1. Enter your rocket's parameters

2. Select the engine manufacturer and type

3. See the results

Altitude by numerical solution (feet)

Velocity by numerical solution (feet/second)

Acceleration by numerical solution (feet/second/second)

Thrust interpolated from the .eng data (newtons)

Assumptions:

• You're launching at sea-level with moderate temperature and humidity
• You're launching with no wind at an angle of attack of 0 (straight up)
• Drag is based solely on the Cd you entered - 0.75 is typical
• Only single engine/single stage simulations are supported
• The design is stable
• Ejection is after apogee
• Engines are modeled using RockSim .eng data. Because JavaScript can not load files, the data for selected engines have been extracted and coded in strings. I picked the engines I use the most.
• The engine you select will fit in the rocket and is otherwise appropriate

Known bugs:

• If you get an advisory regarding the format of the data input, you must correct that error before selecting another parameter. If you don't you will get hung in a state in which you ping-pong between those two input fields. The only way out is to close the browser.
• The engine manufacturer radio buttons do not always default to Aerotech when the page is reloaded. Thus, the button may say 'Estes', but the drop down list will have defaulted to Aerotech as it should. If you reload the page and note that the slected manufacurer and drop down list do not agree, just reselect an engine manufacturer.

References and credits:

• Handbook of Model Rocketry, G Harry Stine, 5th Ed., 1987
• javascriptdraw.class by Maxim V. Kollegov (http://www.geocities.com/siliconvalley/lakes/8620)
• Additional graphics code by Tim Cera (http://home.earthlink.net/~timcera/)

Revision history:

• Rev. 2.00, 3/7/2004, removed frames to allow inclision in EMRR's tools page
• Rev. 1.12, 3/27/2001, fixed bug that required an alert at start-up (the script was trying to access the 'motors' frame before it was loaded)
• Rev. 1.11, 3/26/2001, fixed bug (v_min and a_min variables were not converted to feet)
• Rev. 1.10, 3/25/2001, added graphs, fixed bug caused when three thrust pairs are within 0.05 sec. of each other
• Rev. 1.00, 3/24/2001, inital working version, beta testing