Author Topic: Bfx ballistic calculator with 6-dof corrections  (Read 16514 times)

mman

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Re: Bfx ballistic calculator with 6-dof corrections
« Reply #30 on: December 03, 2013, 11:53:58 AM »
Okay after thinking this a while I think there is no reason to add anything on my calcuculator. It turns out you and Litz are both correct, in a way. In genaral you are right:

Eötvös = vertical coriolis + centrifugal acceleration

However in case of small arms shooting cetrifugal acceleration is zero and furthermore in this special application

Eötvös = vertical coriolis

So basicly Litz got this right. I think this is also the reason why McCoy didn't mention cetrifugal acceleration in his book.



See the picture with exxaggerated dimensions. When shooting with the rifle you can actually see the target. It means that line of sight is the reference line for ballistic corrections and this centrifugal acceleration is automatically compensated. In the picture angle A is the scope correction value (taken from ballistic calculations).

However in the case of artillery fire horizontal level is the reference from which corrections are calculated. Then this centrifucal acceleleration is not automatically compensated but has to be taken into account in ballistic calculations.

375CT

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Re: Bfx ballistic calculator with 6-dof corrections
« Reply #31 on: December 03, 2013, 07:02:11 PM »
Sorry if I wasn¡t clear enough. Litz is wrong in the way he describes the equations to compute Coriolis. It's a bad interpretation of how McCoy addressed it.

I concur with your analysis, but my original point was, that technically speaking, Eötvös is not the Coriolis vertical deflection, because it's not.

A very different thing is not to consider its effects as you pointed out.

By the way, nice picture! Hope I have your skills with technical drawings! :)

mman

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Re: Bfx ballistic calculator with 6-dof corrections
« Reply #32 on: December 03, 2013, 08:01:42 PM »
We have to remember that Litz's book is meant for average shooter to present ballistics as simple as possible. It's not technical book like McCoy's is.
However this was useful exercise for me. Lesson learned. Thanks for bringing this up.

See "Hit probability" thread about one fundamental error in Litz's book. It's quite big one for a guy who wrote whole another book about hit probability...

375CT

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Re: Bfx ballistic calculator with 6-dof corrections
« Reply #33 on: December 03, 2013, 10:51:03 PM »
We have to remember that Litz's book is meant for average shooter to present ballistics as simple as possible. It's not technical book like McCoy's is.
However this was useful exercise for me. Lesson learned. Thanks for bringing this up.

See "Hit probability" thread about one fundamental error in Litz's book. It's quite big one for a guy who wrote whole another book about hit probability...

Any chance to make your spreadsheet available again? I tried the dropbox and is dead... :(

mman

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Re: Bfx ballistic calculator with 6-dof corrections
« Reply #34 on: December 04, 2013, 07:45:33 AM »
Latest version is in Finnish but I can share the old one.

375CT

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Re: Bfx ballistic calculator with 6-dof corrections
« Reply #35 on: December 04, 2013, 04:07:09 PM »
Latest version is in Finnish but I can share the old one.

If there is not much finnish, no problem I can use a translator. Anyway, the old one is always welcomed ;)