Weird flying - EMAX Hawk 5

betaflight
hawk5

#1

So updated the EMAX hawk 5 with Betaflight 3.5. Restored the settings from the previous backup which worked beautifully. Everything was going ok until I tried hard throttle and started to do a roll using pitch. This happened:

Any thoughts on what it may be occurring here? It was only under high throttle that this happened. Everything else worked fine (well apart from OSD which I forget to set up)


#2

This only happens in 3.5

I would go back to 3.4 and make sure everything is ok

If it is ok then theres more than likely BF is misbehaving for some reason.
Trying flying 3.5 on defaults and make your changes my hand and try and find what breaks it


#3

I assume it was flying fine the rest of the flight?

My first suggestion would be to look at the blackbox logs, particularly look at the RC command values along with the motor outputs and also the gyro readings. Check that the RC commands correlate roughly the motor and gyro response, and for the gyros check for excessive vibrations or flat lines.

Update: @DoomedFPV beat me to reply, but his ideas are also a good place to start too :slight_smile:


#4

Alex, Dnuts - thanks for the advice. Will do what you say and let you know how I get on.
Have to say though - regardless of the Hawk 5 misbehaving - it’s one beautiful craft to fly. So much easer than the TBS Oblivion on standard PIDS. :slight_smile:


#5

Ok update on this: Took Betaflight 3.5 back to default settings and left as is. Didn’t try restoring my 3.3 backup. Took the Hawk out tonight and for a while it flew absolutely fine. After hard landing (not quite a crash) and a bent prop (bent back) the weird yawing came back. It only happens above 1/2 throttle. Keep it below that and everything is fine (makes for some bum clenching loops :wink: ) Other thing noticed - above 1/2 throttle the Hawk vibrates like crazy and the props do not sound good.

Going back to Betaflight 3.3 and restoring the Hawk back to known good flying settings. Hopefully that’ll cure the problem.


#6

Might be worth having a look at the logs as it sounds like it may be a intermittent fault on the yaw gyro as hard bumps can damage them. Another way to test is to enable expert mode on betaflight and view the sensors tab, then the yaw gyro (Z axis) may show some strange readings or drift alot more than the other gyro axes.

Alternatively if you slow down the update rate that could also offer some band aid if the gyro is on its last legs.


#7

I hope the gyro isn’t on its last legs Alex as I only bought it off you a few weeks ago! I suspect it is more likely to be the upgrade to 3.5 as the Hawk was running a dream before then. Fingers crossed anyhow. I’ve downgraded but probably won’t get chance to fly until Monday, so will let you know results on the effect of downgrading.


#8

Any update on this, seem to be having the same issue now after updating to 3.5. Full throttle flips seem to cause a strange reaction and sends the quad into a frantic spin, mine is more aggressive than even shown here.


#9

I’ve gone back to a previous version of Betaflight and all works ok now. I’ve got another drone build in the works with the same Emax flight controller stack, so will be interesting to see if that does the same on 3.5


#10

I will talk to Emax engineers about this and get back to you guys here, but maybe its got something to do with gyro filtering on V3.5.


#12

Good to know, thank you for the update anyway and do let us know with your new build if you stumble across the same issue, will revert back to 3.3 so as it seemed to fly dandy on that. Thanks Alex for your efforts, curious to find out what the issue may be… no excuse to buy new shiny motors now :frowning: