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#111
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In message , phil hunt
writes On Tue, 16 Sep 2003 22:00:06 +0100, Paul J. Adam news@jrwlyn ch.demon.co.uk wrote: Too vague to be useful, then. It's some use. 1/4 would mean detection range is decreased by 30% At what frequency and over what extent? Is this a narrow little null, an averaged plot, or actually a nasty nose flash? You're just not going to get *useful* RCS data in the public domain. -- When you have to kill a man, it costs nothing to be polite. W S Churchill Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk |
#112
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In article ,
"Paul J. Adam" wrote: In message , phil hunt writes On Tue, 16 Sep 2003 22:00:06 +0100, Paul J. Adam news@jrwlyn ch.demon.co.uk wrote: Too vague to be useful, then. It's some use. 1/4 would mean detection range is decreased by 30% At what frequency and over what extent? Is this a narrow little null, an averaged plot, or actually a nasty nose flash? Unless there's some exteme qualifiers, you have to assume it's a fairly general average. With even moderately ambitious stealth, you can get a good reduction in cross section across the board (even a 10% reduction gives you several extra miles of "shoot first" at long ranges). By keeping in mind that you're limited in the frequency ranges you have to deal with for long and short range radars, it's reasonably easy to handle everything. The big problems on aircraft are the intakes and exhausts. By using RAM in the intake, along with moderate intake duct work, you can minimize that aspect pretty nicely (by 1/4, for example - this was late-stage design "add on" for the Eurofighter). To get a bigger reduction on the intakes, you have to do some fairly radical ducting and materials work, or design the aircraft around the problem (this makes the plane much bigger internally, and is part of the reason the Raptor is so bulky for its mass). You're just not going to get *useful* RCS data in the public domain. But it shows you where to bet. Having an overall RCS of 1/100 of a "typical" fighter, but with a few spikes and odd flashes, makes the job incredibly easier, especially when it comes to breaking lock on incoming missiles (or in not being acquired in the first place). Consider the old-tech F-117. They fly it through some of the most heavily-defended airspaces, *ever*, and manage to not get shot down (except for one case when they got nailed in a low-level raid by visually-sighted AAA). And it's practically obsolete, in most "stealth" respects. The F-22 may have a couple of weaknesses (the aforementioned intake and exhaust), but even those are relative. Dogfighting is cool, but the missile is currently reigning supreme. And when the other guy can fire six shots before you even have a good idea where he's at, you're not going to come out ahead of the game. -- Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
#113
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![]() "Just looking" is often a deceptive activity. For RCS, the devil is in the details. That's true BUT RAM ingredients aside all that shaping and stuff is pretty much open and using those criteria the Eurofighter comes up short in MANY ways. In Ben Rich's book "Shunk Works" he mentioned that during the developement of Have Blue there was an incident where ONE screw was protruding an eight of an inch and it made the difference between not being detected to having the RCS blown to **** and being easily detectable. One screw an eight of an inch. Just speaking from looking at the two aircraft visually and comparing surfaces, discontinuaties and edges, there is no comparison. |
#114
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![]() "phil hunt" wrote in message . .. On Wed, 17 Sep 2003 16:43:24 +0100, Keith Willshaw wrote: So the fact that people don't apparently want to use the Unix version of *one particular software package*, is somehow meant to indicate that the govmts of these countries haven't set up initiatives to switch some or all of computers in govmt use to Linux? Erm no We are a multinational who write MANY software packages. But feel free to browse the web for commercial software developed for Linux and compare that developed for Windows. If that's the state of your logic, I hope they don't employ you as a programmer! BTW, the last car I owned was made by an American company; this proves that no companies outside the USA manufacture motor vehicles. I am only commenting on the reality of our customers preferences, personally I prefer Unix but the reality is most end users dont, Dell had it as an option on their PC's for a a while, they dropped it from the Desktop range due to lack of interest For specialist applications some organisations withing those countries may well choose Linux, we use it for our web servers but I'll bet that 90%+ of the PC's on desks in those nations are running Windows Yes, you're probably right -- after all, if no-one was using Windows, then there would be no desire to switch from Windows. The question is, what will they be using in 5 or 10 years time? If I knew I'd be investing in it not talking about it, that said governments have a poor track record in forecasting IT developments. The fact that the French Government backed Linux would hardly be a confidence builder. Keith |
#115
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In message , Scott Ferrin
