Introduction: Dual Thruster RC Airboat
Today, we’re gonna make a simple low power diy airboat from recycled materials which will take less 20minutes to complete.
An airboat, also known as a fanboat, planeboat, swamp boat, is a flat-bottomed watercraft propelled by an aircraft-type propeller and powered by either an aircraft or automotive engine. When the propeller is working, it pushes air behind the boat, which pushes the boat forward. It is used by the military and also for fishing. Steering is done by rudders attached to the back of the boat that steer the air pushed out by the fan, making the airboat move and turn in the direction you intend on going. In this project, we are not using rudders, instead the propellers will rotate in order to steer the boat.
Step 1: Supplies
This project requires little supplies, some of which you might have already have lying around.
1. Coreless motor *2 Buy it on Amazon
2. Propeller *2 (The motor comes with a pair of propeller)
3. Li-on or Lipo 3.7v battery Buy it on Amazon
4. Switch (You can salvage this from an old electrical device) Buy it on Amazon
5. 3v dc motor (any kind) Buy it on Amazon
6. 3v dc motor (round shape) *2 (You can salvage this from an old DVD player) Buy it on Amazon
7. Motor gears *2 Buy it on Amazon
8. Craftwire or metal wire
9. Rc transmitter and receiver
10. Two identical bottles
11.Long screw with 3 hex nuts
13.Old hardcover book
1. Super glue
2. Soldering iron
4. Heat shrink tubing
5. 5-minute epoxy
7. Hot glue gun
If you’re like me, that likes to reuse stuffs, well you can getaway with spending as little as 5$ for this project. The two round shaped motors can be salvaged from an old DVD player. Coreless motors from old kids Rc helicopter. Transmitter, receiver and 3v motor from kids Rc car. Lipo 3.7v battery from a damaged PS3 controller.
Step 2: The Base
The first step is to create a base on which we can mount the motors and other stuffs. Cut out one of the covers of the hardcover book and cut out a 16cm by 11cm rectangle. This will be the base. Now we need to waterproof the base with packing tape. Run strips of packaging tape over and over the base to waterproof it. I didn't waterproof mine as the tape reflects light which affects my images. Corriflute sheet would have been a better material for the base, it’s just that I didn’t have it available at the time of making this instructable(and it’s also lightweight).
On the seem of the bottles, make a mark 3cm from the bottom seem of the bottles. Squeeze some hot glue along the seems, this’s where the sides of the base will be glued to. Lower the base making sure that the two bottles are properly aligned. To make sure that the bottles are aligned, do this near a wall. Add more glue to the underside of the base to strengthen the bond between it and the bottle.
Step 3: Steering Mechanism
This particular airboat uses two independent motors on each side of it to provide more thrust. For the airboat to turn, these two motors must rotate at the same time. So we need a mechanism that will rotate them at the same time. To do this, cut out two pieces of the pen tube each 3.5cm long. Cut two pieces of rectangles out of plastic each 1.5cm wide and 5cm long. Cut another piece of rectangle 1.5cm by 7cm long. Drill a hole whose center is at least 1cm from the edge. The holes needs to be just big enough for the pen tubes to fit snugly through. Drill another hole 0.5cm from the end of the two smaller rectangles. Push the pen tubes through the holes of the two rectangles leaving the rectangles 0.5cm from the bottom of the tube. Super glue that in place. On the larger piece of rectangle, we need to make a 0.5cm long cylindrical looking hole that’s 0.5cm from the other end of the plastic. Push the plastic into the one of the pen tubes with the cylindrical hole looking in the opposite direction of the smaller plastic rectangle we’ve glued earlier and glue that also into place. Refer to the pictures above to get a better understanding of what goes where. We need to tidy up the mechanism.Using a sandpaper, sand the edges of the rectangle to a curve. Use a fine grit sandpaper to roughen-up the surface of the plastic to allow the spray paint to stick to it. If you want to spray paint the mechanism, now it’s the time to do so.
Step 4: Steering Mechanism Part 2
Cut out two circular pieces of the plastic sheet (they mustn’t necessarily be perfect circles) and make a small hole in the center of each. On one of the circle, push the small nail straight into its center hole and then glue it in place. Next, pick one hex nut and place it on top of the head of the nail and superglue it in place. The type of nail I’m using has a small enough head so that it will slightly fit into the hole of the hex nut when placed on it. Now pick another nut and then place it standing on top of the opening of the hex nut we’ve glued earlier. Add a little bit of superglue to the sides of it to keep it in place before applying epoxy, but be careful not to get it into the threads of the nut. Mixup a small batch of epoxy and reinforce the joint between the standing nut and the lying nut. Let it solidify for a few minutes before proceeding to the next step.
