Howitzer Aiming

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
djsnowman06
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Sat Nov 23, 2013 6:53 pm

planning a large coaxial combustion type . first I don't know if combustion and coaxial will work as I cant find much about them. second I'm planning to mount it like a howitzer cannon, using track wheels to move and recoil system, maybe model it after the M777. I was wondering if anyone had any ideas for aiming, especially when lobbing spuds as opposed to directly shooting at a target.
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jackssmirkingrevenge
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Sun Nov 24, 2013 6:44 am

First off, in order to have any chance of hitting a target smaller than a barn, you need consistency. This means projectiles that are of similar shape, size and weight, and putting the same amount of fuel in your cannon every time.

Once you have that sorted out, you need a way of changing the angle of fire in a way that can be measured, precise and locked in place, same goes for traverse.

As to the actual aiming, have a quick read through this: http://en.wikipedia.org/wiki/Gun_laying
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Ragnarok
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Sun Nov 24, 2013 7:43 am

djsnowman06 wrote:first I don't know if combustion and coaxial will work as I cant find much about them.
Sure. It's not uncommon. Many breech loading combustions are coaxial, with the barrel extending back through the chamber and being loaded via a screw cap on the end of the chamber (also serving as a way to supply fresh air to the chamber).
I was wondering if anyone had any ideas for aiming
It's going to depend on your projectiles, but there's not much of a chance on that one. The consistency and repeatability of most spudguns is pretty poor to start with, something will only be exacerbated by a high launch angle.

Unless you're talking about a combustion with fuel metering, chamber fans, good ignition and very consistent (stable) projectiles, getting any degree of repeatability out of it is highly unlikely.
Even then, a high launch angle is probably going to put the range at at least a few hundred metres - and aside from that being further than it's actually possible to see a small, high-speed projectile in mid-air (or, likely, your target) that's far enough that you shouldn't expect a grouping smaller than tens of metres across even without the complications of wind and its unpredictability.

Basically, if you're "lobbing" projectiles high in the air, don't expect to hit any point targets. In fact, according to Murphy's law, you should only expect to hit things you don't want to.
Does that thing kinda look like a big cat to you?
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kydavies
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Sun Nov 24, 2013 2:17 pm

my only advice is lots of practice to get it dialed in and maybe one of those range finders for golf and set up some 6 foot tall targets down range.
mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
djsnowman06
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Mon Nov 25, 2013 10:27 am

Right on. I have a cabin on large lake for a range. in thewinter I can setup some targets and try hitting em so thats why I ask ... I think I can dead reckon it but I was looking for something more "sophisticated" lol. as for coaxial combustion, Will ABS hold? About the only thing I can get my hands on. That or sewer grade pvc
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jackssmirkingrevenge
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Tue Nov 26, 2013 9:47 am

djsnowman06 wrote:Will ABS hold? About the only thing I can get my hands on. That or sewer grade pvc
Better ABS than PVC in this case.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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