writes "Just looking" is often a deceptive activity. For RCS, the devil is in the details. That's true BUT RAM ingredients aside all that shaping and stuff is pretty much open and using those criteria the Eurofighter comes up short in MANY ways. Depends what it's claiming, doesn't it? This is one of the problems - if you say that 'reduced RCS' means 'invisibility' then the US wasted a _lot_ of money on signature reduction for the DDG-51s. But if you mean "confuses anyone trying to analyse the returns and form a track from them and identify what they're looking at" then they got their money's worth. In Ben Rich's book "Shunk Works" he mentioned that during the developement of Have Blue there was an incident where ONE screw was protruding an eight of an inch and it made the difference between not being detected to having the RCS blown to **** and being easily detectable. One screw an eight of an inch. After ten years of hard squadron service, you're promising the F-22 will still be immune to such errors? Meanwhile, the Typhoon has less to lose. Again, "reduced RCS" is useful because it makes your ECM much more effective and is easier to keep. Invisibility is glorious while it lasts... but harder to achieve and maintain. Just speaking from looking at the two aircraft visually and comparing surfaces, discontinuaties and edges, there is no comparison. Compared to each other? Or compared to the threat? -- When you have to kill a man, it costs nothing to be polite. W S Churchill Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk |
#116
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![]() "Chad Irby" wrote: Consider the old-tech F-117. They fly it through some of the most heavily-defended airspaces, *ever*, and manage to not get shot down (except for one case when they got nailed in a low-level raid by visually-sighted AAA). And it's practically obsolete, in most "stealth" respects. The F-22 may have a couple of weaknesses (the aforementioned intake and exhaust), but even those are relative. The F-117, serial 82-806, was not flying a low-level mission. It was on egress from Serbia when it was shot down. The claim of the F-117 goes to the 3rd Division of the 250th Rocket Brigade and its SA-3 Goa missiles. The 250th Rocket Brigade AD received the National Hero Medal, the highest military medal for their service during the war. Here are some of the interesting parts of the "For Free Sky" documentary that was shown on Serbian TV to mark the first anniversary of the conflict during 2000. These are the interviews given by the Air Force staff for the occasion coupled with some information given by the commander of the 250th AD brigade that operated the Neva-M system (SA-3). Apparently all the SA-3 missiles had girls names stenciled on them! Tanja, Ivana and Natalija have been identified as fired missiles. During 2001 a further interview with a 250th Rocket Brigade battalion commander, Lt. Col. Bosko Dotlic, highlighted that an SA-3 named Natalija downed the F-117. From the 2000 documentary "For Free Sky" Colonel Zoltan Dani explained: "When whole crew were on their positions and when the new wave was on, the target was detected on azimuth 195 suddenly appearing and that was an very important reference upon which we concluded that it may be a new target. Crew done the rest routinely, since we are well trained. The speed was that counts. Practically the F-117 was downed in less than 18 seconds" Dragan Matich (standing in front of Neva missiles): "In the war I have been tracking officer on 4 missile launches among them the biggest success was the downing of the F-117 and F-16" Further evidence is on display at the Yugoslav Aeronautical Museum, Belgrade International Airport where the remnants of the SA-3 missile and missile booster used to shoot down the F-117A can be found. Serbian TV video of 82-806 shows the tell tale fragmentation damage to the wings and tail that comes from SAM warhead damage. This was initially commented on as being from AAA damage, but the fragmentation warhead consists of tungsten balls which would cause similar damage as indicated on the video. There is not one mention from any of the interviews or 250th Rocket Brigade commemorative websites of anything other than an SA-3 being responsible. The only unit accredited was the 250th Rocket Brigade for both the USAF F-16CG lost on the 2nd May and the F-117A. TJ |
#117
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![]() But advanced camouflage is. Once again, read up in it. I'd be more interested in a demonstration. Which Raptors is this "advanced camouflage" flying on? I think what he's referring to is one of two things. (Keeping in mind I'm not in the industry and all I've read is what's been made public and what I can see with my own eyes). The first is I've read that the paint scheme is designed to make it difficult for IR seekers that look for edges to find them. The second (and this is just something I've noticed) is that haven't you ever noticed the paint on the F-22 just looks. .. strange? In many pictures it almost looks like bare metal. I've been looking through a bunch of pictures and Raptor 01 was painted with "normal" paint and the rest appear to be painted with the other kind. I'm not saying just because it's different that it's something special or anything BUTthere is definitely something unusual about it. First of all it's reflective unlike the paint on other fighters (and yeah I know everything relfects which is why we can see it- that's not what I'm talking about.) It's not like glossy paint reflective but more like burnished metal reflective. Secondly, unless they frequently repaint Raptor 002 it *appears* to do something funny when it comes to color. I'm not saying it actively matches it's surroundings. But maybe it has an affinity for picking up the color of the light that hits it. Who knows? I've posted several photos of 002 in various lighting conditions to show what I mean. In photo one you could almost convince yourself the far vertical stab is made of glass and you can see through it. Pictures 1 and 8 show what I'm talking about to best effect. Pictures 5,6,7 show it flying with Raptor 01 which has *normal* paint. Now I'm not one to think the Raptor is made of parts from Roswell or anything like that, I've just noticed that the paint seems unusual. Or am I on crack? http://www.xmission.com/~sferrin/1.jpg http://www.xmission.com/~sferrin/2.jpg