DSHOT sucks, at least in some specific cases

INAV 2.1 finally introduced DSHOT and just like we expected, introduced some problems. Like quads falling out of the sky. The problem is more prosaic: it is the hardware or to be more specific the cable. The longer the signal cable between FC and ESC gets, the more probable it is that it will not be able to transfer DSHOT. Things like slew rate and bandwidth show themselves.

How much does a propeller weight? Mass vs. moment of inertia

How often, when you watched or read a brushless motor review you've heard a sentence like "this motor will not have any problem spinning a heavy propeller" or "this motor is designed for light propellers". Or "this is a very light propeller". But what does that really mean?

Thanks to our good friend Sir Isaac Newton we know that

F = ma

Where F is the force, a is acceleration and m is the mass of an object. In this case, mass is the unit of inertia. This is all true for propellers if you want to throw them in linear motion. But propellers rotate and that changes a few things. Instead of mass we are interested in the moment of inertia and mass distribution around the rotation point.

The news – INAV 2.1, Betaflight RPM filter, IMU-F goes open source and Matek 4in1 ESC with SerialShot

In this episode of The News

  • INAV 2.1 is here and we have a lot of code waiting for INAV 2.2
  • Betaflight 4.0 is coming closer and closer together with RPM filter that analyzes RPMs of motors (via ESC telemetry) to set up very narrow notches. What a nice idea!
  • Something very fresh in terms of hardware: Mateksys aka Matek has built their own 4in1 ESC. But instead of doing what everybody else is doing (putting 4 separate BlHeli ESCs on one board) the wrote their own ESC firmware, flashed a single STM32F405 with it and called it a day. Of course it took much longer than a day (a year) but finally something very very fresh in the 4in1 ESC world! Kudos, I can not wait for the actual hardware