Simon Dube, Isabelle Gilbert, Mireille Gascon,
Dept. of Mechanical Engineering, University of Ottawa
An airboat is a flat bottomed vessel usually used
in swamp and marshy area where the water is shallow. It is made
of three main parts which work together: the propeller produces
a column of air, air passes across the rudder which deviates the
air column and the hull keeps those two components out of the
water. For the first part of our project we wanted to build an
air boat from material that you would usually find in your
household so to minimise the cost. Then, we established a
second goal to make it more reliable, powerful and efficient.
We used an air hockey table fan as the propeller
and we powered it with a direct current brushed motor from a toy
car powered by six 1.5V batteries in series. Two switches were
installed as they work together to invert the direction of the
current our airboat the possibility to reverse. We also use a
potentiometer to adjust the power given to the motor to be able
to adjust the speed of the watercraft. You can find
potentiometers in the household switches that adjust the lights
intensity or the sound volume.
For the rudder, two galvanised stainless steal
plates were attached in parallel with each other. The steal
plates move from left to right to steer the boat with the help
of a direct current brushed motor taken from another toy car.
The motor contains a plastic gear inside to reduce the speed and
increase the torque. Also it would complete a full rotation but
stops once it is turned at the max due to the geometry creating
resistance. We sealed the space between the rudder and the
propeller to maximise the effect of the air column.
For the hull a Styrofoam board was use as it is
light and easy to carve its shape which is flat bottomed. The
Styrofoam board floated perfectly, but all the weight was in the
back and we wanted to make sure it would not tip, so, weight was
added at the front of the ship to level it. The propeller and
the rudder were installed on the hull. This prototype isn’t
perfect. Its major deficiency is that the remote control is not
wireless and the thick wire interfered with the steering of the
boat. So without the wire, we believe we would have had a much
better control of the airboat.
After we had achieved our original goal to build
our project out of materials found at home only, we decided to
come up with a second goal which was to make it more powerful,
more efficient, but most importantly, to make it wireless. So we
went and bought a wireless remote, we chose the “TACTIC TTX240”
as it was recommended to us by the dealer. It is a 2.4 GHz
transmitter, so there is no interference by the FM/AM radio
frequencies. The remote also came with the matching receiver in
which all the components of the airboat (propeller motor, servo
motor powering the rudder) will be connected to.
We also got a more powerful motor that propels
the propeller and a servo motor to control the rudders more
precisely. We decided to keep the original design since we found
that it was efficient even with the mediocre equipment. We
constructed the tunnel that would hold the propeller and the
rudder out of an aluminum sheet. This way, it was lightweight
but sturdy enough. But with testing, we realised that it wasn’t
sturdy enough, so we had to add an aluminum bar around to
prevent it from wiggling from side to side. We mounted the motor
on a bracket and riveted it in the wind tunnel. The bracket is
made of metal which helps to dissipate the heat created and
released by the motor. We then used O-rings and glue to attach
the propeller to the motor. We had purchased a two blade
propeller because we learnt that the fewer blades there are on a
propeller, the more efficient it is. But using more blades on a
propeller allows reducing the diameter of the propeller and
still getting an equal thrust. We decided to go with the more
efficient one since size wasn’t an issue for this prototype. The
propeller we chose has a diameter of 8 inches and a pitch of 8
inches. The pitch represents the angle of the blades; it is
calculated by measuring the distance travelled by the propeller
in a gelatine substance when completing a full rotation. The
higher the pitch, the higher the thrust will be but the harder
it’ll be for the motor to turn the propeller. To be able to
control the speed of the motor, we also had to get an electronic
speed controller “ElectriFly C-25” that will be connected
between the receiver and the actual motor which is a “Titan 550
Motor 12t”. While adding this to our circuit, the power source
must now be connected to the ESC instead of the receiver.
For the rudder, we built it using the exact same
design as we did for our original design with the only
difference being that we used more bars on the plates to act as
a skeleton to give it more strength and rigidity. We also used
the servo motor “HiTEC servo HS-311” to turn the rudders to
allow a better, more accurate control of the steering as
As for the power source, we purchased an “Onyx
1800mAh 7.2V NiCD” battery pack with the charger as they are
more efficient than AA batteries and more convenient since it’s
All the electrical components except for the
motor and servo motor are stored in a plastic container to
prevent water from coming into contact with them causing a
malfunction. We also decided to add a wireless camera mounted on
the cover of the plastic container on the watercraft to be able
to control the airboat without having to keep eye contact with
it. One has to simply connect the receiver to a television. The
camera we got is the “DIY Security Camera Kit” due to our low
budget so the quality isn’t the best but is sufficient for its
purpose on our project. The camera itself uses a 9 volts battery
which is also stored in the container.
