A little Gun, Shell & Range calculation Tool

snip · September 02, 2010, 11:52:08 AM

What im really confused on is exactly what the drag coefficient represents. Also I have noticed that there is a few boxes in the metric colom that don't change to match there imperial values wile others do.

Nobody · September 02, 2010, 12:45:13 PM

Quote from: snip on September 02, 2010, 11:52:08 AM
What im really confused on is exactly what the drag coefficient represents.

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

QuoteAlso I have noticed that there is a few boxes in the metric colom that don't change to match there imperial values wile others do.

That should not be the case. It would be helpful if you could tell me which one.

snip · September 02, 2010, 12:58:17 PM

The rifleing box was the only one that look wrong to me. I can check the others later

Nobody · September 13, 2010, 03:01:00 PM

Another update (http://www.navalism.org/resources/Ballistic.zip).
Apart from some little things, the interpolation between datapoints know works smoothly.

P.S.:
In the meantime I have added a "Save" and "Load" functionality and some other things, but it's not working properly, meaning saving works fine but after loading a gun the program crashes on the next occasion with what seems like no reason at all.
I don't like publishing something that doesn't work, but if you want to test it well maybe it could be made available in a different location as "Alpha" or something?

Nobody · July 02, 2011, 06:43:14 AM

I'm planning to continue working on this project - maybe as a definitive gun design tool for N4 (?) - and was wondering how I could "add" angles. That is: the "angle of fall" of the projectile, the sloop of the armor and the deflection of the target ship. I should be able to figure it out eventually, but maybe someone already knows a way to do this? If so, please tell me!

Logi · July 02, 2011, 10:19:39 AM

I got it n my program, but it tracks the movement of the shell step-by-step, so it can easily tell you the angle of impact. It may not work for your program, depending on your approach.

P3D · July 03, 2011, 10:27:21 AM

Quote from: Nobody on July 02, 2011, 06:43:14 AM
I'm planning to continue working on this project - maybe as a definitive gun design tool for N4 (?) - and was wondering how I could "add" angles. That is: the "angle of fall" of the projectile, the sloop of the armor and the deflection of the target ship. I should be able to figure it out eventually, but maybe someone already knows a way to do this? If so, please tell me!

It is fairly straightforward, although non-trivial. At the end, you have two planes crossing - the vertical plane of the shell trajectory, and an arbitrary plane of the armored plate.
First step, make an angle of incidence calculator that takes only angle of fall and target bearing into account. The math is the same for the original problem.

Or dig up your linear algebra textbooks, and treat the problem as a series of rotations in 3D.

Nobody · August 07, 2011, 02:20:01 AM

Because Tanthalas said:

Quote from: Tanthalas on August 03, 2011, 01:03:44 PM
its a cool thing to have around to play with.

I thought it might be a good idea to look at it again and make some improvements. I don't have much time for testing though. So please have some more fun and report any error/bug you find:
http://www.navalism.org/resources/Ballistic-v2.zip

Should you encounter a serious problem, then there is still the previous one.

EDIT:
Click "About" to see the latest changes.
These include a "create a gun with given nominal length" for which the bore diameter and the date of design should be set beforehand, and a untested potentially buggy save & load functionality.

Tanthalas · August 14, 2011, 08:13:02 PM

it apears to work just fine on my box anyway mate.

Tanthalas · August 31, 2011, 05:44:39 PM

so while messing aorund with your tool Nobody, I ran into what might be an issue with it. Armor Penitration apears to be right but im getting what apears to be anomolus Data for Deck Penitration. I was using the UKs 12/25 as a testing gun and realised the max Deck Armor it could penitrate acording to the tool was .9 inch. I tryed the same gun in both versions with the same result.

Nobody · September 01, 2011, 01:15:35 AM

Well the penetration function uses the rather primitive "F-Formula", which I think isn't satisfying at all. Most importantly however, is that the constant it uses has not been calibrated yet.

So, if you find a value which gives reasonable results for several guns from a certain era, we would love to know it.

Something similar applies to the air drag, were we still need to determine which function with which constants & factors should be applied to guns of different generations.

EDIT
I would like to point out that saving and loading seems to work properly now. If you encounter any problems, don't hesitate and report them. Thank you.

miketr · September 19, 2011, 12:04:58 PM

I have a number of reservations about using this program but will play around with it some more and talk to Guinness and Charles.

Michael

Nobody · September 19, 2011, 02:37:36 PM

Quote from: miketr on September 19, 2011, 12:04:58 PM
I have a number of reservations about using this program but will play around with it some more and talk to Guinness and Charles.

I was about too agree to that, considering the current, very technical approach.
But then I remembered that save & load works now. So you could offer save files pre-setted to a certain tech level. Then all the user would have to do is to choose a caliber, run the barrel length script and set the shell weight.

That still leaves room for some improvements and the question whether the "F-Formula" is a good choice and which alternatives could be approached.