SpudFiles Wiki - User contributions [en]

Breech loading

2005-10-19T21:06:44Z

Wesman987: added link

Many types of breech loaders are employed. The most common methods are to use male and female adapters to connect the barrel to the chamber, as seen here: http://www.spudfiles.com/forums/viewtopic.php?t=183

A method favored due to speed is to use a type of [[Cam lever coupling|cam lock]] fitting to connect the barrel and chamber. one such example is here: http://www.spudfiles.com/forums/viewtopic.php?t=311

One method that is one of the more challenging to make is a bolt action, which can be seen here:
http://pneumaticsniper.mypicgallery.com/

Stoichiometry

2005-10-19T20:59:19Z

Wesman987:

[http://en.wikipedia.org/wiki/Stoichiometric Stoichiometry] is an important concept in [[combustion cannon|combustion]] and [[hybrid cannon|hybrid]] launchers, since they use the energy from combustible fuels. A stoichiometric mixture is one where the ratio of fuel and oxygen molecules is balanced, so all the fuel and oxygen in the chamber is (in optimal conditions) consumed in the reaction. A [[fuel meter]] system is usually designed to ahcieve this mixture, which will yield the most power out of the combustion reaction.

===Calculations===

The stoichiometric ratio for gaseous fuels can easily be calculated. When the hydrogen and carbon in a fuel burns, it combines with oxygen as follows:

C+O2 --> CO2 
4H+O2 --> 2H2O 
CxHx + O2 --> CO2 + H2O

If the fuel molecule contains oxygen atoms, they will replace oxygen atoms from the air in the reaction. So for each oxygen atom the fuel contains, one less atom of atmospheric oxygen is needed. To begin calculating the stoichiometric ratio of a fuel, first find the chemical formula for the fuel, and count how many hydrogen, carbon and oxygen (if any) atoms it contains.

Since hydrogen combines with oxygen to make water (H2O), and two hydrogen atoms combine with every oxygen atom, four hydrogen atoms will consume one O2 molecule. Conversely, it can be said that one hydrogen atom will consume 0.25 O2 molecules.

Carbon atoms combine with oxygen to form CO2, so each carbon atom will consume one entire O2 molecule.

Any oxygen in the fuel will lead to one less oxygen atom being consumed from the air. Two oxygen atoms will prevent one O2 molecule from beling consumed, so each oxygen atom "saves" 0.5 O2 molecules.

Now we need to find how many O2 molecules are consumed by each fuel molecule, which is calculated as follows:
*for each hydrogen atom, add 0.25 to the amount of oxygen molecules needed
*for each carbon atom, add 1
*for each oxygen atom, subtract 0.5
The resulting number is the oxygen to fuel ratio. To find the fuel to oxygen ratio, divide 1 by the oxygen to fuel ratio. The amount of oxygen in air is 21%, so to find the fractional fuel to air ratio, the fuel to oxygen ratio is multiplied with 0.21. To find the ratio in percent, multiply this value by 100.

To find the volume of fuel needed for a particular chamber, the fractional ratio is multiplied by the chamber volume.

===Concrete example===

Formula of [[propane]]: C3H8

*number of carbon molecules: 3
*number of hydrogen molecules: 8
*number of oxygen molecules: 0

number of oxygen molecules needed = 3*1 + 8*0.25 = 5 molecules 
the actual combustion reaction is as follows: C3H8+5O2 = 3CO2+4H2O

fuel/oxygen ratio = 1/5 = 0.2 
fuel/air ratio = 0.2*0.21 = 0.042, or 4.2% 
fuel volume in a 3000 cc chamber = 3000*0.042 = 126 cc

Single formula for fractional fuel to air ratio: (1/(C+(H/4)+(O/2)))*0.21

Stoichiometry

2005-10-19T20:58:18Z

Wesman987: /* Calculations */

[http://en.wikipedia.org/wiki/Stoichiometric Stoichiometry] is an important concept in [[combustion cannon|combustion]] and [[hybrid cannon|hybrid]] launchers, since they use the energy from combustible fuels. A stoichiometric mixture is one where the ratio of fuel and oxygen molecules is balanced, so all the fuel and oxygen in the chamber is (in optimal conditions) consumed in the reaction. A [[fuel meter]] system is usually designed to ahcieve this mixture, which will yield the most power out of the combustion reaction.

