From: De Eye-lands, Mon
You got a fiz-max-slant, fiz-max-horizontal, fiz-max-vertical. Then you got a max-eff-slant, max-eff-horizontal, max-eff-vertical, and max-eff-fire-control-altitude. And on top of all this, you have max-fuse-setting-time-out. So there’s 8 different choices for ceiling for a gun and boy-oh-boy do the fanboi sites milk this for all it’s worth.
Wikipoedia just publishes the data from the most popular websites, so it’s 100% wrong 92% of the time. The last 8% will become important as shown further on. But so many people just post up Wikipoedia crap as though it was something worth looking at. It isn't.
The “fiz” refers to fiziks (physics), the Isaac Newton stuff. The math is middle school level (maybe high school). What goes up, will come down. A mass (shell) M leaving the earth at velocity V and at angle A, against the force of gravity ‘g’, and against an air resistance ‘k’ (that decreases with altitude according to a known parameter), will describe a very well behaved curve. So it’s incredibly simple to make fiz-max curves for any gun, given shell weight and muzzle velocity. Woof !!!
But AA guns aren’t shot quite that way. They are most effective at their best ‘slant’ range, usually 70 to 75 degrees. Ok, so plug in 75 for angle A and get more curves. That’s fiz-max-slant. Now, one has to look at the ‘effective’ part of the thing.
Simple Newton is cool, but you also have atmospherics. Cross-wind shear buffeting, at multiple altitudes will affect a 12-14 lb shell way more than a 28 lb shell, according the a power law function applied to the wt/aeral cross section presentation. Because of this spread, accuracy needs to be adjusted on a shell wt basis. So a really shoot-hot, hi-velocity 75mm, might have exceptional technical characteristics, but fall short of a lower velocity, higher caliber, weapon when it gets down to “effectivity” cases.
And then there’s an effective fire control altitude, but that depends on national technical means, which are impossible to determine with any degree of accuracy for the various nations represented.
And then there’s a physical/time altitude defined by the shell fuse type/timing. Again, a national technical means thing, which is impossible to determine with any degree of accuracy for the various nations represented.
Best guess I can come up with is generate the fix-max-slant curves, and adapt them with the atmospheric parameter. Then get the best data I can for FC and Fuse timing, graph that and pull everything else onto that curve and get arbitrary for some specific weapons.
It really is a graphical solution, with Newtonian physics as a baseline, atmospheric effects as an adder, and a modulo plus/minus on the later war FC/Fuse data.
Does this help at all? JWE
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