A quadcopter is a multi-propeller helicopter that is propelled by for motors. In this tutorial we will be taking you through the process in which we created our very own quadcopter. By the end of this tutorial you should be familiar with the design process and learn how quadcopters function.

Step 1: What You Will Need...

3D printer

HUBSAN Replacement 2.4GHz Receiver Board for X4 H107C Quadcopter

HUBSAN 4-Channel, 2.4GHz Transmitter (TX) for X4 H107C Quadcopter (Controller)

3.7V 500mAh LiPO Battery

Battery charger

3D modeling software (we used solidworks)

HUBSAN X4 H107 motors (4)

HUBSAN X4 H107 propellers

Double-sided foam tape/ Velcro/ rubber band

Soldering iron

Solder

Step 2: Starting Your Design

The first thing you want to do when designing anything is recognize your constraints. For the quadcopter, we had the following constraints: it must hold the engines, propeller blades, and circuit board but still weigh under 9 ounces to achieve flight. The frame has to be strong enough to hold everything, but also light enough to achieve lift.

There were also other things we had to take into consideration, like the .35 mm tolerance on the 3D printer. It is important to keep all of those things in mind while brainstorming design ideas. Create a design that is well balanced so that the quad copter will fly well. Make sure to measure all of the physical parts (motors, propellers, circuit board, battery) so that you know how large to make the frame. You can see our brainstorming in the picture above.

We included a removable guard in our design (the outer ring) so that it would provide crash protection for the body. Once you have mastered the art of flying a quad copter, you may not need a guard.

Step 3: 3D Modeling the Frame

Now that you have brainstormed your ideas, you must model your first iteration of the frame in a 3D CAD software like SolidWorks. You can also use free software online like Tinkercad. Keep in mind that this is your first iteration, and you will likely need to revise your design several times to get the best design possible.

Based on your measurements of the motors, propellers, etc., make sure that you leave some wiggle room in the motor housings so that your parts can fit snugly in the frame. You want it to be a tight fit so that the motors will stay in place during flight, but not too small so that it is too hard to get the motors in the housings. We also designed our frame so that the bottom was flat in order to make printing it easier.

If you are so inclined, you can stress test your frame to see how it will hold the weight of the other components.

Step 4: 3D Printing the Frame

Save your 3D model as a STL file for the 3D printer that you are using. Use the software included with your printer to position the frame on the bed of the printer. Use the appropriate fill necessary to achieve low weight and structural integrity. We used anywhere from 2%-20% fill for our iterations, using trial and error to determine the best combination of being lightweight and strong.

**TIP: the fill for the guard does not need to be very high.**

Step 5: Assembling the Quadcopter

Now that you have your printed frame, you can begin to assemble your quad copter! This is how we assembled ours, but you can attach components based on your design's needs.

Attach your motors to your frame. Make sure that the different color wires are diagonally across from each other.

Solder the wires to the motor connections on the circuit board (see picture 1 above). Make sure to solder red and white to the positive terminals and black and blue to the negative terminals.

**TIP: Make sure not to solder the motor leads to the LED terminals; they won't do anything for you.**

Attach the propellers to the motors. The A propellers are diagonal from each other, and the B propellers are also diagonal from each other. Since the propellers are shaped in two different orientations, they need to be diagonally across from each other to keep the quad copter from spinning, and to generate lift.

Attach the circuit board to the frame. We used double sided foam tape. Make sure that the orientation of the board corresponds to the motors, with each corner pointing to a motor. (See attached pictures 2 and 3 above for reference)

Attach the battery (see picture 4 above). You can use foam tape, Velcro, a rubber band, or something else.

Step 6: Flight Testing

Now that you have completely assembled your quadcopter, you are ready to start testing!

Plug in the battery to the circuit board. The lights on the board will flash, letting you know that it is on. Then, turn on the controller and it will automatically connect to the quadcopter. If the battery disconnects or dies, you must restart this process, turning on the quadcopter first, and then the controller.

Trim the flight of the quadcopter using the buttons on the controller to level the quadcopter's hovering.

Fly away!