Look at the examples to get a feel for velocity.
3 variables and one function define the trajectory - They are:
Drag Function - 5 are selectable in the program.
You can calculate any one of the variables if the other two are known against a specific drag function.
Velocity and Barrel Elevation are easy to measure. The Ballistic Coefficient and Drag functions are expensive to measure. Velocity can be measured in a number of ways:
Chronograph http://www.shootingchrony.com/ about 100 dollars
High Speed Photograph - expensive about 1200 dollars
By sound - http://arxiv.org/ftp/physics/papers/0601/0601102.pdf - very inexpensive
Doppler Radar - Radar guns are cheap but do not measure velocities at cannon velocities - high end systems like the military use provided velocity, BC, and drag function information no comment on their cost.
Time of Flight and range will give an average velocity for the trajectory. A modul can be written for muzzle velocity - no big deal - but you still have to know the BC and select a drag function that describes the projectial's air resistance.
This question regarding velocity is why I am interested in developing an internal ballistics model for cannons and mortars.
An approximate equation for muzzle velocity for ball with a diameter of 1.68" is:
Muzzle Velocity = 2.0258 X grains of powder + 8.2488 - the equation is valid for fg, ffg, and Cannon grade poeders.
Hope this helps.
The program also crashed a lot for me also, using Vista.
How do I select a projectile from you library.
I will send you one of my golf ball mortars and one steel ball and one one golf ball.
Using the methods suggested above you measure the velocity of the two projectiles.
I have a chronograph Oehler 35 and I would wouldn't put my sky screens in from of my golf ball mortars in from of i
I like the idea of your program, but I think you are making it to complex for our purposes. Apply the K.I.S.S. formula.
Provide a library of projectiles to select from with precalculate BC's and drag functions.
We can live with average velocities.
Since you model predicts velocities with a given charge of powder how about a module that lets plug in the powder charge and gives a predicted velocity.
Once I had your predicted velocity numbers from the powder/velocity equation and put that in your program the results I got compared with the results I get on the range..
My 30 yard charge for a golf ball is 24 grains. Your program predicted 94 feet.
I think your little program has some real potential for our use, so keep on working on it
I would like to see it it work in reverse.
I am shooting a golf ball at a target 100 yards away, how much powder do i need.