Sorry,

the max I could do I did. Took a fresh XP machine, installed Office XP, then BfX fresh from the site, and it worked out of the box.\

Robert

Kept thinking about the different shapes of the drag function. The max horizontal range of the 105gr 6mm scenar is 3990 m with the radar measurement, whilst using a g7 function with the Litz bc of .248 it would fly 4722m - both distances computed with quicktarget!

this is not what I did expect. I would expect that with the radar data the bullet would fly a longer distance, as the drag of bullets flying below the speed of sound is much lower as with the g7.

Since ages it was possible to enter a bc of 0 - excel would crash. Nobody complained, how is that possible? anyhow this is fixed now.

Because of a small project that will end up in another spreadsheet to download  I added the unit mil (=mili radian, = 10 cm per 100 m) well known from scope recticles

Paul, see if you have the following files somewhere:

Packaging file 'msvcr100.dll'...
Packaging file 'BfX.xll'...
Packaging file 'msvcp100.dll'...

Quote from: mman on May 09, 2011, 03:04:19 PM

Quote from: admin on May 08, 2011, 09:41:12 PM
No, it is not a problem, but an awful lot of work. BfX needs these functions as a set of power laws - the basis of Pejsa method. For power laws many physics equations can be integrated mathematically.

How about multi BCs? Is that awful lot of work too? Bryan litz offers multi bcs and some times using them leads to better results. There also several cases when single bc is simply not enough. Couple good examples are most air rifle pellets and 22 lr bullets. That is first hand experience when I have tried to fit those to drag functions. My guess is that there is some degree of dynamical unstability involved. For short distances path fits fine but for longer distances drop tends to grow more than traditional A, RA4 or G1 drag curves would estimate. That's where you would have to correct the effect with multi BCs. Another case is ELR shooting where bullet slows down to transonic velocities..

IMHO multi bc input is programmed wrong in ballistic programs which even offer the possibility to use this feature. Program should be done so that BC would be interpolated between given bc values. Linear interpolation is very good default but in best case scenario advanced user could choose polynomial interpolation degree. Another thing is that multi bc boundaries should be tied to mach number and not to the velocity like it's done in QTU.

Well BfX supports custom drag functions now. Mman show me what you would like to do with air rifle drag functions!

More examples on the use of custom drag functions.

Well I played a bit around with BfX_CD and the new abilities of the user supplied drag functions. It was a 1 minute activity to plot the measured drag function of the Lapua 6mm 105 gr scenar with g7 in a graph.

One might say that the shapes differ - rather much. The absolute magnitude is not very important as the ballistic coeficient is used to fix the agreement with data in the case of g7. It is a pitty that we do not know how Lapua did the measurements and how accurate they are. The discussions about the best drag function for long range shooting seam however rather pointless.

Paul,

I finished the following
1)took a windows xp machine who for the last time run in 2008. It never saw office before
2)did not do any updates.
3)installed excel2003
4)did not update excel2003
5)downloaded bfxsetup.zip
6)extracted the two files in there to the desktop (I do not run them from a zipped folder)
7)ran bfxsetup, typed only next next next
8)started excel2003
9)installed the addin
10)typed =bfx_help()
it worked
11)downloaded getting started
12)opened it in excel2003
13)typed ctrl-shift-alt-f9
and thousends of calculations ran in the wink of an eye.

I do have administrator rights.

There must be somethin wrong with your installation. Maybe you run the excel installation again, in the repair mode.
BfXsetup installs bfx.xll
The setup.exe installs
C:\Program Files (x86)\Common Files\Merge Modules\Microsoft_VC100_CRT_x86.msm
containing
Visual C++ 10.0 CRT (x86)

No idea yet. Today or tomorrow I'll come up with suggestions. The new additions to bfx have doubled its size, 400kb is indeed the new size. If you unzip the installer you have to run bfxsetup.msi. There is also setup.exe which is important because it installs run time libraries from MS. It should be run from bfxsetup automatically. Do you know if they are installed?

Robert.

deinstall and re-install can't harm, i do it all the time when debugging. Download the last version.  I do test BfX on Excell 2003 and Win XP however. I'll try to find an old virtual machine that has no traces of all my debug activities and who did not have had a Microsoft update for ages. This might take a day or two.

You can download now a BfX version capable of working with custom dragfunction. Read the gettingstarted workbook to understand how. As this is the most complex addition to BfX since its beginning, and although the software is full of checks, there is increased risk of crashes. Take care and save your work regulary.

The Lapua dragtables can be downloaded here: http://www.lapua.com/upload/ballistics/qtulapuaeditiondragtables.zip You can also download a free ballistic calculator, a rather sophisticated one from the Lapua site that works with these dragfunctions. You'll see then that BfX accurately reproduces its results.
The Lapua drag tables can be opened with a normal text editior. Then, bassically, cutting and pasting will put the table in Excel.

How does the custom dragtable work in BfX?

As said before, read the GettingStated workbook. Bassically however, you fill a range in Excel and supply it to BfX instead of the dragfunction string:
=bfx_vt(750;300;1;<range>). One has to use a ballistic coefficient of 1.

Expect in future other types of drag function. The next big project is the 6DOF extension.

Robert

If you see bfxxll2003 that is realy a good sign - it should work. Security does interfer with this.


Please tell me if you see in the menu "insert" "function" bfx functions.

Please try the following: copy the xll to the desktop, remove the other one from excel, close and open excel load the desktop xll. Tell me if this work.

Good news, at least for me.

after some hefty programming I managed to extend BfX with the ability work with custom drag tables.

In the figure you see how it will work. To the right you see the custom drag table, in this case one for a Lapua bullet and supplied via Lapua's QuickTime software.

To the left you see a comparision of the results.

After I have removed some bugs, an update of the getting started documentation and rigorous testing I will release the new addin within a week or two.

if BfXXll2003 shows up then the installation was a succes. Can you check the security settings of Excel see (enabling macros)-http://www.bfxyz.nl/docs/bfxexcelsettings.shtml

... soon I'll will post another update - the one in which you can supply your own, Lapua's or other drag functions.