Now. a bit of hydraulic mathematics done by a person who has never-ever done that before.

I tried to figure out what kind of pressures and fluid flows is this about.

I also found out that there are a lot of www sites that have calculators for this but they are almost all talking about inches....

Here is an illustration I draw for myself to figure that out

First I tried to calculate the displacement for one degree rotation angle with the following dimensions:

Shaft diameter: 20mm

Cylinder diameter: 100mm

Cylinder height: 100mm

After some calculation the displacement came into a VERY comfortable figure 2.09 cubic centimeters.

After that I decided that one degree would cause 10 mm movement on the end of the leg. So for every centimeter there is a displacement of 2 cubic centimeters. Just for pure luck the leg is about 50 centimeter long in this case - which is near the length I like.

Now, if there is a pressure of 1 kilogram per square centimeter then the force at the end of the leg will be 2 kilograms.

With those dimensions of the actuator I need a pressure of 25 kilograms per square centimeter to be able to lift 50 kilograms.

Now I need Your opinion on a few things here:

1. are my calculations and estimation even near what that could be in reality ?

2. is a pressure of 25 kilograms per square centimeter manageable ?

Thanks for reading !

Edit: About using water as hydraulic fluid. In Finland we must add some antifreeze to it. A bio version of that would be Vodka !