[omi] hydraulics - order of technology acquisition

I think before jumping headlong into potentially a $10k project, we should figure out how to put together a hydraulic system. For the basics of fluid control, pneumatics are very cheap and simple compared to hydraulic systems. There is a compressor at the shop, and I have a small air cylinder we could use to do some closed-loop actuation tests. Also a few 24V air valves, and I'll be ordering a 24V - 15A power supply and some more air equipment that should round out the required bill of materials when i get back in town. So a quick and dirty control project using pneumatics would be very beneficial for us even though the behavior is alot spongier due to the compressibility of air. Afterall, that's what they used for robot air hockey. One we get the taste of controlling valves to actuate 2-way cylinders and/or motors, we can raise funds for a 12V hydraulic power unit which can be had for about $300 including reservoir and some valving. From there all we need is some hose and tubing, and I propose both a piston (~$60) and a motor (~150) so we can gain experience with the whole power loop needed for various projects. This is applicable to the CEB press, reverse trike, rocket thrust vectoring, well drilling, you name it. Just getting this basic technology under our belts would be pretty sweet and informative for alot of our people. I bet we could build a small drill rig for under a thousand bucks - groundwater harvesting, foundation drilling, secret stashing of cannon, plenty of options there. Anyway, just getting started is going to be a task of its own and I would propose picking something with a relatively short design-build-redesign cycle so we feel rewarded at regular intervals with a working machin e. On safety, I'm looking into veggie oil etc as hydraulic fluid since that stuff can be pretty nasty. Below are some links. Biodegradable hydraulic fluid: http://www.research.psu.edu/capabilities/documents/biohydraulic.pdf more info on different biofluid products: http://www.technologylubricants.com/Technical/Rexroth_90221_1.pdf On another note, I returned my car to an operational state recently and having never worked on a car (this was my first time to even change my own oil) it was interesting to open the hood with a freshly installed knowledge of some of the components, and actually feel like I had a rough idea of what was going on and how to debug the mechanical/electrical problems that I encountered. A cool project if we ever do incorporate an internal combustion engine would be a custom ECU using whatever standard automotive sensors etc we can get off the shelf and some creative 8-bit math. Any objections to designing around second-hand 90's volvo components? Cheers, Hol