Video Caption: WARNING: I was told it’s loud so turn down the volume. Two state rocket more tests at the FAR site on January 5, 2019. First test was a 100 mm seven grain 7615 N-sec KNSB motor with a new lightweight forward bulkhead welded into the motor case with a new titanium nozzle machined by Sugar Shot to Space member Chris Coveny.
The motor failed when the bulkhead gave way resulting in the motor thrusting down into the concrete test stand foundation. That caused the nozzle to be forced up into the aluminum motor case that mushroomed as a result of the impact.
The nozzle was cut from the motor case and used a second time in a six grain 6,900 N-second previously launched flight motor with conventional bolted in bulkhead. This second successful test showed no erosion of the nozzle throat. The nozzle was also cool to the touch soon after firing, something not possible with a steel or graphite nozzle.