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#11
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In article ,
"Rich S." wrote: "Richard Riley" wrote in message ... I can see it now, Threshold numbers - 140 kt dash speed, 16 hours endurance, 1500 AH available power, 300 lb payload, 500 watt surround sound system, 5g flash memory with Ozzy Ozborn's Greatest Hits. Oh Lord, let it be so. Let Thy lift elevate that *&^%$ in the Mitsubishi, with the 16" bass speaker, that drives by my house at 2 am, unto Thy bosom and keep him forevermore. Selah. Tempts one to put wheels on an acoustic homing torpedo, it does. |
#12
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In article ,
Steve Hix wrote: In article , "Rich S." wrote: "Richard Riley" wrote in message ... I can see it now, Threshold numbers - 140 kt dash speed, 16 hours endurance, 1500 AH available power, 300 lb payload, 500 watt surround sound system, 5g flash memory with Ozzy Ozborn's Greatest Hits. Oh Lord, let it be so. Let Thy lift elevate that *&^%$ in the Mitsubishi, with the 16" bass speaker, that drives by my house at 2 am, unto Thy bosom and keep him forevermore. Selah. Tempts one to put wheels on an acoustic homing torpedo, it does. "Push the button, Max!" -- I don't have a lifestyle. I have a lifeCSS. |
#13
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On Sun, 21 Aug 2005 23:34:20 GMT, Chad Irby wrote:
In article , Steve Hix wrote: In article , "Rich S." wrote: "Richard Riley" wrote in message ... I can see it now, Threshold numbers - 140 kt dash speed, 16 hours endurance, 1500 AH available power, 300 lb payload, 500 watt surround sound system, 5g flash memory with Ozzy Ozborn's Greatest Hits. Oh Lord, let it be so. Let Thy lift elevate that *&^%$ in the Mitsubishi, with the 16" bass speaker, that drives by my house at 2 am, unto Thy bosom and keep him forevermore. Selah. Tempts one to put wheels on an acoustic homing torpedo, it does. "Push the button, Max!" "More brandy! Throw more brandy!" Ron "The sloppiest tucker-inner in all Pottsdorf" Wanttaja |
#15
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In article ,
Ernest Christley wrote: Charlie Springer wrote: On Sat, 20 Aug 2005 16:31:43 -0700, wrote (in article . com): Here's some news that recently came out: http://www.newscientist.com/article.ns?id=dn7867 http://abc.net.au/science/news/stories/s1439827.htm Apparently, soundwaves can help airflow stay near the wing and increase lift. This can help smaller aircraft to avoid stalling at lower airspeeds. Is this a technology that could be usefully applied to existing small aircraft? Or would it require some totally new design thinking? I'll just say I'm skeptical. No need to be skeptical on this on Charlie. The technique will work. Unfortunately, the five pounds of high-maintainence, active equipment can be replaced with a few ounzes of turbulator strips. I read one of the NASA reports, done YEARS ago, on the Larc website. They used the same techique, using sound waves to re-energize the boundary layer. Pointless was their conclusion if I remember correctly. Kinda makes you wonder if they used a particular kind of "noisy" sound wave, or simple shapes like sine waves. It'd be really funny if it turned out to work with random or less-patterned noise, and they missed it because they were too organized... -- I don't have a lifestyle. I have a lifeCSS. |
#16
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On Sun, 21 Aug 2005 19:22:47 -0700, Chad Irby wrote
(in article ): Kinda makes you wonder if they used a particular kind of "noisy" sound wave, or simple shapes like sine waves. It'd be really funny if it turned out to work with random or less-patterned noise, and they missed it because they were too organized... One would be tempted to think this, but all noise (including triangle and square waves) can be constructed from a sum of sines and cosines. It is called Fourier's Theorem, and it works so well nearly all digital signal processing is based on it to some extent. Note that the researcher's 400 Hz signal (close to the A flat above middle C) could form some pretty irritating beats with the engine/propeller. Concert A is 440 and I suspect anybody who has worked with military aviation is familiar with the sound of the 400 Hz power systems. -- Charlie Springer |
#17
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In article l.net,
Charlie Springer wrote: On Sun, 21 Aug 2005 19:22:47 -0700, Chad Irby wrote (in article ): Kinda makes you wonder if they used a particular kind of "noisy" sound wave, or simple shapes like sine waves. It'd be really funny if it turned out to work with random or less-patterned noise, and they missed it because they were too organized... One would be tempted to think this, but all noise (including triangle and square waves) can be constructed from a sum of sines and cosines. Technically, yes, but there could be too many situations where "simple" noise has nothing like the same effect "complex" noise does. Considering that the airflow across the wings of small aircraft is generally subsonic, simple versus complex waveforms could make a real difference (for the generation or prevention of standing waves?). -- I don't have a lifestyle. I have a lifeCSS. |
#18
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If you look at the theory you will see that it is counteracting the
effect of vortices. In fact the perceived noise fron the aircraft is REDUCED. It is in fact antisound. |
#19
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#20
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On Sun, 21 Aug 2005 22:55:17 -0700, Chad Irby wrote
(in article ): One would be tempted to think this, but all noise (including triangle and square waves) can be constructed from a sum of sines and cosines. Technically, yes, but there could be too many situations where "simple" noise has nothing like the same effect "complex" noise does. Considering that the airflow across the wings of small aircraft is generally subsonic, simple versus complex waveforms could make a real difference (for the generation or prevention of standing waves?). Yet the researchers say they used 400 Hz sinusoidal signals and make no mention of phase adjustments or feedback compensation to null out situations that would cause detachment. As for "technically, yes" I would say "and physically". Water waves are a good example. The bow or stern wave from a boat is not a sinusoid. But there is dispersion in water surface waves based on wavelength, so sinusoidal components that can be added together to get the original shape, separate over time till you see the longest waves leading and the shortest bringing up the rear. You get a chance to see the "Fourier components" that make up the original wave, and with no special equipment. -- Charlie Springer |
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