Christopher wanted to do a science project on making rocket motors. He wanted to do and experiment making sugar motor where he would increase the catalyst and chart how the thrust changed. While I appreciated the enthusiasm that he brought to the proposal, I had to tell him that what he would be doing was essentially finding where a motor became a bomb. I suggested we talk to some of the people at the launches we attend that actually make motors to see if there was a way he could so something similar.

We ended up talking to several people and the consensus was that building actual ammonium perchlorate motors with formulas that had know characteristics would be safer than any other experimental chemistry (like sugar motors). We were able to find a member of our club that had experience and a setup to make the propellant that agreed to help him so I agreed that he could move forward. I didn’t what him to just do some motor experiment because it was cool with no real purpose so I told him in order for me to support him, he would have to come up with a multi year project that would include building and launching a standardized satellite platform, CanSat, CubeSat, etc., to a significant altitude an perform an experiment. He agreed, so we were ready to proceed.

The first hurtle was to satisfy the science fair officials that the experiment was sound, and would meet the ISEF safety requirement. To do this Christopher collected the relevant ATF and NFPA regulations and submitted his proposal. It was initially rejected because the proposed propellant weight exceeded the limit they were using which was based on the old propellant guidelines. Once he pointed this out and let them know he had a Junior Level 1 certification, they agreed to allow us to proceed.

While his experiment was rather simple, it involved several components that gave it some depth as a learning experience. First he had to design and build a test stand that would be safe and stable. He did this by looking at test stands he found around the internet and adapting components of the designs into something he could make. He then had to come up with the electrical circuit that would measure the force and send the data to a computer for collection. Even though there were off the self systems that would do this, they were expensive and I wanted him to have to do some of the engineering himself.  To our great fortune, we found a group that had been working on an open source test stand solution using an Arduino board and a bread board amplifier circuit as well as having written a software solutions for the board and recording the data on the computer.

While the project at opendesignengine.net manned by members of Mach30.org, had been designed for use with low power motors, they were gracious in helping him understand how to build the latest version of the circuit and how to modify the software to measure the higher levels of thrust. They were also very helpful in trouble shooting the calibration of the system once it was assembled. This gave Christopher a tremendous lesson in what open source is all about and how a community of people can come together to make incredible things happen!

The next challenge in the project was making the motors to be tested. Our long time friend Mitch Guess, who is an experienced motor maker, agreed to help him though this process. Mitch helped Christopher decide on a motor formula that was well know and stable and hosted him in is lab to make the motors. Using a custom made spreadsheet, he explained to Christopher how the measurements must be made using the molecular weights in order to get the right proportions. They then worked together to mix the propellant and cast them into the proper sized liners for the casing he would be using.

to be continued...