Electric Beetle - Single Print Drone Frame (No supports needed!)

Design:

I have spent quite some time refining and optimizing various drone frames for my Tiny Whoop, and this is the first one I feel confident in publishing. 

It features a fully ducted design to both protect the propellers and to boost the drone's efficiency. The design of the ducts is primarily informed through Donald M. Black and H. S. Wainauski's 1968 study of ducted fans, and is optimized for my estimations of the parameters the drone will be under. For my 40mm props I designed the ducts with a 14.5° Exit Diffusion angle, a tip clearance of 0,3mm and an inlet radius of 2mm. (See pictures) Although a Prop-setup with more blades than 2 might be better here, but they haven't arrived yet.

Apart from the ducts, the design is also a single print, with no need for supports. And everything is designed to be as light as possible, so even though this is a big frame, with Nylon CF, I got it down to just 20 grams. 

As for the electronics, I originally found a video on YouTube, and they have, more or less, stayed the same, apart from the Flight Controller-AIO, the Video recommends an F411, but I only found a G474 available for me at the time. Though the G474 has a black box, while the other doesn't, so I guess it's an upgrade.

"Building a GOOD Micro FPV Drone for $65 (Beginners Guide)" by Mediocre Nerd

Parts List:

Printing Instructions:

I have printed this frame in both PA-6 CF (Black frame) and in Prusament PC-Blend (Grey Frame), but I recommend the PA-6 CF (also known as Nylon CF), due to its better mix of rigidity and impact resistance, as well as its overall density.

If you print this frame in Nylon, here are some tips: 

• Make sure the filament is dry, this stuff is really hygroscopic and at this point I just throw a spool in the oven (80°C for +3h) before every print. If you see a lot of oozing and stringing, then this is the cause. It will also make the print weaker and harder to print

• Make sure your printer has an enclosure, and can hold the temperature well.

• Pro-tip: Use a 1 layer raft, with low Z-separation, and set the first layer temps to 215°C and 60°C for the bed. Then start the print with PLA and put a filament swap after the first layer is done. That way you won't need glue and the PLA layer peels off super easily after the print cooled down.

• After printing, put it into the oven at 80°c again for 4h to allow the material to settle (tempering) and after that, put the frame into a moist environment, so it can absorb the moisture from the air again. Through this, you are relieving the internal stresses and the humidity re-adds the impact resistance to the frame.

Settings are basically standard, the only special stuff is the afore mentioned PLA-raft, and then 0%infill, 3 Perimeters minimum, and 7 bottom layers. 0.2mm layer height, with adaptive layers.

Assembly:

I recommend to not shorten the motor leads, since they already come with some solder at the end, and if they are too short, the cable-routing can become quite a chore.

I also recommend keeping the leads on the capacitor, as well as the Battery, nice and long, so they can be positioned easily.

Lastly, take one of the rubber shocks and cut it into 2 pieces, so they can be threaded onto the M2 screws around the VTX, to give it some more dampening.

Solder the Motors to the Flight controller

Solder the VTX to the FC, using the diagram on the Sale's Page. (GND to GND, 5V to 5V, VIN to VTX and RX to TX (on the FC))

Solder the Camera to the FC (GND to GND, 5V to 5V and Video to CAM)

Solder the Battery leads and the Capacitor to the FC. (Make sure the polarity is correct on both!!! Otherwise, the capacitor will explode)

Alternatively, here is the video I used for the electronics:

Once you have soldered everything together, and tested whether everything works, you can move to the rest of the assembly.

Position the Flight Controller above the Frame, and begin by bending the Motor cables downwards, so they can be threaded through the big central hole in the frame. Also make sure that the Camera and the VTX stay above the FC. Take the 2 antennae (FC and VTX) and thread them through the hole at the back of the frame, by tilting the FC and letting the motor leads and the battery connector come out of the bottom of the frame. Then move the FC downwards and angle it around until it is seated correctly, over the 4 screw holes in the frame. (This is a bit finicky) Then use the 2 M2x8's to secure the board at the front and back. Take two of the halved rubber shocks and thread each onto the M2x12's. Using some tweezers, move the other 2 halves under the VTX, and concentric with the rubber shock's of the FC, so the screws secure the VTX to the main board, and then the Frame. Then secure the camera to the frame using the 2 Included screws. (If you have issues later with not seeing the camera-feed, make sure the cameras settings are set correctly for your goggles - that's what the other small circuit board in the packaging is for.)

Lastly, screw on the motors, put the propellers on them and Zip tie the battery to the Top of the Frame.

Run Beta flight for the software setup.