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5 Posts |
 Posted - Aug 06 2001 : 08:07:16 AM
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Several Months ago i posted an article asking for help with my designing a Spudgun. Everything had gone pretty well n the construction and develoing phases, however I had a slight ignition problem(one that, to this day, has cost me the hair of my left armpit...) Things didnt work out right and i ended up smashing my spudgun with the ramrod in a fit of rage, effectivly destroying aforementioned spud gun. Recently I have returned from my final semester at Marshall University, with a *promise not to laugh* Bachalors Degree in History*QUIT LAUGHING.... HISTORY HAS ITS PLACE IN SOCIETY TOO!*
While away at college I had developed yet again, another, smple spudgun, however i never had the time to test it. Recently my parents ceebrated their 25th anniversary and threw a rather large party, effectivly bringing both redneckish sides of the family together, and forcing the Intelectual bunch to gather together. Somehow the converstaion turned to potatoes, and I brought up my spudgun, explaining i destroyed the first one and never had a chance t develope a good ignition system for the current one. Well Needess to say, 5 six packs or so and 5 coege degrees(2 accounting, one engineering, one physics, and one History) later, along with the arge monetary investment, we had the spudgun working. Basically the gun I designed is a very simple foot ong section of 3inch pipe, a 3 to 1 1/2 inch venturi adapter(for sewage pvc pipe, not a reducer, a venturi....) a screw trap back, and a 4 foot ong 1 1/2 inch barrel.... After indudging in a few achaholic beverages, my intellectua cohorts and I tried several ignition devices.... Grill ignightors, the stun gun, even a damned aim-a-flam... and Nothing seemed to work.... Then taking a cue from the great ones, and especially NAPOLEON(see i told you history has its place!) a sudden stroke of genius hit me. Old school cannons utalized a device called a "Flash Hole" The cannon was loaded and primed, and then a "wick" was paced into a small hole on top of the cannon. After the wick burnt down below the hole, one solitary and brave(perhaps stupid???) soul placed his finger over the hole, effectivly sealing it and the cannon would fire once the powder was ignighted. Basically, what my dad, brother, cousins and I did to create our "dirt cheap but drastically effective" ignition system is this.
1... Drill 2 holes in he cumbustion chamber.... They need not be perfectly aligned opposite from each other aor anything like that, just enough that you can see one hole when ooking though the other.....
2. Take 1 aluminum/brass Bolt and a nut....(I learned this weekend that stainless steel is a bad conductor) Screw the nut onto the bolt, then place a smal amount of PVC glue on the threads of the bolt and thread it into one of the holes in your combustion chamber....
3. After the bolt is in place, Utalize a sheet of DiAluminum Trioxide(aluminum foil, yet another thing i learned this week...) crumple the sheet rather loosly and puffy like, and place it over the bolt, inside the chamber.....
4. 2 More six packs and a blown out football later..... Take the self sealing pin valve from a football and epoxy it onto the other hole, make(lesson.... use epoxy on both sides of the chamber less you wish to take out someones eye with a self sealing pin valve) sure to epoxy on both sides of the combustion chamber.....
5. The electrical ignition... We struggled with this thought for quite a while after several faild attempts with the grill ignitor, stun gun, cigarettes, cannon fuse, aimaflame etc etc...
6. Find yourself some heavy duty(EXTREMLY) electrical cable.... We used 8 gague power cable commonly used in the installation of car stereos, first, then heavy duty tripple insulated single core copper wire used in wiring houses(this is where the pin valve comes in)
7. If you're going to use the 8 gague cable etc, fray the end of it and dont use a pin valve, fraying the end makes for several hundered gapping points against the aluminum on the inside of the chamber, instead of just one. If you use the copper wire, then use the pin valve. Pushing the wire thorugh the pin valve makes an airtight seal allowing you to ignite the gun without loosing gas through the *flash hole* as we did with the power cable.....
8. Now came the actually sparking device.... Since all had failed before we were at a loss, we had a great contact system going on but no juice.... That was the moment i remembered the greatest invention of mankind.... THE JUMP PACK.... A portable 12 volt, 3000 cold cranking amp, .002 couloumb device of ignition power(or a car battery and jumper cables works just as well we discovered.....) This type of device works rather well because the carbattery/jump pack produces hot sparks compared to cold sparks of grill ignitors ac current etc though not as dangerous as creating an accellerator coil to get the same effect.....
THE FIRST EFFECTIVE LAUNCH!!!!!!
