Thanks to fishpepper for sending in this tip. Fishpepper writes:
This is how i built the lightest brushless FPV quadcopter on earth 😉
I developed all the electronics on my own and I release all HW files under an open license.
With 32.4grams including the battery, this is the lightest brushless fpv quadcopter you can find. Even though it is light, it still has enough power for indoor fpv racing practice.
The whole copter uses only open source hard- and software.
You can find a flight video on one of my latest blog posts:
Welcome to drone day on the Adafruit blog. Every Monday we deliver the latest news, products and more from the Unmanned Aerial Vehicles (UAV), quadcopter and drone communities. Drones can be used for video & photography (dronies), civil applications, policing, farming, firefighting, military and non-military security work, such as surveillance of pipelines. Previous posts can be found via the #drone tag and our drone / UAV categories.