Fuel Meter Volume To Combustion Chamber Volume?

spudkilla224 · Sun Oct 25, 2009 5:42 pm

Hello everyone, I am new to the hybrid side of potato cannons. And I have searched all over spudfiles, the spudtech archive and google and the wiki, and have not found anything that would tell me how I would calculate the fuel meter size to the combustion chamber size of a hyrbid cannon?

Any help would be appreciated!

ramses · Sun Oct 25, 2009 6:08 pm

Just like a normal combustion, except you would multiply the pressure or volume of the meter by the mix number you want. For example, if you want an 8x hybrid, you would multiply by 8. Hope that helped!

spudkilla224 · Sun Oct 25, 2009 6:12 pm

Oh ic! I thought about that but I didn't think I was correct. so basically i should design the meter for the Highest mix i want to shoot at?

kjjohn · Sun Oct 25, 2009 6:22 pm

Download HGDT, enter in the specs of your cannon, and then go to the load/mix calculator in the tools menu.

ramses · Sun Oct 25, 2009 6:23 pm

It would be a good idea to design the meter to work at around the max propane pressure for the highest mix you want. That way, you can turn down the pressure and get a lower mix with the same meter tube. The propane pressure you use should be dictated by the lowest operating temperature you can foresee.

If that pressure is easily by the mix number, you make life easier on yourself. Ex. at 100psi, it will give you enough fuel for a 10x mix. That way, 6x=60psi, 7x=70psi, etc.

Hybrid meters can be more touchy than normal combustion meters, so it would be a good idea to measure the chamber volume with water or oil, and do the same for the meter.

obviously, don't make your hybrid out of PVC. A PVC meter should work okay though.

spudkilla224 · Sun Oct 25, 2009 6:27 pm

Ok thanks for all of the info and help everyone!