We unscrewed the back of the Starch Accellerator,and (we used cutter bug spray and static guard as accellerent) sprayed up into the bottom of the chamber ( discovered spraying up focuses more gas into the chamber, with less chance for moisture, you get pure gas! If you are using the flash hole tecnique here too, you have to hold your finger over the hole while priming, or else all the gass escapes, with the pin valve this problem is solved.... We screwed on the endcap while still holding the cannon upwards(witht he ammo loaded alrieady i might add)
Finally we placed the negative lead from the jumppack/battery onto the bolt(the one with the tinfoil on the inside) and the positive leade onto the bare copper wire.... Pushed the copper through the pin valve made contact with the tin foil and BOOOOOOOOM! a sucessful launch.... I nearly urinated myself with joy at such a sucessful launch...
As far as i can see there are no real disadvantages with this system except that you may loose a little fuel due to the flash hole if you are going to use the 8 guage cable, but the benifits of all those points of contacts makes it much easier to ignighte said fuel.... Another advantage I can see is safety, if one uses a jump pack, they come direct from the factory, with their leads installed, they are super heavy insulated, produce many cold amps and have a nice couloumb charge, and a relativly low voltage.... Meaning that even with all the amps behind it, it wont really kill you like the accellerator coil from a car will.... It'll just give you one nasty shock... Secondly it cant knock you out and make you piss your pants like a stun gun will... and its very portable, considering that jump packs ARE relativly small and light for the power they produce.....
This is not to say they are not HEAVY but for the POWER they produce they are lighter than a car battery, coil, flyback etc and they come with nifty handles and storage places for your leads.... The leads look and act exactly lke jumper cables for your car, but they are insulated quite a bit more, along with the wire/cable that you use, will also have a nice insulation to it(especially f you use powercable for car stereo amplifiers) One final advantage that I see with this type. As I said before as well, 12 volts and 1000-3000 cca isnt really enough to kill you or hurt you that much which makes it rather safe.... But besides the safety factor, as I mentioned before, car batteries and jumper packs produce a nice hot spark to ignight most if not all of your fuel making for a nice bang, and accelleration up the barrel of the cannon....
As for the disadvantages, this type of system is easily designed, but the work to be done on the actualy pvc/abs of the cannon is rather time consuming and tedious.... with 4 other people it goes nice and fast, but i cant imagine doing it myself..... Also you do run the risk of possibly receiving a nasty scrotum shrinking *jolt* of dc power, or an slight electrical burn... Or with a flashole you run the risk of actually being brned by heat/escaping gass if your projectile is jammed too far into the barrel or packed too tightly.... My brother learned this when his Cutter Insect repelent soaked arm went up in flames costing him several patches of body hair..... Sorry for having such a long post and all fellas but im just quite happy*estatic more like it* that I got my spudgun working finally and wanted to share my experience with everyon.... I'd welcome any comments or suggestions anyone would have for me because I am sure that there is a way to improve on this design/fouling of nature *grins* and i would welcome all constructive criticism.... Oh yeah one last final comment if you want to try the pin valve and electrical wire, make sure its a single solid piece of copper wire... Its stiff and it pushes through the valve nice n sleazy errr easy..... Its bastically impossible to get threadded wire through the pin valve.... Oh yeah one other advantage I just thought of and remembered with a jump pack you get hella many ignitions *we launched about 100 potatoes and didnt even drain my jump pack one notch on the charge scale..... Also the risk of wetting the electrodes is minimal because they arent really present during the priming,and you're bound to find a "dry" spot on a nice, big, fluffy, textured piece of aluminum foil....
Also, if you are relaly looking to spend some money...... and no i dont recomend this, even though it made my corn cobs sail like pigeons on acid.... Gold leaf works wonders in place of aluminum foil.... Thogh it is about 20 dollars a sheet... (gold is one of the best conductions known to man, along with lead, copper and aluminum :))
Finally one last saftey advertisment (this is a more of a do as i say thing i guess not as I do....) I learned this weekend that "Spudding"
and alchahol dont mix.... My inebreated father in his haste and excitement happened to well, fire a little prematurely and struck PA state police cruiser square in the windshield with a corn cob........ So.... if you're going to drink and spud do so responsibly, and dont let your old man fire your spud gun............. It may end up costing you 600 bucks and a misdemenor disordly conduct charge.........
Well again i appologize for this being so long and all... Just like i said i was rather excited..... I hope you guys understand, and can offer me some good suggestions :)
When a Bomb is Dropped from the air. It makes a loud noise... And People Tend to DIE....
Edit....Moved to the Lounge by Aaron Cake
Edited by - Aaron Cake on Aug 17 2001 10:48:10 AM |
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Proof That a Kolaj Edjewkayshin does pay off
