SpudFiles Wiki - User contributions [en]

Hybrid cannon

2007-08-11T03:58:11Z

Noname: Metal hybrids hold more pressure.

[[Image:hybrid.jpg|right|thumb|300px| A very well constructed hybrid cannon]]
A '''hybrid''' is a type of spudgun that combines principles of the [[combustion cannon|combustion]] and [[pneumatic cannon|pneumatic]] spudgun. It uses a pressurized mixture of fuel and air to get more power out of a given chamber volume.
The hybrid is capable of higher velocities than a combustion or pneumatic spudgun; projectiles fired by a hybrid have broken the sound barrier (Source). This is possible because of the higher pressure and temperature gases.

A hybrid launcher consists of seven basic elements:

*High pressure combustion chamber
*Pressure-triggered main valve (usually a [[burst disk]])
*[[Barrel]]
*Fuel system (usually [[fuel meter|metered propane]])
*Air filling valve
*powerful [[Ignition source]]
*One or more [[pressure gauge]]s

==Operation theory==
A hybrid is first injected with fuel, then with pressurized air. The amount of air depends on how much fuel was added, and is calculated to achieve a [[stoichiometric]] fuel/air ratio in the chamber.
A hybrid using twice as much fuel and air as a comparable combustion gun is said to be using a 2X mix, higher mixtures can be used and will produce even higher pressures. The fuel and air needs to be measured and matched carefully to ensure reliable operation, [[pressure gauge]]s and fuel [[fuel meter|meters]] are used for this.

The ignition of a hybrid gun is more difficult, as the length of a spark is roughly inversely proportional to the density of the gas. This necessitates the use of high-powered [[ignition source]] such as a [[stungun]].

The resulting gases are released to the barrel via a self-operating valve of some sort, most commonly a [[burst disk]] because of it's simplicity and reliability, although self-venting [[piston valve|piston]]/[[diaphragm valve|diaphragm]] valves have been used. Upon ignition of the fuel-air mix, the pressure rises and the valve opens.

===Safety===
A hybrid is the most dangerous launcher that can be built. It is advised to build with pipe that can handle the high pressure environment (200+ [[Pressure gauge|PSI]]) such as Sch. 80 PVC or metal. Remote ignition is a must, and the limit of a 4x propane/ 4 atmosphere mix should never be breached when using any type of plastic pipe. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most plastic pipe cannot handle the spike, and will shatter, launching plastic shards everywhere. A steel, iron, aluminum hybrid can survive higher mixes than 4x propane/ 4 atmospheres, and have been used at up to 8x propane/ 8 atmosphere mixtures. However, utmost care must be taken with these launchers, in construction and materials used.

Sprinkler valve

2007-06-22T16:50:44Z

Noname: /* Troubleshooting */

The next step up from a [[ball valve]], this is essentially a commercially produced [[diaphragm valve]]. However, they are unfortunately designed to open relatively slowly to prevent "water hammer", and the large number of internal turns decreases the flow of the valve (to roughly 60-70% of a piston/diaphragm valve with the same diameter).

The performance can be improved by replacing the stock solenoid-valve vent with a [[pilot valve]] with more flow. Most often this is a blow gun, although for larger valves a ball valve or even a smaller sprinkler valve can be used. This operation is often called [[sprinkler valve modification|modding]] the valve.<br>
You can download a video of how to modify a sprinkler valve [http://www.bcpneumatics.com/utopia/sprinkler.htm here]

The [[GGDT]]'s website has valve data for sprinklers in it's [http://www.thehalls-in-bfe.com/GGDT/library/library_menu.html design library]

===Troubleshooting===
If you are having problems with your sprinkler valve, these are some things to try
====Valve "Honks" or "sounds like an airhorn"====
You need a larger pilot valve. For more information, see [[honking]].

====Valve won't seal====
If your valve leaks air out the barrel, you should disassemble it and clean the diaphragm and seat. Check for any plastic chips that may have entered the valve. Smear the diaphragm and seat with lithium grease to promote a seal.

For other problems, visit the Sprinkler Valve Troubleshooting Guide [http://www.spudfiles.com/forums/sprinkler-valve-troubleshooting-guide-t8780.html]

[[category:valves]]

Tee vortex BBMG

2007-02-16T05:19:12Z

Noname: I am editing this page to give people the idea that the Bondo block isn't the only way to make them.

This specifically shaped object made of a semi-hard to hard material is used in a [[BB machine gun]] to take bb's located outside of this part and suck them into the barrel of the [[BB machine gun]]. Some people use [[lathe]]s in order to turn pieces of aluminum for the construction of a vortex, while others prefer using [http://www.bondo-online.com/catalog_item.asp?itemNbr=176 Bondo Auto Body Filler] molded in a PVC plug. Designs for building a Bondo vortex can be found on Burnt Latke's [http://www.burntlatke.com/bb.html BB machine gun construction] page. Some other people prefer [http://www.spudfiles.com/uploader/uploadFiles/Vortexdiagram.jpg inline vortex blocks] to those that are housed inside a PVC plug.