Design Overview
The basic design is very similar to the pod launcher. The grenade round stores an air charge that is released into the barrel, propelling the Nerf round into the air. The SPPL launcher uses a directly attached 3.5oz tank and uses a release valve to recharge the grenade. The trigger mechanism simply presses the firing disk on the back of the grenade. To fire you simply remove the barrel plug, load a rocket, charge the grenade, aim, and fire. |
Safety
Clearly safety is a big concern whenever your talking about a custom made launcher. Many scenario games and fields have banned "home made" launchers. This concern is more directed towards the old school ball valve launcher designs. These launchers store compressed air in an expansion chamber that can be very dangerous if over pressurized or improperly sealed. The thunder grenade has been extensively tested by the manufacturer and has been used extensively in airsoft. It is very important to evaluate your own launcher design for safety hazards but using a thunder grenade is by far the safest route when compared to other custom designs. You also have the benefit of not having to regulate the air pressure, incorporate safety release valves, or incorporating many of the other measures taken to ensure the safety of a ball valve launcher. The grenade itself is the regulator, expansion chamber, and trigger all rolled into one little package! |
Air Source
I used a 3.5oz CO2 tank from RAP4 paintball. Smaller air tanks are hard to find and can be expensive due to the limited supply. I have found that most 9-12oz tanks fit the diameter of the outer launcher shroud as well. Obviously you would need to reinforce the ASA to handle the additional weight if a larger tank is used. Other alternative air sources include a remote line (or just a remote line nipple) or breach loading pre-charged grenade rounds like a shotgun. The grenades can also operate on green gas. |
Grenade Selection
There are a wide variety of airsoft grenades available. The thunder grenade is made to fire four .68 caliber paintballs. I have only tested the launcher using the thunder grenades but theoretically there may be other grenades that work just as well, if not better. These grenades fire a wide range of different sized paintballs or airsoft pellets. The disbursement of air from these grenades may reduce the impact of the air on the rocket and potentially increase the life or distance of a rocket. These grenades are also less expensive since the thunder grenade is in high demand. I highly recommend the thunder grenade but this isn't the only option available. |
Rocket Selection
This design has only been tested for use with the Nerf Vortex rockets. These are available in the toy section of many retail stores such are Meijer, Kohl's, K-Mart, and several online stores. There is a 'howler' version of the rocket with a built-in whistle but I haven't tested whether it would work with this design. There are also two different types of Nerf round that I have seen though the packaging is the same. The first type, I assume an older version, has a tail section made from soft foam similar to material used in cheap pool toys. These rockets have a limited life, as the tail section will deteriorate with use (approx 2-3 shots max). The newer rockets have a much more durable tail section made of a rubberized foam that should prove to be much more durable. |
Rocket Preparation
I use 1.5-inch diameter PVC for all of may barrels. The Nerf Vortex football is slightly less than 2 inches in diameter and the tail fins are a little more than 2 inches. Even with a 2-inch barrel the fins will need to be trimmed to fit inside the barrel. Try to keep the fins even and take off as little as the fins will help stabilize the rocket. You can also extend the life of the rocket by creating a small cap on the back of the tail section using a glue gun. The glue should fill the hole in the middle and cover the rear joints of the fins. Make sure the glue being used isn't something that would dry into a hard surface like epoxy or break off in flight. You may also want to create some cardboard sabots to protect your rockets; these can greatly extend rocket life on short barrel launchers. |