2. How to Build a Hovercraft

3. October 2004 2 Patrick Wenzell How to Build a Hovercraft A Cobb County Technology-Based Integration School Special Thanks to Mr. Joe Baker @ Dickerson Middle School for the idea

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

5. October 2004 4 Patrick Wenzell Tape Measure Tri-Square Utility Knife Chalk Line Sandpaper/Block … and MATH SKILLS Tools Required Jig Saw Circular Saw String Drill & Bits & Screws Staple Gun & Staples Paintbrush & ‘guides’

6. October 2004 5 Patrick Wenzell Experimental Hovercraft Goal: –Understand textual plans –Convert into a project plan –Manufacture components –Assemble components –Fine tune craft –Test and experiment –Create interactive experiments What I learned: –How to outline a step by step plan –How to layout the plan on wood –How to use certain tools –How to make ‘jigs’ to guide tools –How to troubleshoot problems –Not to get all my friends over to see it work BEFORE I test it first

7. October 2004 6 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

8. October 2004 7 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 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.

9. October 2004 8 Patrick Wenzell The Hovercraft Drawings

10. October 2004 9 Patrick Wenzell Layout Circle on 4x4 Plywood Find center of square Tie pencil to nail in center of square Adjust string to desired radius – –2’ = ½ of diameter = 4’ : 2*r = d Draw Circle Go ahead and layout: –Label Front/Back –Blower intake –Vent locations 120 o, 1’ from center At least 1’ from Blower Intake 2 rear, 1 front Lift Vents Blower Intake Center Point 120 o BACK FRONT

11. October 2004 10 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!!!

12. October 2004 11 Patrick Wenzell Cut a 4’ Diameter Circle Start at the edge Slowly and evenly cut the circle using the guide Repeat to make even

13. October 2004 12 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

14. October 2004 13 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 blower Sand the inside of the intake hole to widen and make a very tight fit Insert blower attachment

15. October 2004 14 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

16. October 2004 15 Patrick Wenzell 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

17. October 2004 16 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

18. October 2004 17 Patrick Wenzell 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

19. October 2004 18 Patrick Wenzell More Duct Tape… Duct tape, same as before over the stapled plastic Mount 100mph blower

20. October 2004 19 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’ away Use 3” square template tied to 1’ string & utility knife

21. October 2004 20 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 cutouts… Tape Coffee Lid Washer –Around and across

22. October 2004 21 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…..

23. October 2004 22 Patrick Wenzell Problems Encountered… Problem –Coffee can lid ‘washer’ collapsed –Blow out on side –5” lift in back, 3” in front –Bumper creates imbalance –Blow out creates imbalance Solution –Re-attached/Re-inforced w/ Duct Tape –Patched with Duct Tape –Reduced back to 3” lift –Removed bumper –Fixed blowout with tape

24. October 2004 23 Patrick Wenzell The Hardest Part of this Project was…

25. October 2004 24 Patrick Wenzell The Most Fun I Had With This Project was: