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ZOHD KOPILOT Flyaway

#41
Last week i installed the ZOHD KOPILOT in my ranger 1600 .
I'm not very familiar with flight controllers and my main reason for getting one was so i can fly fpv and if i should lose signal it should RTL.
this feature worked great when testing it out last week and the auto launch feature was super cool.

Today i took it out to a new location for an fpv flight (Big dry mudflats in front of me and tall grass over 1.5 meters tall and thick bush land behind me with houses behind that).

I switched to manual mode and launched but when i tested RTL the motor died and was not being able to get the motor to re-arm i tried switching through to different flight modes so had to glide it back down.
This happend on the first 2 launches.
This should have been enough for me to realize something is not right and mabey pull the pin go home and investigate.
But i was so keen to have a fly i plugged the battery back in waited for it to re-arm and went for round 3.
BIG MISTAKE!!
This time when testing RTL the motor didn't disarm but throttled up and i could tell from my fpv feed it wasn't heading back.
I ripped off my googles and desperately tried to find it in the sky.
I could faintley hear it flying away but had no visual and could tell it was a long way away.
Then it went silent ( Either too far away or the motor dis-armed )
I walked for about an hour and a half with my googles with me in the hope i might pick up a video signal and my radio constantly tellling me rssi low,/critical telemetry lost, telemetry found .
I felt sick in the guts as I'm sure the bushland is riddled with snakes and with the tall grass it could be anywhere (Tree, Burried in the tall grass in someones yard or roof) and just as i was about to call it quits and head back i found it.
As luck would have it it landed in the shorter grass (Long way from RTL) in front of the heavy scub and trees
So very lucky.
The warnings were there and i was silly enough to ignore them. ( I've learned my lesson).

So now to my question .
Any idea what might have happened ?
I'm thinking when i hit RTL the ESC's BEC might be having trouble providing enough power for the 4 servos ,receiver and the flight controller .
maybe it's shutting down the ESC temp. and then trying to reboot the flight controller.
Not sure.
I had the first problem with mine, I didn’t allow the gps to connect and switched it to manual to launch and when you switch to stabilized or rth it just cuts the power, as for the fly away I’m not sure I have never had that with mine.
 

Hondo76251

Legendary member
#42
I have several now, have always worked flawlessly for me. It is important to make sure you have a GPS lock before taking off or the system might have problems.

I always set the failsafe on the receiver so that it goes into RTH mode in the event of signal loss, but again, that is counting on the GPS to have the propper home location...
 
#43
just as @Hondo76251 stated you need to get your gps lock......

correct no power to motor without GPS lock in RTH or STAB mode...to help prevent fly aways

if you dont wait for the gps lock and you fly in manual mode while flying the zohd finally acquires sats while flying and if you toggle to RTH or IF you loose signal and your failsafe kicks in IT THINKS HOME POSITION IS where ever it was that it acquired the sats and where it will "fly away to"

have you set fail safe to....... channel 5
 
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Hai-Lee

Old and Bold RC PILOT
#44
If using Failsafe to activate return to home it is important to ensure that your failsafe setting does not reduce the throttle to zero. At distance if a plane drops in altitude its radio horizon also decreases. So if your model does turn for home but it starts to glide down it may be that the signal will never be regained and the model will still be lost out of sight.

It has been months since I have been flying but from memory I set the throttle to around 50% and the model to climb slowly for RTH or geofenced modes.

Just what works for me!

Have fun!
 
