July 28, 2012

Hovercraft WARNING: Building and using a Hovercraft may be Dangerous. Use these instructions at your own risk.

Material • • • • • •

1 – Electric Leaf Blower - 12 Amps, or 300+ CFM, or 200+ MPH 1 – 100’ 12/3 or 14/3 Highly Rated Extension Cord 1 – 4’ x 4’ x ½” piece of Plywood 1 – 6” x 6” x ¼” piece of Plywood 1 – 5’ x 5’ x 6+ mils Sheet of Plastic or Tarp 1 – D-Ring to attach Pulling Rope to 4’ Disk

To Mount 6” Disk: •

8 - ½” small wood screws

To Mount D-Ring: • • •

• • • • • • • • • • • • • •

2 - 1” Flathead Machine Bolts 2 - Lock washers 2 - Cap Nuts

13 ’ - 3/8” Rope Jig Saw Bits for cutting Plywood Counter-sink bits 20’ of Duct Tape ¼ - 3/8“ Stainless Steel Staples 2 Handles for Carrying Paint for Plywood (paint Top only) Plastic Lawn Chair Safety Glasses (wear these while building the Hovercraft) Hearing Protection (use this whenever the Leaf Blower is powered ON) Helmet (wear this whenever on the Hovercraft) Wood for adjusting height of Leaf Blower Wood for mounting chair. Screws for two items above.

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Tools • • • • • • • • •

Jig Saw Drill Drill Bits Counter-sink bits Wood File Hacksaw 2’ x 4’s Sharpie Marker General tools: Screw Drivers, Pliers, Scissors, Tape Measure, etc.

Safety • • • • • • • •

Safety Glasses (wear these while building the Hovercraft) Do not use any power tool without adult supervision. Hearing Protection (use this whenever the Leaf Blower is powered ON) Helmet (wear this whenever on the Hovercraft) Ride the Hovercraft only in a safe place. Do not ride the Hovercraft in a s street or near moving vehicles. Do not stand on the Hovercraft – keep your center of gravity low. When pulling the Hovercraft: o Do not swing it into any person or object. o Do not swing it hard enough to cause the rider to lose their balance or to fall off.

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Building Instructions 1. Cut a 4’ Diameter Disk out of the 4’ x 4’ plywood.

2. File the top and bottom edge of the plywood (just a little) to remove the sharp edges as shown:

Unfiled Edges 1/2”

Unfiled Edges

Filed Edges

Filed Edges

3. Use a piece of the scrap plywood to experiment with making a hole for the Leaf Blower (LB) . a. Trace the end of the LB on the plywood. b. Drill a Pilot Hole for the Sabre Saw. c. Cut-out hole. d. Try another hole but make it bigger so that you can line it with a pool noodle, and see if it’s easier to fit the LB. e. How do you keep the LB from going too far into the hole? May have to shim-up the LB. f. You want the hose (or nose) of the LB to be flush with the bottom of the plywood. 3

4. Then make the real hole for the Leaf Blower centered about 9 – 12” in from the edge of the 4’ plywood Disk. Move it in to towards the center of the Disk if the Leaf Blower will not all fit onto the 4’ Disk.

9 – 12” 4’ Diameter Plywood Disk

Hole for Leaf Blower 5. If there are any sharp edges on the plywood, then file them down. 6. Center the roll of Duct Tape on the edge of the plywood, then run a strip of Duct Tape completely around the edge of the plywood. Then fold down the Duct Tape on the top and bottom side of the plywood. 7. If one side of the 4’ plywood Disk is better than the other, then make that the Top Side.

8. Do this before you put on the plastic! a. Attach the D-Ring to the front of the Top side of the 4’ Disk. Counter sink the head of the bolts on the Bottom side of the plywood, and ensure that the head of the bold is not exposed above the surface of the plywood. Use the Lock washers and Cap Buts to boltdown the D-Ring. b. Cut the legs off the Lawn Chair so that the seat of the chair will sit directly on the plywood. c. Devise a mount for the chair and attach the mount to the plywood. Ensure that none of the mounting hardware is exposed above the surface of the Bottom side of the plywood, or it will damage the plastic that will be attached later, and it could damage the floor.

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9. Cut and Attach the plastic: a. Place the Bottom side 4’ plywood Disk onto the 5’ x 5’ plastic, and center it. The plastic shown here is Black – yours may be clear or a different color. b. Use a 4” spacer to trace a 4” ring, around the 4’ plywood Disk, onto the plastic. c. Remove the 4’ plywood Disk, and cut the plastic following the line just traced above. d. Place the Bottom side 4’ plywood Disk onto the plastic circle, and center it.

4”

4”

e. Easily pull the plastic up over the 4’ Plywood Disk. DO NOT Stretch it. f. Staple the plastic every ~3” (~1” from edge of plywood) to the Top of the 4’ Disk. g. Use Duct Tape to tape the cut edge of the plastic down to the plywood.

Black Plastic

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10. 6” Plywood Disk a. Make a 6” Plywood Disk (circle) from the 6” x 6” ¼” piece of plywood. b. File the edges of the disk to remove the sharp edges. c. Counter-sink 6 mounting holes ~ ½” in from the edge of the Disk as shown:

d. Place the 6’ Plywood Disk so that the Bottom is up (plastic side is up). e. Using the 1/2” wood screws, fasten the 6” Disk (over the plastic) to the center of the 4’ Disk. f. Ensure that none of the screw heads are exposed above the surface of the plywood or they will scrape the floor.

16” 18”

6” Disk Leaf Blower Hole underneath Plastic (you can’t really see it.) 11. Vent Holes a. Use a template to mark six (6) 2” holes about 2” from the 6” Disk and centered around the 6” Disk. Then cut them out, exposing the plywood as shown:

2” Vent Holes

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12. Perform a Quick Check a. Place 4’ Disk with Top side up (plastic side down) b. Insert the Leaf Blower into the hole in the 4’ plywood Disk. c. Turn ON Leaf Blower, and verify that the 4’ Disk floats and moves easily. d. Turn OFF Leaf Blower. e. Have someone sit in center of 4’ Disk. f. Turn ON Leaf Blower, and verify that the 4’ Disk floats and moves easily. g. Turn OFF Leaf Blower. 13. Attach Rope to D-Rings 14. Finalize the mounting of the Leaf Blower so that it is secure to the 4’ Plywood Disk and that there are no air leaks.

Have Fun, and Be Safe!

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