Since the inception of the INAV Fixed Wing group at the end of 2018, there has been a lot of emphasis on fixed-wing, and a lot of refinement in INAV for fixed-wing uses. At its core use, INAV for fixed-wing is getting closer to being fully baked. As Paweł explains it, planes pretty much fly themselves. Thus there isn’t a lot that needs to be done to keep them airborne. Thus, newer versions of INAV tend to offer more goodies for the quad pilots than fixed-wing pilots. However, things do happen. And that’s the main problem. There are so many of us flying INAV fixed-wing planes now that big problems are usually identified quickly. Intermittent problems are harder to find. INAV Blackbox is an invaluable tool to discover intermittent problems.

In the Masterclass tuning guide, Marc Hoffmann highlights the need to read data from the Blackbox to make fine calculations. Also, we use the Blackbox to setup ideal PIDs for new builds. When it comes to obtaining data from members of the group, what we’re after is data from crashes or unexplainable flying occurrences. Anything less than a fatal or serious issue is up to you to learn how to read the data on your own.

What is INAV Blackbox?

The Blackbox is a device that records data throughout your flights. The amount of data it records is impressive: Altitude, location, heading, power consumed, and more.

A Blackbox is not available on all flight controllers. The most recent flight controllers have a MicroSD card slot for the Blackbox. It works best with a 4GB MicroSD card. If you put a larger MicroSD card into the slot it still only recognises 4GB. Marc Hoffmann has suggested a class 10 card.

My thoughts on MicroSD Cards

4GB MicroSD cards are nearly non-existent. There are still a few made here and there. Marc was able to find some in the UK that were class 10 for not too much money. However, I couldn’t find them in the United States.

What I was able to find were class 4, 4GB and 8GB cards used on eBay. They are around $2 each. But, they are name brand cards. From what I can tell about the no-name Chinese cards is that after a year in something like a phone they stop working. If you only have one or a few INAV planes, you can usually find a decent name brand Class 10 16GB card for around $5.

The main takeaway is that you get a decent brand, name card that is at least 4GB. The card will get written to every flight.

Some flight controllers don’t have MicroSD cards slots

There are flight controllers without MicroSD card slots for Blackboxes. The main one that comes to mind is the Matek F411-Wing. There is around $15 difference between this flight controller and the F405-Wing. There are a lot of reasons why the extra money is worth it such as the extra UARTS. But, the SD card is a selling point. If you are going to fly one plane more than any other plane, make sure it has a Blackbox.

I will also note that there are some internal Blackbox options that come with some flight controllers. But, they are usually something tiny like 8mb of storage. If you go this route you have to stop flying your plane as soon as you encounter a problem you want to see on the INAV Blackbox. The memory is good for usually one flight.

Why INAV Blackbox is a benefit to you

You will not believe how much data is these cards can record. With the Blackbox file, we have so much more information about exactly what is going on with the plane. Sometimes the information we need to figure out a problem is in milliseconds of data. The video won’t show the issue but the Blackbox can grab it. If you really want to know what is causing a problem with your plane, the Blackbox is crucial. We can get a complete picture of what your plane is up to and what is and isn’t working.

We also need video from your goggles as well. Please keep in mind that doing all this research is time intensive. So we cannot go to this extreme to figure out yaw waggle issues on your plane. But, if your plane crashes without warning, and you post the video to the group and we’re stumped, the blackbox data can help us sort out the issues.

Take one for the team, setup your Blackbox

How to set up the Blackbox

This is one of the handiest little tools that hopefully you’ll never need. It only takes a few dollars and a few minutes to use it. So, why not?

  • Acquire 4GB or greater MicroSD card. More information on this above.
  • Download MicroSDCard Formatter (https://www.sdcard.org/downloads/formatter/)
  • Format the card with a quick format
  • Place it into the MicroSD cards slot on your flight controller5.
  • Attach your flight controller to your PC
  • Run INAV Configurator
  • Click on the Configuration Tab
INAV Blackbox - Configuration page
  • Go to the Other Features sections and enable Blackbox Flight Data Recorder
  • Save and Reboot
  • Click on the Blackbox tab
INAV Blackbox page

INAV is now set to work with a Blackbox, but we need to change a setting to get it working more efficiently. Change Portion of flight loop iterations to log (logging rate) to 1/32 3%. Look at the image, make sure the onboard MicroSD card (bottom of screen) is blue. This means the card is inserted properly and working with INAV.

Save and reboot.

Note: Logging Rate

1/32 is the lowest logging rate. This is fine for logging with fixed wing models.

You will not need to do anything else. When the card fills up it will overwrite the oldest files.

What to do with the data

Paweł has videos about how to read your Blackbox data. He even shows how to read the GPS data in Google Earth, to plot your entire flight. It’s very cool. When you look at the data for the flight you can see how the servos moved, altitude, motor, and all types of interesting things. If your into lots and lots of data, you’re going to get it. Otherwise, all of this has very little value to you, so why bother?

The answer is is simple, you’re doing this for the INAV fixed-wing community. Let’s be honest. You may install this MicroSD card into your flight controller and never take it out. But, if something strange happens in flight and other people saying the same thing is occurring if you have the card we can figure out what the issue is. You may be the only person who has the card inserted that can help us find the solution to the problem.

If your video goes static and your plane crashes you can post the last few seconds of the flickering video and we’ll all give our theories. If you retrieve your plane and get back the MicroSD card we can figure out the issue. Perhaps one of your LiPo cells died. This information will show up in the data.

You could do nothing

If your plane is flying okay, you may never need to pull the card out. But, if there are problems, we have a lot of information to pull from the card. Just keep track of the date of the incident because we’ll need just the file(s) from that date.

Or you could explore

You can learn a lot about your plane and how it’s flying. There are tools for opening the files and reading the data. It will show you the entire flight. You can get granular information on where you spent your energy, where your throttle positions were, the altitude at any given time in the flight. You can also do a 3D map on Google Earth of your entire flight. Paweł has some very good videos explaining how to tap into your INAV Blackbox.