RockSim Information

What information will you find on this page?

• Introduction: Easy to use Software that Saves You Money, Time and Embarrassment
• Do You Really Need A Program Like RockSim?
• What Does "Design and Simulation" Software Do?
• RockSim Speeds Up The "What-If" Design Process
• Use RockSim To Pick The Best Motors For Your Rockets
• How to Select Model Rocket Motors Using RockSim
• How Does RockSim Work?
• What Else Does RockSim Do For Me?
• Types of Designs That Are Possible With RockSim?
• What Makes RockSim Different From Other Programs?
• Tell Me More About This Thing Called "Dynamic Stability”
• I Heard That RockSim is Hard To Learn. Is That True?
• Educational Aspects of RockSim
• RockSim Also Means "Maximum Compatibility”
• Who Else Uses RockSim?
• Is RockSim Expensive?
• RockSim Articles - Tips & Techniques
• Actual Customer Comments

RockSim is an easy-to-use computer program that allows you to design any size rocket then simulate its flight to see how high and fast it will fly! It allows you to virtually test your new model, even before you start buying components and building your design. You'll find out if it will be stable and safe to launch, as well as meet any payload capacity, speed or height criteria you might want. Instead of wasting money on incorrect components and numerous test motors, imagine how much money you'll save by doing all your test flights with just a few clicks of your mouse!

Get a List Of Rocket Motors For Your Designs

One of the things that is totally unique to RockSim is its ability to recommend motors for your rocket with just three clicks of your mouse button. It test flies your design and finds all the motors, and which ejection charge delay you should use that will give you a safe flight.

This is exactly how we at Apogee Components make all the recommened motor charts for the kits that we sell. It saves us hours of time, and it will do the same for you as well.

Plus, when it performs a simulation, it can generate an animation for you to show you how your rocket will react to wind forces. You’ll see if it flies straight, or weathercocks into the wind. With this information, you can better plan for a more successful flight by adjusting the launch angle so it performs the way you want.

RockSim also has the ability to help you determine how much ejection charge to use for dual deployment. It is simply a matter of drawing a box showing the area in the rocket that has to be pressurized. It instantly tells you the amount to use as you’re modifying the box.

Plus it does so much more, like printing out both 2D patterns and 3D components, fin positioning wraps, creating parts lists, and giving a detailed flight report of the important parameters from the launch, plotting graphs of the performance, and so much more.

Because nearly every rocket manufacturer uses this software, nearly all available rocket kits here at Apogee Components have a RockSim design file that you can open using the FREE 30-day trial version. 

RockSim is also educational. Use it to teach yourself and others about the physics of rocket flight.

RockSim is the first design and simulation program, having been around since 1996. It continues to get better and more powerful to help you make better rockets.

And most importantly, RockSim has support available to help you when you need it. This is not some open-source program, which means you’re on your own. If you have a question, we have numerous videos and articles available, plus live phone support. We’re here to help you succeed.

RockSim is available for both Mac and Windows, ORDER ROCKSIM NOW!

Multiple Programs Combined Into Just One

RockSim has always been a combination of two different types of computer programs. It helps you “design” your rocket, and then “simulate” its performance. But it actually does even more than that.

When people first use RockSim, they typically get it to simulate rocket kits from manufacturers like Apogee, Estes, Loc and Aerotech. A huge number of rocket kits from these manufacturers have RockSim files already created and are in the database that ships with RockSim. But if you can’t find the file for your desired rocket, you can simply go to the manufacturer’s website and download the RockSim files.

Simulating the flight will tell you so much information about the performance of the rocket, that you’ll know as much as the designer that created the kit. You’ll be able to find all the rocket engines that will safely fly the rocket with just a couple of clicks with your mouse. It will also predict how high, how fast, and where the rocket will land. It is the best and most economical way to evaluate a rocket kit before you even buy the model rocket.

Once you see how much information RockSim gives, you’ll realize what a powerful tool it is to design your own rockets. And that is the second key benefit of RockSim - making your own unique designs.

What is a rocket design? A “design” in RockSim is just a collection of components. So when you make a new rocket design, you’re just telling the software what components you want to use.

RockSim helps you design rockets by having an extensive library that includes a variety of components, such as body tubes, nose cones, fins, plus internal parts like centering rings, parachutes, and tube couplers. If you can’t find a part, you can easily create your own to finish out the rockets. Customization is a core feature of the software, because you shouldn’t be limited by what you haven’t thought of yet.

By combining the design and simulation aspects of the program together, you have the ability to optimize your rocket to make it more efficient and easier to build. Plus, it allows you to quickly find all the rocket motors that could safely launch your rocket - something that frustrating and time consuming in other programs that try to copy RockSim’s features.

RockSim also allows you to visualize your designs in both 2D and 3D. Seeing how parts go together will help you stylize your rocket to get that extra recognition from people that see your designs. You can even apply decals to the surface of the parts to make them even more attractive. It’s one thing to design a rocket, but to have a really cool rocket that impresses people will increase your reputation as both a designer and rocket scientist. 

When it comes time to build your rocket, the software will help you out in that regard too. RockSim has the ability to print out parts lists, pattern sheets for the centering rings, fins, and bulkheads. It also has the ability to print out paper fin positioning wraps so you get the fins attached in the correct locations on your rocket body. This is just like the ones that come in a rocket kit from manufacturers like Apogee and Estes.

Besides simulating the launch of your rocket, RockSim can also help you get the rocket back after the launch by aiding in the set-up of the rocket. For example, it will help you calculate the amount of ejection charge your dual-deployment rocket may need to successfully kick out the parachutes. It is also used to figure out where to angle the launch rod and the size of parachute you may need so that the rocket will land closer to the pad instead of floating hundreds of meters away.

RockSim is for people that like to take control of the rocket design process. Curious people like you, really want to know with certainty how their own rocket creations will fly. And you won't be limited to simple shapes and small rockets. If you are going to invest in software, you want it to have features that will allow you to try bigger, bolder, and more complex rockets. You probably want to eventually take on a Level 3 or other complex project, right?

Besides allowing you to design intricate rockets, RockSim will simulate the rocket's entire flight. From the launch trajectory, to finding where they land; this is something no one else can offer you.

Here is what our customers say about RockSim:

"I am really impressed with your software program, not only for the ability to design a rocket, but also the information that can be obtained with launching the rocket under various conditions, etc.– an absolutely excellent tool." — Deanna Mann, Rocketry Workshop Organizer, El Paso County 4H, Colorado, USA

"Wow! Great software. I didn't expect to have the ability to print templates for parts. That coupled with the ability to custom design fins graphically is just super. I found the software easy to use. I've learned more about rocketry in two-hours from using this software than I have since joining the hobby. That speaks for itself. Overall, I give this a perfect score. Thanks for your hard work." -- Ben Taylor

RockSim allows you to take your cool rocketry ideas, and flush out the concept to see if they'll be stable when you launch them. This is important, because you want to make sure all your homebrew creations are safe. Right? This process of selecting parts, and arranging them into a rocket to see if it will work is called "designing" a rocket.

After you have the basic layout of the rocket, you'll probably want to see how it will perform when it takes flight. I'm sure you'll be interested in a multitude of statistics: How fast will it zoom? How high will it soar? How long will it hang in the air after the recovery device is deployed? This is accomplished with a rocket "simulation" program.

RockSim was the first software that combined both "design" and "simulation" into one seamless program. What that means is that you create a drawing of the rocket, and simply click a button to see how that design will perform. That makes it quick and easy to check the feasibility of your ideas.

Using RockSim, you will know long before you actually start cutting parts if the rocket will work successfully. That cuts down on mistakes, and saves you a lot of money and frustration.

• What if... I changed the shape or the number of fins on my rocket?
• What if... I changed the length of the rocket?
• What if... I added pods to the rocket?
• What if... I use a 38mm motor instead of an 29mm?
• What if... I use a streamer instead of a parachute?

From the beginning, RockSim was created to be a true design tool. With RockSim, you specify the components of the rocket (including all the rings and the recovery devices carried inside), and RockSim pre-calculates the weight of the rocket as you are in the process of designing it. At the same time, it is also calculating the CP location of the model and determining if the rocket will be stable. RockSim was the very first model rocket program to do this "on-the-fly" computation, and it revolutionized rocketry. Now you could make changes to your design, and see how the CP and CG are affected.

For example, what if you changed the fin location on your rocket? As shown in the image here, doing so changes both the CG and the CP location. With RockSim, it calculates these changes faster than you can blink your eyes. This seems simple, but until RockSim came along, this was a very complex task that took hours to figure out -- for even experienced modelers.

