What is a Paintball Rocket Launcher?

jcsmkxlauncherIt’s basically an air cannon used to shoot a projectile/multiple projectiles around 230 FPS. They come in many shapes and forms, especially when exploring the world of “Homemade” paintball rocket launchers. They usually have 4 elements, an air source, and expansion chamber, a release valve, and a barrel. The barrels are usually 2″ inches in diameter. This is to allow for the most versatitlity. It just so happens that your average Nerf Rocket fits perfectly into a 2″ section of PVC pipe.

Qualities of a Good PRL

  • Rugged/Durable – Can be hauled through the bush in a scenario game. It also needs to be able to suffer a hit and not become dangerous to operate.
  • Effective operating speed usually needs to be below 240 FPS depending on the field rules where you are playing
  • Easy to reload – My favorite form of this is the breech loading, constant air, version.
  • Reliable – Will keep working consistently no matter what
  • Compact – Isn’t too huge and bulky
  • Aims easily and consistently

Examples of popular homemade versions

Just by searching around the internet you can come up with all kinds of examples of what people have done in their backyards. If you don’t want to put out around $350 for a store bought model, you’ll probably want to go the DIY route.

Breech Loading Model – This is the nicest homemade version I’ve seen. This paintball rocket launcher fires nerf rockets, is fully breech loadable, and is powered by a constant air source. If you are going to build something like this, it will most likely end up costing you around $200 dollars for all the parts.

12 Gram Powered Version – This is a version that is powered using a 12 gram co2 cylinder. It’s a one time use, one shot per 12 gram sort of thing. It fires the same Nerf Rocket round as the others, and has a range of around 190ft.

Information on how to build your own Paintball Rocket Launcher

It’s really hard to find GOOD plans on the internet for building a paintball rocket launcher. There are pleanty of plans that are briefly explained and leave a lot up to you to figure out. There’s especially few plans for building a CONSTANT AIR setup. Here are a few that I found to be pretty good.

Updated version of the above model – This is an adapted version, that I fixed to be more of a paintball rocket launcher. We are currently in the process of building this design, so check back soon for detailed construction notes, and a detailed list of parts, and a how-to.

The Science of CO2 – This web site has A LOT of good information on CO2. Provided on this site, are many formulas for calculating the pressure of a certain volume of co2 at a given temperature in a given volume of space. This is very helpful for calculating the size of an expansion chamber when designing a Paintball Rocket launcher to be used with 12 gram co2 cylinders.

Remote Controlled Cannon

A write-up on how to create a remote controlled cannon for paintball use.

Project Ensis
Jordan Herrema – Denver, Colorado
Special Ops Paintball forum member “Silent-7″

-> The idea for this project came up when brainstorming with my youth pastor about what to do for my senior project in high school. I mentioned that some sort of radio controlled paintball cannon would be really fun, but that it was probably too ambitious. But he encouraged me to think about it a little harder, and I realized that since my parents would probably pay for a lot of the parts (since the project was technically for school) all I’d have to commit would be my time. I was more than willing to do that – I’ve always loved building things. And so, I went to work.

-> The final design called for two entirely independent electronic systems, mounted on a tower with a swiveling head, as well as the cannon itself. The tower is constructed of 3” metal pipe attached to an “I” shaped base of two-by-fours and reinforced with four chains. A 5/8″ solid steel rod runs up the top two-thirds of the pipe into dual heavy-duty flanges bolted to a Plexiglas head. The flanges allow the Plexiglas head to spin 360-degrees around the steel rod, which is fixed in its position relative to the tower.

The first system is used to aim the turret, and is based on a high-current ESC (electronic speed control) adapted to run off of a signal from an ordinary R/C receiver. The ESC is fed from a single 12v, 4.5mAh battery. It steals a small fraction of this power to run itself via BEC (battery eliminator circuit) but the majority of the current is routed to the drive motor for the turret head. This motor is a surplus treadmill motor, modified to run off of direct current rather than alternation current. Because of the relatively high-torque/low-speed of the motor, the only gearing-down that was needed was the combination of a 1.5″ to 3″ pulley system. Because the central steel rod is fixed in the turret tower, the motor effectively rotates itself around the tower – along with the head that it is bolted to. The original plan was to use three 12v batteries in series for a combined 36v and 4.5mAh, but 12v proved sufficient power to allow the motor to rotate the entire head assembly.

The second system is used to fire the cannon. Rather than investing in an electronic switch to run off of the receiver (even though that wouldn’t have been terribly expensive) I opted to use a standard R/C steering servo (that I already had) to trip a mechanical switch. Tripping this switch completed a circuit between the solenoid in the cannon’s sprinkler valve and three standard 9v batteries in series for a combined 18v. The sprinkler valve is only designed to run off of 12v, but the very short period of time for which the valve must remain activated meant that 18v would not damage the solenoid, and thus allowed for the use of a much cheaper, more commonly available battery source.

