The Rocksim software is marketed by Apogee as "Model Rocket Design & Simulation Software".

The software is available for Windows and Macintosh OS X computers. The demo appeared to install fine on Linux using Wine. However, it wouldn't run. It complained about how it would only run in its native environment. As I do have one MS machine around, I figured I'd use that instead of trying to get it to run under Wine on Linux.

Update : It now runs fine under Wine. The same install that wouldn't run before now does. This must be due to a recent Wine upgrade. Once the 30 day demo expired I was convinced that this software would make my rocketry projects easier, more fun, and safer.

Once you receive your copy of the software, you need to generate a key request and email it off to Apogee. It took about 24 hours to get the key at which point the RockSim software can be used.

What does it do?

The short answer to this question is : too much to cover in this review. At the time of writing, I have been using RockSim for several months and certainly haven't yet used all of the features available to me.

Don't let that scare you off, it takes very little to start creating your own projects, or modify existing ones.

RockSim is used to design rockets and simulate their flight. The software, amongst other things, tells you where the center of pressure (CP) is located and if the rocket is stable as designed.

Having an automated tool to calculate the center of pressure is worth the purchase price alone, especially if you like to design your own rockets, or scratch-build scale models.

The image above shows an example of a semi-scale Standard ARM that was designed with RockSim.

The software lists the overall dimensions, location of center of pressure (and center of gravity) and stability margin.

If you use the computer program, be sure to use the "mass override" function and enter the actual weight and center of gravity location. This will greatly improve the accuracy of the stability margin.

RockSim can be used to print out the fin patterns for the rocket you just designed, saving a lot of time. It can also generate a list of items required to build the rocket, giving you an instant shopping-list.

Let's return to the example of the Standard ARM. The next step would be to insert a virtual motor in the rocket and see if it remains stable. RockSim is then used to simulate the rocket's flight.

This will tell you the expected altitude, maximum velocity/acceleration, time to apogee and velocity (and altitude) at time of parachute deployment.

And that's but a sampling of the data, it also shows you the liftoff speed as it leaves the rod/rail. This will (in addition to stability margin) tell you if the rocket is safe to fly on the selected motor.

RockSim also gives you the optimal ejection delay. This help you find the best delay for the motor selected and will help avoid high speed deployments.

The software also allows for flight simulation of clustered and even staged flights.

Note that you can also run these simulations on kit-based models, not just scratch-build ones. Some rocketry vendors even provide RockSim files.

This, in a nutshell is what the RockSim software is used for. In my opinion, it (or similar software) is a must-have for serious rocketeers.

What's not to like?

This review was starting to sound too much like an advertisement for RockSim. To keep things balanced, I figured it'd be good to try and think of things I don't like and list them here.

The manual is not provided in printed form. When I first got the software, it would have been great to have a printed copy of the manual to learn how to use the software. It should be noted that a manual is included (in the software) and you can print it out yourself.

For some reason, the upgrade function doesn't work. It always crashes. I have a feeling this has more to do with how messed up my Windows machine is. That PC needs some clean-up.