I have since made another iteration to this design, and figured out how to get the spoons to nest inside each other to some extent.
I'll upload photos of the cast aluminum copies of the second iteration if i can cast more than one without destroying the plaster mold.
what you see in the photo is car battery lead + 10%(?) tin.
The spoons are about 2.5 inches long and the portion of the spoon that is flat is 1 inch wide.
the exit angle isn't nearly the 20 degrees it should be.
Looking at other commercial Turgo spoons it appears they don't bother to try and get it that low, some of them appear to be nearly 45 degrees, and the spoons do not nest inside each other either.
Mine are probably 35 but what i think i'm going to do is just tilt the turgo spoon away from the jet, so the exit angle is 20 degrees, and keep the basic profile that I have.
In theory they should work for a 3/4th inch wide jet but i don't think they would be very efficient with a jet that wide.
I've since polished one of them up and carved out the inside a bit deeper, and made a new mold.
of which i successfully extracted the metal without melting it out or breaking the plaster (wasn't that hard actually, so i can make (N) plaster molds from one master.)
I have casting sand and plenty of it but never really got it working properly.
Anyone want cast copper turgo spoons?
The application I'm building this for is:
280 gallons per minute at 47 psi, at least 4 jets required for a 6 inch diameter wheel at 1200 rpm.
I'm intending to convert a 480 volt 10 hp induction motor into a 240vac 40 hz synchronous motor, direct drive from the spoon, rectify it to dc, run the 330 volts DC the 1000+ feet and drive a VFD.. hopefully it can handle that.
My previous experiments with induction motors suggested half the nameplate volts per hz is the saturation point.
A shunt regulator or two of them for redundancy will keep the voltage down and the turbine loaded.