What Is a Water Rocket Launcher Kit, and What Can You Do With It?

Water rocket launchers are among the most popular toys among kids and adults, as they can provide hours of entertainment. These are made using a water bottle and are relatively easy to make. This makes them excellent toys for hot and sunny days. Other than helping, you have a good time, you can even learn from water rocket launchers as it uses many science concepts.

Although you can make a water rocket launcher all on your own, if you have a kit, it makes the entire task extremely easy and quick. It is an easy enough process provided that you purchase a high-quality kit that is easy to assemble and includes all the different parts you need. There are many different types of water rocket launchers and kits available, so you must know all the intricacies to pick the perfect one. 

What Is a Water Rocket Launcher Kit?

water bottle launcher catapulting a water rocket into the air.

A water rocket launcher is a handmade launcher that uses water and air pressure to launch a plastic soda bottle high into the air. These rockets are designed in a way to help students understand the principles of aeronautics and physics. Children can also learn about the altitude, distance, and pressure required to make the rocket fly high. 

When using a rocket launcher kit, you can launch a plastic soda bottle into the air, but you need pressure to do that. This pressure comes through either a bicycle pump or an air compressor. In this basic water rocket launcher, your fuel is water and air, which allows you to launch the rocket multiple times without any issues. Most kits are fully upgradable and expandable. This means that if you want to make a more complex model, you can purchase extra parts to make it happen. 

The launcher kit typically includes a launch pad, a pump, and a launch controller.

Part of the Kit  Use
The Launch pad The launch pad is a platform that the rocket sits on before launch, it may have guide rails to keep the rocket in place and may also be adjustable to different angles
The pump The pump is used to pressurize the water in the rocket before launch. It can be a manual pump or an electric pump.
The launch controller The launch controller is an electronic device that controls the launch sequence and timing of the rocket. It may include a pressure gauge and a countdown timer.
Additional accessories Some kits may also include additional accessories such as recovery systems (parachutes), or guidance systems that can help to track and recover the rocket after launch.

Purpose of a Water Rocket Launcher

A water rocket launcher is a popular toy that can help you have a lot of fun on hot and sunny days. When used on a small scale, they are safe to use and do not pose any danger to those using them or the property near them. There are many different ways to use water rocket launchers. They can be used in educational settings, for recreational purposes, for research, and for professional applications. 


Water rocket launchers are often used in educational settings in order to demonstrate basic principles of physics. You can use it to understand concepts such as Newton’s first and second laws. When the rocket is on the launcher, all of the forces are balanced as the surface of the launcher pushes it up, and gravity pulls it down. When these forces become unbalanced, the rocket shoots up, and this force continues until all the water leaves the rocket. Water rocket launchers are commonly used as an educational tool in schools, and educational centers. 

Recreational Purposes

A water rocket launcher is relatively simple and inexpensive and can be an excellent outdoor activity. Additionally, many amateur rocket enthusiasts can refine their rocket-making skills by practicing using water rocket launchers. This is a relatively safe method and can help you explore the field and be creative with your rocket-making skills. They can also allow people to explore the principles of rocketry in a safe and accessible way.


Water rockets can be used for research purposes, for example, to test new rocket designs or propulsion systems, or to study the effects of high-altitude flight on different materials and payloads.

Professional Applications

Water rockets are also used in professional settings such as military and aeronautical research and testing. They can be used to test new technologies and techniques in a safe and controlled environment.

What To Consider When Purchasing a Water Bottle Rocket Launcher Kit

water bottle being launched in a school.

When purchasing a water bottle rocket launcher kit, there are many options to choose from, and it can get overwhelming. To make the task a bit easier, it is recommended that you look for specific features that signal a high-quality kit. Since there are many different ways to make a water bottle launcher, you must choose a kit that seems easy to build and comes with all the necessary accessories. Here are some factors that you should consider. 

Type of Launcher

When purchasing a water bottle rocket launcher kit, you should first decide the type of launcher you want. There are various launchers that come with kits, and choosing one that you are comfortable with is extremely important. 

