A British man, YouTuber “gasturbine101,” has posted a video of the first test flight for his “Swarm Manned Aerial Vehicle Multirotor Super Drone,” a “pentacontakaitetracopter” (aka a multirotor with 54 blades). The flight for this over-the-top flying vehicle lasted for about ten minutes and it looks like most of the time he was only about 4′ to 6′ off the ground. At one point he guns it to maybe 20′(?), but is only there for a few seconds. He concludes from the test that there’s a lack of “yaw authority” (i.e. control over side-to-side movement) and that he’ll probably need to add a tail rotor.
He writes of the build:
Props at 18″ were the largest I could find with contra-rotating pitches and so that defined much of the layout. Also the fine pitch allows them to turn at high speed which reduces motor weight for a given power. Motor KV was chosen to work with 4 cell batteries with 20% or so control margin. This low margin maximizes the ESC [Electronic Speed Control] efficiency, higher margin results in higher circulating current losses in the ESC and motor, reducing endurance.
54 was chosen as this fits the hexagonal close pack layout. 6 more could be added in the center. 18″ props at 5000 rpm though hazardous, are still much less so than 6 5″ ones. Where could you get a low power 5″ prop from weighing less than 1Kg with opposite pitches? The 54 gives good redundancy as mechanical and power electronic systems are the main failure areas. I have had one ESC randomly fail already. Controls could be made fully redundant (9 x KK2.15s) so only the control sticks (and pilot) are single failure points. Redundancy increases the likelihood of failure but reduces the consequences.
Props are standard RC aircraft types used at a relatively low fraction of their thrust/RPM capability. So should be reliable though needlessly heavy. Being inline with my head the polycarbonate dome is for protection. The polythene bubble balloons up catching some ground effect pressure rise contributing to lift. It also doubles as a rain shelter.
Batteries, ESC, and motor are close together to minimize wiring weight which is significant because of the high current 30A. Also the batteries dampen vibration. Individual batteries does mean some may run down a little quicker than others. The front and rear groups are used for pitching, a more common maneuver so far than roll.
You can see a few more videos of the Swarm vehicle being built and tested on gasturbine101’s YouTube channel.
Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.View more articles by Gareth Branwyn