Additionally, as you design your rocket, RockSim performs an estimation of the coefficient-of-drag (Cd), which is used to determine how high and fast your rocket will fly.

The coefficient-of-drag is broken down into various contributors: nose cone and body profile drag, base drag, launch lug drag, and fin drag. You can use this feature to tweak your rocket for optimum altitude performance. Again, RockSim was the first program that had this feature. Without it, you can't really tell with any certainty how high or how fast the rocket will travel, let alone what the trajectory will look like.

People ask us how do you pick the best motor for a model rocket. That is a very simple question to answer once you have RockSim. Just imagine people coming to you for that answer. With just two clicks of your mouse button, you'll have RockSim running simulations and recommending the right motors for your design. It is based on a set of 5 safety criteria that we use here at Apogee Components when we recommend rocket engines for the kits we sell.

YouTube Video - How to Select Model Rocket Motors Using RockSim

Designing rockets with RockSim is a snap. It doesn't take a long time at all. After you've learned the basics of the program, you'll be creating designs in less than 5 minutes. Basically, there are two simple things you do when developing a new design.

1. Create the Design: Typically, you will select parts from the extensive databases; which includes your favorite manufacturers like: Estes, Aerotech, LOC or PML, not to mention Apogee Components. But you can easily add your own custom parts too. Once a new part has been added to the database, you can bring it up for any of your future rocket designs too.

2. When finished with the design, you will then select a rocket motor for it and RockSim will perform a comprehensive launch simulation based on weather conditions you input. RockSim not only tells you how high the rocket flies, but it will show you what the trajectory will look like. Plus it will give you other important information like acceleration, velocity and downrange drift.

RockSim tidbit: You will hear many people talking about a "RockSim design file." What it contains is an orderly listing of the parts that are in the rocket, plus the results from the flight simulations you have performed. RockSim automatically creates them when you save your creations. It is cool to share them with your friends, so they can see what a great designer you are.

Besides the Apogee Components website, another good source of "design files" for many popular kits can be found at: www.rocketreviews.com

RockSim has a number of features that will simplify and speed up the construction process. With it, you can:

• Print out fin templates. RockSim's fin templates can be highly complex and include the through-the-wall fin tab and curvature matching of the boat tail. If the fin is huge, RockSim tiles the template onto several sheets of paper with corner marks so you can assemble them like a puzzle. These templates can be transferred to wood or fiberglass, and cut out to make actual rocket components.
   
• You can also print out transition-section pattern sheets which you can assemble into an actual part in your real rocket.

To use this feature, you simply need to print out the transition template from the print menu. However, there are a few conditions you have to set up prior to printing it out:

1. The transition cannot have shoulder inserts specified.
    
2. The transition must be set to "hollow."
    
3. The transition shape must be set to "Conical."

These pre-conditions makes a lot of sense, as this is how you actually make a paper shroud. Note: That if any of these conditions are not as specified above, you will get the default "side view" of the transition when you print out the template.

Rocket Tip: Do you need help in assembling your transition? Click here to watch a movie on how to make the perfect transition.

• Print out nose cone templates that you can use as an aid in turning or carving your own component.
   
• Print out 2D blueprint-like drawings of your rocket. These serve as a guide, so that you position the components properly when assembling the rocket.
   
• Print out a 3D picture of your rocket, including the paint scheme and your own custom decals. From this, you'll have a guide for painting and decorating your rocket design. And it is something you can share with your friends to prove you designed the rocket yourself, and it really isn't a kit you've built.
   
• Print out a parts list, so you can check them off as you order them from your favorite vendors.
   
• Print out exact centering ring templates, that can be transferred to wood sheets, from which you can cut actual rings.
   
• Export out a .stl file of your nose cone that be printed out on a 3D printer.
   
• You can email your completed RockSim design to vendors who can custom make nose cones, centering rings, and fins directly from your design file. So you can buy many of the custom parts you've made in your design.

Sensible people with a practical bent appreciate RockSim because of these useful features. You may realize you need to invest in RockSim today because you need these features too.