Both of the two systems had separate master power switches hardwired in, to act as safeties. This was especially useful for demonstrations, as I could enable the full range of motion of the turret without arming the firing system. The two-channel receiver that controlled each system was linked to a simple R/C pistol-style transmitter. The steering function was used for the rotation of the turret, and the throttle was used for firing the cannon itself. This system allowed for reliable operation from a great distance. It also made it possible, via the transmitter’s end-point adjustment feature, for me both to fine-tune the motion of the mechanical switch and to limit the motor’s excessive torque from turning the head at a high enough speed to topple the turret.

The cannon is, in essence, a simple PVC air-cannon whose firing mechanism is a standard 1″ sprinkler valve. The barrel is 2″ PVC, and runs through the center of the chamber, constructed of 4″ PVC. A 1″ pipe leads from the chamber to the remote line hookup and pressure gauge, and then to a tee joint at the rear of the barrel. Because the maximum rated pressure of the sprinkler valve is 100psi, a chamber-to-barrel volume ratio of 1:1 was chosen.

-> The turret is loaded by removing the threaded end-cap from the rear of the cannon and inserting a 2″ Nerf rocket, or other projectile. Potatoes, for example, could be used after being cut to size by a sharpened segment of 2″ PVC that I kept separately. A piece of 1″ PVC is cemented to the inside of the end-cap, and pushes the projectile into place – just past the tee fitting leading to the chamber. The chamber is then charged via a CO2 canister, which feeds through a remote coil. The remote’s on/off valve is opened, allowing CO2 to fill the chamber. A regulator installed in the remote line is set initially to minimum pressure, and then adjusted with reference to a 200psi gauge until the chamber reaches the desired operating pressure. Once both electronic systems are manually activated, the turret can be remotely operated through unlimited degrees of rotation, and fired instantly. After firing, and releasing the transmitter’s throttle control, the valve will close and the regulator will automatically recharge the chamber to the preset pressure. Extensive testing, and five or six complete demonstrations, only necessitated one recharge of the primary 12v battery; and the 9v battery pack has yet to need replacement.

-> The entire project was an excellent learning experience for me, and I had a lot of fun working on it. Not only was the turret a big hit at our senior project open-house, it won me an engineering scholarship from my high school to apply towards the college of my choosing. I give a lot of credit to my Youth Pastor for encouraging me to tackle the project in the first place, as well as to my parents for supporting my ambition and (of course) footing the bill! My brother and cousin also deserve some recognition, seeing as I stole some components from our previous “battlebot” project, which they helped pay for. Now that it’s all said and done, I look forward to the next big project that I will work on, paintball related or otherwise.
paintballrocketlauncherplans

 

Store Bought Paintball Rocket Launchers – LAWs

  • JCS – ALIAS MKX SCENARIO LAUNCHER
    • This is the only commercially available Paintball Rocket Launcher that I know of. If you know of others, please post in the “Comments, Suggestions” portion of the forum(ALLIANCE).

Thanks to an email I received I realised I forgot RAP4’s very large selection of paintball rocket/grenade launchers. They probably have the most comprehensive selection of store bought launchers that I have seen. If you are looking for quality visit their site at www.rap4.com and look under the grenade/launcher subject category, Link to category.

This page is definitely not even close to done. If you have any more information or links to plans you would like me to add to this page, or any other page, please let me know via the forum(Alliance).

**UPDATE 7/23/2014**

So, due to popular demand I have found a pretty awesome resource that includes both the aspects of having a breech loaded LAW and also making it to work with an electronic sprinkler valve. Please note that the following information and image was borrowed from the following web site: http://spudgunner.com/sniper.php

With this design there will have to be some common sense modifications made in order for this to work with a 2″ nerf rocket projectile.

Air Cannon Plans

Here also is the basic circuit design for the electronic sprinkler valve:

Sprinkler Valve Circuit Diagram

MATERIALS:

  • Pipe can be bought in 5′ sections.
  • 3/4″ Pipe
  • 1″ Pipe
  • 2″ Pipe
  • 3/4″ 90 deg. Elbow x3
  • 3/4″ 45 deg. Elbow x6
  • 3/4″ Tee x2
  • 3/4″ to 1″ Male thread
  • 1″ to 3/4″ Bushing
  • 1″ to Female thread
  • 1″ to Male thread
  • 2″ x 1″ Bushing
  • 2″ Coupling
  • 2″ Endcap
  • Tire Valve
  • 1″ RainBird In-line solenoid sprinkler valve

Obviously I haven’t included the construction notes, if you are having trouble understanding how the design was put together, please pay a visit to the original creators web site. He has put a lot of time into the design and has detailed how he manufactured and tested it.