Help -- Need to optimize telemetry logs for flights longer than a day

I am getting ready to attempt some very long flights.
Project here:

[Cube/Pixhawk2.1/MavLink/Ardupilot with latest code]

I am interested in cutting down the file size of the dataflash logs and maybe the ground telemetry logs.
My first long endurance flight target is 35 hours.

I know that LOG_BITMASK can be used to limit what is recorded – I could just record gps data and probably be ok. I’m guessing this is my best option.

That said, I would prefer to increase the logging interval to say 1 second (or even more) and record most data types.
I know this can be done with INS_LOG_BAT_LGIN for INS data … but haven’t seen a “knob” to control other data type rates.

Any ideas?
If you were flying for more than 35 hours, how would you configure onboard datalogging and MavLink telemetry?


I am interested in cutting down the file size of the dataflash logs and maybe the ground telemetry logs.

Why? Storage ought not to be a problem on either side.

Decimating the data can be done post-flight if required.



Cool project. Please keep us updated. Is your endurance goal for the VTOL version?


With all the default settings, my telemetry files grow at a rate of about 250MB per hour (~9GB over a 35 hour flight). Even if I cut out some, it will still be fast … and there will be big gaps in my data.

During a long flight, I would like to record most data – just at a reduced rate. That would still help me identify the cause of a crash – the most likely cause of which will be vibration-induced equipment failures.

Anyway, if there isn’t a relatively simple way to do this, I will just pick the most important categories, do a test run, and make sure I don’t fill up my entire SD card.



Thanks! Will do.
Yeah the initial target is 35 hours for the VTOL version which I should be able to do without full fuel. (assuming I don’t stuff it into the dirt)

The current absolute VTOL endurance record is 32 hours by the Aerovel Flexrotor in 2017. Note that this isn’t an officially FAI-sanctioned record – with the advent of GPS and detailed telemetry files, I’m not sure that anyone cares.

Previously it was Latitude Engineering at 22 hours (unoffical) and the Frontier Systems A160 helicopter at 18 hours.

If successful at 35 hours, I plan to try to push past 50 hours – and maybe get it sanctioned.
That said, we just had a baby and I might be getting busy at work again, so I’m only going to be able to work on this thing 4 hours a day tops.


Congratulations for the baby and good luck for the project.for 35hrs what is the fuel consumption ? Will engine runs 35 hrs without any problems ? Have you planned any backup if engine fails.

I don’t know exactly how much it will burn, but ground tests indicate it should be 200 grams per hour or less.
Only one way to find out how long the engine lasts. :slight_smile:
Will be running with good oil.
I plan to fly in a circle within visual line of sight in the desert. If the engine fails, the backup is the wing – and then the VTOL motors to arrest.

Oh nice,:blush: keep posting…