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Hydraulic motors for hovercraft propulsion?

  1. Jul 30, 2009 #1
    For a proposed Hovercraft propulsion system,
    1a) Is it feasible to use separate hydraulic motors to power a) four wheels for land propulsion, b) two water propellors for water propulsion c) two lift fans d) six actuators for retracting / deploying the wheels and propellers.

    1b) Can the motors produce about 10 - 15 hp of power each, about 150 RPM?

    2) Is it feasible to use a 180 hp engine to power a hydraulic pump for all the above? Estimated hovercraft fully loaded weight 3200 pounds, speed 60 mph, hover height 1/2 inch on a 7 inch cushion, 14.5 feet long x 8 feet wide.

    3) Do hydraulic pumps have any feedback control mechanism to control the amount of torque delivered by the device (engine) powering them?

    4) Can hydraulic motors be deployed underwater ie. to power a water propeller?

    5) Do hydraulic pumps come with a pressure regulation / overpressure protection system to allow multiple devices to run at power consumption levels varying over time, as proposed above in items 1,2, and 3?

    6) Can the direction of hydraulic fluid be changed while a motor is in full operation?

    7) Can hydraulic leaking be minimized?

    8) Is environmentally friendly hydraulic fluid available, in case of spills?

    Thank you in advance for your patience and assistance. Ron L
     
  2. jcsd
  3. Jul 31, 2009 #2

    Danger

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    Welcome to PF, Ron.
    I'm not quite sure why you're asking this. The whole point of a hovercraft is that it doesn't require wheels or propellors for movement over any (reasonably smooth) surface. The props are used in the aeroplane sense, in that they force air away from the direction of travel.
     
  4. Jul 31, 2009 #3
    Danger:

    I agree with you. However, I would like to overcome the following undesireable characteristics:
    1. Noise generated by air propulsion systems (both jet and fan).
    2. Uncomfortable vibrations created by propulsion system.
    3. Lack of precision steering, especially over land. Air based controls (flaps) are insufficient.
    4. Inablility to negotiate with precision steering any boundary conditions, such as shorelines, with inclines, rough land conditions (skirts can tear), and any inclines in general.
    5. Generally inefficient power / weight ratio - not "green".
    6. Environmentally rude to neighbours - noise.
    7. Do not fail particularly gracefully during power failure over water- prone to augering in.

    I would greatly appreciate if anyone could direct me to a source that could answer my admittely nieve questions. Regards, Ron
     
  5. Jul 31, 2009 #4

    Danger

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    Strangely enough, I agree with most of your points and addressed them with a hovercraft design that I came up with about 25 years ago. Haven't had a chance to build it yet, because it'll cost a fortune.
    It behaves like a regular HC under normal circumstances. For a panic stop, you hit a brake pedal the same as one in a car. That simultaneously drops hydraulic landing gear with integrated brakes, and throws both the lift and thrust fans into reverse pitch while opening the throttle. The landing gear can also be lowered deliberately to allow taxiing in confined spaces.
    I still disagree with the 'green' side of things and noise factor though. While I'm not an expert, I don't think that much difference would be noticeable.
     
  6. Aug 1, 2009 #5
    Sorry but I can't resist a bit of *Levity* here (pun intended)
    I think the vehicle you describe is called a Pegasus (the winged horse not the missile)
     
  7. Aug 1, 2009 #6
    What your describing is not a hovercraft, but an amphibious land vehicle. Why even have it hover if its going to have wheels, that doesn't make any sense? And to answer your questions.

    1a. Yes

    1b. Yes

    2. I don't know. If might be difficult.

    3) Usually, yes.

    4) Yes

    5) The ones that don't explode do.

    6) Definitely not.

    7) What's your definition of "minimized"?

    8) Not that I know of.
     
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