angle and height calculations

[wrtiii]

Because the shell is moving rapidly? Because it is at its peak only for a very brief time?

[stuntborg]

Originally Posted by bloomboom

Besides drag and initial velocity you must also account for the friction loss of the tube. Length of the tube will also change your results.

Density must also be accounted for in your calc's (density=mass/volume). Mass, regardless of where it is (vacuum or atmosphhere) always remains constant.

IMO you also need to account for human interaction. Calculations of amount of material proportions (lift charge etc.) that go into the production of these "projectiles" will skew your results.

Can someone explain why the angle from the ground to the shell can't be accurately measured?

Getting way to complicated here. Last question first. Follow these simple directions.
1. Stand up.
2. Put your left arn in.
3. Put your left arm out.
4. Put your left arm in. Do the hokey pokey and turn yourself about.

Hmm...doesn't seem right, lets try again.

1. Stand up.
2. Put your left arm out.
3. Put your right arm out but point it at the ceiling light in the next room over.
The angle between your left and right arm is the angle of interest. Now, pretend you are shooting a shell. Your right arm points to the shell as it goes up. You some how need to acurately measure that angle. thats one way to calculate the maximum height of a shell.

Another way would be to use a high speed camera and calculate the muzzle velocity. Friction in the tube, lift charge, height of the tube, all that stuff doesn't factor in since it happens before you measure. You still get the argument about air resistance and all that fun stuff. Probably a valid argument.

Best way to measure the height of a shell? Get a really long and big tape measure. Mount it to something two hundred feet tall. Shoot 20 shells and record the height of each shell based on the tape measure.

[lamrith]

I haven't gone thru my training manuals in a while, but I recall from my training class years ago you don't want that much angle (15*) on your mortars anyway? If I recall I think the max my instructor recommended as Std practice was like 3* with 1.3, as the hieghts involved would do the work to separate the shells, plus the issue of duds falling to earth and wanting them to do that INSIDE the safety zone. Maybe there isn't a code, that was his rule for safety (His shoot, his rules), but it is one I have always followed even on my own private 1.4 shows.

[nepyro]

The link below is to a wonderful piece of work by Developed by John Harradine, Manly, Queensland, Australia with additions by Tom Smith, Davas Ltd, UK. It is called ShellCalc. I use it when I am worried about where a shell will go or where a dud might come down.

ShellCalc - via Journal of Pyrotechnics Archive

Their brains have more wrinkles than mine

Enjoy!

[unipyro]

http://www.ehobbies.com/qus7812.html...mpaign=froogle

so simple..

[Pyro Nut]

Originally Posted by Carmenuchi7

Your way is definitely easier dude. I'm with you on this one.
....my head hurts...

It's like having a slurpee on a hot summer day and getting that brain freeze feeling.........ow, ow, Ow, OW

lol

[stuntborg]

Originally Posted by unipyro

http://www.ehobbies.com/qus7812.html...mpaign=froogle

so simple..

I remember using those back in high school. They work about as well as you would expect a six dollar altitude measuring tool to work.

[unipyro]

Originally Posted by stuntborg

I remember using those back in high school. They work about as well as you would expect a six dollar altitude measuring tool to work.

yes, but if you don't want to do any calculations, its very simple.

[Hfireworks]

This chart may help, I use it to varie shell size and distance.