The screenshots on this website have been
made on computers having a Dutch locale. 2,3 in Dutch (and many other
European countries) is the same as 2.3 elsewhere (UK, US, AS, ...).
This impacts on how formulas in Excel cells are displayed. In my
examples arguments in cell formulas are separated with semicolons ";"
and I separate decimals with a comma ",". On many other computers one
should use a comma "," as a value separator in Excel formulas and a
decimal point "." in numbers.
Please be aware that BfX does not switch to Imperial or metric (SI)
units automatically. This has to be done explicitly in every cell, see below.
Some of the Excel spreadsheets I provide contains Visual Basic for
Applications (VBA) code (computer programs). In VBA always the "." is
used as decimal separator.
- =bfx_d(740;40;0,5) (Netherlands and other European countries)
- =bfx_d(740,30,0.5) (UK, US, AU, ...)
The International System of Units (aka Metric aka SI units) and Imperal Units
If you not specify otherwise for every number you put in a formula in cell, BfX treats the number as being a value within the International System of Units. There is one exception, the ballistic coefficient is always in imperial units [lbs/inch2]. BfX supports however many imperial units also, read on.
Entering formulas in Excell cells
The following picture
illustrates how BfX works in Excel.
BfX_Zx calculates the path heigth
at a certain down range distance. In cell E3 the formula
entered, no additional arguments. BfX returns then help on that
height_at_x=BfX_Zx(v0; s; h;
zx; x; c) [m] or converted to angle
not specified otherwise units belonging to the International System of
Units (aka metric aka SI). However, one can change the units of
all variables. Row 1 and 2 shows
the use of BfX_Zx with all parameters specified in the cells F1:R1 and
F2:R2. To change the unit
of the output variable, specify the unit in the first argument. In the
picture above, this unit is "cm" in cell F1 and "moa" in cell F2. In
latter case, BfX converts the path height (in the example -153,7 [cm])
to minutes of angle. To specify an input unit, place that units behind
the value, e.g. 200 [yd] in the example above. Ballistic coefficients
[kg/m2] are not accepted. Hence the ballistic coeficient c
only be followed by its drag function.
- v0 [m/s] is the muzzle velocity
- s [m] is the height of the line of sight above the muzzle
- h [m] (usually 0) is the height of impact at the
- zx [m] is the distance where the impact is known (e.g. the
scope zero distance)
- x [m] is the distance at which we want to know the path
- c is the G1 ballistic coefficient in [lb/inch2]
be used with the Pejsa drag function
- height_at_x is then calculated in [m]
BfX supplies extensive help on its use in through
n=0, 1, .... 130, click here
for a listing. Similarly,
n=0, 1, .... 100, lists all supported units and drag functions, look here.
It is not neccessary to specify the default units of an argument, one
can omit them in the argument list of BfX functions.