Introduction: Making a Single Motor Hovercraft
Achieve the speed and versatility of a hovercraft with the simplicity and the cost effectiveness of just installing one motor.
With the help of the following steps, YOU could be zipping around with your own hovercraft!
See Videos Above: First and Final Revisions.
In the next step, all the materials and equipment will be presented.
Step 1: Materials and Me
Since you will want to use and maintain your project after is is finished, this list includes products that wont be necessary to build the project itself.
- Utility knife
- Drawing compass
- Ruler/measuring tool
- Hot glue gun
- Turnigy Propeller 7x3.8 Green (CW) (4pcs)
- 3mm Prop Adapter
- Rhino 1750mAh 4S 14.8v 25C Lipoly Pack
- Hobby King 20A ESC 3A UBEC
- Turnigy 5X 5Ch Mini Transmitter and Receiver (Mode 1)
- HXT900 Micro Servo 1.6kg / 0.12sec / 9g
- FC 28-12 Brushless Outrunner 1534kv
- Foam boards
- Garbage bag
- Wooden dowels
- Twist tie spool
- Silicone Wire
- Duct tape
- Carpenters glue or alternative that isn't hot
- Dark annealed steel wire spool
- Basic Electronics Knowledge(Voltage, Amperage and Polarity)
If your E.S.C. does not come with a connector to the battery, you will need to get a connector that matches that type and solder it on.
Also for maintenance you will need:
- Battery Charger
- Power supply for your battery charger (if it doesn't come with one)
- General use Multi-meter
Once you have the prerequisites ready, the next step is to make the base as a starting point.
Step 2: Base
The base is a simple, yet important, starting point to build up from.
It contributes to the size, speed and the hovering capabilities of a hovercraft.
To get started you will need some foam boards and something to cut the foam with; I recommend a utility knife.
Start by planning out a rectangle with the dimensions 50 cm by 30 cm on the foam board.
Cut out the rectangle, this is the base.
Now that we have a basic starting point, we can expand upon it.
To make the hovercraft hover and move forward from a single motor, we must separate the airflow.
Plan out a 15 cm wide and 12 cm long rectangle 25 cm from the front of base. Cut the rectangle so there is a hole in the base, this is where the air will flow into the skirt.
Next we will build the skirt system.
See Image: Base with Hole
Step 3: Skirt
To build the skirt system it is important to understand the following:
- The skirt keeps air in pocket which lifts the hovercraft and decreases friction for movement.
- The problem is that we have a constant air source instead of a locked air bag.
- We fix this by having equal amounts of air go in and out of the skirt: Air IN = Air OUT.
- Holes on a solid surface attached to the skirt material lets air out which maintains air through balanced circulation.
To construct a skirt you will need a durable material, I used a garbage bag, and for the foam surface you will need foam. You will need some duct tape and something to cut with as well.
First start by cutting a foam board 25 cm wide by 32 cm long rectangle, this will be your foam surface.
Then draw three circles with eight centimeters of diameter, that are two centimeters away from each other, lengthwise on the board.
After all the circles are planned cut them out. When hovering air will pass out of the skirt through these holes.
See Image: Foam Surface
Now let's attach the foam surface to the skirt material.
Lay the skirt material on a flat surface and place the foam surface roughly in the middle.
Mark out the edges of the foam surface in the shape of a rectangle onto the skirt material.
Cut out a smaller rectangle, roughly 0.5 cm in from each edge.
Now, place the the hole of the skirt on the foam surface and center it so the edges of the skirts hole are flush with the foam surface.
Use duct tape to seal the edges of the rectangular hole in the skirt material to the surface of the foam until it is air tight.
See Image: Skirt Attached
Next we will attach the skirt with the foam surface to the base of the hovercraft.
Step 4: Attaching the Skirt to the Base
For this step you will need a hot glue gun, or some other way to attach foam together.
First we will attach a foam rectangle on the bottom of the base which will give it some depth.
Cut four foam strips that are 45 cm long and two centimeters wide, then cut four other strips that are 28 cm long and two centimeters wide.
Take one of the shorter foam strip and glue it to the bottom of the base at the front of the base, then glue the other short strip to the bottom of the base 45 cm from the strip at the front of the base.
Glue the two longer strips, between the shorter strips, to the bottom of the base aligned with the ends of the shorter strips, the strips should from a rectangle on the bottom of your base.
Next, repeat the steps above to add another rectangle on top of the existing rectangle.
See Image: Base Rectangle
In order to attach the foam surface to this rectangle we will add extensions to the foam surface with foam strips.
Cut two foam strips that are 28 cm long and two centimeters wide.
Glue one strip horizontally to the front of the foam surface, it should look like a T. Then glue the other strip flat to the back of the foam surface, it should now look like a capitalized i as a whole.
See Image: Capitalized i
Lastly, lets put it together.