===Calculations===

The stoichiometric ratio for gaseous fuels can easily be calculated. When the hydrogen and carbon in a fuel burns, it combines with oxygen as follows:

C+O2 --> CO2 
8H+O2 --> 2H2O 
CxHx + O2 --> CO2 + H2O

If the fuel molecule contains oxygen atoms, they will replace oxygen atoms from the air in the reaction. So for each oxygen atom the fuel contains, one less atom of atmospheric oxygen is needed. To begin calculating the stoichiometric ratio of a fuel, first find the chemical formula for the fuel, and count how many hydrogen, carbon and oxygen (if any) atoms it contains.

Since hydrogen combines with oxygen to make water (H2O), and two hydrogen atoms combine with every oxygen atom, four hydrogen atoms will consume one O2 molecule. Conversely, it can be said that one hydrogen atom will consume 0.25 O2 molecules.

Carbon atoms combine with oxygen to form CO2, so each carbon atom will consume one entire O2 molecule.

Any oxygen in the fuel will lead to one less oxygen atom being consumed from the air. Two oxygen atoms will prevent one O2 molecule from beling consumed, so each oxygen atom "saves" 0.5 O2 molecules.

Now we need to find how many O2 molecules are consumed by each fuel molecule, which is calculated as follows:
*for each hydrogen atom, add 0.25 to the amount of oxygen molecules needed
*for each carbon atom, add 1
*for each oxygen atom, subtract 0.5
The resulting number is the oxygen to fuel ratio. To find the fuel to oxygen ratio, divide 1 by the oxygen to fuel ratio. The amount of oxygen in air is 21%, so to find the fractional fuel to air ratio, the fuel to oxygen ratio is multiplied with 0.21. To find the ratio in percent, multiply this value by 100.

To find the volume of fuel needed for a particular chamber, the fractional ratio is multiplied by the chamber volume.

===Concrete example===

Formula of [[propane]]: C3H8

*number of carbon molecules: 3
*number of hydrogen molecules: 8
*number of oxygen molecules: 0

number of oxygen molecules needed = 3*1 + 8*0.25 = 5 molecules 
the actual combustion reaction is as follows: C3H8+5O2 = 3CO2+4H2O

fuel/oxygen ratio = 1/5 = 0.2 
fuel/air ratio = 0.2*0.21 = 0.042, or 4.2% 
fuel volume in a 3000 cc chamber = 3000*0.042 = 126 cc

Single formula for fractional fuel to air ratio: (1/(C+(H/4)+(O/2)))*0.21

Stoichiometry

2005-10-19T20:57:45Z

Wesman987: Added the combined general formula

[http://en.wikipedia.org/wiki/Stoichiometric Stoichiometry] is an important concept in [[combustion cannon|combustion]] and [[hybrid cannon|hybrid]] launchers, since they use the energy from combustible fuels. A stoichiometric mixture is one where the ratio of fuel and oxygen molecules is balanced, so all the fuel and oxygen in the chamber is (in optimal conditions) consumed in the reaction. A [[fuel meter]] system is usually designed to ahcieve this mixture, which will yield the most power out of the combustion reaction.

===Calculations===

The stoichiometric ratio for gaseous fuels can easily be calculated. When the hydrogen and carbon in a fuel burns, it combines with oxygen as follows:

C+O2 => CO2 
8H+O2 => 2H2O 
CxHx + O2 => CO2 + H2O

If the fuel molecule contains oxygen atoms, they will replace oxygen atoms from the air in the reaction. So for each oxygen atom the fuel contains, one less atom of atmospheric oxygen is needed. To begin calculating the stoichiometric ratio of a fuel, first find the chemical formula for the fuel, and count how many hydrogen, carbon and oxygen (if any) atoms it contains.

Since hydrogen combines with oxygen to make water (H2O), and two hydrogen atoms combine with every oxygen atom, four hydrogen atoms will consume one O2 molecule. Conversely, it can be said that one hydrogen atom will consume 0.25 O2 molecules.

Carbon atoms combine with oxygen to form CO2, so each carbon atom will consume one entire O2 molecule.

