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31
Ballistics / Re: Weapon Employment Zone
« on: June 12, 2014, 12:38:37 PM »
Maybe "Monte Carlo" is a  definition issue. In this case, i imagined that input parameters are generated in such a way that they are consistent with a certain probability distribution. Then a trajectory calculated and evaluated. The process is repeated hundreds of times. This is what one might describe as Monte Carlo.



32
Ballistics / Re: Weapon Employment Zone
« on: June 11, 2014, 12:16:00 AM »
WEZ is a Monte Carlo simulation.

I find it hard to opinate about it - it does what it says.

Quite frequently I use a similar tool understand ballistic effects in a target shoot competition setting.

It is available as download on the BfX site. Look for the descriptive text:

"This workbook hosts a simulator with which you can estimate your results in a (multi distance, multi target) match, e.g. the NRA 90 shot full bore regional match course."

34
Member projects / Re: CFD modelling
« on: May 24, 2014, 07:28:27 PM »
cool!

what I need are parametrizations of 6dof coefficients for boat tail bullets. No other projectiles.

35
The problem with these matters is that assumptions are made "e.g bullet flies in the direction of the wind" and presented as facts.

Even they are somewhere along the trajectory true, there is a period they are not valid. What happens then.

Nevertheless, I have time to spare I will read better the article.

Robert

36
Indeed, BfX does not work on a Mac.

In short I will have a look at your work!

37
Ballistics / Re: Spin Drift
« on: March 03, 2014, 08:16:21 PM »
mman has a 1000m+ range in his backyard! Shall we  ask him?

The problem, of course, is to do the measurements.

In those measurements one has to vary some quantities that affect spin drift and other factors that affect horizontal displacement. Then there is wind and measurement errors. To single out to spin-drift effects one must trust the proper computation of all other effects that deflects the bullet. I would guess that only a professional organisation is able to do the measurements.

As far as I know, the US Army is the only institution that published measurements.

Brian did the best next thing. He used a proffesional 6DOF ballistic program - PRODAS - and fitted the spin drift of bullets.

38
Ballistics / Re: Vertical Wind
« on: February 24, 2014, 04:14:16 PM »
In the Netherlands there is nothing a shooter can shoot at that requires an elevation of more than a degree...

39
Member projects / Re: 6Dof bullet parameters
« on: February 07, 2014, 12:24:30 AM »
no, i cannot lay hands on a proper set of formula's for the bullet 6dof parameters.

40
svorog1, we need more details.

can you post the spreadsheet so that we understand what you are doing?

41
Sometimes I wonder what to add to BfX given that there are spreadsheets, like this one, that does so much! Clearly, being able to run on a Pocket PC brings ballistics in the field.



42
Member projects / Re: 6Dof bullet parameters
« on: December 16, 2013, 06:40:24 PM »
but the missing values are small?

43
Member projects / Re: 6Dof bullet parameters
« on: December 15, 2013, 11:04:15 PM »
Cool! a pitty that I cannot embark on the matter myself, I have other science to do.

I know that you can shoot the distances to test your own calculations. Can you measure the distance that your bullets start to toggle (shoot keyholes) because their velocity goes below that of sound (and the nose pressure gets a factor of 3 to 5 higher?).

I would reload as low as safe, to have low muzzle velocities and put paper targets every 10 meters in the neighbour hood where the bullets goes below the velocity of sound.

Probably statistics is involved, hence you should have statistics of the number of keyholes per meter....

?

44
Member projects / Re: 6Dof bullet parameters
« on: December 14, 2013, 11:46:46 PM »
thx, have a look at the code in ad0915628 - i mentionned in a previous post that i salvaged much of it. however 6dof equations of motions are not so difficult to implement. the hard thing is to get the aerodynamic coefs right,

45
Member projects / Re: 6Dof bullet parameters
« on: December 14, 2013, 07:32:20 PM »
In intlift2 the machnumber is an input value. Not computed from anything
In bfx the speed of sound is taken to be constant, I have to look up its value?

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