lative to the bottom
of the rocket or the bottom of the stage by using the menu button.
Pushing the blue "Launch Rocket" button changes the input
variables which are displayed.
The default input
screen is the Design screen.
You can select a one, two, or three stage rocket for design by using the menu
button at the top of the design screen.
You can use the sliders and input
boxes to change the length and diameter of the body tube, the length of
the nose cone, and the length, width and height of the fins. You can use
the selection buttons to choose either three or four fins located at equal
intervals around the rocket. Most of the
variables on this screen will influence the location of the CP. The "Zoom"
input controls the size of the graphics. To change the value of an input
variable, simply move the slider. Or click on the input box, select and
replace the old value, and hit Enter to send the new value to the
screen is used to provide information which affects the weight and CG
location of the rocket. You can select from a variety of materials for
the nose and fin using the pull down menus. If you choose "Custom" materials,
you must provide the density of that material in the input boxes in units
of grams per cubic centimeter. On this screen, you also specify the engine
to be used during your flight, and the weight of the recovery system.
You can select from three parachute sizes, which will affect the terminal
velocity of your descent. The drag
coefficient is based on the cross sectional area of the rocket and
has a default value of .7. You can enter a different value for your own
rocket design. (In future versions, this number will be computed by RocketModeler
based on your design.)
Launch several buttons, text fields, and sliders appear in the input
screen. The blue "Design Rocket" button returns you to design mode and
resets the graphics and input screens. The red "Begin Launch" button starts
the countdown for a new flight.
At any time during the flight,
you can push the white "Reset" button to return the rocket to the pad.
Pushing the yellow "Pause" button freezes the rocket in flight so that you
can record data from the flight. A purple "Resume" button is pushed to continue
To the right of the buttons are output text fields showing the
elapsed time of the flight, the current velocity, and the maximum altitude attained.
During ascent, the maximum altitude is the current altitude.
Using the sliders beneath the buttons, you are able to set the angle of the launch rail, and to set
the wind speed. Positive velocity is from the right of the graphic.
The "Percentage Real Time" slider allows you to control the speed of the animation. 100% is real time,
and higher values cause the animation to proceed more slowly. (Because of a refresh problem in
Internet Explorer, we recommend using a value greater than 400% for that browser. Otherwise the
instantaneous time, velocity, and altitude outputs are not properly updated. Hitting the "Pause"
button will display the correct values, however.)
The Learning Technologies
Project will continue to improve and update RocketModeler based on user
input. The history of changes is included here:
On 14 Jan 03,
version 1.2 was released. This version includes the multi-stage capability and
some bug fixes associated with the calculation of the engine weight.
On 14 Dec 01,
version 1.1 was released. This version includes controls on the speed of the animation,
options for the number of fins, output of instantaneous velocity and altitude, and a
countdown to launch.