Started by gvp, April 30, 2013, 11:26:57 PM
Quote from: gvp on May 05, 2013, 11:53:42 PMCan I use another BfX formula in order to have a result with an inclination ? -------------> Yes BfX_Zeif pressure, temperature or humidity change are these values change or remain the same ? (logically they change) ... ... so in which temp, humid, press conditions must these values be measured, in order BfX make right calculations ?-------------> BfX assumes T=15 [C]; P=101324.6 [Pa]; H=0.0 [fraction of 1]these qualities modify the air density and that modifies the ballistic coeficient: air density = BfX_Ad(T=15 [C]; P=101324.6 [Pa]; H=0.0 [fraction of 1]) [kg/m^3]Whether one use custom drag functions or standard ones, one deals with the air density effects with BfX_C, e.g.=BfX_Vx(800;200;1*BfX_C(10;765;"mmHg";78;"%H");dt)In the above example the ballistic coeficient is 1 (because the custom drag function used requires it) but modified because of the density effects.2. in your help file you wrote "Cd=BfX_Cd(v0; df=GP)".I think it would be more user friendly if you write "Cd=BfX_Cd(v; df=GP)" because Cd change with velocity, and vo is just the muzzle velocity.-----> good point!
Quote from: gvp on May 05, 2013, 11:53:42 PM1. as you can see I use a custom drag table which I took it from chairgun (GA profile) (black background cells).if pressure, temperature or humidity change are these values change or remain the same ? (logically they change) ... ... so in which temp, humid, press conditions must these values be measured, in order BfX make right calculations ?
Quote from: mman on May 17, 2013, 05:03:13 PMAs far as I know Chairgun fits pellets to a drag function A which is constant as a function of mach number. This is not a good drag function profile to fit any projectile. Drag of every projectile changes wildly close to speed of sound. If your gun shoots pellets at speed of 280 m/s or faster drag function A (chairgun) is not a good fit. I tried to explain this to the programmer of chairgun but I guess he didn't understand what I meant. Or is this problem corrected recently?
Quote from: mman on May 27, 2013, 09:34:20 PMThanks for info gvp. That's nice update for chairgun. Perhaps I give it a try. And impressive work with your own spreadsheet.
Quote from: mman on May 28, 2013, 06:45:58 PMNice! Isn't it fun to make your own calculator? Commercial versions always lack something or you would like to do something differently.
Quote from: mman on May 28, 2013, 06:45:58 PMIs there also options for these mentioned on "about" sheet:Wind weighting factors (McCoy)Effect of atmospheric conditions to vertical zero rangePossibility to use horizontal zero to compensate spin drift for short ranges
Quote from: gvp on May 29, 2013, 03:51:53 PMIf you mean that I must include also the remain 3 factors .... may I'll do it when I find some time ...
Quote from: gvp on May 29, 2013, 03:51:53 PMThe only thing that I want now is to print my scope's elevation turret tape
Quote from: gvp on May 29, 2013, 03:51:53 PMyou google it or the formulas are written in a book ?