Introduction: Hovercraft Model No. 2
In this instructable, I'll go through what I did to acheive greater balance than the standard hovercraft. I havn't done anything for propulsion, however this can be acheived without much difficulty. One of my goals of this model was to have the ability to tote it around in my car (a saturn) as well as support my weight.
Step 1: Acquire Materials
This project isn't nearly as inexpensive as my first model. This model cost over $150 with all new parts and took about 13 hours to build and 3 trips to home depot.
3 Pre-cut Particle Board Circles 2 foot diameter (3.68 each)
5 Street Elbow 90° Fittings 3" (3.38 each)
4 Hub to Hub Elbow 90° Fittings 3" (2.19 each)
3 Flanges 3" (2.99 each)
1 Double T 3" Fitting (13.78)
1 Five and a half by 7.5 tarp 10 mil thick (6.98)
1 Ten foot PVC Tube 3" (12.08)
total cost (before tax): 158.41
The leafblower I got as a gift (my friends know me well) but it fit snuggly inside the 3" pvc tube.
Step 2: Making the Hoverpad
This step will be broken into two parts, the first prepping the pad, the second is adding the skirt. Propping the pad involve the particle board circle, a 3" hole saw and a flange. For the ease of materials we can save the wood circle cut from the hole saw for the skirt. Make sure you save it.
This step will need to be repeated for each pad you use. This model has 3 pads.
First you'll want to find the center of your particle board. Knowing the diameter of your particle board, just measure 2 lines that are that length and their intersection point is the center.
Then, on a radius line (from center to edge) measure half the distance and add an inch or 2 towards the edge. I've found in my experience that offsetting the air input towards the edge, while sacrificing balance, seems to work better.
Then, using the holesaw, cut on the marked line. Remember to save thepiece that is cut out.
Step 3: Adding the Skirt
In this step I'll describe and illustrate the most simple skirt one can make for a hovercraft, the bag skirt. This has ease of initial making, but for repairs, it takes more time and money. But for proof of concept, this works fine. Now, additional materials you'll need here, which you'll likely find around the house include twine, a permanent marker, scissors, a glass (plastic cup), and a tape measure. This step isn't hard, but time consuming to do right, especially without a compass.
Lay out your tarp, this will help you have the least amount of waste when drawing and cutting your skirts.
Measure out a length of twine greater than 1.5 times the radius of your particle board pad (mine had a radius of 12")
Tie the twine to your parmanent marker (sharpie in the image) Measure out 1.5 times the radius of your pad and mark it.
--Congrats you've made a makeshift compass--
Use your compass to trace a circle onto your tarp. (mark your center, it will help in later steps)
Cut out the circle.
Make 4 radius lines at 90° to eachother from the center point.
Measure out from the center, a distance of 1/2 the pads radius + the radius of the wodd circle you saved from cutting the hole for the flange. (In my case approx. 8.5"), mark this point
Trace your cup over the marked point attempting to make the cups center matches the marked point.
Repeat for each radius line and then cut out the traced cup circles.
Step 4: Securing the Skirt
This step I don't have many pictures of, but its fairly simple to do.
Duct tape (or sand I suppose) the edges of the wood insert from the holesaw. Then match the center of the wood insert, the skirt and the pad. Making sure the skirt is between the wood insert and the pad. Run a screw through the center to secure the skirt in place. Don't worry if its not exactly center, thats why there's extra room on the skirt.
Now rotate the skirt around the center point making sure the holes in the skirt do not line up with the hole in the pad, if they do, you won't get much, if any lift.
At this point you'll want to orient the hovercraft pad so the wood insert is on the ground.
Fold the skirt up over the top, but do not pull it tight, you'll want to leave slack so you have your cushion of air in your skirt bag. Staple it into place. I used TC-50 stapes and hammered them flush.
Go around the entire skirt folding over the skirt as evenly as possible, stapling each fold into place. Then duct tape over the edge and staples. This is a primative manner to seal it, but its sufficient for proving the concept. You will likely need to duct tape more after your first run to seal any leaks.
The first picture shows a close-up of the top of the hovercraft pad after it has been duct taped.
Now you have the pad done.
Step 5: Assembling the Pieces
At this point you should have crafted your initial materials and have the following key pieces:
3 Hovercraft pads
A bunch of PVC fittings
1 leaf blower
Now you can start making the hovercraft... seem more like a hovercraft.
I started just conceptualizing how hard it would be to get a balanced hovercraft, and this design, which I've lovingly dubbed a lily-pad design seemed to work wonders. The first image shows how I assembled the pvc pieces. I cut short lengths of pvc to go in the hub to hub pvc connections, you could buy the right pieces, but after three trips to home depot and 10 hours of work (including my lunch and dinner) I just used what I had.
The flanges worked very nicely vor quick assembly, but with all those fittings, a lot of air was lost, I duct-taped each connection, but PVC glue could work too. I would not suggest using the PVC glue or duct-tape to seal the flange connections or the connection to the front pad, this way you can still fit it into your little saturn.
One thing I found while testing the hovecraft is that the engine, while it runs optimally horizontally, wouldn't stay in place so I removed the 90° bend on top of the T and now have it inserted vertically.
This will work, but I added a chair
Step 6: The Chair
I worked as a janitor for several months and in the process acquired many goodies, including a couple dozen folding chairs. This while irrelevant, did not add to the cost of the craft. The basic idea hear is that you can place your balance in the center of the 3 pads and have a much smoother ride. In practice its much more difficult, but what I did was got 2 lengths of 2x4's and ran them from each back pad to the from one. I then set the chair on it and off I went. Unfortunately I've no pictures of this and I'm about 100 miles from my craft as I havn't moved it up with me to my college house.