#video on how 250g+ #flying #drones need to be registered in Germany and some other countries
#video on Luke Bell and Mike Bell #manufacturing #Guinness winning fast #flying #drones called "Peregreen 2", in part by CNC-cutting frame parts out of a carbon-fiber-reinforced plastic sheet (#sheet-cutting). Because streamlining was a top concern, it’s sort of rocket-shaped, which they played with by printing a transparent tail and illuminating it from within. Their fake batteries caught on fire, their motor wires caught on fire, their motor wires desoldered themselves from the ESC, their ESCs caught on fire, their PID control loops went out of control and crashed the drone, their motors turned out to be anemic, rough skin produced excessive drag, etc. But finally they got it to go 133m/s average over 100 meters, 142m/s peak. They were using FPV flying with goggles.
#video by #Nicholas-Rehm of dRehmFlight on #manufacturing a #flying ceiling fan nearly five meters in diameter out of insulation foam, Gorilla Glue, pine boards, and plywood, for the aerial combat part of Flite Fest in Ohio. Video sponsor PCBWay made the motor mounts by #sheet-cutting and bending 4mm aluminum plate. He’s using two 16000mAh 22.2-volt 15C battery packs to power its 15kW in 12 730KV Emax motors. He fried two Teensy microcontrollers because the power line to one of the four arms was hooked up backwards. Unsurprisingly it ran out of battery quickly; the battery packs were only rated for 10.7kW, and for under 4 minutes. He probably should have put some skin on his foam, because one of the blades broke lengthwise along a pine board after an impact, which would have been easy to prevent.
Mike Bell’s #video on #manufacturing the #Guinness winning #Peregreen-2 #flying #drones explains why they wanted inherent stability: so they wouldn’t have to waste differential thrust on stabilization. He explains the batteries were 48V, 12S, 1500mAh × 2, 160C (!!!). To smooth the transparent canopy they printed it from PVA (!!) and misted it with isopropanol for days. Apparently he designed the shape in Blender!
#video on the new #Hacksmith lightsaber, which burns propane preheated with heatpipes with liquid oxygen in order to fit 90 seconds of fuel and oxidizer into a handheld form factor. A chemical oxygen generator would be much more practical.
#video by #Steve-Mould on water-powered timers that oscillate using trapped air, a somewhat more complex design than the geyser pump. Super confusing, I don’t understand it. #mechanisms
#Veritasium #video on expertise and expert performance (Tetlock, Buffett, Kahneman, etc.) Lots of filler: stock footage and talking heads.