The hull is once again made out of a Styrofoam
board because of its floatability, stability and lightweight.
The mechanical components were installed in the stern of the
boat while the electrical components in the container were
installed in the bow of the ship to balance the weight. The
airboat still tilts backwards but this is better as it provides
better aerodynamics to help the boat to “get out of the water”
while in motion.
strongly recommended to read this manual entirely before
using this watercraft! Damage from modifications or misuse
will void the warranty!
Warranty and repair
comes with a one year limited warranty. This manufacturer
warrants this product to be free from defects in materials
and workmanship for a period of one year from the date of
purchase. During that period, the manufacturer will, at its
option, repair of replace without service charge any product
deemed defective due to those causes. You will be required
to provide a proof of purchase (receipt). This warranty does
not cover defects due to abuse, misuse, alterations or
transmitter requires 4 “AA” batteries. Non-rechargeable
alkaline or rechargeable nickel-cadmium (NiCd) or
nickel-metal hybrid (NiMH) cells can be used. Do not mix old
and new batteries. The vehicle does not include an “AA”
battery charger so one will need to be purchased if choosing
the rechargeable batteries.
the batteries, slide the battery door on the bottom of the
transmitter open. Install the batteries in the holder as
shown on the battery door. Close the battery door.
not operate the watercraft with weak batteries as it could
result in possible loss of control!
power switch to turn the transmitter on. The LED should also
turn on. If it doesn’t, check the batteries to make sure
they are firmly in place. If the LED blinks, the batteries
are weak and should be replaced. When in operation, the
antenna should be rotated to its full upright position.
battery should be charged for at least four hours the first
time then requires a 3 hour charge time using the charger
which is also included. Once fully charged, plug the battery
to the vehicle in the right direction; black connected to
black and red connected to red. Turn the device on by
pressing on the push button until the blue light turns on.
The watercraft will make a beeping sound.
transmitter and the watercraft are turned on, make sure all
systems are operating according to the movement of the
Steering: Turn the steering wheel left and right, then; make
sure that the rudder turns in the desired direction. If it
doesn’t, reverse the position of the Steering Reversing
switch. The Steering trim is used to adjust the direction of
the rudders and the Steering rate adjusts the limits to
which the rudders can turn on each side.
Throttle: Squeeze the throttle trigger and get familiarized
with its rate. If it isn’t to the users preferences, adjust
it using the throttle rate knob.
transmitter/receiver have a Fail-safe function which will
automatically center all servo motor (rudder) if the
receiver loses signal from the transmitter and regains its
normal operation once the signal is regained.
watercraft is not in use, turn the transmitter off, turn off
the receiver by pressing on the push button, and disconnect
the battery to make sure the battery doesn’t drain
To use the
camera, the receiver must be plugged in to a power source
and also plugged into the video/audio of a television. If
only “snow” is appearing, use the knob to adjust the
receiving frequency until u get the signal from the camera.
function; Make sure the remote and the watercraft are on.
Remote/watercraft turned on but the light doesn’t come on:
check the batteries and replace/recharge if necessary.
or the rudders glitching: Out of range, operate model more
(one being a servo motor preferably)
Wood or metal
to build the frame
control and its receiver
camera, its receiver and a television
1. Assemble the
propeller to the motor making sure it is turning in the right
direction. Mount it on a bracket measuring its height to make
sure the base is high enough that the propeller can turn freely.
2. Build the
frame for the rudder. For our first prototype we used wood for
the frame and wrapped it with plastic to enhance the air tunnel.
For our second prototype we used an aluminum sheet bend in a
square shape as the frame. It also serves the purpose of the air
tunnel. Make sure the frame is big enough to hold the propeller.
(should be bigger than the diameter of the propeller)
3. Build the rudders. The rudders of both our
prototype were made of two plates. We recommend adding bars on
the plates to add stiffness. Connect your motor to the rudders
using a plastic bar so your rudders move from left to right
simultaneously. Assemble to the base. Also add the propeller.
4. Your motors will need power source. For our
first model, we connected the motor directly to 6 AA batteries
in series. The second motor used to control the rudders was
powered by only 3 AA batteries. Our second model required an
electronic speed controller to which the battery pack will be
connected to. This battery pack will also supply power to the
servo motor used to steer the watercraft.
5. Build your own remote control if a premade
wireless remote control was not purchased. Switches and a
potentiometer will be required to vary the speed and rotational
direction of motors.
6. A camera can be added on the boat. We used a
wireless security camera as it wasn’t pricy. The receiver needs
to be hooked up to the television.
7. Once everything is assembled you get one cool