I wanted to post an update about the exhibit that Ryan Leonard and I designed and built for the SEE Science Center as Ryan’s Eagle Scout project back in September of 2016. The exhibit is holding up well, with only a few adjustments, a couple replacement rockets, and some routine pump service. One thing that I was very curious to discover was how much do our launchers get used? How many launches before the pumps need service? How many launches before I have to replace the rockets? How durable are our standard* launchers?
To answer all of these questions, a way to count the number of launches over time was required. To design the counter, I started where I usually do – my “inventory” in my basement. I found I had a couple of suitable pressure switches – one per launcher, four push to connect tube fittings, a couple Tee fittings, along with a digital counter. I designed around the parts I had available to create a housing for the pressure sensors & the digital counter, and came up with the little red 3D printed housing pictured above on the lower right of the image, and seen between the two launchers. The counter has a built in lithium battery and will last 5+ years, so simply connecting a pressure actuated switch that increments the count when the pressure drops during each launch does the trick. No external power source required, no concern about loosing power, I like simplicity & reliability.
The counter was installed on January 25th, 2018, and as of this afternoon, has tallied 5,880 launches in just 50 days! That’s an average of 58 launches per day, for each launcher! So, extrapolating back to September of 2016, roughly 550 days, that means each launcher has had over 32,000 launches! I love good data. I plan to make regular checks as time passes and try to keep a service record for how long all the components last. Update – counter at 11,380 end of day 5/10/18. We are still averaging 50 launches per day on each launcher.
I also wanted to thank Lezyne for their donation of service parts and seal kits for the pumps in return for some data on how well the pumps hold up to dealing with thousands of kids using them every year.
*The launchers use all of the standard components as our CAR v2.2 launcher, with a couple additions; they are bolted down to the floor to allow the tensioning of the guide wires, the launch tube is customized to clamp the guide wire, a pressure gauge was added in place of the over-pressure valve – which was relocated under the control panel, and the rocket nose and fins are custom designed & 3D printed with built in wire guides but use our standard ABS body tubes.