is a beta 1.2 version of the RocketModeler program written by
Eric Bishop from the Ohio State University. You are invited
to participate in the beta testing. If you find errors in the program or
would like to suggest improvements, please send an e-mail to email@example.com.
With this software
you can investigate how a model rocket flies
by changing the values of different design variables.
If you are an experienced user of RocketModeler, you may prefer
a slightly different
version of RocketModeler
which does not include this manual and loads a little quicker in your browser.
There is newer version of the program, called
which is also available. The newer program simulates a wider variety of
If you experience difficulties when using the sliders
to change variables, simply click away from the slider and then back to
the arrows on the end of the sliders disappear, click in the areas where
the left and right arrow images should appear, and they should reappear.
If you see only a grey box at the top of this page, be sure that Java is
enabled in your browser. If Java is enabled, and you are using the Windows XP
operating system, you need to get a newer version of Java. Go to this link:
try the "Download It Now" button, and then select "Yes" when the download box from Sun
The program screen
is divided into two main parts:
On the left
of the screen is the graphics window in which you will see your rocket
design and test flight. You can switch to the launch graphics by pushing
the blue "Launch Rocket" button. Details are given in Graphics.
On the right
of the screen are the input sliders and boxes that you use to change
your design or to set flight conditions. Details of the input
variables are given below.
There are two main
graphics displays. During the design of a model rocket you will see a
drawing of the current design. As you change tube length, or fin geometry
the graphic will change. On the rocket you will see two circles. The circle
with the black diamonds is the location of the center
of gravity (CG). The circle with the black dot is the location of
the center of pressure (CP). The location of
the CG and CP will change during design. For a stable
rocket, keep the CP below the CG.
When the blue "Launch Rocket" is
pushed on the design screen, the
graphics change to display the location and orientation of your rocket during flight.
Initially the rocket is sitting on the ground on its launch rail. When the red "Begin Launch" button is
pushed, a countdown from T-3 sec. begins. At T= 0, the engine fires and
you will see some small "flames" at the base of
the rocket. The flames remain burning during the powered portion of the flight but are
extinguished during the coasting ascent. If you are flying a 2 or 3 stage rocket, you
will see the spent stage fall away from the stack following staging.
When the ejection charge is ignited, the
nose cone is discharged and a small parachute is deployed for slow descent.
On the left and bottom of the graphics are some numbers which
indicate the location of your rocket relative to the launch rail. The
scales are in meters. When your rocket return to earth, a message
appears telling you how high your rocket flew. Clicking on the blue "Design Rocket"
button will return you to the design graphics.
The input variables
are located on the right side of the screen. During rocket design, you have
two choices of input screens; Design and Materials. You
can select the input screen using the buttons at the top. At the bottom
of the input screen you will see numerical values of the CG, CP,
and the rocket weight.
By convention, input boxes have a white background and black numerals,
while output boxes have a black background and green numerals. However,
if your rocket is unstable, the color of the output numerals will change
from green to red.
If you are designing a multistage rocket, you will need to check the
stability of both the launch (upper stage plus booster) and the flight
(upper stage only) configurations by using the menu button at the bottom.
You can also display the the CG and CP locations re