Any oxygen in the fuel will lead to one less oxygen atom being consumed from the air. Two oxygen atoms will prevent one O2 molecule from beling consumed, so each oxygen atom "saves" 0.5 O2 molecules.

Now we need to find how many O2 molecules are consumed by each fuel molecule, which is calculated as follows:
*for each hydrogen atom, add 0.25 to the amount of oxygen molecules needed
*for each carbon atom, add 1
*for each oxygen atom, subtract 0.5
The resulting number is the oxygen to fuel ratio. To find the fuel to oxygen ratio, divide 1 by the oxygen to fuel ratio. The amount of oxygen in air is 21%, so to find the fractional fuel to air ratio, the fuel to oxygen ratio is multiplied with 0.21. To find the ratio in percent, multiply this value by 100.

To find the volume of fuel needed for a particular chamber, the fractional ratio is multiplied by the chamber volume.

===Concrete example===

Formula of [[propane]]: C3H8

*number of carbon molecules: 3
*number of hydrogen molecules: 8
*number of oxygen molecules: 0

number of oxygen molecules needed = 3*1 + 8*0.25 = 5 molecules 
the actual combustion reaction is as follows: C3H8+5O2 = 3CO2+4H2O

fuel/oxygen ratio = 1/5 = 0.2 
fuel/air ratio = 0.2*0.21 = 0.042, or 4.2% 
fuel volume in a 3000 cc chamber = 3000*0.042 = 126 cc

Single formula for fractional fuel to air ratio: (1/(C+(H/4)+(O/2)))*0.21

Fuel meter

2005-10-19T20:51:00Z

Wesman987:

A fuel meter is used to inject a predetermined amout of fuel gas (usually [[propane]]) into the chamber of a [[Combustion cannon|combustion]] or [[hybrid cannon]]. It typically consists of an adjustable [[pressure regulator]] and [[pressure gauge]], connected to two [[ball valve]]s with a length of pipe in between. The volume of this pipe and the pressure of the gas determines the amount of gas injected. The second ball valve is connected to the chamber of the gun.
A fuel meter is operated as follows:
*The regulator is set to a predetermined pressure for the particular meter and chamber size
*The ball valve closest to the regulator is opened, filling the pipe up until the second ball valve with gas at the regulated pressure
*The first ball valve is closed again, closing off the section of pipe between the two valves
*The second ball valve is opened, the pressurized gas inside the meter expands and enters the main chamber
*The second ball valve is closed, and the cannon is ready to fire

The regulator usually only needs to be set the first time, and further fueling can be done simply by opening and closing the two ball valves. A fuel meter provides fast and very consistent fueling, and is the easiest way to use bottled gas for fuel.

Constructing a fuel meter and determining the correct pressure to use requires a few [[Stoichiometric|calculations.]]
The Fuel Tool (found on Burnt Latke's [[http://www.burntlatke.com/calc.html performance calculators page]]) automates the fuel meter calculations.

Hybrid cannon

2005-10-19T20:31:51Z

Wesman987:

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
*powerfull [[Ignition source]]
*One or more [[pressure gauge]]s

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. In order to fire, the operator first inserts a [[burst disk]], usually consisting of aluminium foil or plastic, between the chamber and barrel. A [[Cam lever coupling]] or [[union]] is used to hold the burst disk in place. The operator then loads projectile into the barrel, adds fuel to the combustion chamber, and then adds 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. when the ignition source is triggered, the pressure from the combustion ruptures the burst disk and propels the projectile out of the barrel. The hybrid is capable of higher velocities than a combustion or pneumatic spudgun, projectiles fired by a hybrid have broken the sound barrier (Source). 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 gauges and fuel meters are used for this. A pressure gauge with a check valve can also be added to record the peak chamber pressure of the gun.

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. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most pipe cannot handle the spike, and will shatter, launching plastic shards every where. Therefore utmost care must be taken with these launchers.