Also, with RockSim the following features are possible:

1. External Pods can be added to the outside of the main body
2. Strap-on Booster Pods are ejectable during flight
3. Fins can be attached to other fins
4. Ability to scale your design up or down
5. Scale custom fin shapes up or down
6. Plot (graph) screen. You can zoom in on any area of the graph for a closer look at the data.
7. Export out the flight data to Microsoft excel spreadsheet so you can compare one flight to another.
8. Anti-alias of the 2D image.
9. Three 2D views: Side view, Top view and base view.
10. Rotatable 3D view: See you rocket from any angle, with decals applied to surfaces
11. Stability overlay to see if your asymmetrical designs are stable in all axis.
12. Automatic inclusion of new motor data files on the web site www.thrustcurve.org

Click on any picture for a larger image

Besides these features, RockSim has many other one-of-a-kind features that are still NOT available in other programs. These advanced (but easy-to-use) features are there to make the program the easier to use, and/or to allow you to design out-of-the-ordinary rockets.

First of all, RockSim allows you to make fins with any shape. These are called "Custom Fins." Again, RockSim was the first design software that allows you to make truly any shape you want. Everyone else copies what RockSim can do, and they don’t even do that well.

What is even more cool is that if you position the fin on a curved nose cone or drag-reducing boat tail. on the bottom of the rocket, the root edqge automatically conforms to the shape of the curve!

So when you print out your fin templates, you'll have the perfect curve to match the rocket. Just think of how much time this will save you.

RockSim also allows you to create tube fins, and ring-tail arrangements. This is also something that RockSim was the first to accomplish.

Another feature is the ability to create asymmetrical designs, where you have more fins and tubes on one side of the rocket than the other. For example: say you wanted to make a rocket that had the appearance of an airplane. The two wings and the tail fins would be impossible to design without RockSim, because they violate the Barrowman Stability Equations. You see, in the Barrowman Equations, a set of fins must have at least identical three fins. It does not allow a two-fin set, like the wings of an airplane-like rocket. Nor do the Barrowman Equations allow just a single fin, like the vertical tail of an airplane.

RockSim allows these types of fin configurations. You can have any number of fins in a fin set, even just one fin. Only RockSim has the capability to determine the stability of this type of rocket. So, doesn't it make sense for you to own the finest rocketry program available?

Not only can you design them, but you can view them in 3D and rotate them around. You'll get to visualize your dreams long before you build them.

But what is more important is that RockSim plainly tells you whether your unique looking design is safe to fly. That is the real trick. Regardless of how neat the rocket looks, if it isn't stable, it will crash if you launch it.

Another feature that only RockSim has is its ability to run very sophisticated launch simulations. This is to give you the most realistic prediction of the performance of your new design. We call it "Dynamic Stability Analysis." And only RockSim has it.

The ability to predict how a rocket will fly in windy conditions, and what it will do when launched at an angle is what Dynamic Stability is all about. When you know how the rocket will react to different conditions, you can take precautions and angle the launch rod appropriately so that you get a better and safer flight.

Dynamic Stability is much harder to determine than "static stability." Why? Because it is not only affected by the relationship between the Center-of-Pressure (CP) and Center-of-Gravity (CG) of the model, but also by the speed of the rocket, wind, launch angle, and even by the shape and mass of the internal components that make up the rocket.

There are many equations that govern dynamic stability of the rocket. They have techno-speak-mumbo-jumbo names like: damping moment coefficients, Longitudinal Moments of Inertia, Coupled Damping Ratios, and Angular Accelerations. Most people have little desire to figure out what it all means. If you're interested, see our Newsletter Archives for a 6-part series on the topic of Dynamic stability. The free series of articles starts in issue #192.

So to make it all easy to understand, RockSim creates a movie of the model's flight. By watching this "Flight Profile" animation, even the youngest modeler can see if the rocket is oscillating back and forth or if it weathercocks too far into the wind. It is really easy to see the effects of changing the fins, using a different rocket motor, angling the launch rod, or varying the wind speed at launch. Any of these types of things will change the trajectory of the rocket and how high/fast it will fly.

Playing with the "Flight Profile" feature is a blast. With RockSim, it is even possible to simulate an unstable model, and watch it do loopy loops on the computer screen! These simulated flights are fun to watch, but you wouldn't want this to happen to a real rocket. Because statically stable rockets can go unstable, RockSim should be used on all your rockets to check for dynamic stability.

Imagine spending time teaching your family and friends about rocketry using the Flight Profile feature. Not only will you have a lot of fun, but it bonds you together in an educational way.

For additional features of RockSim see the Technical Specifications page.

How do you know when you have a program that is a good value?

RockSim is used by over thousands of schools throughout the USA. Plus, people that have never even used a computer before in their entire lives purchased one specifically to use RockSim. (WOW!) They are very happy with how easy it is to use. If these people, and kids as young as 10 years old, can quickly learn to use it, so can you.

Like any computer program, there is a learning curve that the user has to go through. All programs have it (such as Microsoft Word), even if they say they don't. I don't ignore this fact. I realize that there is a learning curve. And as soon as you get through it, you'll be designing rockets like a professional engineer.

The "parts tree" shows how each of the components is arranged in the rocket. For example, the fins are attached to the body tube; the engine mount is also attached to the same body tube. Makes sense, doesn't it?

How do you get through this learning curve quickly and easily? First of all, the program itself has to "make sense." If you've flown rockets before, RockSim will seem very intuitive to you. The parts in the rocket are arranged from the tip of the nose cone, down to the base of the motor. Sounds simple, right? For example, you put the engine mount into the body tube -- and that's the way you input the parts into RockSim too.

A feature in RockSim allows it to anticipate your moves in the design process. It assumes your first choice is to grab a part from the manufacturer's component database. Therefore, it automatically opens up the database when you tell it you want to add a part into your design. This allows you to complete your design even faster. For example, if you tell RockSim you want to add a nose cone by clicking the "add nose cone" button, it will automatically open the nose cone database. From the database selection screen, you can either pick from any of over 100 nose cones from your favorite manufacturers, or you can override it and input your own custom dimensions into RockSim.

But if you want to know a secret, I'll tell you the hardest part of the design process right now...

It does NOT have anything to do with rocketry. It has to do with the names of parts used by manufacturers. For example, if you're brand new to model rocketry, you probably don't have a clue what a "BT-50" is. Right? But if you've been in rocketry more than a couple of launches, you know that a BT-50 is the name that Estes gave to their size tube that is about 1 inch in diameter. It is the same with every other manufacturer. Each has their own part names, even though they may be identical parts. That's the hardest thing about designing your own rockets; learning all the silly part names...

To tell you the truth, I don't know the shortest way over the "learning-the-part-names" speed-bump. It may take you some time. However, what I can do is show you how to design a simple rocket. And that is what I do in the series of "how-to" . You can view all of them here: Quickly learn the basics of RockSim by watching video instructions.

These step-by-step videos walk you through creating a designs, running simple simulations, modifying the user settings, creating asymmetrical fins, playing with the competition settings, and viewing the flight profiles.

In about 20 minutes, you'll be designing your own models, and having a lot of fun playing with the program. At that point, you'll need to start learning all the silly names of the parts that manufacturers create.

RockSim is a low-risk investment, because it is tried, true, and tested by thousands of others. You'll be joining a community of visionaries that really know the value of a good design tool with a proven track record.

The new enhanced "flight profile" movie is an excellent teaching aid for showing new modelers what to expect when they launch their rocket. Even advanced modelers will gain more flight experience in one evening of "play" with RockSim than they'll get over an entire year of trial-and-error out at the rocket range.

More importantly, with RockSim they can determine if the rocket will land within the field with the motor they have chosen. How many times do kids want to put the "biggest" motor into their rocket, only to find out that it is lost as it drifts away into the next county?

Quickly learn the basics of RockSim by watching video instruction clips.

By running simulations prior to launch, they'll be able to see clearly what to expect when the rocket takes off, and where it could land if they choose a rocket motor that is too big.

RockSim also generates a lot of data that your students can explore. It can graph out 68 different flight parameters, which includes things like: altitude, velocity, acceleration, and Mach number. There is so much information that your students will learn a lot about rocketry and how to interpret graph data.

Besides displaying the information on a graph, the data can be exported out and read into a spread sheet program. Then your students can get some practice manipulating data in spread sheet software too.

You can read about all the different uses of RockSim in your classroom! Here is another link for you too; it shows how to use RockSim to specifically teach science with a sample lesson.

You have to ask yourself, "Why did these other companies choose RockSim?"

With RockSim, you have compatibility with most of the rocket flying world. You'll be able to email files to your friends, and offer them advice on their own rocket designs.

