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Re: So, what about potato cannons? | |
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by Cheopis » Tue Jun 23, 2015 2:58 pm | |
Cheopis
Posts: 1633
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Lots of good stuff here.
My main interest in the spud gun concept is that spud gun design is capable of using far weaker, far lighter materials for the barrels. Steel would not be necessary. You could make them out of iron-banded wood. An entire industry of coopers could be brought into the war effort. The weaker barrel materials are possible because spud guns harness very large volumes of low-energy expanding gas to propel their projectiles. Very large compression chambers, and long barrels. The muzzle velocities are lower, yes, but they are quite high enough to be weaponized. Imagine a spud gun like what you see on Youtube, able to fire wooden projectiles through sheet metal. Now, they are far lighter than any portable cannon, but they are still are big and cumbersome, so instead of your infantry trying to carry them by hand, imagine every squad has one light cart that they drag behind them with ammo and four of these weapons mounted on it. Because the weapons are made of wood, it's a very light cart. In a fight, they turn it around, put a small splash of alcohol in each barrel, and load a leather ball full of glass fragments or rock into the barrel. If they are retreating, they can fire the things while they are moving, because it is so light. The idea of a man-portable unit designed for plunging fire against fortifications is also very possible. One man carries the weapon, another carries the ammo, a third carries the fuel. The church could come up with the idea completely out of the blue. Some guy working on a new cannon design decides to model it in wood, so he can visualize it. When he puts it together he looks at it in his workshop, over a strong glass of brandy, and a light bulb goes off in his head. That sort of spontaneous idea-generation is how a LOT of inventions come about. |
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Re: So, what about potato cannons? | |
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by SWM » Tue Jun 23, 2015 4:38 pm | |
SWM
Posts: 5928
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I'm still waiting for someone to tell me that you can't do the same thing (light-weight low-strength barrels) with low power explosives. Can you? If you can, then there is no advantage to potato guns. --------------------------------------------
Librarian: The Original Search Engine |
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Re: So, what about potato cannons? | |
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by awaykent » Tue Jun 23, 2015 7:01 pm | |
awaykent
Posts: 1
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The late Leo Frankowski in the Conrad Stargard series used excess steam pressure from the river boats as "potato cannons", which for practice actually fired spuds, otherwise they fired grenades or solid shot.
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Re: So, what about potato cannons? | |
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by Cheopis » Wed Jun 24, 2015 1:03 am | |
Cheopis
Posts: 1633
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I think the abrupt shockwave of the gunpowder explosion is too great for a spud gun. Pouring a little bit of gunpowder into the large chamber of a potato gun might provide enough energy and expanding gasses, but it's going to do so from a much smaller initial volume than a combustion chamber full of alcohol fumes. A lump of gunpowder sufficient to accelerate a spudgun projectile is going to generate a very dense high pressure wave which will quickly tear apart a wooden compression chamber. With a very advanced gunpowder design, you might be able to build something to finely meter and evenly combust a dusting of gunpowder in a large volume. If you can do that, just make regular weapons. The combustion characteristics of gunpowder are very different than combustible gasses. Combustible gasses do quite nicely though, if you utilize them appropriately. Automobiles don't run on gunpowder, nor to they typically run on liquids. Internal combustion engines run on combustible gasses. |
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Re: So, what about potato cannons? | |
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by AirTech » Wed Jun 24, 2015 2:53 am | |
AirTech
Posts: 476
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They are called infantry mortars....(works better with smokeless powders though). You have a combustion chamber with a vent, burn your powder at high pressure and then vent to the low pressure launch tube. If you look at a modern mortar round the base has a vented tube, which is the single use combustion chamber and contains the launch cartridge. When the round is dropped into the tube a firing pin in the bottom of the tube triggers the primer, which lights the main charge, the combustion gases then rupture a covering over a series of ports and the gases then launch the mortar round out of the tube. Compressed air is fine if no-one is shooting at you, if they are, a gas bottle is an artillery shell strapped to your back, if it is hit (the bang will take you out and anyone within 5 meters (15 feet) for a SCUBA size cylinder). This is why SCUBA tanks (especially aluminium) are supposed to be filled in water baths (for blast absorption when they fail (note when, not if)). (Steel tanks have a much longer life if you keep them dry and clean). Last edited by AirTech on Fri Jun 26, 2015 5:34 am, edited 1 time in total.
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Re: So, what about potato cannons? | |
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by Keith_w » Wed Jun 24, 2015 6:52 am | |
Keith_w
Posts: 976
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Crap, I hadn't heard he died. I really enjoyed the high-tech knight series. Thanks for sharing that. --
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. |
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