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Short question topic

A place to ask general spud cannon related questions.
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Re: Short question topic

Unread postAuthor: hectmarr » Thu May 09, 2019 10:00 am

I do not know if I understand what you explain to me ...
You mean that the area "B" must be 4 times larger than the area "A", and assuming a mixing pressure in the combustion chamber of 10 bar, the pressure on the "B" side of the piston, debris to be 30 bar ?, so that the piston opens at approximately the peak pressure of explosion, and not before ... :roll:
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Weapons do not exist, they are built. This hobby is a science - totally procedural art.
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Thu May 09, 2019 10:30 am

More or less, here are the numbers in a less imperial context:

The pressure on area A is trying to open the piston. The pressure on area B is trying to keep the piston closed.

Let's say that A is 1cm and B is 1.5cm and you have 10 bar pre-mix in the combustion chamber. The force trying to open the piston is 8kg, while the force keeping it closed is 18kg. This means that it will open when the force on A is 18kg, equivalent to about 22 bar in the chamber in our example. Since a 10 bar pre-mix can be expected to generate upwards of 70 bar, this means a lot of the energy will be wasted.

In order for the piston to open at 70 bar chamber pressure, the pressure on B in this example needs to be 31 bar.
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

Unread postAuthor: hectmarr » Thu May 09, 2019 10:37 am

OK understood.
It will be a bit annoying to have to compress at two different pressures, because I will need to include a pressure regulator at the outlet of the air pump, say 10 bar to pass through the doser and 30 bar of air only, to the rear of the piston.
Muchas gracias por la explicación.
 
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Re: Short question topic

Unread postAuthor: jackssmirkingrevenge » Thu May 09, 2019 11:02 am

You can always use a bigger piston, there will be more dead space but I think the bigger pop-off pressure will more than compensate for this...
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Short question topic

Unread postAuthor: wyz2285 » Wed May 15, 2019 3:08 am

Temperature raised considerably here so manually pump and keep the Yong Heng cool is getting tiresome. I'm ready to order the booster pump. Just one last question, how high is the maintenance of it? If I had put enough effort (which I would be very uncomfortable with) like open all the parts and clean every few uses with the Yong Heng I suppose it could have lived longer so, is the booster pump same thing? Or I have a relatively trouble free use?
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