#45
you are correct for most FC ofcourse, but this doesnt apply to the zohd kopilot
guys have been testing and found that as long as channel 5 is set to failsafe the zohd deals with the rest, no real worries if you set to wrong toggle position the zhod doesnt care it only only cares that it is set to failsafe to channel 5 and it does the rest it speeds up when necessary and fly's at quite the clip, then it slows down when it approaches home destination ...you can hear it adjust throttle

just to be clear you still need to program it to a 3 position switch that you can manually change modes, but for failsafe just tell in channel 5 and your good to go

zhod takes over throttle in RTH mode whether you toggle it or loose all radio signal, but the model requires to be moving so many meters per second for the throttle to be operative

this is why launch assist works, before you launch you can set the throttle to say 3/4 throttle toggle to RTH mode and chuck the plane in the air, the zohd calculates the inertia of the model moving and then throttles up and flys to its return to home altitude and loiter pattern till you take control
 
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#46
there is one other failsafe issue we should talk about while we are at it

its a good idea to run a 5 volt ubec voltage regulator in your planes and remove the red and black wires from your ESC to your receivers just leave the white wire and replace the red and black wires with 2 wires both + - from the 5 volt ubec so that your now powering your receiver from the ubec, and the reason for this is if your ESC dies yes you will lose your motor and its thrust but your receiver and kopilot ARE STILL BEING POWERED BY THE UBEC so your servos flight controller and RTH will still work and you can glide your way back and finally touch down as opposed to dropping out of the sky with complete loss of control
this is getting pretty geeky I know but if we are spending the money on flight controllers as insurance to get your gear back then think about this its worth the effort
 

Flite Risk

Well-known member
#47
trouble shooting is something I do often, so the concept is not lost on me. sometime even troubleshoot well. other times i just need another set of eyes on something. I sleep better that way.

Trouble shooting it, I threw quite a bit at that kopilot;
multiple receivers,
multiple esc's
multiple transmitters, wires, batteries and protocols to boot. in every instance I can not control the mode switch nor the throttle.

i think the kopilot is bad....


 
#50
first thing ....my zohd gets twitchy when I test "return to home" on the ground....because its trying to fly to the last recorded GPS position and get to RTH altitude JUST AS IT SHOULD BE DOING but because the gps see's the plane is NOT moving the zohd wont allow the motor to run....

I would mount your GPS puck on the outside that foam fuse for best reception and distance the GPS from the other electronics reducing elec interference

did you wired up the zohd by pwm or sbus and what brand of ESC are you using, there are some incompatibility issues with ESC's

how comfortable are you with Open TX I could send you my Taranis QX7 setup files and you can look at my settings or even import and try them but you must be comfortable with backing up your taranis in openTX and importing and exporting files into the taranis




and if in the event you got a defective unit and you wont be the first, I suggest you return it and buy this one ....
Sparrow FC Flight Controller Stabilizing 6-Axis Gyro With M7 GPS Module for FPV RC Airplane Fixed-Wing
https://www.banggood.com/AFPV-SN-Sp...p-1356353.html?rmmds=myorder&cur_warehouse=CN

it IS a clone of the zohd so you will feel fairly comfortable with setup but its been improved, more features and more importantly...RTH altitude is over 300ft ...the zohd altitude is only just above 114ft and fly's into trees
 
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Hondo76251

Legendary member
#51
It would be nice if the altitude was adjustable... although I want it lower! lol I generally fly from a hill if I can and there is nothing around me for miles. My trees are 50' at the tallest so I don't need a 300 ft RTH. I actually prefer the ZOHD's 100' height.

I wouldn't test RTH on the ground. Like @Aireal Anarchist said, it doesn't tell you much and if you inadvertently have your throttle up it can arm and try to fly its loiter circle. :oops: I did this once when playing with the "auto launch" feature. I walked a ways from my truck, decided to fiddle with something, went to walk back and it must have thought I launched and it went full throttle. No big deal, it was ready to fly anyway so I just gave her a toss and let it do its thing but it would have been a bit of a handful if that had happened inside!
 
#52
It would be nice if the altitude was adjustable
absolutely adjustable Altitude Hold for RTH mode....I like it, that would suit us for flying in different locations to suit the terrain

I am surrounded by cotton wood farms contracted to the mill down river, for 2021 Bounty Paper towels, and with the rest of the aborial rain forest here in Oregon most of the wild cotton woods are above 100ft ....when I use return to home I still have to watch my FPV goggles so I can switch to manual mode to dodge a tree :rolleyes:....so the Sparrow with 300ft RTH altitude will work for me, there is also an altitude hold mode apparently
 
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#54
You say "i think the kopilot is bad.... ". It is easy to miss something and the KoPilot will not work right.

