There’s almost nothing that can’t be created using LEGO Bricks, which is evident through projects such as a functioning V8 engine, a replica of the USS Harry S. Truman, and a life-size, 23-ton X-Wing, to name a few. Now an unknown engineer with a YouTube channel known as the Brick Experiment Channel has designed a flying quadcopter made almost entirely out of the popular building bricks. To be honest, the first several minutes into the video had convinced me it would never achieve flight, as the thrust-to-weight ratio of some of the motors were unbalanced, favoring weight rather than thrust.
It turns out, I was wrong, and after some tweaking of his design, his drone managed to become airborne and controllable. On the hardware side, the engineer used four Lego Propeller 1 Blade 14L (89509), and four LEGO Power Functions L-motors (88003), which have a 1:1.67 gear-up for each rotor. He then constructed the frame out of LEGO Technic liftarms and other assorted pieces, which helped provide a level of rigidity to achieve flight.
On the electronics end, the engineer employed a Matek F411-mini for the flight controller, along with four MOSFET IRLR2905s, a Schottky diode 1N5819, and a 12 kOhm resistor for the motor driver circuit. He also used a FrSky R-XSR Micro (2.4GHz) for the radio receiver, a FrSky X-Lite (2.4GHz) for the transmitter, and a LiPo 9s 33.3V 200mAh battery he made using nine Turnigy nano-tech 200mAh 3.7V 35-70C Pico batteries to power the craft. In the end, the engineer's LEGO drone achieved controllable flight at a weight of 410 grams (with battery), a max thrust of 470 grams, at a flight time of around two minutes.