One of the few original design specifications that never changed was the dimension of the hovercraft. The hovercraft was cut out of a square four-foot piece of plywood. The original design called for a smaller radius, however, with one of the goals of the hovercraft stating one person should be able to ride it, a new radius of 2 feet was decided, thus allowing enough room for one person to hover. Due to this, the plywood needed to be at least a half-inch thick to support this amount of weight. We decided not to use plywood of any greater thickness so as to reduce hovercraft weight.
The hovercraft’s circular origins were created under considerations for the skirt. First, a square shape would inherently be difficult to put a skirt on. Here we lucked out, relying on pure intuition. We did not know until putting on skirts later how difficult it is to center a skirt. And secondly, the square corners would puncture the thin nylon of the skirt material. Under considerations of puncturing the skirt, after cutting out the four-foot diameter circle, the edges were heavily sanded. Thus, after a few hours of work, we were left with a four-foot diameter sanded circle.
The next step involving the hovering of the hovercraft is allowing an air inlet. We needed to bore a hole in the circle, however, not too large as to be counterproductive and let out air and not too small as to not let in an adequate amount of air. Deciding to use a hose from a shop-vacuum as a guideline, we cut a two-inch diameter circle out of the circle. Once again, after taking under consideration the placement of both a person and a shop-vacuum, the whole was cut approximately nine inches off center. Finally, the hole was also sanded.
The key element in our hovercraft was to be the thin nylon skirt. Seeing as we could not obtain enough power to hover off of a blower alone, we had to rely on a pressurized air bubble. To this extent, a circular plastic skirt provided the pressure bubble. We foresaw the intrinsic problem with this; the hovering ability of the hovercraft lies in the pressure buildup in the thin plastic skirt, any hole or laceration would inevitably lead to lower air pressure, ultimately leading to impair the hovering ability. Therefore, the greatest thickness possible was chosen for the plastic material, in the end this was a meager six-millimeters.
With the six-millimeter plastic, an approximately five-foot diameter skirt was cut out. Even though the hovercraft is only four feet in diameter, we needed enough extra plastic to inflate so as to rise the wood off the ground a couple of inches. What would hinder this would be two factors. The first being that we decided to rely on the original schematic instructions of using duck tape to attach the skirt. With the duck tape we needed to pull the skirt up a couple of inches on the topside of the wood, thus allowing enough plastic skirt for the duck tape to attach to. The second factor was due to the inherent nature of a hovercraft. Hovercrafts in commercial use hover on a ring of air located on the underside of the hovercraft. There are several reasons for this, the first being the reduction of surface area for the skirt. This equates to less money spent on the cost of a skirt, less power needed to inflate a skirt, less time spent inflating a skirt, and less wear on a skirt. Secondly, in our case, this gives the hovercraft the ability to hover. This ‘skirt ring’ took on a more doughnut shape for hovercraft. To create this ‘doughnut’ shape, we drilled a quarter inch hole through the center of the hovercraft. Next we took a quarter inch bolt and attached a three inch plastic lid around the bolt’s top. Placing the bold through the center of the skirt, and then through the underside of the hovercraft, we effectively created the ‘doughnut.’