The type of launcher you choose also depends on the size of the rocket you are using. If the rocket that comes with the kit is large, then you should ideally choose a large launcher that you can mount on a tripod or a stand. On the other hand, if your rocket is small, you can opt for a hand-held launcher, which are much like hand-held catapults. These smaller launchers are easy to handle and portable as well. Additionally, due to their small size, they are less likely to cause harm to you and your property. You should also make sure the kit is compatible with the type of water bottles you plan to use.


One of the most critical factors that you need to consider when purchasing a water rocket launcher is the material that it is made of. There are many materials that you can use, including PVC, wood, and even metal. PVC is the most preferred of these materials because it is both lightweight and expensive. If you plan on placing the launcher in one place and not moving it around too much, you can opt for a wood or metal launcher, as they are more durable than PVC launchers. 

The durability you want your launcher to have also depends on the size of your rocket. The larger your rocket is, the stronger you will want your launcher to be. If you have a small rocket and are using a hand-held launcher, then you can purchase one made using PVC. Not only will it be cheap to replace, but you will have no trouble carrying it around with you. Always look for a launcher that can withstand repeated launches.

Size of Launcher

The size of your launcher is also a deciding factor when purchasing a water rocket launcher. Ensure that the launcher you choose is able to accommodate the size of the rocket you intend to launch. Most water rocket launchers are designed to work with water rockets that are sized around standard 2-liter soda bottles as they are used to construct them. 

If you plan to make a larger rocket, you must purchase a launcher that accommodates the rocket. Otherwise, you will not get enough momentum, and the rocket will not launch. 

You should also determine the number of rockets you plan to launch, as that also plays into the launcher’s size. If you plan to launch one or two rockets simultaneously, you can easily make do with a hand-held launcher. On the other hand, if you intend to launch multiple rockets simultaneously, you will need to purchase a much larger launcher that can accommodate all the rockets. 

Design Considerations for Water-Bottle Rockets

When using a water rocket launcher kit, you want to ensure that the rocket flies at least 200 to 300 feet. For this to happen, the rocket must be aerodynamically stable during its flight. To ensure and increase stability, it is crucial that you determine the center of the mass and tie a string around it at that point. 

For your rocket to fly stably, the center of mass of the rocket must be forward of the center of pressure. Additionally, it is recommended that the center of pressure is located towards the rocket’s tail and the center of mass is towards the nose. 

By adding fins to the rocket, you can increase the surface area of the tail section and help move the center of pressure toward the fins. The larger your fins will be, the further back the center of pressure will be, aiding the rocket to fly high. 

You can also add weight to the nose cone section, which will help move the center of mass toward the nose of the rocket. You can do so by using modeling clay. After adding the modeling clay, check to see that the rocket is stable. Be careful not to all too much weight on the nose, as it can slow down the rocket. You can also add parachutes for them to descend safely.

Water Rocket Safety

When using a water rocket, it is vital that you stay safe. Ensure that you only fly the rocket in a grassy field that is at least 30 meters in width. Keep the launcher in the center of the field and anchor it in place. If you do not anchor it, there is a danger of it getting knocked down, and you may end up hitting yourself or anyone nearby. When launching the rocket, it is crucial that you do not stand too close to it. Many recommend that you stand back several meters and that you rope off the launch site.

You should also take care to never point the rocket at another person, object, or animal. They take off with immense speed and pressure and can cause significant damage and injury. Ensure that it is always 90 degrees and pointing up at the sky. 


What is the best fin size for a water rocket?

If you are using a 2-liter soda bottle for a water rocket, you should ideally use thinner fins that are 3/16 inches or less. This size helps reduce the effect of drag.

Does the size of a water rocket matter?

Yes. The longer your water rocket is, the larger the surface area will be, and the harder time it will have launching. However, longer rockets are much more stable. 

How can I make my own water rocket launcher?

If you want to make your own water rocket launcher, you need a water bottle and a small piece of PVC pipe. First, cut the hole in the bottom of the water bottle and insert the PVC pope. Ensure that the two fit together tightly. Then, fill the bottle with water, and the pressure with which the water flows into the bottle will launch the rocket.


Water rocket launchers are entertaining toys that can also teach children many physics concepts. At the same time, they can have fun in the hot and sunny weather. They are incredibly useful in various different ways, provided that you choose the correct kit. If you keep in mind certain factors like the size of the launcher, material, and type of the launcher, you will be able to purchase a kit that fits your needs best.