Place the the foam surface on the bottom of the base.
Align the edge of the capitalized i to the end of the hole from the front of the base.See Image:
See Image: Aligning
Then, glue the capitalized i to the rectangle of the base where they contact. Wait for the glue to dry until the foam surface is sturdily attached to the base.
Flip the base so the foam surface is on the bottom.
Now stretch the skirt onto the top of the base on each edge and cut out anything further that four centimeters.
For the next step, do not use hot glue because it will melt the skirt material.
Glue the skirt material onto the top of the base on each edge so that it reaches about two centimeters in --this leaves two centimeters of slack material that inflates with air.
See Image: Slack
Then, using duct tape make a air tight seal where the skirt material meets foam.
Do this until all of the edges of the skirt material are taped to the base.
See Image: Skirt Attached
Now that the skirt has been attached to the base, we will work on the motor support.
Step 5: Motor Support
We want to make sure that the motor does not fall off or become unstable when spinning extremely fast with the propeller.
We also need the support to bring the motor high enough to prevent the propeller from colliding into the base while being aware of air resistance.
Use wooden dowels or chopsticks as support and twist tie wire spool for tying.
First cut the wooden dowels to make four eight centimeter long pieces.
Then mark a line from the left to the right of the base that is 7cm from the start of the hole in the hovercraft, this is the width line where the eight centimeter dowels will be glued. Now mark a short line lengthwise of the base 15 cm from either left of right of the base, this is center of the width.
After marking the lines, glue two dowels each nine centimeter either left or right from the center on the width line. Then glue two 30 cm dowels going from the top of each eight centimeter dowels to where they land toward the end hovercraft. From either side it should look like two right angle triangles on both sides.
See Image: Two Right Triangles
Now, glue the two other eight centimeter dowels each 2.5 cm either left or right from the center of a 18 cm dowel. This structure should look like a T with two vertical lines.
Cut two three centimeter by three centimeter foam squares. Then, glue each on either front or back of the 18 cm dowelbetween the dowels on the T structure. This will be where the motor is mounted.
See Image: T
On the width line, slide the T structure under each of the triangles so that it is slightly slanted forward and upward. Then glue the ends of 18 cm dowel to the angles of the triangle where they contact. Then glue the bottom of the eight centimeter dowels on the T structure to the base.
See Image: T Structure
The support should now be sturdy and have a place for the motor to be mounted.
Step 6: Air Foil and Control
To be able to hover and steer the hovercraft we have to focus air onto the control surfaces.
First, we will add a control surface that separates air through the hole on the base and into the skirt for hovering.
Cut out a 20 cm x 18 cm rectangle of poster paper or a thin alternative. Orient the rectangle so that its shorter and longer sides matches the short and long sides of the base.
View from the front of the base and align the start of the of rectangle to the end of the hole in the base.
Tape the top of the rectangle, through the hole of the base, to the bottom of the base.
See Image: Taping to the Bottom
Then flip the rectangle to rest it on the top of the T structure. We will glue this to the T structure after installing the motor, this will separate the bottom half of the motor's thrust to go into the skirt.
See Image: Air Separation
Now we will add a foil to send air through and out of the back of the hovercraft. For this you will need some aluminium foil and a dark annealed steel wire spool.
Cut out three steel wire pieces that are 45 cm, 30 cm and 28 cm. Then cut out two aluminium foil rectangle that are 45 cm by 15 cm and 36 cm by ten centimeters.
Centered and fold the starting one cm of the bigger aluminium foil onto the longer steel wire spool and then cut out small V's into the end because it will have a smaller circumference. Now you can bend the wire into a semi circle along with the foil.
Fold the end of the foil with the V's onto the second longest wire. Then cut out small V's into the end and the start of the second aluminium foil and fold one side onto the last steel wire. Finally, bend it into an semi circle, even without a second wire.
Now we can attach these parts onto the base and it will become a frustum.
In order to attach the wire to the base we need some foam foundation that it can dig into. First, cut out four foam squares with sides of four centimeters.
Then, orient the squares to be perpendicular to the base and parallel with the motor support triangle. Place two squares each eight centimeters in front of the start either triangle. After that, place the other two squares each 15 cm behind the start of either triangle.
See Image: Squares
Now take the ends of the longer wires from the bigger aluminium foil and stuff them into the squares at a slight angle so that it is a bit opening up.
See Image: Opening Up
Then tie the wires at the end of the foil to the wooden dowels of the triangle.
Place the free end of the other foil about five centimeters in and on top of the other foil and tape them together at their boundaries. Finally, stuff the wire ends into the other two squares.
See Image: Air Foil
Now that the foil is done we can finally assemble the electronics.
Step 7: Battery and Rudder
First, we will create a pocket for the battery to sit in.
Cut out two foam triangles by marking sides of four and about 5.8 cm at a right angle and then connect them to create the hypotenuse. Then, cut out a rectangle with the dimensions of seven by 13 cm. Next, mark a small line parallel to the longest side and two centimeters into it.
