Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!europa.asd.contel.com!gatech!hubcap!ncrcae!ncr-sd!sagpd1!monty
From: monty@sagpd1
Newsgroups: comp.robotics
Subject: Re: Small Hovering Hobby Robots
Message-ID: <1991Jun20.155520.12703@sagpd1>
Date: 20 Jun 91 15:55:20 GMT
References: <00949D78.A594B600@vms.csd.mu.edu> <25523@well.sf.ca.us>
Reply-To: monty@sagpd1.UUCP (Monty Saine)
Organization: Scientific Atlanta, Government Products Div, San Diego, CA
Lines: 35

In article <25523@well.sf.ca.us> bkoball@well.sf.ca.us (Bruce R Koball) writes:
>Re: small RC hovering models...I saw an amazing example of same at a
>conference last fall...fellow had purchased it in Japan...consisted of 4
>small PM/DC motors (the type you see in cheap toys) mounted on a
>styrofoam ring about 12" in dia.... each motor had a plastic prop about
>4' in dia....control electronics and batteries (about 8 oz. worth) in
>the center...stability was accomplished via a small *GYROSCOPE* (no
>kidding!) in the center pod...gyro had small, dual-gimbeled flywheel
>with some sort of proportional sensor feedback (don't recall the
>method)...gyro parts (except the flywheel and bearings) were
>injection-molded plastic....owner said the whole thing cost about $400
>US....I might be able to track him down if anyone's desperately
>interested....reply by email 
>

	This discussion of hovercraft has made me think of a possible
    way to increase stabilty. What if some or each of the "props" that
    are supplying the air pressure were sort of wheel shaped. The spokes
    would be the lifting/pressure blades and the outer ring would act like 
    a gyroscope. This would make banking difficult ( unless the whole motor-
    blade assembly was gimbled), but could not steering be accomplished by
    vectored thrusts? Also if the vehicle had a "skirt" that was inflatable
    could you not use helium as the inflating gas to produce additional lift?
    I don't propose a huge gas bag, just a compromise to add additional
    "lift". In a rc vehicle you would run the props at a constant speed and
    use servo controlled air valves to vary the amount of lift. For that
    matter it might be better in a full size vehicle to run the props at
    a constant speed to aid in noise  and smog emmision control. The props
    could be variable pitch in a full size vehicle or a venting system could
    be used.


    Just thoughts,

    Monty Saine