Hey look Hovercrafts are boats

Discussion in 'Boatbuilding' started by Boston, Mar 13, 2011.

  1. Boston

    Boston Previous Member

    Ok so just how much of a dork am I

    I'm building this thing ( ya I got the idea off the net ) for the upcoming star trek convention, Its never going to see water and its only gotta work for a few minutes at a time, power is electric and the big ducted fan is basically just for show. I'm going with foam core construction with something like vinyl goo over a layer or two of either glass or something else. which brings us to my first question, what to use that's cheap effective and gives enough of a finish to fool the occasional bystander. Oh and its going to be dressed up as a Borg thing so lots of superfluous tubes and lasers

    whats a cheap option for getting a good finish over foam, my first thought was paper mache but I'm not sure that would be strong enough, particularly on the bottom which I might just be using 1/4 inch on.

    ideas or jibes cause I'm sure some of you are laughing your asses off right about now.

    [​IMG]

    friend of mine and I are about done with the locutus outfit and now for the machine

    according to the hovercraft calculator at 12x8 and 500 lbs I'll need something like 1.25 hp to get it off the ground, my options are on board batteries if I want electric, so I have several 24 volt motors floating round 10 amps or about 1/3 hp each I'm thinking four of those two to a lift fan one lift fan on each side. I've no clue how many HP it will take to make it go on pavement or grass but its gotta be less than a couple, where's Gorge when you need him eh

    I suppose I could just put casters under it but thats not quite what I"m after
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    AC duct mastic or drywall seam compound. Both are water soluble, so clean up is easy, though if you're going to put it in water, it will not survive long.

    I would think the Borg would have anti-grav technology, which pretty much makes hovercraft stuff so 20th century.
     
  3. Boston

    Boston Previous Member

    I've done more than my share of drywall finish and that stuffs way to brittle, also really heavy. I was thinking some kind of polyester or vinylester resin over glass maybe for the bottom, might still go with paper for the upper surfaces tho.

    gotta keep it light so it will fly as well

    if it ends up batteries and motors weigh to much I just might end up using an old lawnmower engine and a chain to drive all three fans off of

    whats the cheapest form of epoxy substitute
     
  4. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    It reminds me of some podracer from Star-Wars Episode 1. But, hmmm, it doesn't have pods...
     
  5. Boston

    Boston Previous Member

    getting some sona tubes today and picking up some foam, glue and 1/4 ply
    got my friend to sow up some skirts for the thing soon as I find some sail cloth around here so she can get started

    [​IMG]

    Ya gotta love Dawna she makes all her own stuff, its like a fashion show every weekend

    ok so guys whats a cheap option for resin cause I'm likely going to be gluing something up by tomorrow or the next day and ready for resin by the weekend assuming I can get ahold of something that fast
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

  7. rwatson
    Joined: Aug 2007
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    rwatson Senior Member

    Try Plaster of Paris - light ,easy to sand, water soluble.

    Mix in some chopped up fg fibres where it might get stressed. Varnish it, then paint it -
     
  8. Boston

    Boston Previous Member

    hmm
    still sounds pretty heavy
    its gotta be light if its going to do any hovering
     
  9. rwatson
    Joined: Aug 2007
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    rwatson Senior Member

    True, but then why even hover - just get a few electrically operated hydraulic jacks on wheels, hidden behind a skirt - or better yet a fog machine to really look space age.

    I bet the noise of a revving two stroke engine to pump air will ruin the party atmosphere, 'cause you sure aint going to lift a couple of people from a 110 power point.
     
  10. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    PVA on 'glass cloth. you'll need a fairing filler, but this could be anything light (except epoxy).
     
  11. Boston

    Boston Previous Member

    doesn't have to be all that fair

    I've got a few DC motors, I was thinking of using along with a couple batteries, it wouldn't take long to drain them but it doesn't have to work for very long anyway.

    I'm definitely considering just using casters and maybe one DC fan to inflate the skirts, dry ice seems like a pretty hip effect by the way, and easy to. Hmmmmmmm gonna have to include that as well as a car stereo playing some sound effects

    PVA eh going to have to make a few phone calls tomorrow
     
  12. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The things that guys will do to get laid . . .
     
  13. alaskamokaiman
    Joined: Oct 2006
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    Location: Palmer Alaska

    alaskamokaiman Junior Member

    cardboard and paper mache will work. use cooked corn starch instead of flour and water much stronger. I would use a leaf blower or two, auto battery and an inverter for short time run.

    You can get cardboard from an appaliance outlet and make anything.

    Dry ice will have little effect if it is in the air flow Co2 fire exhtingusher
     
  14. viking north
    Joined: Dec 2010
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    viking north VINLAND

    Boston, what are the dimensions of this machine. If it's say a 1/2 scale model, think off the shelf items. Say a kids circular plastic swimming pool inverted with the skirt attached to it. If bigger get a blow up pool or an inexpensive rubber dingy or borrow beg or steal a circular life raft and attach the skirt. Shouldn't be too complicated to build a frame assembly to install a lift fan under any one of those items. Whatever you build it must be super light as you will be very limited by lifting power. The batterys alone to provide enought power could possibly weigh too much as they will have to lift their own weight also. Why not set up a 120v lifting motor and simply have an assistant follow the machines travel with the extention cord. Thinking cap; off the shelf items-- wish i were there for the challenge of the build ---Geo.
     

  15. viking north
    Joined: Dec 2010
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    viking north VINLAND

    Boston, more food for thought, rent one of those big air moving fans 4 to 6 ft. dia. blades from the construction rental people. Dismantle the stand and make up a couple of attachment brackets and use this as your lift fan also maybe a second one as your propulsion fan. Reassemble after use and return. When you rent try to rent the most used unit as the lift fan that way if you have to bore a couple of holes they will not notice on return, just play dum as to where they came from if they do.---Geo.
     
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