Hybrid cannon

2005-10-19T20:28:56Z

Wesman987:

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
*powerfull [[Ignition source]]
*One or more pressure gauges

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. In order to fire, the operator first inserts a [[burst disk]], usually consisting of aluminium foil or plastic, between the chamber and barrel. A [[Cam lever coupling]] or [[union]] is used to hold the burst disk in place. The operator then loads projectile into the barrel, adds fuel to the combustion chamber, and then adds 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. when the ignition source is triggered, the pressure from the combustion ruptures the burst disk and propels the projectile out of the barrel. The hybrid is capable of higher velocities than a combustion or pneumatic spudgun, projectiles fired by a hybrid have broken the sound barrier (Source). 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 gauges and fuel meters are used for this. A pressure gauge with a check valve can also be added to record the peak chamber pressure of the gun.

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. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most pipe cannot handle the spike, and will shatter, launching plastic shards every where. Therefore utmost care must be taken with these launchers.

Talk:Stoichiometry

2005-10-19T16:18:29Z

Wesman987:

== Calculations ==

Is this an okay format for presenting calculations, or should there be more/less info, or ordered in a different way? I tried to make an explanation of how everything is done so someone not familiar with the calculations involved can get to understand how the formula is derived and works, as well as providing a short answer for those just looking for the hard math. I'm interested to know if someone has problems understanding something in the article, so that it can be improved upon. --[[User:GalFisk|GalFisk]] 19 October 2005 05:28 (CDT)

I think including the actual chemical formulas (both a generic example of a hydrocarbon combustion, and the specific propane reaction) would help, mainly to clarify the concept of balancing the equation.--[[User:Wesman987|Wesman987]] 19 October 2005 11:18 (CDT)

Main Page

2005-10-18T23:15:45Z

Wesman987:

Do you really know what this website is about? Do you? This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. And all of this, is totally free so be happy and get on to registering and posting!

-PCGUY, maker of spudfiles

Note - This page (Main Page) is open for editing!

[[Cannon Construction]]

[[Legal Issues]]

[[Launcher configuration]]

[[History]]

[[Combustion Cannon]]s

[[Pneumatic Cannon]]s

[[Hybrid Cannon]]s

[[BB Machine Gun]]s

Main Page

2005-10-18T23:02:25Z

Wesman987: added legal issues

Do you really know what this website is about? Do you? This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. And all of this, is totally free so be happy and get on to registering and posting!

-PCGUY, maker of spudfiles

Note - This page (Main Page) is open for editing!

[[Cannon Construction]]

[[Legal Issues]]

[[Launcher Configuration]]

[[History]]

[[Combustion Cannon]]s

[[Pneumatic Cannon]]s

[[Hybrid Cannon]]s

[[BB Machine Gun]]s

Stoichiometry

2005-10-18T23:00:08Z

Wesman987:

[[http://en.wikipedia.org/wiki/Stoichiometric Stoichiometry]] is an important concept in spudguns, mainly in combustion and hybrid launchers that use a flammable type of fuel. Using stoichiometry, a fuel meter system can be designed to yield the most power out of the combustion reaction.

Talk:Fuel meter

2005-10-18T22:59:40Z

Wesman987:

Formulas for manual fuel meter calculations should be added.

:I can handle that, but shouldn't the information be included in the seperate "stoichiometric" article? --[[User:Wesman987|Wesman987]] 18 October 2005 17:59 (CDT)

Talk:Pneumatic cannon

2005-10-18T22:47:18Z

Wesman987:

Shouldn't there just be one page for modding a sprinkler valve?
:Probably should, it could also be put in the [[sprinkler valve]] article, but I think it's better that it has its own. Could be called [[sprinkler valve modification]] perhaps? --[[User:GalFisk|GalFisk]] 18 October 2005 13:48 (CDT)

:Ok, that seems good. --[[User:Wesman987|Wesman987]] 18 October 2005 17:46 (CDT)

Talk:Pneumatic cannon

2005-10-18T22:46:53Z

Wesman987:

Shouldn't there just be one page for modding a sprinkler valve?
:Probably should, it could also be put in the [[sprinkler valve]] article, but I think it's better that it has its own. Could be called [[sprinkler valve modification]] perhaps? --[[User:GalFisk|GalFisk]] 18 October 2005 13:48 (CDT)

Ok, that seems good. --[[User:Wesman987|Wesman987]] 18 October 2005 17:46 (CDT)

Hybrid cannon

2005-10-18T22:39:13Z

Wesman987:

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
*Ignition source
*One or more pressure gauges

