just getting that good? will f-22 not be stealth when it comes out? :?
elkaboingo said:gf0012 said:Back to detecting stealth aircraft....
Australia's Jindalee system spotted F117s flying over Baghdad during Desert Storm. At that stage, the Jindalee portion was the only part of the JORN OTH system in operation. The publicly disclosed range of JORN is about nine million square kilometres. The system is now fully operational.
Our agreement with the Americans under which we give them all our intelligence from JORN is called Project Dundee.
jeez, thats all i've been hearing, russians deteced f-117, old british destroyer detected f-117, austrailians detected f-117, so and so detected f-117, commercial airliner weather radar detects f-117 200km out, whats wrong with this plane? or are radars just getting that good? will f-22 not be stealth when it comes out? :?
To be fair the F117 is 15-17 years old, so detection opportunities should have improved, and they improved only because there was a requirement to find them.
I take a different view than some of my associates, I think that stealth manned aircraft have a limited future. The F117 has an RCS the size of a steel ballbearing, so that means that it will still be usefull in the majority of the worlds nations. Otherwise, all it means is that the tasking for it is different than what it was say 4-5 years ago. Now it has an F15e that might provide partial CAP.
I firmly believe that once the US declares a technology, it is because it already has moved on to something more efficient or useful.
after all, they flew the F117 on missions for 9 years before it was announced.
as for the F22, its role is different from the f117, it will all get down to an issue of tasking that determines whether it is compromised in a theatre.
its not the F22 I'd worry about, its the aircraft that has replaced the f117 that I would be concerned about.
jerrybault
New Member
Having read through this thread completely I can say that absolutely none of you have a clue as to how stealth and/or radars really work. I have a Masters degree in electrical engineering concentrating in radar, sonar and communications systems and have designed both military and commercial radar systems. I Know how each work I will discuss some of the radar issues. I will not discuss stealth hows and whys.
The F117s you talk about being detected were detected when they were not flying directly at the radar site I'll bet. The F117 was designed to reflect the radar returns (echoes) away from the transmitting radar site best when it was on an incoming approach towards the radar. So the smallest radar cross section occurs for that head on angle. As the angle of the plane to the radar rotates to a side or back view the RCS increases somewhat. Thus the plane can be detected at somewhat longer ranges. No stealth vehicle is totally invisible to radar. They just reflect less energy back to the radar receiver. RCS is just a measure of how much energy they reflect back. RCS is defined as the size of a spherical perfect reflector that reflects the same amount of energy that the target reflects. Solid metals are perfect reflectors so a steel ball bearing can be used to calibrate a radar system in an anechoic chamber.
Receivers have to receive above a threshold energy level for multiple pulses before a target is declared detected. As the range to a target is reduced the reflected energy seen by the receiver increases. As a target of a given RCS gets closer the reflected energy received at the receiver increases so the target can be detected if it is close enough so that he energy is above the threshold. Reducing the RCS reduces the detection range. make it small enough and radar cannot detect you till it is to late to shoot you down.
increasing the transmitter power will increase the energy incident on the target and so will increase the energy reflected back for any RCS. So increased TX power will increase detection range.
some stealth features are frequency dependent so a radar at a different frequency that the one the stealth plane was designed to defeat may be able to detect it.
Three ways to reduce RCS
1- reduce size of object
2-scatter incoming pulse
3- absorb incoming pulse
1 works at all frequencies
2 and 3 only work over limited frequency ranges so a radar outside of stealth design range will defeat it
The F117s you talk about being detected were detected when they were not flying directly at the radar site I'll bet. The F117 was designed to reflect the radar returns (echoes) away from the transmitting radar site best when it was on an incoming approach towards the radar. So the smallest radar cross section occurs for that head on angle. As the angle of the plane to the radar rotates to a side or back view the RCS increases somewhat. Thus the plane can be detected at somewhat longer ranges. No stealth vehicle is totally invisible to radar. They just reflect less energy back to the radar receiver. RCS is just a measure of how much energy they reflect back. RCS is defined as the size of a spherical perfect reflector that reflects the same amount of energy that the target reflects. Solid metals are perfect reflectors so a steel ball bearing can be used to calibrate a radar system in an anechoic chamber.
Receivers have to receive above a threshold energy level for multiple pulses before a target is declared detected. As the range to a target is reduced the reflected energy seen by the receiver increases. As a target of a given RCS gets closer the reflected energy received at the receiver increases so the target can be detected if it is close enough so that he energy is above the threshold. Reducing the RCS reduces the detection range. make it small enough and radar cannot detect you till it is to late to shoot you down.
increasing the transmitter power will increase the energy incident on the target and so will increase the energy reflected back for any RCS. So increased TX power will increase detection range.
some stealth features are frequency dependent so a radar at a different frequency that the one the stealth plane was designed to defeat may be able to detect it.
Three ways to reduce RCS
1- reduce size of object
2-scatter incoming pulse
3- absorb incoming pulse
1 works at all frequencies
2 and 3 only work over limited frequency ranges so a radar outside of stealth design range will defeat it
Excellent. send us proof of your qualifications so that we can verify them.
BTW, a couple of us have worked in signals management across different services, some of us work in the signals management spectrum currently.
I look forward to seeing your CV. Then we can re-open the thread.
If you're that good then people I deal with will know about you and your credentials will check out.
as you know, Its a small small community .... radar engineers and signal management specialists are like rocking horse scatalogical material
If you could nominate the systems you've designed then that will make it much easier to validate.
Hell, if you're that good then I can use you myself or refer you on to one of the vendors as they're always looking for experts.
I should add, that for someone who professes to be a crow, you seem to be completely oblivious as to what series of events led to the serbs killing the stinker.
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