Tarot 680 Newbie

[bobster1982]

Before reading and face palming I apologise! I'm brand new to DIY builds.

So I search for lost dogs in my spare time and I set about building a thermal drone around a FLIR duo R

I bought a 2nd hand tarot 680 and I'm rapidly starting to wish I hadn't!

Specs are;

Tarot 680 frame
Sunnysky V3508-20 580kw motors
DYS 30Amp ESC
Tarot 2d gimbal
13" CF props
unbranded chinesium retractable landing gear
NAZA v2 Fight controller
IOSD mini
600mw 5.8ghz VTX
Taranis X8R and Taranis X9D plus radio gear
LED lighting

I've now modded the following.

Fitted Flir Duo with a custom bracket to the gimbal and a custom DIY USB lead to the camera
Modded electrics with a 12v ubec to run from one 10,000mah 4s Lipo as it was running one 4s and a 3s for the gimbal and camera
Fitted gimbal to correct rail brackets as it was mounted on a block of wood. (yes wood  )
Fitted longer landing gear skids made from 10mm Carbon rod.
Removed VTX plug and extended on wires to allow the Antenna to be underneath the Drone.

Now my issues where I'm hoping for some guidance!

When I lift off the drone will always try to lift off banking to the left. Its not uncontrollable but it can be a pain.

Yaw drift when turning. It can be quite severe and takes a while for it to find its home point after letting go of the sticks. It can be a bugger to fight in ATTI. I've tried an advanced Cal on the IMU and I've checked the props are level and also I've tuned the gains down. ( I now have the gains on remote adjustment on a dial)

Landing

Will always try and land again banking. Its never a smooth landing. I've adjusted battery placement and gimbal placement to bring the CG on the centre arms and it sits level if I hold the opposite arms. I've shortened the Gear legs slightly as there was a lot of slop in the gear actuators and the skid T pieces.

I hope some of this makes sense and someone could give an idiots pop up picture style advice where to look from here? I may not understand straight away but I'm a quick learner and pick things up quick.

Many thanks,

Rob

[hoverfly]

I would reset the esc throttle values for a start, if this dosen't sort it,  recalibrate the imu but offset it in the opposite
direction to the tilt as a last resort.
Another thing to check is that the f/c is mounted flat in  register with the frame, as although the frame may be set up level if the f/c is offset it will never fly level.

[ched]

As hoverfly said but if the gains are too low it will be too slow to respond to things. I would up the gains, I seem to remember there are some suggested ones on DJI site for a hex.
The Naza should be very good at holding position etc. I would say go through all the calibrations you can with the hex on a flat level surface including setting up the tx.

[bobster1982]

I would reset the esc throttle values for a start, if this dosen't sort it,  recalibrate the imu but offset it in the opposite
direction to the tilt as a last resort.
Another thing to check is that the f/c is mounted flat in  register with the frame, as although the frame may be set up level if the f/c is offset it will never fly level.

By reset the ESC values do you mean reset the throttle calibration in the NAZA software on the PC?

[ched]

Just had time to find the speadsheet that might help you : https://docs.google.com/spreadsheets/d/1O74-AtgwDmYoWErgZocGJnhkJ8qgFJRrvQI3IYQctDk/edit?pli=1&pli=1#gid=0 There are over 100 different setups with dji naza and weights gains etc. It might give you some clues?

[hoverfly]

I would calibrate each esc separately, Turn on T/X  move throttle to top then power up the esc, after it does its warble bit quickly pull throttle to bottom.  After this recalibrate the throttle  on the Naza software  although this just gives the throttle range to the f/c  it won't do any harm..

edit , after thought , are the esc ordinary aircraft ones or flashed with  quad firmware.?

[bobster1982]

Just had time to find the speadsheet that might help you : https://docs.google.com/spreadsheets/d/1O74-AtgwDmYoWErgZocGJnhkJ8qgFJRrvQI3IYQctDk/edit?pli=1&pli=1#gid=0 There are over 100 different setups with dji naza and weights gains etc. It might give you some clues?

thats brilliant! thankyou!

[bobster1982]

I would calibrate each esc separately, Turn on T/X  move throttle to top then power up the esc, after it does its warble bit quickly pull throttle to bottom.  After this recalibrate the throttle  on the Naza software  although this just gives the throttle range to the f/c  it won't do any harm..

edit , after thought , are the esc ordinary aircraft ones or flashed with  quad firmware.?

I couldn't tell you I'm afraid. Googling my ESC comes up with a listing that features simon K firmware but without an interface I don't know whats on them.

When It comes to programming the ESC's can I calibrate them leaving them plugged into the NAZA or do I have to plug them into the Controller directly? It's setup to use Sbus at the minute with a few channels for the rest of the equipment.

[hoverfly]

Don't think you can do them plugged into the Naza as it would have to pass  the signal. Usual way is the esc plugged into the throttle channel on the receiver..

[bobster1982]

Don't think you can do them plugged into the Naza as it would have to pass  the signal. Usual way is the esc plugged into the throttle channel on the receiver..

Okay I'll have to re programme the Receiver to no sbus mode

[6705russell]

I personally do not recommend testing each esc on there own, I would always try and use a 6 way servo adapter to make sure these all work in sync with each other, just my view after experiencing similar problems..

