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#31
December 2nd 03, 01:29 AM
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In article ,
"Brian" wrote: Missiles like the SA-12/20 and SM-2 have incredibly high speeds and altitudes.....the SR-71 is not in a favorable position being up in the sky with no clutter around. If it could reach M3.2 on the deck, there would be more problems with targeting. You have to remember that the SAM-20 tops out at about 4600 MPH, about a third faster than the SR-71, which makes it a *lot* easier to spoof the missile's radar, and doesn't give it enough of a speed advantage to make a strong chance of catching a Mach-3+ aircraft from behind. They *do* have a much better chance to hitting one nowadays, which is part of the reason you wouldn't see many SR-71-type planes anywhere near the big SAM sites. Or why there's that persistent rumor about an SR-71 followup out there... -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. 
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#33
December 2nd 03, 02:14 AM
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On Tue, 02 Dec 2003 01:29:36 GMT, Chad Irby wrote:
In article , "Brian" wrote: Missiles like the SA-12/20 and SM-2 have incredibly high speeds and altitudes.....the SR-71 is not in a favorable position being up in the sky with no clutter around. If it could reach M3.2 on the deck, there would be more problems with targeting. You have to remember that the SAM-20 tops out at about 4600 MPH, about a third faster than the SR-71, which makes it a *lot* easier to spoof the missile's radar, and doesn't give it enough of a speed advantage to make a strong chance of catching a Mach-3+ aircraft from behind. Why the fixation of hitting the aircraft from behind? The idea with a SAM is to hit the target from the front BEFORE it's dropped it's bombs or hit the target. The reason I think the Bomarc would have a fair chance is because it certainly had the altitude and head to head it doesn't have to chase it down. They'd have seen it far enough out and with that 400 plus mile range it's going to be at speed and altitude well before the Blackbird would be overhead. Hell even the limited maneuvering the Blackbird could do at Mach 3 wouldn't help it because the Bomarc had the energy to maneuver too.
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#34
December 2nd 03, 02:52 AM
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In article ,
Scott Ferrin wrote: On Tue, 02 Dec 2003 01:29:36 GMT, Chad Irby wrote: You have to remember that the SAM-20 tops out at about 4600 MPH, about a third faster than the SR-71, which makes it a *lot* easier to spoof the missile's radar, and doesn't give it enough of a speed advantage to make a strong chance of catching a Mach-3+ aircraft from behind. Why the fixation of hitting the aircraft from behind? Because about half of all engagements with long-range missiles happen from the rear aspect, or from the side (which can be worse in some cases). Very few aircraft drivers are going to run right down the throat of a radar when they can sit off to one side and make the missile work harder. Even with a very long range (400 kilometer) SAM, you have to have about a 50% overlap with the systems on either side to make sure you have good coverage, or the penetrating aircraft will just look at signal strengths on their RWR and drive in between, forcing that long-range tail chase (or avoiding your engagement ranges altogether). Even at 7200 KPH, you're looking at a delay of a couple of minutes to get out to a couple of hundred klicks, which can be a problem when the target is doing 2/3 of that speed, jamming madly. Most countries have no chance of affording to cover their entire border with high-speed, high-altitude, long-range missile sites, especially places like the former Soviet Union. Sure, you could ring your major cities with them, but even that's too expensive in the long run. Even putting one next to each major military target gets pretty darned expensive. ....and if you do, and you turn those radars on at any time, you get "tagged" for later attention, which is death on the modern battlefield. Big radars and fast missiles are great in some cases, but they're easy targets. They move slowly and they're easy to kill. -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly.
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#35
December 2nd 03, 02:57 AM
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(Peter Stickney) wrote in message ...
In article , (The Enlightenment) writes: (frank wight) wrote in message . com... SNIP The SR71 is limited in speed by the shock wave from the nose of the aircraft impinging on the inlet lip of the engines over about Mach 3.5. The dash speed of the aircraft is not limited by either engine thrust or or short term thermal issues. Theoreticaly the A12 should be faster becuase of its shorter nose. Uhm, Bernie - Frederick actualy. Bernxard is my spanish blue cat. I use his email. If one of the limiting factors in an A-12/SR-71's speed is shock impingement, (Which it is, a;though IIRC it's shoc impingement on the leading edges of the wings, not the nacelles), how is a shorter nose going to give you a higher Mach Number? A longer nose would allow a steeper included angle. (Y'know, all that Opposite vs. Adjacent stuff from High School Trig.) Unless, of course, Shock Waves work backwards in Australia? You got me there. The shockwave story re impingingment on the nacels I though I read in a review of sled driver published in Air International. Are you sure its wing tips? The solution I think is in a protractor and a photocopy of and SR71 outline.
