Hydraulics for Dummies
Hydraulics for Dummies
Hi there Joe,
To get any horse power out of a weed wacker motor, it needs to be at around 8000 - 10,000 RPM. At this RPM they develop abt 3 HP.
The old Mac 101 Go-Kart engine produced around 15HP at 10,000RPM hence the large ratio chain drive.
A miss conception with hydraulics is that you need pressure as the main component. This is wrong. You need FLOW.
Once you know how much oil you need to move around, you then need to know how much power will be required to get the job done.
You will also have to choose a high pressure or low pressure. Low = 1500psi
High = 2500psi. There are other pressure ranges, but for a fixed system, like the one we are talking about, these will do.
So, to find the power required to push the oil around AT the FLOW we need, we use this formula:
hp = gpm x psi x .000583
As you can see in this relationship that an increase in either pressure or FLOW will increase the horsepower.
The GPM (gallons per minute) will be decided by the driven MOTOR, at the rotor head. Then you need a PUMP to provide the FLOW required to turn your MOTOR at the speed you want.
There are many combinations of MOTOR and PUMP available. The biggest stumbling block I see with a GoPed motor is the RPM it has to turn at to develop the house power required.
On a shaft drive system this can be accommodated with a chain drive reduction and connected to the shaft etc.
The same woud apply to a hydraulic set up. A small redrive would be needed to reduce the output RPM to about 1000RPM, like around 10:1.
This ends section 1 of this primer.