Eachine TX805 5.8GHz video transmitter with SmartAudio review

I love Team BlackSheep Unify Pro series of video transmitters. But they are bloody expensive. $50 for an HV version is way too much in my opinion. Still, I own several of those. Whey on Banggood I've found a presale of Eachine TX805 VTX with SmartAudio for $16, I could not resist and I've ordered a couple of them. This is what came out of it:

Want to fly longer with a drone? Here is what you have to do!

I will keep it short: drones are not designed for a long flight. Sure, you can put bigger props, bigger batteries and make it lighter, but comparing to even simplest airplanes, there is nothing to compare.

The conclusion is: try airplanes. They are cheap, simple, easy to fly with modern flight controllers and are much more efficient than drones!

Flying R2-D2 or SpaceX Falcon 9? Both – RC coaxial dualcopter

The second generation of my 3D printed coaxial dualcopter is here! And this time it works almost as I wanted.

3d printed RC coaxial dualcopter

Just watch the video

On the more technical details:

  1. It runs INAV 2.0 with a custom mixer
  2. Thrust and yaw control is provided by 2 counter rotating propellers
  3. Upper motor is 2205 2300KV with 5×4.5×3 propeller rotation in CW direction
  4. Lower motor is 2205 2600KV with 4×4.5×3 propellers rotating CCW
  5. Control surfaces are rotated 45 degrees from the long axis to fit servos
    flight controller is also 45 degrees rotated
  6. Any 9g servos will do
  7. runs on the 4S battery that has to be on the top of the device
  8. All 3D printed parts can be downloaded from Thingiverse

Required parts:

  1. 2205 2300KV brushless motor
  2. 2205 2600KV brushless motor (2300 also will do but will have less yaw authority)
  3. 5×54.5×3 propeller
  4. 4×4.5×3 propeller
  5. 2 14mm carbon pipes (12mm internal diameter), each around 270mm long
  6. 2 2g servos
  7. 3M bolts to secure the motors
  8. good adhesive tape to make control surface hinges
  9. pushrods
  10. hot glue
  11. flight controller compatible with INAV
  12. radio receiver

3d printed RC coaxial dualcopter

It’s time to start to think about INAV 2.1 – DSHOT and braking mode

It's time to start thinking about INAV 2.1. No, I will not give you any timeline, but I can point two features that are very likely to go into the upcoming INAV release.

The first one is Braking Mode for multirotors. I already made a video about it, so you might want to watch it first. Right now there is an open test phase for this feature made as part of my fork of INAV. If you want to test Braking Mode, please visit this page and download the hex file for your board.

On top of that, it's very probable that DSHOT will finally make it to INAV too! DigitalEntity started to tackle with the DSHOT implementation so yes, this is finally happening for INAV!

DIY 4S battery pack from 18650 Li-Ion for RC FPV drone

've made me an endurance Li-Ion battery pack for my 7 inch endurance quadcopter. With good quality Sony 18650 VTC6 it is possible to get 20A constant current which is enough for an airplane or endurance quadcopter. Works just fine and with reasoable speed of 40-50 km/h I'm getting more than 15 minutes of real flight. Not hover. Flight. And at the end, it still has some juice inside. Not bad, not bad at all.

When Red Cat tries to buy my Blackbox logs, it smells fishy

Out of nowhere a company, RedCat, jumps with a super duper web page that allows you to analyze your blackbox log with something that apparently is based on Blackbox Explorer and Plasmatree PID Analyzer, puts blockchain, artificial intelligence, law regulations into the mix and on top of that, almost offers to pay you for that. I say what?? This just does not adds up. RISC-V, blockchains, commercial drones…. too much in one product…

7 inch quadcopters fly like shit? Well, kind of, yes…

So, you got yourself a 7-inch quadcopter drone, you try to tune it, and you finally discovered that something is bloody wrong? Whatever you do, no matter how long you tune the PID gains and filtering, you can not get rid of jello and some strange vibrations? Welcome to the club mate!

Apparently, scaling 5-inch frames to 7-inch ones in XY axes does not work! Longer arms equal lower modal frequencies. Bigger propellers equal lower vibration frequency. After combining both factors, we have frame oscillations that are happening on the hardware level. No way you can tune that thing out. To make thing worse, 2205 and 2206 (even 2207) motors does not have enough torque to quickly change 7-inch propeller rotation speed.

For the details, watch the video.