
Simple Trajectory Program V2.0

STP is a simple trajectory program that will allow for simplistic
calculations of pellet trajectory and create a chart with a scope
turret setting listed on it for a given distance. The data is an
approximation of the pellet flight and must be veryfied at the
airgun range. The program is best viewed on monitors in 800x600 
resolution or higher. 



1.0 Simple Trajectory Panel
-----------------------------

To use the program, simply enter the data in the data fields on 
the left of the main display and press the "Calculate Trajectory"
button below the main display to see the trajectory data. 



1.1 Trajectory Panel Field Description:
-----------------------------------------

Pellet Name: This is the name of the pellet for which the trajectory
is being calculated. This name will appear on the the trajectory
chart and when the trajectory is save to a file. 

Pellet Weight: The weight of the pellet in grains.

Pellet BC: The ballistic coefficient of the pellet. 

Pellet Diameter: The diameter of the pellet in inches.

Muzzle Velocity: The velocity of the pellet at the muzzle in
feet per second.
 
Scope Height: The height of the center of the socpe above the
center of the rifle bore. 

Clicks / MOA: The number of clicks per minute of angle at 100 yards.

Clicks / Revolution: The total number of clicks per turret
revolution. 

Old Bushnell Elite Turret: This field refers to the older style 
Bushnell Elite scopes that had turrets marked with numbers from
0-23. These turrets had one click in between the whole numbers. 
Most turrets are marked in minute of angle. The newer Bushnell 
turrets are marked from 0-5 with seven clicks between the whole
numbers. Most major scope turrets use minute of angle markings.

Zero Range: The range at which the pellet will cross the view 
of the scope.

Starting Range: The range in yards at which the trajectory 
calculations will start. 

Ending Range: The range in yards at which the trajectory 
calculations will end.

Increment (Yd): The distance in yards between each trajectory 
calculation, typically this an even number like 1, 2, 5, 10, etc.

Wind Speed: The speed of the wind in miles per hour. 

Wind Angle: The angle that the wind is travesing the field of fire.
This field will not take into affect head or tail winds.



1.2 Trajectory Panel Button Description:
------------------------------------------

Load Data: Load trajectory data from a file.

Save Data: Save the current trajectory data to a file name of 
your choice. This will allow easy recall of the setup later.

Calculate Trajectory: Calculates trajectory data based on the 
data entered in the trajectory fields and displays the data 
in the main display window. 

Save Trajectory: Saves the trajectory data in the main display
to a file of your choice. 

Print Chart: Prints a chart with the distance and turret setting
from the trajectory data. The chart is printed in two columns to
make it small and easy to attach to your equipment. Use the Print
Size control to choose the print size of the Chart. Each number 
roughly corresponds to a font size. Use the Print Turret/Print Clicks
control to determine if the chart will print the turret values
or click values on the chart. Please note, printing has been tested
on a limited number of printers, if you experience problems printing
please email me. 

Save Chart: Save a chart to a text and Excel file of your choosing
that can be viewed and edited at a later time. 

Load Pellet: This button will open a panel into the pellet 
library. The Pellet library will be described later.

Calculate BC: This button will open a panel that will allow you
to calculate the ballistic coefficient. The BC panel will
be described later. 

Exit: Saves the current trajectory data and exits the program.




2.0 Pellet Library Panel 

The pellet library allow you to store pellet information in a simple format 
that can be loaded into the Simple Trajectory Program. 



2.1 Pellet Library Panel Field Description:
---------------------------------------------

Name: Pellet Name to enter into the library.

Weight: Weight of the pellet in grains.

Ballistic Coefficient: The ballistic coefficient of the pellet.

Diameter: The diameter of the pellet in inches.



2.2 Pellet Library Button Description
----------------------------------------

Add Pellet To Library: Add the pellet data shown in the Pellet Editor
display to the library list.

Delete Selected Pellet: Delete the highlighted pellet in the Pellet Library
List display from the library.

Edit Selected Pellet: Edit the highlighted pellet in the Pellet Library
List display in the Pellet Editor. The pellet data will be added to the
Pellet Editor fields and then the data will be deleted from the Pellet
Library. Once the data is edited, it must be added back into the pellet
library using the "Add Pellet To Library" button, even if no data was
changed. 

Cancel: Leave the Pellet Library panel without selecting a pellet to display
in the Trajectory Panel.

OK: Leave the Pellet Library panel and load the highlighted pellet data
int the Trajectory Panel fields.



3.0 Calculate BC Panel 

The Calculate BC panel allows you to calculate the ballistic coefficient
of any pellet fired from your rifle. The BC can vary from airgun to
airgun so you may need to calculate a BC for the same pellet in 
different airguns for a more accurate trajectory. This panel will only 
calculate the BC based on your inputs so be as accurate as possible with 
your data. The BC will not be inserted into the Trajectory Panel or Pellet
Library so you will need to enter that data yourself.

You will need to shoot several pellets across two chronographs. One should
be near the muzzle and the other downrange, the further the better. I 
recommend 1 yard and 50 yards. Record the two veolocities and enter the 
distances and velocities into the panel to calculate the BC. 

If you have only one Chronograph, you can shoot a string over the 
chronograph at the near distance and then move the chronograph to
the far distance and shoot another string over it. Then use the average
of the two strings to calculate the BC. 




3.1 Calculate BC Panel Field Description:
---------------------------------------------

Near Distance: The distance in yards of the closest reading.

Near Velocity: Velocity in feet per second of the close reading. 

Far Distance: The distance in yards of the far reading.

Far Velocity: Velocity in feet per second of the far reading. 

Temperature: The temperature in Fahrenheit at the time of the measurement.

Pressure: The atmoshperic pressure in inches at the time of the measurement.

Humidity: The relative humidity in percent at the time of the measurement.

Altitude: The altitude in feet at the location of the measurement.

BC: The calculated ballistic coefficient.



3.2 Calculate BC Button Description
----------------------------------------

Calculate BC: This button will calculate the actual ballistic coefficient
and place the results in the field next to the button. 

Use BC: Exit the Calculate BC panel and use the calculated BC in the 
trajectory panel. 

Cancel: Exit the Calculate BC panel and discard the calculated BC. 



4.0 Trajectory Dipslay
------------------------

The Trajectory display will display shows the pertinent trajectory data for
the data entered in the trajectory fields. 


4.1 Trajectory Dipslay Data
---------------------------------------------

Range: The range in yards from the muzzle of the airgun. 

Turret Setting: The location to set the turret to so that
the crosshair will be zeroed on the target. Note: if a + or -
sign proceeds the number, that means that the turret is rotated
one rotation above or below the zero point. Example, if the
click value is -2 or two clicks below the zero point, a - sign
will be placed in front of the number to denote that it is 
below the zero point rotation. If the click value exceeds one 
rotation above the zero point, then a + sign will procced the
number.

Clicks U/D: The number of clicks up or down from the zero point. 
A negative number means the turret must be turned in the downward
direction from the zero point. 

Path: The actual path of the pellet over the distance selected. Negative 
values means the pellet will hit below the zero point, positive values 
means the pellet will hit above the zero point. 

Drift: The amount of drift given the entered wind speed and direction. The
value is an absolute value that isn't dependant on which direction the
wind blows. If the wind if from the left, then the drift value will be to
the right and visa versa. 

Velocity: The velocity of the pellet at the given distance.

Energy: The energy of the pellet at the given distance.

Time: The time of flight of the pellet at the given distance.

Drop: The actual drop from the barrel at the given distance. This
would be the physical drop if the barrel were held parallel to
level ground, or so the theory goes. 