Now take this piece and insert the pointy end of the nail into the slot we’ve made earlier on the longer rectangle. Push the smaller circle into the nail from underneath the rectangle, leave a little gap between the rectangle and the circle so as to allow free rotation of the nuts.
Step 5: Making the Support Bearing
Add a bit of super glue to the motor gears holes and attach them to the motor’s shaft. Hold the motor upside down when doing this to prevent the glue from freezing the motor. If your gears fits tightly in place, then there is no need for you to glue them. We need the motor to be able to rotate freely. The motor serves as a bearing, so we don’t need it to work. Therefore cut off the wires of the motor. Hot glue the motors on the left and right edges of the base. Measure the distance between the left motor’s shaft and the right motor’s shaft. This distance will be used to make the steering linkage.
Next, glue the pen tube(steering mechanism) on top of the gears which we’ve attached to the motors. The type of pen tube I used fits perfectly on top of the gears. Bend the metal wire like shown in the picture above. The length of the wire after being bent should be the same as the distance between the shaft of the two motors. Insert the bent wire into the hole at the back of the two rectangular plastic.
Step 6: Attaching the Coreless Motors
Before you attach the coreless motors, add a bit of hot glue on top where the motor’s wires comes out to relieve some stress as these motor’s wires easily breaks. Glue the motor on top of the pen tube we’ve attached earlier to the base with the spinning shaft looking in the opposite direction as the smaller (former) rectangles(just like in the pictures above).
Step 7: Setting Up the Steering Motor
The 3v dc motor will be used to steer the airboat. So we need to attach the long screw to the motors shaft gear. This’s the tricky part. In order to do this, we first need to temporarily connect the motor to the battery with a switch in between like in the above image.
Once you’re done with that, you need to work very fast. Add a blob of hot glue to the gear and at the back head of the screw. Put the screw standing straight on top of the motor gear keeping it as straight as possible, let it cool a bit for like 2 seconds before switching on the motor. Once the starts spinning fast, all those forces involved will try to align the screw inline with the center of the motors shaft. It might not look that it’s aligned, but the only way you will know if it’s aligned is if the screw remains in place and if the motor continues to rotate without much vibrations. Beware!! You might not get this in the first try, it took me three tries to get it, so be willing to try again if it fails. Switch off the motor and allow the glue to dry. Once dried, screw a nut right until it reaches the bottom of the screw. After that, mixup some epoxy and further reinforce the joint, but be careful not to get the epoxy on the screw. Allow the epoxy to dry completely before proceeding. Next, screw the screw into the nut we’ve attached earlier in step 4. Stop once the screw is halfway into the nut. You might have noticed that the motor is lower than the steering mechanism’s nut, so we need to elevate the motor. Depending on the thickness of your hardcover sheet, cut out 5-6 rectangular pieces of it and stack them on top of each other and then glue on the motor in place. A servo motor would have been a better choice, but it’s just that I don’t know how to control it with a receiver that has only two wires. So if you know how to do it, pls comment down below!
Step 8: Connecting Everything Together.
Connect the positive(usually red) wires of the motors together and then cut a length of red wire and then solder it to the two red wires we’ve connected earlier. Use heat shrink to keep everything neat. Repeat the same step for the black wires of the motors. Run the wires underneath the base and solder the positive motor wire to the “F” (forward) wire of the receiver. Do the same to the black motor wire and solder it to the “B” (backward) wire of the receiver. Mount the receiver on the top left corner of the base using small screws or hot glue it in place(you can choose anywhere you like to place the receiver). Solder the positive steering motor wire to the “L” (Left) wire of the receiver. Do the same to the black motor wire and solder it to the “R” (Right) wire of the receiver. Again, use heat shrink to make your connections neat. I decided to hot glue the battery on the base between the two motors. Connect the positive wire of the battery to the positive wire of the receiver. Do the same for the negative(black) wire.(The positive wire is usually labelled as VCC while the negative as GND). I’m using a Lipo battery to get more juice. If you want longer running time, stick to a Li-on battery. The receiver I’m using has an onboard switch, so if yours doesn’t have one, add the switch in between one of the wires supplying power to the receiver from the battery. I didn’t solder the wires together so that I can easily charge the battery.
Step 9: Testing
I built this Airboat during the winter, so most lakes are either dried up or frozen. I'll upload a test video once i can find a place to test it. Sorry for that.
Step 10: Troubleshooting
1. If the airboat goes backwards when you move the transmitter stick forward, you can either do one of these things.
-Swap the positive and the negative wires of the coreless motors connecting to the receiver.
- Make sure that the propeller are properly installed not backwards.
2. if the airboat turns left when you move the transmitter stick right, simply swap the steering motor wires connecting to the receiver.