http://www.xmission.com/~sferrin/3_(002_is_in_rear).jpg http://www.xmission.com/~sferrin/4.jpg http://www.xmission.com/~sferrin/5(01_is_in_rear).jpg http://www.xmission.com/~sferrin/6(01_is_in_rear).jpg http://www.xmission.com/~sferrin/7(01_is_in_rear).jpg http://www.xmission.com/~sferrin/8(This_one_is_006).jpg (for some reason that "(" is causing the whole name not to show in the link. Just do a copy past into your browser) You might want to double-check that: those engines not only have vectoring thrust but afterburners. That's getting to be a _real_ challenge to build effective IR suppression into. Part of it is their cross-section and that ^ poking to the rear will cause the exhaust to mix with the surrounding air quicker. Which isn't to say it would be invisible but that it would dissipate quicker than a convenctional round nozzle. Dish. Aerial. Antenna. Plate. That emitter-thingy gizmo in the pointy end. (That blasts out kilowatts of coherent microwaves) And there are some very nice ways to make antennas to lower that sort of problem. Remembering, of course, that the US has been working on such tech since the Carter administration (and succeeding quite nicely, from the results we see in the Nighthawk and B-2). Not to mention radomes that are transparent at only certain frequencies. That with the LPI and low side lobes of an AESA radar go a long ways toward making it more difficult to detect. (after that it was difficult to follow who said what :-) ) |
#118
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On Wed, 17 Sep 2003 23:38:14 +0100, "Paul J. Adam"
wrote: In message , Scott Ferrin writes "Just looking" is often a deceptive activity. For RCS, the devil is in the details. That's true BUT RAM ingredients aside all that shaping and stuff is pretty much open and using those criteria the Eurofighter comes up short in MANY ways. Depends what it's claiming, doesn't it? This is one of the problems - if you say that 'reduced RCS' means 'invisibility' then the US wasted a _lot_ of money on signature reduction for the DDG-51s. But if you mean "confuses anyone trying to analyse the returns and form a track from them and identify what they're looking at" then they got their money's worth. In Ben Rich's book "Shunk Works" he mentioned that during the developement of Have Blue there was an incident where ONE screw was protruding an eight of an inch and it made the difference between not being detected to having the RCS blown to **** and being easily detectable. One screw an eight of an inch. After ten years of hard squadron service, you're promising the F-22 will still be immune to such errors? Meanwhile, the Typhoon has less to lose. Again, "reduced RCS" is useful because it makes your ECM much more effective and is easier to keep. Invisibility is glorious while it lasts... but harder to achieve and maintain. Just speaking from looking at the two aircraft visually and comparing surfaces, discontinuaties and edges, there is no comparison. Compared to each other? Or compared to the threat? I think when it's said that the Eurofighter is stealthy most people equate that to mean the manufacturers are implying it's stealthy like an F-22 not stealthy like a Super Hornet (which would be a more accurate comparison). |
#119
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![]() "Scott Ferrin" wrote (phil hunt) wrote: On Mon, 15 Sep 2003 19:46:49 -0600, Scott Ferrin wrote: I remember reading that the kinematics of the -9X are much better than previous Sidewinders and that it's range is significantly higher as a result. That sounds very plausible. Unfortunately, the USAF specified that the AIM-9X use the same motor, warhead and fuze at the current AIM-9M with TVC added to roughly the same planform. I don't expect much different kinematics in the AIM-9X. IIRC, Raytheon proposed an optional 6 inch motor but the USAF declined. |
#120
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![]() "Paul J. Adam" wrote in message ... In message , Chad Irby writes In article , "Paul J. Adam" wrote: Got numbers for that one? Be interesting to see what they're using. The only claims I see are from various Eurofighter sites, which variously compare it to the F-16 or the Tornado. Basically, it's about 1/4 ot the frontal RCS of most standard fighters. Too vague to be useful, then. Over what aspects? Over almost all aspects. You can see a lot of this just by looking at the structure of the planes. The Eurofighter is a basic F-16/F-5 replacement, with some blending and a lot of composites, but not anywhere near ehough of the full blending and special treatments that you need for a real stealth plane. Okay, there's the disagreement. You're looking for "real stealth", we're looking for significant RCS reduction. Invisibility gets expensive fast: there are other ways to improve your odds. .... Then why are you in such complete denial of how stealth works? I'm serious... if you know about planes and stealth, this is kindergarten-level stuff. Depends if your mantra is making the aircraft invisible, or making it harder to detect, tricky to track and a lot more difficult to hit. Paul, this is silly. As you say, F-22s are highly unlikely to do battle with EUian Typhoons in this universe at least. That said, you know as well as I that detection range is a 4th root function of RCS. That means that small changes in RCS make_very_small changes in detection range. While no-one is publishing "official" RCS measurements, Typhoon is likely to have an RCS on the same order as an F-18E/F while the F-22 has been described by official sources to be in the F-117 range. The difference in detection ranges between the two is likely to be at least a factor of 10, militarily important especially when each type, now retasked to air-to-mud, has to deal with things like SA-10/20s. |
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USAF = US Amphetamine Fools | RT | Military Aviation | 104 | September 25th 03 03:17 PM |