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HubbardRA

Hydraulic Formulas

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HubbardRA
For those of you who are thinking of designing your own hydraulics the following formulas may help: Fluid pressure (psi) = Force (lbs.) ÷ Cylinder Area (sq. in.) Cylinder area (sq. in.) = 3.1416 x Radius² (in.) = (Piston Dia.)²x .7854 Cylinder force (lbs.) = Pressure (psi) x Area (sq. in.) Cylinder speed (ft./sec.) = (231 x GPM) ÷ (12 x 60 x Area (in.²) Pump output flow (GPM) = Speed (RPM) x Displ. (cu. In.) ÷ 231 1 Gallon = 231 cubic inches Input Hp (Power needed from engine) = psi. x GPM x .0007 Volume (in³) = Area (in.²) x Stroke (in.) Also if any of you are thinking about using a power steering pump, I was told yesterday that most pumps on mid and full size 60-70 American cars and trucks move about 2 GPM of fluid at 3000 RPM. This is only an approximation but can be used as a start. Rod H.

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Capt_Ron
quote:
Originally posted by HubbardRA: For those of you who are thinking of designing your own hydraulics the following formulas may help: Fluid pressure (psi) = Force (lbs.) ÷ Cylinder Area (sq. in.) Cylinder area (sq. in.) = 3.1416 x Radius² (in.) = (Piston Dia.)²x .7854 Cylinder force (lbs.) = Pressure (psi) x Area (sq. in.) Cylinder speed (ft./sec.) = (231 x GPM) ÷ (12 x 60 x Area (in.²) Pump output flow (GPM) = Speed (RPM) x Displ. (cu. In.) ÷ 231 1 Gallon = 231 cubic inches Input Hp (Power needed from engine) = psi. x GPM x .0007 Volume (in³) = Area (in.²) x Stroke (in.) Also if any of you are thinking about using a power steering pump, I was told yesterday that most pumps on mid and full size 60-70 American cars and trucks move about 2 GPM of fluid at 3000 RPM. This is only an approximation but can be used as a start. Rod H.
Rod, I've been playing with a couple of pumps with the idea of cobbing together a light weight fel w/4n1 to pick up piles of leaves. One of the pumps came off an 85 Honda Civic and is a 3 section cast iron design that turns the wrong direction. I checked the output originally with the one revolution/cubic measured method which yeilded 3.42 gpm @ 1800 rpm. Later I took it apart and measured the gear width, diameter, and length. Plugging these into the equation and x 47 for 1800 rpm resulted in 3.6 gpm. I think that it will have enough gpm to power my design. Now about the rotation...fixed that too. The end section houses passages for the output, inlet, and pressure relief valve. I turned a plug on the lathe to press into the inlet and outlet ports sealing them off. The center section is 1" thick and was drilled, tapped, and milled to accept a straight thread o-ring fitting. The original output side was milled to match the input side, Finally a plate was bolted over the original connections to make it look better. Now the pump works in either direction and is smaller and easier to mount. Looking at the posibility of building my own spool valves and cylinders too. I have far more time than money and the equipment to do the work This fel is going on an 11hp verticle shaft engine, thinkng of designing a pulley drive on the flywheel end like the horizontal shaft engines. just rambling, Cspt Ron

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HubbardRA
Go for it Ron! I have much more fun building things to upgrade my machines than I would ever have by just leaving them stock and looking at them. Ya got ut use them, abuse them, and fix them up better. Enjoy the challenge. Rod H.

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Capt_Ron
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Originally posted by HubbardRA: Go for it Ron! I have much more fun building things to upgrade my machines than I would ever have by just leaving them stock and looking at them. Ya got ut use them, abuse them, and fix them up better. Enjoy the challenge. Rod H.
Thanks Rod. I decided to repair the 36" mower deck and put it back on while I gather parts and pieces for the fel. Besides I won't really need the fel until next year. I had to replace the clutch arm bushings and reweld the shaft. The other tractor that I have has a 45" deck w/high lift blades and covers me with dirt so I like the Wards better. Just in case though I'm building the fel to fit either tractor. Capt Ron (spelled right this time)

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HubbardRA
Ron, I use my 61 Wards for tractor pulling, and my AC 716 for mowing and other yard work. I am planning to build the FEL for a Sears (Roper) that I have sitting in the back yard. The ignition on this one died so I am replacing the Tecumseh with a Kohler, and then going to build the loader. This Sears has the high/low range three speed tranny which should be good for moving loads. Rod H.

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