How to Build a Hover Craft - Tea by fjhuangjun

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									How to Build a Hovercraft
               How to Build a Hovercraft


                                             Special Thanks to
                                              Mr. Joe Baker @
                                             Dickerson Middle
                                             School for the idea

                              A Cobb County
                    Technology-Based Integration School




October 2004              Patrick Wenzell
2
                 Primary Steps & Materials
 • Make Circular Platform                  • Required Materials:
 • Work from Center to:                       –   4x4’ ¾” Plywood
       –   Drill holes per plan               –   6x6 8mil Plastic
       –   Add riser for seating              –   2x2 ¾” Plywood
       –   Mount seating                      –   12” ¾” Diameter Particle Bd.
       –   Mount blower                       –   1 ½” x 3/8” Carriage Bolt/Nut
       –   Attach envelope                    –   2 ½” wood screws
 • Duct Tape Edges                            –   Coffee Lid
                                              –   Lots of Duct Tape
 • Cut & Attach Envelope                      –   Sandpaper/Sanding Block
 • Paint as you wish…                         –   Paint


October 2004                       Patrick Wenzell
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                   Tools Required

 •   Jig Saw                               • Tape Measure
 •   Circular Saw                              • Tri-Square
 •   String                                  • Utility Knife
 •   Drill & Bits & Screws                    • Chalk Line
 •   Staple Gun & Staples               • Sandpaper/Block
 •   Paintbrush & ‘guides’   … and MATH SKILLS



October 2004          Patrick Wenzell
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                     Experimental Hovercraft

• Goal:                                    • What I learned:
      –   Understand textual plans            –   How to outline a step by step plan
      –   Convert into a project plan         –   How to layout the plan on wood
      –   Manufacture components              –   How to use certain tools
      –   Assemble components                 –   How to make ‘jigs’ to guide tools
      –   Fine tune craft                     –   How to troubleshoot problems
      –   Test and experiment                 –   Not to get all my friends over to
      –   Create interactive experiments          see it work BEFORE I test it first




October 2004                      Patrick Wenzell
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                                             Project Plan
 •    Step 1
 a.   cut a 2’ section of string (with a little extra).
 b.   tie the string to a pencil and the other to a tack or nail.
 c.   place the tack/nail in the center of the board.
 d.   keeping the string tight, draw a circle.
 •    Step 2
 a.   cut a circle with a jigsaw.
 •    Step 3
 a.   measure the diameter of your vacuums hose and drill the hole size accordingly.
 b.   drill a hole using the 1 ½ or appropriately sized bit approximately 1 foot from the center of the hover craft.
 •    Step 4
 a.   sand the edge of the disk on the top and bottom.
 b.   tape around the disk.
 •    Step 5
 a.   drill a 11/4 hole in the center of the plywood for attaching the plastic skirt
 b.   cut the plastic sheet into a 54 x 54 square and lay it out on plywood disk
 c.   the carriage bolt washer coffee lid apparatus will be used to hold the plastic sheet to the plywood disk.
 d.   Poke small hole in the center of the plastic sheet.
 e.   Reinforce the hole with duct tape and then pass the bolt through the plastic sheet and bolt securely to the ply wood disk




October 2004                                      Patrick Wenzell
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                          Project Plan (continued)
•   Step 6
•   a.    trim the plastic sheet into a circle a little bit larger than the ply wood disk.
•   b. The plastic should be cut approximately 2 inches larger than the disk all the way around
•   Step 7
•   a.    looking down on the hovercraft plastic side up draw 3 x3 squares on the plastic approximately 1 ft from
    the center with 120-degree angles between each square.
•   b. The holes should not be directly above the hole where the shop vac will be attached
•   c.    Space the shop vac hole between two of the square holes .
•   d. Use scissiors to cut
•   Step 8
•   a.    over lap the plastic onto the opposite side of the ply wood disk leaving some play in the plastic .
•   b. staple the plastic to the ply wood on the top all the way around the disk leaving about 11/4 gap between
    staples.
•   Step 9
•   a.    wrap duct tape at least 2 times around the edges for protection.
•   Step 10
•   a.    place chair centered on ply wood disk.
•   b. Place the shop vac or any blowing device (leaf blower/ air blower for air track behind the chair.
•   c.    Connect the hose of the vacuum to blow the orifice and attach the other end of the hose to the hole on the
    hovercraft.




