KiteModeler was developed at NASA Glenn Research Center. It is a very easy-to-use Java applet that can help you check the dimensions you are planning for in the kite design process.

1. Go to http://www.grc.nasa.gov/WWW/K-12/airplane/kiteprog.html
2. Scroll to the bottom of the page and press the Download button. All of the information about graphics and variables in the software will occur on the web page when you run the software, so DO NOT PRINT IT.
3. When the program is downloaded, a zip-compressed file will be placed on your computer or disk (wherever you specify, unless a default placement has been chosen). If you cannot find the zip file, you can use the find function on your computer to locate it. It should be saved as KiteModeler.zip.
4. Decompress the program and save its contents (21 class files, 2 html files, and 1 Java file).
5. Run the applet by dragging the KiteModeler.html file into a browser window like Internet Explorer or Netscape. It should load after a few seconds and be fully functional.

The program is simple and extremely easy to use! Follow these steps to build your kite and see how stable it is, as well as estimate vectors.

Press the shape button and pick the type of shape you would like from the menu to the right of it.

Press the material button and choose the four kinds of materials you will use. The first material is for the kite surface. The second material is for the rods that make up the kite's frame. The third material is for the tail, and the last material is for the line. You will notice that as you pick materials, different weights are inputted, which will help calculate aspects of kite aerodynamics later. Pick the closest item if you are unsure about the material. Weights are approximate.

Press the shape button and pick the kite's different dimensions. Use the four left-right scrollbars to choose the two heights and widths. The view of your kite should change as you manipulate the scrollbars. You will likely return to these dimensions to alter your kite. Notice that changing these dimensions changes the data in the black boxes in the top right quadrant of the screen. You may notice that as you change to some values, a red and yellow warning message appears in the view portion of your screen, to indicate that the design or trim of the kite is not stable. You may notice that this happens when Torque becomes negative, Lift is far less than Drag, or Weight is too high. If your kite size is bigger than the view window, you can use the vertical yellow scrollbar on the left of the viewing box, to modify your perspective to a larger or smaller one.

Press the Trim button to alter how the bridle line is connected to the kite. You will probably want to view the kite from the side view. To change this, pick the option Select View at the top of the view box, and press the Side option. If you are unclear about the different variables involved in trim, scroll down the applet screen to read about them. You can set the trim angle by pressing the Set Trim Angle option on the menu at the center right of the page. Similarly, the computer can calculate the trim angle with the other menu option.

See how your kite would be flying in a field by changing the view to a field view (Use the Select View and Field options at the top of the viewing box). X and Y vectors are labeled, so you could potentially use this picture to help you determine the force along your string, using the lift and drag data from the black boxes in the applet.,

Once you are happy with your results, record your data. Notice that data can be recorded as Metric or English units. You can change between these by pressing Metric at the top of the viewing box.

Please remember that the KiteModeler Software is not perfect, but can be used as an indicator for poor or excellent design choices!

You Decide Intro
You Decide Scenario