Engineers at the University of Manchester set themselves the task of building and flying the largest quadcopter drone in history, and in order to get it legally regulated by aviation authorities, they chose some interesting materials. The UK Civil Aviation Authority allows drones with a take-off weight of less than 25 kilograms (55 pounds) to fly without special permission, so the Manchester team designed a drone that weighs 24.5 kilograms (54 pounds) to get around this restriction.
The Giant Quad Flyer project began as "a curiosity-driven venture to inspire students' design creativity by utilizing a suitable alternative, low-cost material to create lightweight aerospace structures that is more environmentally friendly than common carbon fiber."
High-strength, lightweight carbon fiber was ruled out, and the students ultimately settled on a hollow box frame design made from 5 mm (0.2 in) thick foam board, composed of a foam core and paper skin. The frame is created by laser cutting foam boards and gluing them together with hot glue.
"Foam board is an interesting material," said research engineer Dan Koning, leader of the design and construction team. "Used in the right way, we can create complex aerospace structures where each component is designed to be as strong as it needs to be - there is no room for over-engineering here. Thanks to this design discipline, and following extensive background research, we can confidently say that we have built the world's largest quadcopter drone."
The drone reached a height of 6.4 meters (21 feet) from corner to corner. "As of the time of writing, no unmanned quadcopter (four rotors) larger than the Manchester aircraft has been recorded in any weight class," a press release from the University of Manchester reads.
Of course, there are much larger electric VTOL aircraft prototypes - but they use more than four propellers. The team’s self-imposed carbon-free restrictions mean that anyone willing to put in the time can easily set a world record through reasonable means!
You can watch the big bird take off in the video below: