Need Larger Accumulators

Posted Sat, 03/20/2010 - 15:47 by Brian

I bought some test foam yesterday and did some penetration tests with Nassau's cannons. As expected, they are firing a little soft. So I spent a little time experimenting to see what the best solution is for increasing the volume of the accumulators. As I mentioned in the comments for an earlier blog post (Quick Test Firing) I should only need about one cubic inch more volume. However, time is running short for the Maker Faire so I am not experimenting anymore. Plus, now that I've made some progress on the aluminum gun mounts (opps - I had not mentioned those before) I have a better feel for where there is more room. I am going to remake the accumulators with the following changes

  • Allow the bottom of the accumulators to drop an additional 0.2" below the firing valve
  • Lower the top of the accumulator so that it is 1/16" lower than the level of the top of the breach/magazine center.
  • Increase the pipe fitting size from 1-1/4" to 1-1/2"

These changes will allow me to mount the tray for the rest of the magazine to the top of the accumulator which will make things a lot easier to fit together. More importantly it will increase the accumulator volume by almost two cubic inches. I will have to give up on any hope of a 12 or 16 ounce CO2 bottle but the cannons will be at their scale locations and heights with a 9 ounce bottle. Here is a picture of an unfinished 1-1/4" and unfinished 1-1/2" accumulator side by side

DSCN0975.JPG

 

Does anyone know of a good source for CO2 bottle dimensions? I would love to find some tall narrow 12 or 16 ounce bottles.

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Drew's picture

Re: Need Larger Accumulators

by Drew - 03/20/2010 - 19:44

The one on the right looks MEAN    Why can't you stick with the smaller size and make them taller/longer?

Brian's picture

Re: Need Larger Accumulators

by Brian - 03/21/2010 - 10:23
FYI:
I will be ordering some plastic from McMaster-Carr today. If anyone needs anything they want to add to the order please give me a call.

I considered making them taller but it doesn't get me as much volume. I only have about a half inch more height I can add before reaching the deck. That gets me about one cubic inch. I can get about another half cubic inch by dropping the bottom a little. This is fine but then I loose that space for magazines and have to make certain I protect the accumulator from impacts from the rounds coming out the feed tubes. Plus, I still can only fit a 9 ounce bottle unless I want to move the cannons from their scale locations.

If I go with the larger pipe fitting I get more volume and can actually lower the accumulator a little - which will make it easier to place the magazines on top of the accumulators. A nine ounce bottle still fits (barely) so there is no effective difference there. I think the space savings for the magazines is probably the most important factor that is actually effected by the choice so I let it drive the decision.

I am going to give magazines some more thought today before cutting the new accumlators.

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