I was very excited about this project because I had decided to use air power for this based on the great animation the Spooky FX hanging man exhibited which was also pneumatic, and I had in mind the perfect air cylinder for the job. For many years now I have been waiting for a project that called for a short but wide cylinder, such as this prop would need, so I could try out a foot operated pump as the cylinder. I had never seen one used for a prop before and was curious if it would hold up like the standard steel tire pump does for so many of my other animatronics. After doing some rather exhaustive layout of the mechanics of the hanging guy I determined on CAD that the size of this cylinder would be perfect! So now that I have the beating heart of the thing as it were, I am ready to begin in earnest assembling a fully animated jerking, gurgling, hanging man. Just a note here as to the needed width of this ram, or at least the perceived needed width is due to the simple fact that an air cylinder of a wider width and short stroke will trigger to full extension much quicker than a smaller cylinder   cylinder while under load. Without knowing how much the legs of my guy will really weigh with his foam build-out, clothes and shoes on, I had to imagine that I would need this fat air cylinder to move the legs of the guy quickly since I was using a very short lever to activate it's legs.  

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  I learned that this foot pump will not work as an air ram, or at least won't continue to work at the pressure level I had to use to trigger the event here which was 28 pounds. For some reason the air began right away to leak past the seal and the cylinder was rendered useless in only a few cycles. 

   The fun continued on this project, as once the foot pump failed, I had to move on to another idea. Next I decided to cut down the length of a standard bicycle pump for the length needed here, threaded the end of the rod at the right length to match the overall length and throw of the foot pump the prop was designed around.

---Tragically---

   Once again I learned that this tried and true bike pump air cylinder will not work on this prop. Simply put, when the cylinder is turned upside down, as needed in this design, the oil that keeps the leather seal lubed inside runs out the cylinder and down the shaft, causing the cylinder to lose it's seal! The cylinder  is slick though and I am sure it will work just fine on another prop if vertically mounted. So all that wasn't totally for nothing, but dang, after the first 10 or so major setbacks on this prop it did seem rather a bleak thing to happen, sending me back to the drawing board once again.

   In the end I wound up ordering an industrial two way air cylinder that would work in any position forever. So much for SAVING money!  The cylinder shown here was a 75MM (3")  stroke X 40MM (1 9/16") Diameter unit from Kreepers.Biz.

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   It wasn't cheap, but it was certainly 20 times stronger than this prop will ever need, so at least I should never have to worry about it!