I built this quad mainly for a 360-degree camera platform (GoPro MAX, Insta360 ONE X, etc.). The landing gear retracts to that there is no obstruction to the 360-degree view when camera is mounted underneath.

Features:
Besides the retractable gear, this quad features a Holybro PixHawk4 running ArduCopter V3.6.11 for autonomous flight using Mission Planner. The flight controller spins four T-Motor NAvigator Series MN3508-29 380kva brushless motors with 13 x 5.5 inch carbon fiber props through Hobbywing XRotor 40A ESCs. A pair of Holybro 915Mhz 500mW Transceivers establish the ground station radio link. MAVLink telemetry is also passed through the FrSky X8R receiver SmartPort for display on the Taranis X9D using Craft & Theory FlightDeck software. For FPV, the quad has a Foxeer Monster Pro 16:9 1200 TVL camera mounted on the front. A MinimOSD provides on-screen display and it is wired for up to three video sources that can be switched remotely to the 1200mW AKK FX2-Ultimate VTx. Regulated +5V @ 4A and +12 @ 4A is supplied by a Matek U4A2P UBEC mounted on the underside of the quad. I'm using a Tattu 6S 25C 8000mAh Lipo for power (~2 lbs).

Build:
The frame I used, the TFModel 650, has been discontinued by HobbyKing. It is a great looking and sturdy frame (similar to the Tarot Iron Man 650), however, it was a pain to work with and required some extra fitting and drilling since the holes and hardware didn't quite line up in some cases. I had to cram all the ESCs inside the frame since they did not fit inside the motor mounts and I did not want to hang them on the outside of the arms. So, the ESCs, MAVLink LED controller, and retract controller are inside the frame. The power distribution board is the next layer up followed by the flight controller, then the RC receiver perched on top of the stack. Since the PixHawk4 does not have built-in OSD, I had to also add a MinimOSD externally. The larger form-factor OSD is easy to hook up a FTDI USB serial link to a computer for easy firmware updates and programming.

Visibility and Status:
Although the TFModel 650 frame came with very bright LEDs mounted to the underside of each arm, I added four additional addressable RGB LEDs to each arm and two to each side of the quad. These LEDs give visual MAVLink status information controlled by a Fishbonne (electHawk) LED controller. I plan to add strobes to comply with FAA requirements for flying before sunset. I also mounted two extremely bright 1.5 W LED head lights for visibility and orientation.

Voltage Monitoring:
The +5V status is sent via the receiver S.Port telemetry to the transmitter and displayed along with the other telemetry data. However, the status of the regulated 12V supply is not sent (since it is not present in the S.Port data). I added a voltmeter display near the receiver on top to monitor the 12V regulator output. That way, I can at least see the status of the 12V supply at preflight. The 12V supply is for the VTx, retracts, and OSD.

All ready to maiden!