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
                 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
                   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
                     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
                                             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
                          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
•   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

October 2004                                     Patrick Wenzell
               The Hovercraft Drawings

October 2004          Patrick Wenzell
                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
  • 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
                   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
                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
            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
               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
  • Sand the inside of the intake hole
    to widen and make a very tight fit
  • Insert blower attachment

October 2004                   Patrick Wenzell
      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
                      Center Seat on Riser

 • Sand Interlock between Riser
       – 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
      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
                Attach Plastic Envelope
 • Fold edges a couple of times for
 • 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
                 More Duct Tape…

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

October 2004            Patrick Wenzell
               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’
  • Use 3” square template tied to
    1’ string & utility knife

October 2004                 Patrick Wenzell
       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
 • Tape Coffee Lid Washer
       – Around and across

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

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

October 2004    Patrick Wenzell

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