[bobster1982]

I personally do not recommend testing each esc on there own, I would always try and use a 6 way servo adapter to make sure these all work in sync with each other, just my view after experiencing similar problems..

I've got servo wires and plugs and crimps. Is it worth making one?

[6705russell]

Yes definitely, can I ask what your gain settings are and is your gps measured correctly for position on naza software?

[hoverfly]

I have had problems doing all ESC at once, the reason being  that they don't all start at the same speed ,doing them one at a time ensures the setting is accurate.. As you can hear when the top throttle is set.
Should be easy enough to do just disconnect the sbus connection and plug straight into the throttle  channel.

[bobster1982]

Yes definitely, can I ask what your gain settings are and is your gps measured correctly for position on naza software?

GPS is measured correctly, double checked and I used a laser line for accuracy

Gains are

Pitch 64%
roll 64%
Yaw 93%
Vertical 100%

Max angular rates are

150 pitch 150 roll

All up weight is 3.5kg with a 10,000mah 4s lipo

[ched]

I know mine is very different (F450 1045 Props, 3S, 920kv motors with gimbal etc 2.5kg) but here are my gains: Well they are the last notes I have and I cant hook it up to computer as middle of house move.

Pitch: 130%
Roll: 130%
Yaw: 120%
Vertical: 130%

Attitude Pitch: 120%
Attitude Roll: 120%

I set mine by taking a Win10 tablet to field and taking off flying a little and then landing and tweeking gains and seeing if it was more responsive or introduced oscillations. The Vertical does introduce a bit of oscillation on fast decent but that is just prop wash.

I did notice that having the gains too low it was very sluggish and sometimes even difficult to control as it was responding too slowly and sometimes it couldn't recover from gusts etc.

I will check my PC for notes if I made any changes to the above.

[bobster1982]

I know mine is very different (F450 1045 Props, 3S, 920kv motors with gimbal etc 2.5kg) but here are my gains: Well they are the last notes I have and I cant hook it up to computer as middle of house move.

Pitch: 130%
Roll: 130%
Yaw: 120%
Vertical: 130%

Attitude Pitch: 120%
Attitude Roll: 120%

I set mine by taking a Win10 tablet to field and taking off flying a little and then landing and tweeking gains and seeing if it was more responsive or introduced oscillations. The Vertical does introduce a bit of oscillation on fast decent but that is just prop wash.

I did notice that having the gains too low it was very sluggish and sometimes even difficult to control as it was responding too slowly and sometimes it couldn't recover from gusts etc.

I will check my PC for notes if I made any changes to the above.

Thanks for that! interesting you say about gusts. so the gains also effect the auto pilots abilities. That will be why it looked like a leaf in a 9mph breeze. I have the gains set to a dial on the trans so I can adjust them in flight as I don't have anything PC wise I can take in the field with me and I have android gear or I'd buy the bluetooth unit.

[ched]

I think the gains are also used for 'auto pilot' control. I think the Attitude ones are more auto but that may be wrong way round. It is about 6 months since I have had the F450 out so difficult to remember.

PC wise I bought a Chuwi 8" dual boot (win10+Android)  tablet for about £70. I used to mainly fly from our caravan site so lugging laptop/pc wasn't ideal :) So tablet was bought. Must admit Win10 partition is too small and don't really use Android so may just delete Android partition and extend Win10.

[6705russell]

Your gains are way to low, you will get a lot of drift with your settings, will let you know tomorrow what would be acceptable..

[bobster1982]

I was on a tarot owners club group and had this reply from a member:

This post is deja vu all over again from years past. The go-to concern is always gains, which in fact, very few know what they are or do. The solution is almost NEVER gains. So, here's the technical solution from real live rocket scientist. You are under powered. A 580kv motor running ANY 13 inch prop on a 4S battery is a 400g thrust motor at 50% throttle. In a hex that equates to 2.4kg all up. At 65% motor throttle, your motor is rated at 600grams. You have a few solutions. First, carry less battery. Second, extend your arms and spin 14" props or better yet, increase the size of your motors to a MN3510-630kv. Ideally at your AUW, you should have used 630kv motors, extended arms and spun 15x5" blades. Had you done that your efficient would increase to 8-9 grams/watt, from 6-7 grams/watt which has a side benefit of improving your air time... which is predictable at .71*10000*9/3500 or 18 minutes.

Does this make sense to people? If so if I do upgrade the motors will I need to change the ESC's?

[ched]

OK so I am no expert and I was thinking that the motor kv seemed low.
If your motors are a little low for the weight then it will just need more than 50% throttle to get off the ground. Note the Naza should hover at 50% throttle on you TX but it may be giving the motors more power, it's just 50% tx throttle is 'hover' point for the Naza.

So I believe that the 'getting brown about in the wind like a leaf' is down to gains. Hey what have you got to loose by upping the gains (there are on your tx!). Give it a go and see how it goes.

As for drift just make sure you have calibrated the FC on a level surface and do the Naza dance to get compass calibrated.

I did have a yaw problem on my F450 and this was traced to a loose magnet in a motor bell!

Best to try things without the camera and maybe even remove the gimbal to test things. That way you are risking less and have less weight to lift. That might help to prove if the motor/prop/weight theory is correct. Remember the hover position will be 50% as Naza is taking care of that (in gps mode, not sue about Atti).

Good luck and give it a go.