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#36
December 2nd 03, 03:40 AM
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In article ,
(The Enlightenment) writes: (Peter Stickney) wrote in message ... In article , (The Enlightenment) writes: (frank wight) wrote in message . com... SNIP The SR71 is limited in speed by the shock wave from the nose of the aircraft impinging on the inlet lip of the engines over about Mach 3.5. The dash speed of the aircraft is not limited by either engine thrust or or short term thermal issues. Theoreticaly the A12 should be faster becuase of its shorter nose. Uhm, Bernie - Frederick actualy. Bernxard is my spanish blue cat. I use his email. But it's pronounced Raymond Luxury-Yacht. Bright cat. If one of the limiting factors in an A-12/SR-71's speed is shock impingement, (Which it is, a;though IIRC it's shoc impingement on the leading edges of the wings, not the nacelles), how is a shorter nose going to give you a higher Mach Number? A longer nose would allow a steeper included angle. (Y'know, all that Opposite vs. Adjacent stuff from High School Trig.) Unless, of course, Shock Waves work backwards in Australia? You got me there. The shockwave story re impingingment on the nacels I though I read in a review of sled driver published in Air International. Are you sure its wing tips? The solution I think is in a protractor and a photocopy of and SR71 outline. Yep. That's how I figured it out. The wingtips would be impinged upon first, then the chines on the outboard sides of the nacelles, then the outer nafelle lip. Of course, you'd get some complicated shock interactions going on in the region of the nacelle, so simple straightedge and protracter stuff is only approximate. There's a whole bunch of stuff going on that would limit the max speed to somewhere between Mach 3.2 - 3.5. The shock impingement stuff, the air temperature at the compressor face, the ability of the fuel to carry heat away from critical components pop into mind at a first stab. Those factors all meet at or about Mach 3.5. -- Pete Stickney A strong conviction that something must be done is the parent of many bad measures. -- Daniel Webster
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#37
December 2nd 03, 06:40 AM
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(Kevin Brooks) wrote in message . com...
(robert arndt) wrote in message . com... Chad Irby wrote in message . com... (robert arndt) wrote: Funny how the all-white Mach 3 XB-70 seemed to hold up to kinetic heating all right... and that was just simple nuclear anti-flash white. They did that by using a fairly scary system of pipes that ran through high-heat areas, and used the plane's fuel as a heat sink, combined with extensive use of titanium in the worst spots. In a combat-ready version, you can safely assume that they would have used the "iron ball" black paint for radar reduction and heat protection. "Iron Ball" black paint was derived from the Third Reich's radar-absorbing "Schornsteinfeger" (Chimney Sweep) carbon paint meant for the Go-229 jet flying wing. Rob Geeze, you probably think the integrated circuit and microprocessor were both derived from Nazi research, huh? What is it with this Pavlovian reaction you demonstrate to all things (allegedly) Germanic? It's quite possible that German research in this area influenced or inspired later western work. The Germans were using a sort of rubberised ironball for u-boat snorkels and conning towers. Screens were also carried on board u-boats that could be errected around the conning tower. Finaly the Go 229 was to recieve a sort of carbon black based 3-ply skin that had RAM properties and the aircraft showed use of re enterant structures. Surely opperation paperclip must have made use of some of this or been aware of German approaches to the issue. German pre war doctrine held that radar or radio emisions would reveal one to the enemy and empphsised passive techniques and this may have influenced their neglect at maintaining their lead in radar. It has to be rememberd that Randle and Boots magnetron was developed because they wanted a cheap radar emiter for the detector and direction finder they were developing. If they had of been given a bigger budget they may not have stumbelled upon it. As far as Germans inventing the integrated circuit goes? Well that never happened but it might have because an ex Luftwaffe technician may actualy have invented a transistor. It's quite a sad story actualy: http://home.t-online.de/home/Benduhn/summary.htm
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#38
December 2nd 03, 07:49 AM
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Scott Ferrin wrote in message . ..