EDIT: With all that jittering of the elevons, It is not that your pots are wrong on the control board. A photo of the control board would be good.

Calibration MUST be done properly and miss one small thing and you get problems. I had a twitching servo from new and had to replace it. I guess you checked there was not too much tension from the elevon hinges. Sometimes you need to move the elevons fifty times to full extent to ensure there is not too much pressure put on the servos. Also with the power off is there a loose spot when moving the servo?arm. It should be firm.

The jitters may be from the KoPilot but make sure the pots on the control board are not too close to the top. Here is a few things to check. (just a few)

Transmitter Throttle ESC Calibration

Do transmitter throttle ESC calibration as you should do with all new installations.
https://www.youtube.com/watch?v=kIQ74qp5BaY

Radio Calibration
  • Plane level
  • Wait for Kopilot to start and put switch to Stabilized.
  • Both sticks Bottom and Centre. Wait 5 seconds until Mode indicators 1 & 2 & GPS Indicators flash at the same time.
  • Wait until flashing stops
  • Remove Control Board with the power on. IMPORTANT !!!!!!!!!!
  • Unplug LiPo.
  • Calibration completed
Kopilot Angle Calibration
  • Make sure the plane is perfectly at the flying angle.
  • Switch to Stabilized mode, throttle to lowest position, other joysticks neutral position.
  • Long press the Set button for more than 3 seconds.
  • Don’t move the radio and wait a few seconds and the elevons will move two times.
  • Remove Control Board with the power on. IMPORTANT !!!!!!!!!!
  • Unplug LiPo.
  • Calibration completed.
KoPilot Operation

The Red led on the controller should blink fast as soon as you plug in and when you go outside and gets GPS lock it goes solid red. I put my wing on the ground and walk away a bit so as not to block any sats. It beeps when you get GPS lock AND Red led with be solid red. Always make sure the transmitter is not to close to plane.

The following is how the two green LEDs work:

SWITCH AWAY FROM ME IS RETURN TO HOME
Two blinking green leds.
After GPS lock and put throttle up fast but motor will not start until you throw it. To test the motor on the ground just spin around and the motor will just start a little.
With GPS lock the control surfaces will twitch a lot before you launch
.

SWITCH MIDDLE POSITION IS Not Stabilized
Both leds off.
Motor works all the time including without GPS lock.


SWITCH TOWARDS ME IS Stabilized
Two solid green leds.
Motor will not start unless I have GPS lock

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

WHEN READT TO LAUNCH
The following should occur:


STABILIZED
The elevator/elevons should be level when plane is level.
When you move the plane wings up and down sideways the elevator/elevons should move appropriately to raise the lower wing.
When the nose is up or down the elevator/elevons should move to level the plane.


UNSTABILIZED
The elevator/elevons should be level when plane is level. Adjust push rods if necessary.
When the plane is moved from left and right and up and down the controls should not move.
With the transmitter make sure the the controls are working the correct way
.

RETURN TO HOME
With GPS lock and the plane level, the controls should be level but may twitch a lot.
When the nose is up at the angle it would take off about 30 degrees, the elevator/elevons should be level.
When you move the plane left to right KoPilot should move the controls to level the plane.



Without GPS lock when moving the switch to the three positions the elevator/elevons should be level and all in the same position without twitching.

Let me know if any of the above can be improved.
 