Then cut out a rectangle that goes two centimeters down and one centimeter wide centered on that line. The wire of the battery will come out of here.
See Image: Rectangle and Triangles
Now, glue the rectangle to the two triangle so that is flush with their hypotenuses. This prism will hold the battery in place while the hovercraft its moving.
Orient the prism so the hypotenuse faces up and forwards and the four centimeter side is perpendicular to the base. Next, align the start of the triangles to the very front of the base, center them to to the width and finally glue it to the base.
Grab a small foam piece and place it parallel to the base at the side opposite to the hole in the rectangle.
Finally, put your battery inside this pocket and bring the wire out through the hole.
See Image: Battery Prism
With the battery taken care of, we can now focus on the rudder.
Orient a servo so the side closer to the rotating shaft is facing forward, then glue it, centered on the width, two centimeters behind the end of the hole in the base.
See Image: Mounted servo
Now to make the rudder control surface, cut out three foam rectangles:
- one that is six by 15 cm
- one that is three by nine centimeters
- and one that is two by four centimeters
First orient your servo horn and the smallest rectangle to be parallel to each other. Then match the ends of your servo horn and the longest side of the rectangle. Lastly, glue the two together.
Next, orient the two other rectangles to be parallel to each other and then match the end of their shortest side. Then glue them where the contact on their longest sides.
Now orient the smallest rectangle to be perpendicular to the other rectangles and then match the front of the smallest rectangle to the free end of the largest rectangle. Glue them together and this will be your rudder control surface.
See Image: Control surface
Finally attach the rudder control surface to the servo via the servo horn on the control surface.
Next we will install the rest of the electronics.
Step 8: Motor, E.S.C and the RC Receiver
To finish off this project, we will install the motor, E.S.C and the RC receiver.
Firstly, lets attach the propeller to the motor with the prop adapter. Since many people have trouble doing this part I will link this video instead of explaining it myself: https://www.youtube.com/watch?v=BGZdTQbua-c.
Next we will attach the motor to the foam squares on the T structure of the motor support. First put some double sided tape on top of the square facing forward, this will act as padding.
Now, cut some twist ties into 15 cm pieces and then put them through and around each of the holes around the motors base.
Then align the motor so the holes are pointing up, down, left and right.
Follow these instructions for tying the left tie:
- Pull the tie to the top of the horizontal dowel
- Then loop it around the left vertical dowel going from outside to inside then out again on the backside
- Finally pull it to the left of the left vertical dowel and loop it around on the horizontal dowel until its totally tied.
For tying the right:
- Pull the tie to the top of the horizontal dowel
- Then loop it around the right vertical dowel going from outside to inside then out again on the backside
- Finally pull it to the right of the right vertical dowel and loop it around on the horizontal dowel until its totally tied.
For the top tie:
- Crisscross the two ends
- Pull them behind the square then down
- Pull the left end to the left of the left vertical dowel and loop it around on the horizontal dowel until its totally tied
- Pull the right end to the right of the right vertical dowel and loop it around on the horizontal dowel until its totally tied
Follow the same steps for the bottom tie but on the second step, pull them behind then up
Change the tension of these ties so the propeller doesn't collide with then base or the air foil when you spin it gently with your hands.
See Image:Motor Mounted
Lastly, glue the air separation control surface to the top of the foam squares.
Now, connect your rudder servo to the pin labeled "RUD".
Then, gently pull your transmitter towards the front as much as you can and then use double sided tape to tape it down there.
See Image: Servo-Receiver
Next, connect your E.S.C to the pin labeled "THR".
Then, gently pull your E.S.C towards the front as much as you can and then use double sided tape to tape it down there.
Now, take the wire of the motor and pull them to the side that your transmitter is on. Then make a temporary connection between the three motor and E.S.C. Keep in mind that the three wire do not short circuit.
Next, power the transmitter first, then connect the batter to the E.S.C.
Once you connect the transmitter to the receiver, slightly increase the throttle stick on your transmitter.
If the propeller is thrusting air forwards you have to power off and switch around two wires from the E.S.C. to the motor and then try again.
If the air is being pushed to the back, then you can make the connection from the E.S.C. to the motor more permanent.
Now, you are ready to enjoy your hovercraft!
Step 9: Final Thoughts
See Image: Final Top-Down View
It may take time to fully master how to fly this hovercraft.
Once you have finished your joy ride, you will want to charge your battery if necessary.
Put your multi-meter in the voltage setting that can handle the batteries voltage.
Use the chart above to determine if your battery needs to be recharged.
Next, set your charger to match your batteries properties then start charging.
Some improvements include:
- Changing the center of gravity to the center of mass
- Coloring and theme styling
- And polishing
On that final note please enjoy this project and leave your feedback.