On 1 Dec 2003 11:27:25 -0800, (Jens Peter) wrote: Can someone confirm or deny the design "flaw/feature/consequence" of the SR71/A12leaking fuel tanks? I have heard stories which varied from this being a feature (to allow for expansion of the fuel tank structure due to aerodynamic heating) to a design flaw which was never fixed to a known consequence of aerodynamic heating which was never resolved with the high temperature sealants available at the time. I just cannot believe that Kelly Johnson's team would allow such a flaw to exist in their design. I would rather believe that the Skunk Works team knew that aerodynamic heating would seal the tanks and so did relatively nothing to resolve the fuel leakage on the ground issue. Both of your reasons apply. They couldn't come up with a sealant and since the expansion sealed them they pretty much said "screw it" and decided to live with it. The SR-71 airframe expanded IIRC 4 inches in flight and the leaking tanks posed no threat as the fuel had a very high flash point. Rob
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#39
December 2nd 03, 10:00 AM
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"The Enlightenment" wrote in message om... (Kevin Brooks) wrote in message . com... (robert arndt) wrote in message . com... Chad Irby wrote in message . com... (robert arndt) wrote: Geeze, you probably think the integrated circuit and microprocessor were both derived from Nazi research, huh? What is it with this Pavlovian reaction you demonstrate to all things (allegedly) Germanic? It's quite possible that German research in this area influenced or inspired later western work. Hardly since the Germans didnt actually do any work in this area. The Germans's fell far behind the allies in terms of electronics and electronic warfare as the war progressed. The transistor came out of work done at Bell Labs that began in 1939 by Russel Ohl and the IC was invented at Texa Instruments by Jack Kilby. The Germans were using a sort of rubberised ironball for u-boat snorkels and conning towers. Screens were also carried on board u-boats that could be errected around the conning tower. Finaly the Go 229 was to recieve a sort of carbon black based 3-ply skin that had RAM properties and the aircraft showed use of re enterant structures. Surely opperation paperclip must have made use of some of this or been aware of German approaches to the issue. Hardly , the german countermeasures were almost entirely ineffective since they were working on the assumption that allied radars were operating in the metre band rather than the centimetric radar that was actually being used. German pre war doctrine held that radar or radio emisions would reveal one to the enemy and empphsised passive techniques and this may have influenced their neglect at maintaining their lead in radar. It has to be rememberd that Randle and Boots magnetron was developed because they wanted a cheap radar emiter for the detector and direction finder they were developing. That would be Randall and Boot who developed the cavity magnetron at Birmingham University in 1940. The Germans also developed active radar systems and Telefunken had been working on just such a device as early as 1935 but had been unable to get even close to the efficiencies and power levels that Randall and Boot achieved. If they had of been given a bigger budget they may not have stumbelled upon it. As far as Germans inventing the integrated circuit goes? Well that never happened but it might have because an ex Luftwaffe technician may actualy have invented a transistor. It's quite a sad story actualy: http://home.t-online.de/home/Benduhn/summary.htm What it describes is interesting but its not a transistor but a cold cathode tube and that was first demonstrated by Philo Taylor Farnsworth II in 1934 Its entirly possible that your ex Luftwaffe technician was aware if it since an article in Radio by Arthur Halloran described it in detail in the issue published in October 1934. http://www.borderlands.com/archives/arch/multipact.htm The claim that the first tubeless radio was built in 1948 is so wrong its farcical. The crystal set was common in the 1920's. Keith
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#40
December 2nd 03, 11:46 AM
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In message , Keith Willshaw
writes snip As far as Germans inventing the integrated circuit goes? Well that never happened but it might have because an ex Luftwaffe technician may actualy have invented a transistor. It's quite a sad story actualy: http://home.t-online.de/home/Benduhn/summary.htm What it describes is interesting but its not a transistor but a cold cathode tube and that was first demonstrated by Philo Taylor Farnsworth II in 1934 Its entirly possible that your ex Luftwaffe technician was aware if it since an article in Radio by Arthur Halloran described it in detail in the issue published in October 1934. http://www.borderlands.com/archives/arch/multipact.htm The claim that the first tubeless radio was built in 1948 is so wrong its farcical. The crystal set was common in the 1920's. The oscillating crystal was also discovered in the '20's. Mike -- M.J.Powell
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