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#55
Radio Calibration
  • Switch to Stabilized mode, throttle to lowest position, other joysticks neutral position.
  • Long press the Set button for more than 3 seconds.
  • Don’t move the radio and wait a few seconds and the elevons will move two times.
  • Unplug LiPo.
  • Calibration completed.
When Calibrations Completed – Remove Control Board

  • Unplug LiPo if connected.
  • Plug in Lipo.
  • Wait for KoPilot to boot up. IMPORTANT !!!!!!!!!!!
  • Remove Control Board with the power on. IMPORTANT !!!!!!!!!!
  • Remove LiPo.
this part of your instructions is incorrect and can cause crashes.....for some reason it causes the reversal of the ailerons settings to SOME peoples setups....and this is the symptom some experienced (including me ) when the control board was not removed BEFORE POWERING DOWN....this issue doesnt affect everyone and people have argued that its not necessary but too many users did infacty experience this issue and caused crashes, its thought its related to the radio/receiver equipment or ESC the user is using

with your instructions above the setting are not being saved and next time you repower the ailerons may get reversed and cause bad things to happen. THE CONTROL BOARD MUST BE REMOVED BEFORE POWERING DOWN TO SAVE SETTINGS

the point of removing the control board while still being powered is to save the settings ,
your instructions have the power killed then repower remove the control board....you negated the saving of the settings this way

also quite a few ESC's are not compatible with the zohd and I addressed this in the how to video

I made this how to for my grandsons a few months ago and it has helped many many users already getting their zohd FC to work properly
 
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leaded50

Legendary member
#56
and if in the event you got a defective unit and you wont be the first, I suggest you return it and buy this one ....
Sparrow FC Flight Controller Stabilizing 6-Axis Gyro With M7 GPS Module for FPV RC Airplane Fixed-Wing
https://www.banggood.com/AFPV-SN-Sp...p-1356353.html?rmmds=myorder&cur_warehouse=CN

it IS a clone of the zohd so you will feel fairly comfortable with setup but its been improved, more features and more importantly...RTH altitude is over 300ft ...the zohd altitude is only just above 114ft and fly's into trees
Have you tried the Sparrow? I have it, but not installed in any plane yet.
 
#57
I have not yet got mine.............. but many have been using it for quite some time over at RCG and I have had others do some testing over at RCG on theories I have about it and was correct
the instructions do not list Launch Assist as a feature ( I dont think the manufacturers know it does they most likley stole the technology ) but when I read the sparrow trouble shooting that when using the sparrow the motor will NOT spin up when in RTH untill the aircraft is moving 2 Meters per sec that triggered my memory that the zohd operates similar and given the setup procedure is almost identical to the zohd I felt it could accomplish the Launch assist too......members said NO it doesnt have that feature because it DIDNT SAY SO IN THE INSTRUCTIONS :rolleyes:and then one guy actually tested my theory for me as I asked and the sparrow will infact do the launch assist.... hootie hoo :)

despite its not in my hand ..... I do have a better understanding of the unit than some that already own and use one
 
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#58
Aireal Anarchist
Thanks I changed it as you said and was able to remove the When Calibration Complete paragraph. But I was sure I did it like I had it and removed the controller board after I did the two calibrations. Anyway all fixed now.

Great instructional video you did. I also like your post number 46 on the UBecs. Most can get away without one but people with larger planes should have a UBec. That is what I have been mentioning on the other forum but most that should have UBecs do not install them.
 
#59
Great instructional video you did. I also like your post number 46 on the UBecs. Most can get away without one but people with larger planes should have a UBec. That is what I have been mentioning on the other forum but most that should have UBecs do not install them.
thanks for that
yes that Ubec to power the receiver and zohd becomes more important, the more money you spend on these electronics... well thats not entirely true ...ITS IMPORTANT IF YOU DONT WANT YOUR PLANE TO FALL OUT OF THE AIR AND BE DESTROYED DURING ESC FAILURE period......you should power the Receiver and FC by alternate power sources ....ubec"s

radio controls and Return to Home is useless when your ESC dies.........5.5 volt Ubec's (voltage regulators) to power the receiver gets you down safely:giggle:

Im certainly not a youtube "how to guy" my videos are amature junk the video was primarily for my kids but the setup of the zohd info is correct and I try to make easy to follow...... but I think I should make a how to video on this subject as I dont think everyone understands how easy this is to do and what great insurance your plane gets and survives ESC failure
 
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Bricks

Master member
#60
Doing some reading on the ZOHD and it seems the return to home has limited altitude which does not work well for many if trees and such are in the area.