Back in the time when I was building my Arduino based Ludwik Drone I faced a problem of choosing proper motors and propellers. I didn’t know anything about drones at that time so I had to trust motor manufacturer and the datasheet of a motor those are most likely to be a good source of information but what if you want to combine different motors and propellers together? You still need to know the thrust of the motor and propeller, golden rule for drones is to have at least 2 times bigger thrust than weight of your drone (it depends on what type of drone you want to build this rules doesn’t work for racing/acrobat drones and some other). I thought that there must be a device for measuring thrust of a motor, I found some online but those were really expensive so an obvious decision for me wast to design my own! I found some time during my internship at CIT (I was working on airfoil design and testing for a VTOL drone here, that was very cool!) to design a PCB without prototyping and any of the parts, just online datasheets. Surprisingly PCB work just fine! If you want to test your motors keep reading!”