If someone wants to use 1.1 then they can take the middle column and multiply by 1.1 to get their numbers. For shooting if one uses my numbers there should be little question as to whether or not they have to worry about stability due to going transonic. Thus the huge change in wing profiles for supersonic flight.Įverything I have read from wikipedia to the tech reports from the Ballistics Research Laboratory at Aberdeen tends to agree that mach1.2 and above would be a "safe" number for our purposes out of the transonic zone, If I had done mach1.1, I would have been told I should have used 1.2. One of Bernoulli's assumptions is NO standing pressure waves. These discontinuities may result in Mach wave separation (often incomplete) slightly above the speed of sound for a slowing bullet. Surface discontinuities (like the cannelure often used to lock the jacket to the core) create localized flow discontinuities resulting in the attachment of Mach waves when the projectile is just below the speed of sound. Traditionally +/- 10% has been used (90% on the way up, 110% on the way down). I think it was about 5fps difference from zero to 100% humidity. Now if you add in humidity you are adding water, water molecules have less mass than oxygen and nitrogen so adding humidity reduces density but pressure and temp can stay the same so humidity does have an effect. The slowing down from the effects of density is cancelled out by the heating effects of pressure. Now from what I have read, pressure and density are proportional and so are their effects. If you make it really dense it might make the molecules really close together but it shouldn't change their speed but would change the amount molecules the sound has to go through perhaps slowing it down. If you pressurize air what effect will it have on the air? I guess it would raise the temperature causing the molecules to move faster. As I understand it, sounds is transferred through a medium by the collision of molecules, heating those molecules makes them move faster and have more energy so they collide with other molecules in a shorter amount of time so the sound/wave moves through the medium faster. That I don't believe everything I read on the Internet.įair enough, what is hard to believe, the altitude thing? You just have to think how sound transfers through a medium and what effect altitude would have on that medium. I might have been convinced easier if had you not cited WikiĮdit: Not 100% convinced yet.doing my own research. Checked your cross post and looking into that link and checking my own reference material. I was ready to raise the BS flag at first reaction, but I will look into it more.
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