RockSim is made in the USA, and was developed by a real aerospace engineer that actually worked at Cape Canaveral in Florida launching the big rockets into space. That experience has led to a program that can do the things that other manufacturers have come to trust. That is why you should consider it for your projects too.

RockSim not only allows you to design and simulate your rockets, it comes bundled with another program called "Engine Edit" (shown here). You can use this additional software to create new engine files for RockSim if you are making your own rocket engines, or to edit other engine files to make them more accurate.

Well over 10,000 people have invested their own money in RockSim. That includes nearly all of the Level 3 certified fliers, hundreds of aerospace engineers, all the champions in the Team America Rocketry Challenge, hundreds of teachers, and also the innovative modelers that know a great value when they see it. Plus, nearly every major model rocketry company uses RockSim to design their own kits (and they've paid to use it)! That includes Estes, Quest, Aerotech, PML, LOC, Aerospace Specialties, Semroc, Cesaroni, and Balsa Machining Service.

When you invest in RockSim today, you'll be joining a select group of people, educators, engineers, and companies that are concerned about the future of rocketry. They know the value of rocketry as an educational tool, and they want to pass it down to future generations of modelers. So they are investing in RockSim because it allows them to teach others about rocketry, and it keeps their own rocketry projects safe and legal.

Based on this information, take a brief moment and answer this question: "What would you do if a fellow rocketeer or teacher told you that RockSim is a bargain and you should invest in it?"

• Tried, Tested and True: People that spend thousands of dollars on big rocketry projects trust the results of RockSim. For them, it is very cheap insurance on making sure their expensive rockets will work correctly.
   
• Compatibility: More people use RockSim than all other programs combined. Nearly all the major rocketry manufacturers use RockSim too. This allows you to swap and download RockSim designs to save you even more time and money.
   
• Educational: With RockSim's advanced 2D flight profile, you'll learn about rocket science faster and with greater clarity than any other method. And it is so fun, you won't even realize the educational value you or your students are absorbing.
   
• Useful: The best aspect of RockSim is that it offers something for everyone in your rocket-loving family. From your kids, to yourself -- each of you will gain something new and unique from using RockSim.
   
• Money Saving: You'll end up spending less money on your rocketry projects, because you'll experience fewer crashes, and your rockets come back in tip-top condition because you've optimized them to be stronger and fly straighter.
   
• Reputation: Can you imagine how you look to your family as they watch you being congratulated by your peers because of your impressive launch -- all thanks to RockSim? Man, I'm telling you, you're going to be unbelievable.
   
• Innovation: If you really want to be on the cutting edge of technology, then RockSim is for you. RockSim continues to pioneer many useful features. Here are just a few: Free-Form Fin shapes, Dynamic Stability analysis, Asymmetric fin configurations, 2D flight profiles that show you the trajectory of your rocket, Drag prediction, Ring-tail fins, Tube fins, and now stability determination of falling booster stages.

Customers have told us on numerous occasions that they'd willingly pay $250 or more for RockSim's features. But I want all modelers to design, build and fly the safest and most spectacular rockets. So I am allowing people to invest in RockSim at a tiny fraction of what it is actually worth.

I want you to imagine something for me. Pause for a moment, and please describe how much fun it would be for you to be sitting in front of your computer running RockSim.

Then ask yourself out loud, "What would happen if I did invest in RockSim to help with my next project?" What could you see yourself designing and building as your next project?

If you can be certain that RockSim is an "A+" rated software, will you feel comfortable investing in it today? Why not give it a try right now, and Download The FREE Trial Version! You have no obligation to buy; just try it out for 30 days and see if it fits your needs.

If you are ready to invest in RockSim, you can place your order by choosing your version here.

For articles on RockSim check out the Peak-of-Flight Newsletter index. This is a list, by topic, of all of the great articles the Peak of Flight put out over the years.

There is endless amounts of RockSim information found in this newsletter.

"After a lot of searching on the Net, RockSim is the best rocketry simulation software I have seen. Anyone who hasn't downloaded the shareware version is missing out big time. In terms of sophistication, "RockSim" is to "VCP" as "VCP" is to "cutting out pieces of cardboard".  -- Brian Crosse

"I bought RockSim and have loved using it from the first day. My son and I have designed dozens of rockets using it. The rockets, that we have already built, work exactly as predicted by RockSim. I have also used your program to test and IMPROVE other kits that I purchased & built." -- Ray Mancuso Jr.