Introduction: 3D Printed Mini Quadcopter
This is a guide for a beginner to learn the basics of Quadcopter Design. At the end of this tutorial you will be able to understand the basics of quadcopter flight and important Design skills to put towards making your own.
To make a quadcopter you will need the following:
1. Hubsan reciver H107
2. 4 Hubsan H107 motors
3. 4 Hubsan H107 propellers
4. Hubsan H107 li-po battery
5. Access to a 3D printer
6. 3D Modeling software(like Solidworks)
7. Soldering equipment(Iron and Solder)
It will be important to make improvements and iterate on your design as you test, we made several different models and 3D designs and printed 3 iterations of them. (the white square one, the circle one, and the red one)
Step 1: Starting the Design Process
It is very important to have a really good design before you start trying to 3D print things. The best way start your design is by drawing out some basic sketches to help visualize what you want the QC to like. We would call this a conceptual design. We have some examples of our own sketches that we came up with while designing our own. we came up with the 2 designs at the start.
There are 4 forces that will be involved in the flight of your quadcopter; lift, drag, thrust, and weight. It is important to have at least a basic understanding of these forces before continuing, so you can know how they will interact with your design. The image above is not of a quadcopter, but the principles are still the same. The motors provide the lift to the quad, drag is from gravity and wind resistance on the body, thrust is provided by tilting the quadcopter to redirect some of the lift in a new direction, and the weight is the full weight of the quadcopter will all of the flight components in it.
Step 2: Adding Detail to Your Design
So now that you have some basic sketches its time to start measuring your materials so that you can make sure they will fit into the chassis you are designing. Luckily we already measured the Hubsan parts for you, if you are using different parts it is important to take the time to measure them yourselves.
Dimensions for the Hubsan parts are:
Board Dimensions L=29.15mm W=20.05mm H=2.1mm
Motor Dimensions D=8.45mm H=20.1mm (Height with shaft =25.45mm)
Propeller Dimensions L=55mm W=8mm H=6.15mm
Battery Dimensions L=31.8mm W=20mm H=7.85mm
Wire Length = 128mm
Now it is important you make sure your sketckes going foward are the right size to fit these parts. We have some examples of the rough skethches we made in the tutorial.
Step 3: Understanding How to Build
Now that you have your dimensions in mind it is important to have a good idea how it will all fit together before you start 3D modeling. it will help to come up with a circuit diagram for your model to see if you should make any changes. with the quad-copter the position of the motors is very important to how effective your quad-copter will fly. if they are positioned wrong you will not be able to fly.
The diagram provided shows how the board connects the 4 motors and batteries. In order to achieve flight you need to position the motors the right way so that the motor can tell which is which. You need to have the motors in an +or X formation for the board to be able to compensate correctly. You also want to make sure they are spinning the right way to get the thrust going downward. To get the thrust in the right direction you need to make sure the motors have the right propellers on them. we also show which propellers should be used on which motors. You can see how to attach your wires to the board (we will go in to more detail on this later.)
Step 4: 3D Modeling
Now after we have a good design in mind with the proper dimensions and knowledge on how we would put the copter together we can start to 3D model our copter. We used solidworks but really any kind of 3D modeling software should be sufficient depending on your design. The reason we don't just start with the 3D design is that it will save us a lot time when deciding how big to make certain pieces or to long to make the arms because we already made the measurements and adjusted our designs accordingly.
Step 5: Mathematical Model
So after you have your design made you should do some test to make sure everything will work the way you expect. Using Solidworks you can find the out how much your copter will weigh. Than by adding that to the weight of your board and motors you can have an estimate of the final weight of your quadcopter. you can also calculate how much force your motors will have to generate to lift your copter. for a good design you should try and aim for the weight of the body(without the other parts) to be about 10 grams.
You also can use Solidworks to stress test your models. by selecting the material you plan to make your copter out of,we used ABS in our test but ended up printing with PLS plastic, you can see how different parts will react to certain amounts of forces in what ever direction you chose. We have provided some examples of our mathematical models and the results of our stress test.
Step 6: Printing Your Model
Now its time to print your model. you should be prepared to print multiple copies of your model because there can be some errors when printing. It is also important to note that the some parts depending on how small or general shape may not print out the way you expected them to and you may have to go and change your design.
We have included the first prints we have of our quadcopters.
Step 7: Putting It Together
So now you need to put your copter together for some test flights. Depending on your design you may need to put in the parts before you solder with our design was best to solder first. you will use a soldering iron for this part and certain safety precautions must be taken.
wear proper eye protection
solder in a well ventilated space
When soldering it is important to make sure you connect the motors properly,see Circuit diagram made earlier, your motors will spin in different directions and will need to be place in a certain order. Motors 1 and 4 need to be across from each other and spin in the same direction, in our case the spun clockwise. The same thing applies to motors 2 and 3.
After solder the motors to the board you can put the motors and board into your body. After putting everything else in you can attach the battery to the body as well. our designs have built in sections for the battery and board so no kind of adhesive was required but if you must you can use double sided tape to ensure a good hold and reduce vibrations on the board.
Step 8: Test Flight and Making Changes
Now you can test fly your copter. you may run into some issues and in this section we will give some advice on how to deal with them.
1. One or more of my motors won't spin.
there can be several reasons for why your motors wont spin. you could have made an error in soldering the motors to the board and should check and make sure every thing is where it needs to be. if that is not the issue than it may be a balance issue. if your board is tilted it will alter the power of the motors to try and balance itself out. to fix this try and make sure that you are putting the board in flat, if using tape you can adjust how your board is leveled.
2. My motors are spinning but the copter won't fly.
one possible cause of this are that your propellers are not on the right motors. if you don't have the propellers on right they will generate the thrust in the wrong direction and wont generate lift. Assuming however that everything is one correctly and the board is balanced it could be that your quadcopter weighs to much and you will have to try and make a lighter design.
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