December 7th 2013 Firing report

The December 2013 Firing went well. It was attended by 8 members in addition to a group of students from USC RPL.

Except for a few spots on the road right after the asphalt ends it was in pretty good shape. There were some light rain early in the day and strong winds persisted all day. This kicked around a lot of sand. And again I’ll be dismantling my camera to remove all the sand. (At least the wind was kind enough not to shatter one of my car windows with a rock this time like it did last time.) The video quality suffered because of the winds. I had to film from inside the blockhouse and through the not so clear windows.

 

There were 6 static firings for the day. Three where from the USC group. These tests where designed to test additives to their basic AP-Aluminum propellant formula. All three were fired successfully. (I only captured footage from the first and last test.)

 

Chris Lujan, brought and static fired another one of his Potassium Nitrate/Sucrose Rocket motors, with some modifications from his previous designs. Unfortunately in exploded upon ignition. The casing was made of PVC and in disintegrated into pretty small pieces.

 

The firing of my Gaseous oxygen and Propane rocket went well save for a few issues. The buzzing sound that can be heard in the video was being caused by the check valves. They didn’t quite have enough flow to keep them fully open. Also debris from the ablative liner partly obstructed the nozzle canting the plume to one side.

 

My second firing was another Potassium Nitrate/Sucrose rocket. This was a build of one of Richard Nakka’s design (his website http://www.nakka-rocketry.net is a great resource for sugar based propellants) This time we mixed the propellant there at the MTA. Chris was really helpful with this and he showed us how to prepare the propellant. This propellant type “rocket candy,” while being one of the most widely used armature propellants, has never caught on strongly at the RRS. Our three Pyro-Ops who where there that day, (Jim Gross, and Richard and Maryann Butterfield) where keen to observe the process and be satisfied that the propellant could be safely made at the MTA. When we fired the rocket the bolts retaining the nozzle sheared clean off and the nozzle was launched upwards at high speeds. We couldn’t find it afterwards. This happened because the bolts needed to be steel but when I originally put it together I forgot to check and used some bolts I happened to have laying around that turned out to be zinc and they could not stand the load.

 

Mark Smith a USC alumni showed up with a solid propellant aerospike rocket motor with a molybdenum spike. He hopes to research ways of reducing erosion of aerospike. We didn’t have time to get to his rocket, maybe next time.

 

-Richard Garcia

 

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