A hybrid is a type of spudgun that combines principles of the combustion and pneumatic spudgun. It uses a pressurized mixture of fuel and air to get more power out of a given chamber volume. In order to fire, the operator first inserts a [[burst disk]], usually consisting of aluminium foil or plastic, between the chamber and barrel. A cam coupling or union is used to hold the burst disk in place. The operator then loads projectile into the barrel, adds fuel to the combustion chamber, and then adds 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. when the ignition source is triggered, the pressure from the combustion ruptures the burst disk and propels the projectile out of the barrel. The hybrid is capable of higher velocities than a combustion or pneumatic spudgun, projectiles fired by a hybrid have broken the sound barrier (Source). 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 gauges and fuel meters are used for this. A pressure gauge with a check valve can also be added to record the peak chamber pressure of the gun.

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+ 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. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most pipe cannot handle the spike, and will shatter, launching plastic shards every where. Therefore utmost care must be taken with these launchers.

Hybrid cannon

2005-10-18T22:38:23Z

Wesman987:

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
*Ignition source
*One or more pressure gauges

A hybrid is a type of spudgun that combines principles of the combustion and pneumatic spudgun. It uses a pressurized mixture of fuel and air to get more power out of a given chamber volume. In order to fire, the operator first inserts a [[burst disk]], usually consisting of aluminium foil or plastic, between the chamber and barrel. A cam coupling or union is used to hold the burst disk in place. The operator then loads projectile into the barrel, adds fuel to the combustion chamber, and then adds 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. when the ignition source is triggered, the pressure from the combustion ruptures the burst disk and propels the projectile out of the barrel. The hybrid is capable of higher velocities than a combustion or pneumatic spudgun, projectiles fired by a hybrid have broken the sound barrier (Source). 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 gauges and fuel meters are used for this. A pressure gauge with a check valve can also be added to record the peak chamber pressure of the gun.

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+ 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. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most pipe cannot handle the spike, and will shatter, launching plastic shards every where. Therefore utmost care must be taken with these launchers.

Hybrid cannon

2005-10-18T22:37:19Z

Wesman987:

A hybrid launcher consists of seven basic elements:

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

A hybrid is a type of spudgun that combines principles of the combustion and pneumatic spudgun. It uses a pressurized mixture of fuel and air to get more power out of a given chamber volume. In order to fire, the operator first inserts a [[burst disk]], usually consisting of aluminium foil or plastic, between the chamber and barrel. A cam coupling or union is used to hold the burst disk in place. The operator then loads projectile into the barrel, adds fuel to the combustion chamber, and then adds 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. when the ignition source is triggered, the pressure from the combustion ruptures the burst disk and propels the projectile out of the barrel. The hybrid is capable of higher velocities than a combustion or pneumatic spudgun, projectiles fired by a hybrid have broken the sound barrier (Source). 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 gauges and fuel meters are used for this. A pressure gauge with a check valve can also be added to record the peak chamber pressure of the gun.

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+ 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. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most pipe cannot handle the spike, and will shatter, launching plastic shards every where. Therefore utmost care must be taken with these launchers.

Chamber fan

2005-10-18T22:24:41Z

Wesman987: added references

A chamber fan is a device used in combustion or hybrid cannons to create an even mixture of fuel within the chamber. A chamber fan system usually consists of a CPU fan from a computer, a switch to operate the fan, and a power source such as batteries to power the chamber fan. The fan is usually controlled manually by a switch but sometimes a [http://www.burntlatke.com/fan-controller.html timer circuit] is employed to automatically turn the fan off when not needed.

The benefits of using a chamber fan include, but are not limited to:

*Mixing the fuel within the chamber to provide an even distribution.
*Venting the chamber of exhaust gases after a shot.

The effects on cannon performance include [http://www.burntlatke.com/jpg600/fan-data.gif increased] [[muzzle velocity]], and the ability to quickly vent the chamber of exhaust gases.

