burnsim.com

What It Is

BurnSim is a steady-state internal ballistics simulation tool for solid rocket motors on Windows. It is aimed at rocket motor design and solid propellant grain design. After users enter the motor, nozzle, and propellant characteristics, the software calculates Kn during the burn and estimates chamber pressure, thrust, and motor performance. It is more of a professional desktop tool for rocket motor designers than a general-purpose development framework.

Core Features and Ecosystem

BurnSim supports a range of grain geometries, including BATES, end-burning, Moon/Offset Core, D Grains, C-Slot, Finocyl, Star, and X-Core, and it allows different grains to use different propellant types. Once a design is created, users can adjust parameters such as nozzle diameter and grain core diameter, then immediately view graphical changes in Kn, chamber pressure, thrust, mass flux, and other metrics. The software also supports importing test data for side-by-side plotting against simulation results, and can save motor designs, propellant properties, notes, and test data. In terms of ecosystem integration, it can export .ENG files for rocket flight simulators such as RockSim and wRasp, and can also export CSV files for Excel or other system-level analysis.

Pricing and Licensing

BurnSim can be downloaded for free and used in trial mode. A time-limited full-feature license is available by contacting the author; students can activate it for free with a .edu email address. A personal license costs $39, with volume discounts for multi-user purchases and discounts for educational licenses. Payment methods include PayPal, credit card, check, or money order. For a specialized professional tool, the entry price is relatively low.

Pros and Cons

Its strengths are its tight focus: it covers grain geometry, nozzle optimization, simulation curves, comparison with measured test data, and data export, making it suitable for iterative design. The limitations are also clear: the documentation states that BurnSim currently assumes steady-state operation and does not account for erosive burning, which can significantly increase chamber pressure in motors with high length-to-diameter ratios. Pressure drop, transient simulation, and erosive burning simulation are still future features. In addition, the text does not mention open source, self-hosting, or API/SDK support, and only explicitly supports Windows.

Who It’s For and Access from China

BurnSim is suitable for solid rocket motor design, amateur rocketry research, teaching, and post-test data review, especially for users who need to export .ENG files to RockSim or wRasp. The source text provides no information about access from China. Although PayPal and credit cards are supported, actual network connectivity and payment availability should be verified independently. Alternative or complementary tools include RockSim and wRasp, which are mentioned in the text, but they focus more on flight simulation than internal ballistics design.