GGDT and hammer valves

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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jackssmirkingrevenge
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Tue Dec 11, 2018 6:48 am

Had some discussion on the GTA forum and a few users modeled their hammer valve PCPs using GGDT and the predicted performance in terms of energy was much lower than measured results, with the former being in the order of only 30% of the latter. In order to approach measures results, the hammer force has to be ramped up to unrealistic levels to increase the valve opening time.

Perhaps D_Hall could comment on this, personally I don't have a lot of experience with modeling this type of valve and it would be interesting to know what factors are taken into account.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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jrrdw
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Tue Dec 11, 2018 4:12 pm

I wonder if matched porting would make up the difference?
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jackssmirkingrevenge
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Thu Dec 13, 2018 5:13 am

jrrdw wrote:I wonder if matched porting would make up the difference?
The valve parameters allow the valve seat diameter to be included, I would think that the program assumes that the transfer port to the barrel is the same diameter.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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jrrdw
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Thu Dec 13, 2018 5:33 am

a few users modeled their hammer valve PCPs
Mass production models or home built I wonder? There would be differences in the builds.
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jackssmirkingrevenge
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Thu Dec 13, 2018 6:39 am

jrrdw wrote:Mass production models or home built I wonder? There would be differences in the builds.
Home builds with conventional valves, technically it's the same sort of design.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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