Adding Drive Fans
These are the dimensions of the drive fan brackets. The
brackets are Styrofoam and easy to cut with a hot knife.
The Hobby Lobby sells the perfect electric knife next to the
The lift fan fills the skirt to create an even seal to the
floor and the cushion of air that the HoverBot will ride on.
However, what drives and steers the HoverBot? There are
two additional fans — the drive fans — mounted to the top
of the top deck that act as the wheels and motors of the
HoverBot. The GWS company mounts the ducted fans in
the interior of a Styrofoam airplane fuselage. They don’t
use or even make brackets for the fans — the Styrofoam
fuselage is shaped into a bracket that holds the ducted fan.
Therefore, you’ll have to make our own brackets for the
HoverBot’s drive fans. For this, I selected blocks of two inch
thick Styrofoam; the kind of blue Styrofoam sheeting used
in house insulation.
Cut two blocks of two inch thick Styrofoam measuring
three inches wide and two inches tall. Find the center of
the block’s three inch long face and draw a vertical line.
Use a circle template (or make one with a compass and
index card) to draw a semi-circle at the top of the block (on
the three inch wide face). The ducted fan is 2-1/8 inches in
diameter, so use a circle template 2-1/4 inches in diameter.
Draw the semi-circle at the top of the block and centered
on the vertical line you just drew. Then, use a hot knife to
cut the semi-circles out of the top of the Styrofoam blocks.
The fan will lie on its side inside this bracket with a little
clearance all the way around.
After cutting out the two drive fan brackets, use hot
glue to mount them to the top side of the top deck. I
mounted my drive fan brackets at the ends of the top deck;
however, they don’t have to be that
far out. As long as the drive fan
brackets are glued the same distance
from the center of the top deck,
they’ll be fine. However, I
recommend gluing the brackets near
the ends of the top deck so the drive
fans are more effective at steering
the HoverBot (further out and they
generate a larger torque on the
After the hot glue has cooled,
glue the ducted fans to their
brackets. The plastic housing or
jacket of the ducted fans are made
of flexible plastic and can be warped
when you squeeze them. If a ducted
50 SERVO 10.2010