October 2004                                     Patrick Wenzell
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               The Hovercraft Drawings




October 2004          Patrick Wenzell
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                Layout Circle on 4x4 Plywood
  • Find center of square
  • Tie pencil to nail in center of square
  • Adjust string to desired radius –                                        120o      BACK

        – 2’ = ½ of diameter = 4’ : 2*r = d
  • Draw Circle                                                                  Blower Intake
                                                         120o
  • Go ahead and layout:                                          Center Point
        – Label Front/Back
        – Blower intake
        – Vent locations 120o,                           Lift Vents         120o
               • 1’ from center                    FRONT
               • At least 1’ from Blower Intake
               • 2 rear, 1 front


October 2004                           Patrick Wenzell
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                   Build a Jig to Guide Saw

  • Notch the end of a board to fit lip on
    guide of saw
  • Drill hole to set blade at 2’ from center
        – Hint, on a 4x4 square, center is exactly
          2’ from perpendicular sides
  • Nail to center of 4x4 sheet
    • Note: Safety Goggles & Mask
      are required for protection!!!



October 2004                       Patrick Wenzell
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                Cut a 4’ Diameter Circle


      • Start at the edge
      • Slowly and evenly cut
        the circle using the guide
      • Repeat to make even




October 2004               Patrick Wenzell
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            Smooth and Tape the Circle Edge

  • Sand the edges
        – 100 grit
        – Round edges to protect plastic
  • Apply 3 layers of duct tape
        –   Cut about 1’ sections
        –   Apply tangentially to Top
        –   Fold over edges
        –   Repeat from Bottom
        –   Final layer center around edge
            and seal top and bottom


October 2004                     Patrick Wenzell
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               Everything Must Fit Smoothly

  • Drill 3/8” hole for carriage bolt in
    center of circle
  • Drill hole for intake slightly
    smaller than the diameter of the
    blower
  • Sand the inside of the intake hole
    to widen and make a very tight fit
  • Insert blower attachment




October 2004                   Patrick Wenzell
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      Make Template, Build & Attach Riser

 • Riser is 2 pieces of scrap wood
       – Model with cardboard, first
       – Layout and cut notches to
         provide access to center bolt
       – Notch both pieces to interlock –
         for strength and stability
       – Screw in from bottom




October 2004                   Patrick Wenzell
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                      Center Seat on Riser

 • Sand Interlock between Riser
   components
       – Must be smooth
       – Must be level
 • Center 12” Seat on Riser
 • Attach with Screws into the riser
 • Can cover seat with foam
       – …or just paint




October 2004                 Patrick Wenzell
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      Cut Plastic 2-3” Larger than Platform

  • Plastic provides the Envelope
    to provide lift for hovering
  • Set the platform on plastic
  • Cut circle around platform
    about 3” from the edge
  • Use scissors or utility knife




October 2004             Patrick Wenzell
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                Attach Plastic Envelope
 • Fold edges a couple of times for
   strength
 • Staple every ¼” to edge
 • Reinforce center and perimeter of
   plastic with duct tape
 • Puncture small hole to receive 3/8”
   carriage bolt
 • Attach Coffee Lid
 • Secure with coffee lid, washer & nut




October 2004                 Patrick Wenzell
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                 More Duct Tape…

 • Duct tape, same as before
   over the stapled plastic
 • Mount 100mph blower




October 2004            Patrick Wenzell
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               Cut Holes for ‘Lift’ Factor
  • Place platform upside down
  • Center plastic over platform
  • Draw 3 - 3” squares on the
    plastic approximately 1 ft from
    the center at 120-degree angles.
  • The holes should not be directly
    above the intake hole where the
    blower will be attached – 1’
    away
  • Use 3” square template tied to
    1’ string & utility knife


October 2004                 Patrick Wenzell
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       Reinforce Holes – More Duct Tape…

 • Tape edges of square cutouts
 • Tape front and back of edges
       – 3” pieces of tape
       – Tape edge of cutout, then fold
         over to reinforce inside
       – Especially the corners of the
         cutouts…
 • Tape Coffee Lid Washer
       – Around and across


October 2004                   Patrick Wenzell
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               Ready for Testing & Tuning

  • Do Not Call Your Friends, Yet!

  •   Two people lift platform
  •   Another removes sawhorses
  •   Place gently on clean floor
  •   Test first w/o pilot
  •   Test next w/light weight pilot
  •   UP & DOWN ONLY!!!!!!!!!!
                For now…..

October 2004               Patrick Wenzell
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                  Problems Encountered…

  • Problem                              • Solution
        – Coffee can lid ‘washer’           – Re-attached/Re-inforced w/
          collapsed                           Duct Tape
        – Blow out on side                  – Patched with Duct Tape
        – 5” lift in back, 3” in front      – Reduced back to 3” lift
        – Bumper creates imbalance          – Removed bumper
        – Blow out creates imbalance        – Fixed blowout with tape




October 2004                    Patrick Wenzell
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      The Hardest Part of this Project was…




October 2004       Patrick Wenzell
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The Most Fun I Had With This Project was:




October 2004    Patrick Wenzell
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