Range Report Another Ipod Ballistic app problem

[jb7032]

Ok, I've had the standard version of Ballistic for a couple of years. I just updated it to the current version of the basic App(not the FTE). I was playing with the coriolis acceleration function. When I change the latitude, it has an effect. However, no matter what value I put in for the "Azimuth of Fire", there is no effect on the windage. I have an Ipod touch, with no built in compass. But shouldn't I be able to manually input that info? For example If I enter 39 deg for the latitude and 180 deg for azimuth on my paticular load, it tells me 2.5" at 1000yds. Now, if I change the azimuth to 270 it tells me the same 2.5". Nothing else was changed, 0 wind entered, and the Spin drift funtion was turned off.

Does anyone have any input? I did do a little searching on the hide and google and didn't find anyone with the same problem.

BTW I have Ballistic v2.5.2

 

[jb7032]

Re: Another Ballistic problem, or am I just Stupid?

Bueller? Bueller?

 

[Dodgefan]

Re: Another Ipod Ballistic app problem

In the book Applied Ballistics by Bryan Litz he talks about this. Basically in the Northern Hemisphere horizontal drift is always to the right regardless of azimuth of fire. The book is a good read and a good source of info.

 

[jb7032]

Re: Another Ipod Ballistic app problem

Thanks a bunch!

I guess if I would have read the wikipedia article about coriolis effect I would have answered my own question. I did figure out that to express south latitude to simply put a minus sign in front of the latitude.

Now I have another question. If the azimuth of fire is not important, why does this program ask for it?

 

[BryanLitz]

Re: Another Ipod Ballistic app problem

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jb7032</div><div class="ubbcode-body">Now I have another question. If the azimuth of fire is not important, why does this program ask for it? </div></div>

Azimuth of fire is important to the vertical component of coriolis. Shooting east, POI is up, west it's down, north and south is zero.

In summary:
Latitude alone determines only the horizontal coriolis drift
Latitude and Azimuth determines the vertical coriolis drift.

-Bryan

 

[Lindy]

Re: Another Ipod Ballistic app problem

Bryan knows this, but actually the vertical component is not precisely coriolis but is properly termed the Eötvös effect. A reference for the interested finikin may be found here:

http://en.wikipedia.org/wiki/Eötvös_effect

 

[BryanLitz]

Re: Another Ipod Ballistic app problem

Lindy,

It's not highly important to me what the effect is named, but I would like to cite my source for referring to the vertical component of coriolis.

Modern Exterior Ballistics by Robert McCoy, page 178 states:
"...In 1835, a French civil engineer, Gaspard G. de Coriolis (1792-1842), described the complete Coriolis effect as we know it today, and the effect is named in his honor."

The text goes on to present Gaspard's complete vector acceleration including vertical, horizontal, and range components.

Again, it's not important to me by what name the effect is know as, so long as the math works. I just wanted to share my source and the reason why I refer to "the vertical component of coriolis" instead of the Eötvös effect.

Another reason is because I don't know how to get the dots over the o's. I have to wait till someone else writes it then copy-paste

Take care,
-Bryan

 

[Lindy]

Re: Another Ipod Ballistic app problem

 

[VJJPunisher]

Re: Another Ipod Ballistic app problem

just put a coriolis compensater on your gun and be done with it

 

[Lowlight]

Re: Another Ipod Ballistic app problem

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: VAJayJayPunisher</div><div class="ubbcode-body">just put a coriolis compensater on your gun and be done with it</div></div>

It's called a Left Hand Twist barrel in the Northern Hemisphere ... if it was such an issue we'd all be sporting them.

 

[762frmafr]

Re: Another Ipod Ballistic app problem

This thread and all of it's responses was meant as a late April Fools joke correct?

 

[jb7032]

Re: Another Ipod Ballistic app problem

Don't get me wrong, I'm totally not worried about all this shit. I just got to playing with this program and was confused. The effect is totally not enough to worry about. I can't read the wind well enough to also worry about the cornholeies effect anyway. Now my questions have been answered. Thanks all