Can anyone help me? I need to know if this idea is possible. Airboats are boats that drive from thrust produced by a car engine that turns a propellor and pushes the boat along the water or land. Can a hydraulic system be designed to propell a boat hull with an aircraft propellor. My current boat has a gm 454 with a 2 to 1 gear reduction box turning a three blade 78 inch aircraft propellor. I would need a hydraulic drive system capable of 500 h.p. with an output of 485 pounds of torque turning at 2500 r.p.m.s weighing under 750 pounds without fluids. Is this possible? Help!!!!
Thanks

This message has been edited. Last edited by: apj,

Hydraulic systems for this use aren’t nearly as efficient as a mechanical drive.

For your present system you have a loss in your PSRU of about 5% and I will give a propeller efficiency of 85%.
If you have a 500 BHP engine after parasitic losses your thrust horsepower (THP) will be:
500 x .95 x .85 = 403 THP

With a hydraulic system with 85% efficient pump and motor you have:
500 x .85 x .85 x .85 = 343 THP
You have loss 60 THP and that does not include losses for valves, lines, and the drive to match the speed of pump to engine and propeller to motor. You could increase efficieny some at extra cost.

Bud T posted this in another forum:
http://www.machinerylubricatio...intenance+Department

Thanks for the response. I am still pondering a bigger hydraulic motor to compensate for the loss. I am thinking the motor could be placed in the bottom of the boat to give it a lower center of gravity. Does anyone have any idea what a hydraulic drive unit would weigh to accomodate my application. Also what would I be looking at in total cost for a system like this. This boat would be one of kind, it would be cool to possibly have reverse for an airboat.