Hovercraft Frame Construction
When constructing a hovercraft frame it is best to use the lightest solid material available.
Styrofoam worked perfectly for this purpose. It is easy to model and holds it shape well
for its weight. In constructing our hovercraft frame we were able to obtain a five-inch
block of Styrofoam that gave us lots of room to work with.
The first task in shaping the frame was
achieving an approximate block size to
represent the hovercraft model. Using a table
saw we cut the larger block of Styrofoam into a
smaller piece and pushed it horizontally along a
board to keep the edges straight. This process
could also have been carried out with a hot wire
mounted on a table but any flexibility in the
wire could easily lead to an unwanted grove or
deformation in the edge of the craft (particularly
when dealing with a thick piece of Styrofoam).
Next we used two metal pans to draw a rounded outline around the corners of the block.
Using this outline we were able to drag a hot wire
along the shape draw to get an even curve. Hot
wire can, however, leave dents and groves in the
shape it is cutting so to get a smoother corner
after making a hot wire cutting we ran a sander
over the freshly cut corners.
The next step in constructing the hovercraft frame
involved shaping an air pocket within the frame to
keep the craft afloat. It is important that this
pocket be relatively wide otherwise the craft may
not be stable during operation. The cutout should also be symmetric with the shape of the
craft to avoid weight imbalances as much as possible. To get the correct shape we
dragged a small piece of wood holding a marker
pen around the perimeter of the frame with the
marker pen being held approximately 1 inch
inwards from the outer edge of the frame.
After the air pocket shape was drawn we used a
router mounted with two boards (for even
depth) to cut a grove into the block of
Styrofoam. When cutting Styrofoam in this
manner it is important to keep electronics and
any other devices that may be at risk when
clogged with Styrofoam bits away; the router
will blast out Styrofoam bits making a mess of everything within close proximity.
In our craft we decided to use a dome shaped piece of Styrofoam to cover our electronics
so after routing out the air pocket we routed out a circular shaped area to sit the bread
board and micro controller that will be driving
the craft. We also decided to sit the airlift
motors under this dome so we used a drill to dig
two holds in the Styrofoam for mounting our
two motors.
To finalize the frame of the craft and provide
more of an aesthetic appeal to the craft we use
the table saw once more to carve a groove
around the outside of the craft. Then fitted a
bicycle tire to sit firmly in the groove and to act
as a bumper should the craft hit obstacles.