Babyhawk 4" Full Throttle Issue

[controlz]

Hello,

My brand new Babyhawk 4 has had an issue since I took it out of the box. When increasing the throttle a little, it suddenly goes to max power and the only way to stop it is to kill it. I have tested on betaflight without the props and with air mode disabled and the throttle is responding perfectly. It doesn't appear to be an issue with the radio.

Either way I thought the best option is to download the latest CLI dump from the Emax website and overwrite the preconfigured one. I have added this to Betaflight but getting the attached errors.

1. Does anybody know why the quad is responding like it is?
2. Does anybody know why these errors are displaying in the CLI dump?

Thanks

[ched]

First thing to check is does the cli dump match the betaflight version? If it does then check the target of the cli vs your original cli backup?

Not sure on the errors but make 100% sure target and betaflight version are all matching.

One other thing to check is does the 'model' in Betaflight moves the same as the real quad. As the increase in throttle could be because the quad thinks it's facing a different way i.e. FC direction is different to what BF is expecting. Calibrate gyros.

If all versions are correct then maybe reinstall same version of BF (with correct target) but reset to defaults. Setup manually - don't use cli dump. Then test to see if it behaves normally. If it does then make a backup (cli dump /all). You could compare the cli's with ref to PIDs but it could be the PIDs that are the issue (I term way too high?).

Hope that helps, let us know.

[controlz]

Thanks for the response Ched.

Here is the CLI file I downloaded from the Emax website.

My flight controller is

# Betaflight / MATEKF405 (MKF4) 4.0.0 Apr 11 2019 / 07:25:14 (9ad2cc844) MSP API: 1.41

I can confirm everything is set up correctly as I am usually able to fly it for around 5-10 seconds at low throttle before I give it a little more and it goes FULL. This is a BNF quad so it is very frustrating I am even having to do any of this.

(Also a side note. My Babyhawk 3" behaved similarly after I flew it in the rain and it got wet! After I dried it out and ran a CLI dump it was fine, but extremely coincidental..)
Many thanks for your help.

[ched]

The cli dump is 'MATEKF405 (MKF4) 4.0.4' Where as your BF version is 'MATEKF405 (MKF4) 4.0.0'!!!!! You need to flash BF 4.0.4 (target MATEKF405 (MKF4)) then use the CLI dump.
 A dump from 4.0.4 will give issues trying to run on BF 4.0.0!!!!!!

[ched]

I seem to remember that BF 4.0.0 was iffy with something about hypersensitivity to D term making quads try and fly to the moon!!!!

So you definitely need to try BF 4.0.4 and the CLI dump.

This references 'the moon' https://github.com/betaflight/betaflight/wiki/4.0-Tuning-Notes

[badger1]

I seem to recall that there have been issues with BF4.0 on smaller (sub-5") quads causing fly-aways, which sounds like the problem you're having.

I don't know offhand what the fix would be - maybe upgrade to a newer version of 4.0.x?  but I hope that pointer might be some use.

edit: dammit - beaten to it by ched

[controlz]

@badger1 and @ched

Firmware upgraded to 4.0.4 and CLI updated with no errors. Thank you!

I will take her for a flight tomorrow. Fingers crossed no more flyaways.

On another note, this quad is made for 3S to 6S batteries and is included with a 4S. I have quite a few 3S batteries from my 3" that I want to use though, however, the velcro strap included is too loose for me to secure them in place. It seems to be for 4S and above. Any ideas?

Also, do I need to be using a different PID profile for 3S? I assume it is tuned for 4S.

[badger1]

On another note, this quad is made for 3S to 6S batteries and is included with a 4S. I have quite a few 3S batteries from my 3" that I want to use though, however, the velcro strap included is too loose for me to secure them in place. It seems to be for 4S and above. Any ideas?

shorter strap?  a strip of something to pad out the battery so it's thick enough for the supplied strap?

Also, do I need to be using a different PID profile for 3S? I assume it is tuned for 4S.

see how it flies on 3S with the default tune.  change it if you think it needs it. 

[Bad Raven]

This is where its useful to have:-

1. A DVR running on the video output to look later on at specific warnings and symptoms.
2. You do have to have all Warnings turned on! 
3. If it has a micro SD log ability use it.

The battery strap issue isn't one, use a lump of stiffer foam and/or turn the battery 90 to clamp on its longer edge.

Don't have the 4" but EMax have started putting profiles for differing battery configs in their default, does this not? As Ched says don't alter anything till you have flown AND looked closely at recorded video output for stability, judder, over or underrun, jello, etc, etc.


I don't have to alter my Babyhawk 3" between 4S and 3S, nor my Tinyhawk Freestyle and Tinyhawk Race between 1S and 2S.

[controlz]

I used a few felt pads and worked a treat with the battery strap :)

Emax have 3 PID profiles but only explain that the first one is set up for 4S.  I am going to run my 3S on this and see how it goes.  I am a total novice though so don't really know what I am looking out for.

Should I expect considerably less flight time on the 3S 650mAh compared to the 4S 850mAh that was included?

[ched]

Don't worry about PIDs yet, it will fly fine on what ever is there. You only really notice issues when you either review dvr footage or you can fly without thinking and you have a bit of spare brain power to analyse things   
I tend to have lots of info on my osd as I like data but I can only really read it when no doing maneuvers 
So just keep things simple take it slowly and remember that it only needs little stick movements.

I assume you have set your rates to something you like? If your rates are too high then the sticks will be megga sensitive. I have my rc rate at about 1.0 and super rate at 0.76 with 0 expo. I found rates I liked by playing with rates in velocidrone. These rates only effect roll, pitch and yaw.
If you want you can tame the throttle a bit by using the throttle expo but you need to set the mid point to the approximate hover % of throttle stick then give it some throttle expo.
As for flight times not sure but use cell voltage as your guide. Personally I come in to land at about 3.5v per cell, a few mins after landing v is about 3.75v. On osd I have single cell v and pack v, sometimes its easier just too use single cell v (not as accurate) as then it doesn't matter 3s or 4s lading v is same on single cell v reading.
3s will be more docile.

[Bad Raven]

Emax have 3 PID profiles but only explain that the first one is set up for 4S. 

Should I expect considerably less flight time on the 3S 650mAh compared to the 4S 850mAh that was included?

So, if the first PID is stated for 4S, the others by extrapolation aren't!        


Duration is another matter, often the prop recommended my makers for 4S is different for 3S, do they state that?

You would expect a 200mAh difference over the 650/850 range, quite a large percentage change, regardless of the cell count, to make a difference to duration, but a larger voltage allows a higher current, so that will pull back its capacity advantage.

A LOT depends on the prop loading and how well matched the motor kV is to the prop.

Long way of saying no bloody idea, go for it and find out!!!