Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - admin

Pages: [1] 2 3 ... 15
1
Updates / Small extension uploaded
« on: February 16, 2021, 08:57:30 PM »
one can specify that one wants to use the density of a certain material in BfX_Bcs, eg =bfx_bcs(1;"Cu/m^3";0,5;"in") calculates the ballistic coefficient of an 0.5 inch copper round ball

2
Updates / Update uploaded Feb 2021
« on: February 11, 2021, 08:57:33 PM »
Today I have uploaded a freshly compiled version of BfX.
Furthermore I have added a BfX_Bcs(density of bullet;diameter of bullet) to compute the ballistic coefficient of spherical (round) bullets. These can be used in combination with the GS drag function.
The new version of Getting Started.xls(x) illustrates computations with BfX_Bcs.

E.g the velocity of a .50 inch lead round ball, with muzzle velocity 2012 fps at 100yd: =BfX_Vx("fps";2012;"fps";100;"yd";BfX_Bcs(0,41;"lb/in^3";0,5;"in");"GS") (which would result in 1046 fps)

3
Updates / New update coming soon
« on: February 10, 2021, 11:08:49 PM »
I have added bfx_Bcs
That computes the ballistic coefficient of spherical bullets.
I have to updated  the "Getting started" to and check some other things in the code
Lydia

4
Ballistics / Re: Shotgun Ballistic Calculator
« on: February 10, 2021, 04:09:34 PM »
by the way,
bfx looses accuracy for elevations above 15 degrees. In practice this affects max range / long distance calculations.

5
Ballistics / Re: Shotgun Ballistic Calculator
« on: February 10, 2021, 03:07:15 PM »
e.g.  .50 round lead ball bc= 0.107 lb/in^2

6
Ballistics / Re: Shotgun Ballistic Calculator
« on: February 10, 2021, 03:01:36 PM »
I have (re)done the research.

The ballistic coefficient is computed from m/(d*d) where m is the mass of the pellet in lb and d its diameter in inch

or bc = density*pi*d/6

density lead = 0.41 lb/in^3
density steel = between 0.280 and 0.291 lb/in^3
The drag function to use is "GS" in bfx which matches the one in the above link


7
Ballistics / Re: Shotgun Ballistic Calculator
« on: February 09, 2021, 10:49:05 AM »
I couldn't resist googling. Since 2008 some scientific papers were produced on the matter. https://www.sciencedirect.com/science/article/pii/S2214914717301459 has an interesting one which I quickly scanned
you can use it to check your table.
Next posts on the bc calculation

8
General discussion / Re: Problem downloading
« on: January 21, 2019, 11:29:11 AM »
try again?

9
Updates / Site problems solved and a new version of BfX
« on: January 03, 2019, 04:16:41 PM »
A happy new year!

I have solved the problems with my servers certificate and now bfxyz.nl is not regarded as a bogus site anymore. 8) Furthermore I have recompiled bfx, so that the software includes the latest upgrades from Microsoft. I also have upgraded the simulator "what do I shoot today". You find the simulator at the bottom of the download page. The simulator is able to simulate a multi target (at multiple distances) match under various range, wind and wind fluctuations ammunition/gun and shooter accuracies. Helas, depending if you run the 32 or 64 bits version of Excel, one has to change the visual basic code to point to the file locations where the bfx.xll and bfx64.xll can be found. Unless you store them as C:\bfx\bfx.xll or C:\bfx\bfx64.xll.

Personally, I use this spreadsheet a lot. Soon to see how much points I gain in typical Dutch rifle matches at 100 and 300m if I upgrade my barrel to a more accurate one. As I am a quite able shooter with the service rife (3rd in the National Championships 2018 @ 100m, 2nd at 300m) and the competition is fierce, an additional point from the accuracy is welcome.

10
Updates / bfxyz.nl now fully supports SSL
« on: March 27, 2017, 12:05:39 PM »
The site is now only (and automatically) accessible through SSL. You will see https:// (instead of http;//) in the address bar of your browser. Https, through the use of SLL, would make the use of websites secure and private to use.  SSL is used by https as in: https://en.wikipedia.org/wiki/Transport_Layer_Security

11
Worksheets / launch angle
« on: February 11, 2017, 12:19:58 PM »
Hello,
straightforward computation of trajectories and launch angles (elevation) for two bullets with different bc zeroed at same target

12
Updates / BfX is recompiled
« on: January 13, 2017, 06:10:03 PM »
Happy 2017  with the recompiled version of BfX!

13
Updates / Error
« on: January 05, 2017, 10:18:37 AM »
Happy 2017.
Something went wrong with the forum. Helas. I had to install the backup of january 2016.

14
Ballistics / Re: Pejsa and 3DOF PM
« on: December 09, 2015, 11:00:26 AM »
I would like to add a speculation,

given the purpose of Pejsa's applications in AA guns he probably has some formulas that work for large elevations too.

15
Ballistics / Re: Pejsa and 3DOF PM
« on: December 08, 2015, 02:41:47 PM »
the effect of the flat fire approximation is that it simplifies the math.
That is why Pejsa is able to give formula's.
Formula's can speed up the computation quite a lot - and could be programmed in the computers of the early sixties

BfX, due to the flat fire formula's can be used to 15 degrees.
Due to progress in computing, however, PM can be done at an instant, compared to the early sixties
In priciple I can switch BfX to point mass as I already have the technology to do that.
yet I do not want to support applications that go beyond 15 degrees - these have nothing to do with target shooting

Pages: [1] 2 3 ... 15