GOSHEN, Vermont USA — A new program for nitrous oxide hybrid rocket motors has been written by Kevin O'Classen, a Champlain Regional Model Rocket Club member from Vermont. The software is released for beta testing and the author has asked for users to try it out.

A sample report from the new Nessalco Motor Classifier software.

Written for use on Microsoft Windows®, Nessalco Motor Classifier comes with a standard Windows installer package and several motor data files in a ZIP archive. Some motor profiles are installed by the installer, others you can add manually. All you have to do is unzip the package and run the setup.exe file. O'Classen has tested the software to run on Microsoft's XP and Windows Vista® formats.

The software was written to do three things:

1. Give general information on the performance and characteristics of the hybrid motor as it was certified, including the motor class, the average thrust, Isp, mass fraction, ready-for-flight weight, and motor's total propellant weight (N₂O + fuel consumed).
2. To allow the user to discard the portion of the thrust curve that results from "blow down" to give you a better idea of the "real thrust" of a hybrid motor.
3. Attempt, with emphasis on the word "attempt," to predict how the hybrid motor might perform as the N₂O temperature is varied from the temperature at which it was certified. O'Classen stated this area is functional but still under refinement.

A user can calculate various changes to the data, print out motor reports as well as save the hybrid motor information for future use. The beta installer has motor profiles for Contrail Rockets J416 and M2281 hybrid motors as well as Sky Ripper G63, K257 and K347 hybrid motors. Additional motor files from the Nessalco Motor Classifier website includes the HyperTek J250 and Contrail Rockets O6300 hybrid motors. Note: The motor files included contain certain assumptions about testing conditions, which may or may not be correct. They are for demonstration purposes only, and are not intended to make statements or comparisons.

To add your own motor profiles, you simply locate the appropriate motor certification document and the motor thrust curve, then fill in the blanks. Once you have it like you want it, you can save the file for future use. Since this is beta software, the help system doesn't exist, but the program is pretty straight forward to use.

The author would like your input on his work, since that is how software gets improved: by user input. "This is beta version software, and contains bugs," O'Classen said. "I'd be interested in having folks try it out and tell me what they think, or what they find that doesn't work."

You can download it here: http://www.crmrc.org/programs/NMC-v1-1.zip

You can also check the Nessalco Motor Classifier home page, to check for recent updates, and download new motor profiles that are available.

Website: http://www.nessalco.com/nmc.htm

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