The 1st prototype that consisted of 35/65 casted KNSU propellant to a 0.375″ inner-diameter with a 1″ outer was a great success. The peak thrust was roughly 115N, and the total impulse was just about 65N, which puts us at just in the middle of the F motor. The total cost of this motor came out to be just around $2.55. This is quite impressive given the usual F-motor costs about $10-15 per firing. The sound that the motor produced was significantly quite than other tests I have done the the forward closure remained closed-off quite nicely. The nozzle came out with some slight char, and obvious ablation due to the chemical composition of the “Rockite” cement which is quite acceptable for the ease of use and speed of creation of a nozzle. The pictures of the nozzle gave me good insight on the ablation of the outer rim of the PVC end-cap, which would signify that the layer is not getting good enough thermal-insulation from the flame, OR, that the flame is expanding outwards and ablating/melting the surface of the nozzle:

The diagram is a little messy, but in summary the expansion of the high velocity, hot gasses melts and ablates the surface material fo the PVC end-cap which leaves it with a uniform circle, flush with the cement through-hole diameter.

Overall, this is most definitely considered a success and I am quite happy with the results, more tests are coming up this weekend with different diameters and slightly tweaked designs. The video of the firing is available here.