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Refuting blackbird folklore
There was a time when I thought that
the blackbird could secretly hit 5 on the mach meter--but isn't there solid science agains this? Such as: I don't think the engines have the ability to rev up to such a speed. Maybe the jet fuel itself cannot produce sufficent BTU's (thrust) to propel it that fast, maybe the fuel lines are too small to exceed Mach 3.3 Perhaps the real inhibitor is the lack of enough combustible oxygen to feed the engines to shatter established speed records. I know that the outer metal shell of the jet couldn't sustain the high atmospheric friction. Am I right about all this, or is there OTHER things to consider? |
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On Sat, 29 Nov 2003 19:54:46 -0800, Mary Shafer
wrote: On 29 Nov 2003 12:48:59 -0800, (frank wight) wrote: There was a time when I thought that the blackbird could secretly hit 5 on the mach meter--but isn't there solid science agains this? Such as: If you go faster than Mach 3.5 the bow shock off the nose will impinge on the leading edge of the outboard section of the wing and melt it off if you do it for very long. It's OK for a dash, but not for cruise. That's pretty solid science. You know out of all the "how fast will it REALLY go" discussions that's the first time I've heard an answer that satisfied me. Many here are familiar with that X-15 that burned off it's ventral fin from shock inpingment from that test ramjet. Most of the answers I'd heard in the past for why it can't go a lot faster than 3.2 is "because it can't". The shock thing makes total sense. I'd read that one of the A-12s hit 3.6 at 97,600 which is probably close to the alltime best. It's definitely the best I've ever seen published. |
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Chad Irby wrote in message ...
In article , (frank wight) wrote: There was a time when I thought that the blackbird could secretly hit 5 on the mach meter--but isn't there solid science agains this? Such as: I don't think the engines have the ability to rev up to such a speed. Maybe the jet fuel itself cannot produce sufficent BTU's (thrust) to propel it that fast, maybe the fuel lines are too small to exceed Mach 3.3 Perhaps the real inhibitor is the lack of enough combustible oxygen to feed the engines to shatter established speed records. I know that the outer metal shell of the jet couldn't sustain the high atmospheric friction. Am I right about all this, or is there OTHER things to consider? A lot of that is pretty much on the mark. I've heard Mach 3.5 for short sprints, but not more than 3.3 for sustained flight. Mach 5? No way in hell, although I've seen a very few claims for Mach 4 sprints (extremely informally on that one). Even if they could manage the power to do it, the skin would be melting (see the thread on the Sanger Amerika Bomber for some of the problems with sustained very high speed flight). Same here. I live in northern California so I have heard all the stuff coming from Beale AFB and the Mach 3.0-3.5 range seems to be the truth; however, the airframe of the SR-71 is stressed for Mach 4.0 flight. Maybe like the Foxbat this was for emergency only with resulting damage to the engines and a/c. But I see little need for such speed given the Blackbird's height invunerability. Rob |
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owever, the airframe of the SR-71 is stressed for Mach 4.0
flight. Where did you hear that? |
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"robert arndt" wrote in message om... Same here. I live in northern California so I have heard all the stuff coming from Beale AFB and the Mach 3.0-3.5 range seems to be the truth; however, the airframe of the SR-71 is stressed for Mach 4.0 flight. Maybe like the Foxbat this was for emergency only with resulting damage to the engines and a/c. But I see little need for such speed given the Blackbird's height invunerability. What height invulnerability? It worked in the 60's but in todays environment, there are quite a few missiles that could reach out and touch the SR-71. |
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On Sun, 30 Nov 2003 07:21:36 -0500, "Brian"
wrote: "robert arndt" wrote in message . com... Same here. I live in northern California so I have heard all the stuff coming from Beale AFB and the Mach 3.0-3.5 range seems to be the truth; however, the airframe of the SR-71 is stressed for Mach 4.0 flight. Maybe like the Foxbat this was for emergency only with resulting damage to the engines and a/c. But I see little need for such speed given the Blackbird's height invunerability. What height invulnerability? It worked in the 60's but in todays environment, there are quite a few missiles that could reach out and touch the SR-71. Even back in the day there are some they couldn't ignore. If you counted both sides I'd give the SA-5, Nike Hercules and Bomarc B fair odds. |
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In article ,
"Brian" wrote: "robert arndt" wrote in message om... Same here. I live in northern California so I have heard all the stuff coming from Beale AFB and the Mach 3.0-3.5 range seems to be the truth; however, the airframe of the SR-71 is stressed for Mach 4.0 flight. Maybe like the Foxbat this was for emergency only with resulting damage to the engines and a/c. But I see little need for such speed given the Blackbird's height invunerability. What height invulnerability? It worked in the 60's but in todays environment, there are quite a few missiles that could reach out and touch the SR-71. Well, there's "reach," then there's "reach with a decent chance of hitting it." The problem is that the few missiles with the height (80,000 feet plus) didn't have enough targeting capability to hit the Blackbird at that height, especially in a stern chase. The best they could do would be to loft one up and try to get in the way. The newer ones, like the "big" SA-20, might be able to do it, but it would still be a fairly tough targeting solution - you'd need to loft one up before the SR-71 was in range, then acquire it while in midair. -- cirby at cfl.rr.com Remember: Objects in rearview mirror may be hallucinations. Slam on brakes accordingly. |
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