Author Topic: Cannon ballistics ? (Read 1038 times)

Calamity Jane · « **on:** September 21, 2003, 10:24:42 AM »

Got a question fer you experienced cannon shooters....

Took the cannon out to the range today to fire a few more shots. Loaded 1/2 Ounce of FG powder behind a 1" ball (1/5 Lb. or about 1400 grains), sighted it along the top of the barrel fer azimuth and down the side of the barrel fer elevation at a point on the berm about 110 Meters away. I pulled the lanyard 'n' that ball hit within a foot of what I thought was a straight line from the bore.

Is it possible that the ball dropped less than a foot in 110 Meters?

:shock:

BTW: Thar's a few more pictures now over at http://www.geocities.com/winnonad/index.html

This cannon shootin could get addictive :eek:

Cat Whisperer · « **Reply #1 on:** September 21, 2003, 01:53:48 PM »

One foot drop in 110 meters. Expected. Cannon are direct fire devices. Howizers and mortars are indirect, high arching parabola.

People talk of 1000's of yards range for golf-ball caliber cannon with 4' long barrels. That scares ME! The same people talk of "you bring it over, & I'll shoot through it. Refrigerator, range, etc."

I expect that the time of flight was relatively short - a fraction of a second or so.

Time of flight from the mortars, at 100 or so yards range, is from 8 to 10 seconds. That's shooting at from 45 to 75 degrees elevation. Lots of hang time.

OK, now the REAL question.

How many wet phone books will your cannon shoot through?
Does the sphere mushroom much?
I won't ask any questions about hunting....

Calamity Jane · « **Reply #2 on:** September 21, 2003, 03:18:14 PM »

Donno how many phone books - I just know that last time it went thru a 4x4 at 50 yards 'n' left a hole as clean as if it was drilled!

Flight time waz a fraction of a second. On the third shot, we heard it go down-range! Strange "woosh" sound.

We look fer the cannon ball but I expect it buried itself purdy deep in the berm - we couldn't even find the hole 'mong all the prairie dog holes

I didn't expect a 1" ball with only 1/2 Ounce of powder to have that flat a tradjectory! It must'a been truckin right along to stay that straight. I waz expectin more of an arch.

This is gonna be FUN!

Cat Whisperer · « **Reply #3 on:** September 21, 2003, 03:30:22 PM »

Hmmmm. Prairie dogs.....

On a serious note, there must be tables of balistics for round ball, given velocity, mass and elevation. It's a straight forward equation - but you have to know (or calculate) the ballistic coefficient (which for round ball isn't good).

It's a little different with artillary shells. The shape has an effect and the round stays somewhat at the angle at which fired which influences the equation.

When I was in the Artillary, we had tables of trajectories, coupled with wind velocity (each 500 feet of altitude) and direction, direction of fire (to determine the effect of the rotation of the earth), powder temperature, altitudes of firing battery and target, and exact weights of the rounds. All used to calculate the range and time of flight and give the azimuth and elevation to the firing battery.