Talk:Combustion cannon

2005-10-18T22:19:09Z

Wesman987:

Hey, where's that trouble shooting guide?

https://netfiles.uiuc.edu/hanson2/www/CLTG/start.htm

Spark gap

2005-10-18T22:15:30Z

Wesman987: typo

A spark gap consists of two metal electrodes placed close to each other with a gap in between, where an electrical spark can jump. They are used for igniting the fuel in [[combustion cannon|combustion]] and [[hybrid cannon]]s. Spark gaps are normally made by screwing two bolts through the side wall of the chamber, at an angle that puts the tips of the screws close together. The screws should be mounted to keep the heads a good distance apart, to ensure that the spark will not jump between the heads outside the chamber. The distance must be small enough that the voltage from the ignition source can jump across it. The distance is about 1.1 mm/kV, this varies with the shape of the electrodes though, sharp points allow longer sparks than flat surfaces. It should be noted that the pressurized mixture of a hybrid will shorten the max spark length, so a hybrid spark gap should be a fair bit smaller than max spark length to ensure reliability.
Spark plugs can be used for spark gaps, and are especially useful in metal guns, where the chamber wall would short out the screws of an ordinary spark gap.
Two or more spark gaps can be connected in series to generate multiple sparks, as long as the width of the combined gaps is smaller than the maximum spark distance. Spark gaps can not be wired in parallel, since the spark will then only jump the smallest gap.
[[Spark strip]]s are a popular method of achieving multiple spark gaps.

Burst disk

2005-10-18T22:06:42Z

Wesman987: spelling

A burst disk ruptures when the pressure gets to a certain point, allowing the gas to propel the projectile down the [[barrel]]. Due to this method of "opening", they have the fastest [[opening time]] of any valve in existance. They are nearly always used for [[hybrid cannon|hybrids]], and occasionaly as the main valve in a [[pneumatic cannon]].

They are a very close rival to a ball valve in cost, at roughly 13$ for a 2" [[union]] in sch 40 PVC. More expensive (but conveinent) devices exist, such as [[cam coupling]]s.
To use, [[solvent weld]] your chamber to one half of your union or cam coupling. One then 'loads' the valve by puting a layer of some weak material (such as multiple layers of aluminum foil, or a peice of a beverage container)in between the 2 halves of the union or coupling. The union or cam coupling is then tightened down, locking the disk of material in place.

In a hybrid cannon, they fail when the pressure builds due to the combusting gasses. Prior to this, they where containing the flammable gasses at a relatively low pressure. They are also sometimes used on [[combustion cannon]]s - for their noisemaking capabilities, and/or their ([http://www.advancedspuds.com/burstdisk.htm debated]) performance improvement.

In a pneumatic cannon, they can be used in the same way, simply pointing the cannon in the correct direction and filling it until it fires. However, many opt to use another system because of the inherent saftey issues with this. Such systems include puncturing it with a pointy object (such as a nail) attaced to the end of the object, and a 2 burstdisk system.

Hybrid cannon

2005-10-18T18:42:27Z

Wesman987:

A hybrid launcher consists of seven basic elements:

*High pressure combustion chamber
*Pressure-triggered main valve (usually a [[burst disk]])
*Barrel
*Fuel system (usually metered propane)
*Air filling valve
*Ingition source
*One or more pressure gauges

A hybrid is a type of spudgun that combines principles of the combustion and pneumatic spudgun. It uses a pressurized mixture of fuel and air to get more power out of a given chamber volume. In order to fire, the operator first inserts a [[burst disk]], usually consisting of aluminium foil or plastic, between the chamber and barrel. A cam coupling or union is used to hold the burst disk in place. The operator then loads projectile into the barrel, adds fuel to the combustion chamber, and then adds 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. when the ignition source is triggered, the pressure from the combustion ruptures the burst disk and propels the projectile out of the barrel. The hybrid is capable of higher velocities than a combustion or pneumatic spudgun, projectiles fired by a hybrid have broken the sound barrier (Source). 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 gauges and fuel meters are used for this. A pressure gauge with a check valve can also be added to record the peak chamber pressure of the gun.

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+ 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. If a higher mix is attempted, DDT (deflagration to detonation transition) can occur, causing an extreme pressure spike. Most pipe cannot handle the spike, and will shatter, launching plastic shards every where. Therefore utmost care must be taken with these launchers.

Main Page

2005-10-18T18:38:19Z

Wesman987:

Do you really know what this website is about? Do you? This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. And all of this, is totally free so be happy and get on to registering and posting!

-PCGUY, maker of spudfiles

Note - This page (Main Page) is open for editing!

[[Cannon Construction]]

[[History]]

[[Combustion Cannon]]s

[[Pneumatic Cannon]]s

[[Hybrid Cannon]]s

[[BB Machine Gun]]s

Talk:Pneumatic cannon

2005-10-18T18:18:58Z

Wesman987:

Shouldn't there just be one page for modding a sprinkler valve?

Main Page

2005-10-18T18:13:10Z

Wesman987:

Do you really know what this website is about? Do you? This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. And all of this, is totally free so be happy and get on to registering and posting!

-PCGUY, maker of spudfiles

Note - This page (Main Page) is open for editing!

[[Cannon Construction]]

[[History]]

[[Combustion Cannon]]s

[[Pneumatic Cannon]]s

[[Hybrid Cannon]]s

Main Page

2005-10-18T18:12:32Z

Wesman987:

Do you really know what this website is about? Do you? This website is here to teach you about potato guns, also called spudguns, spudzookas, and spud chuckers. So far there are pneumatic, combustion, hybrid, and BB type cannons/launchers. Here you will learn all about spud safety, how to make things like breech loaders and what types of fuel to use in your spud gun (like propane, butane, hairspray, rightguard, etc.). You will learn the good and bad types of ammo to use as well as learn the best types of ignition (like stunguns, flint ignitors, BBQ ignitors, etc.) and how legal your cannon is. You just may learn how to get something totally free. You will learn about ABS and PVC pipe and how to correctelly mount a pressure gauge into your cannon. You will learn all about the different kinds of valves and how to use them. (sprinkler valves, diaphragm valves, pistons, etc.) You will learn how to make a hybrid and a pneumatic/combustion cannon. You can even learn about strafers and submachine BB guns! Above all you will be able to find instructions on how to build things that you will love for years to come. And all of this, is totally free so be happy and get on to registering and posting!

-PCGUY, maker of spudfiles

Note - This page (Main Page) is open for editing!

[[Cannon Construction]]

[[History]]

[[Cannon Safety]]

[[Combustion Cannon]]s

[[Pneumatic Cannon]]s

[[Hybrid Cannon]]s

Combustion cannon

2005-10-18T18:12:22Z

Wesman987:

Combustion powered spudguns have four basic elements:

* Fuel system
* Combustion chamber
* [[Ignition source]]
* [[Barrel]]

In order to fire, the operator loads a projectile (usually a [http://en.wikipedia.org/wiki/Potato potato]) into the barrel, adds [[fuel]] to the combustion chamber (for example [[aerosol]]s or [[propane]]), and triggers the ignition source (e.g. a piezoelectric BBQ ignitor). The fuel should then ignite, create hot expanding gases, and force the projectile out of the barrel. Distances vary greatly depending on the type of fuel used, the size of the launcher, and the "idealness" of the fuel/air mixture; 100 metres is a common distance.

High tech combustion launchers may now include [[fuel meter|metered propane]] injection, [[chamber fan]]s, multiple [[spark gap]]s ([[spark strip]]s), and high voltage ignition sources ([[flyback circuit]]s, [[stun gun]]s, [[camera flash]]es, etc). Combustion launchers are mechanically simple, but are less powerful in [[typical situation]]s compared to a pneumatic launcher of the same size. Potato guns are often painted to increase their aesthetic value and to cover unsightly primer stains. Krylon Fusion, a type of paint specifically made for plastics, is the most common type of spray paint used on potato cannons.

Chamber fan

2005-10-18T18:07:05Z

Wesman987:

A chamber fan is a device used in combustion or hybrid cannons to create an even mixture of fuel within the chamber. A chamber fan system usually consists of a CPU fan from a computer, a switch to operate the fan, and a power source such as batteries to power the chamber fan. The fan is usually controlled manually by a switch but sometimes a timer circuit is employed to automatically turn the fan off when not needed.

The benefits of using a chamber fan include, but are not limited to:

*Mixing the fuel within the chamber to provide an even distribution.
*Venting the chamber of exhaust gases after a shot.

The effects on cannon performance include increased [[muzzle velocity]], and the ability to quickly vent the chamber of exhaust gases.