CC3D _ F450 _ Very Unstable Take Off & Flight
« on: June 16, 2018, 09:33:43 am »
Dear Multirotor Team,

Vehicle Specs :

1000kV motors
1045 Props
Revo
30A Ebay (Yellow) ESCs
f450 Frame
2200 maH, 3 Cell
Flysky Fsi6 Transmitter
Flysky FsR6B

ESCs calibrated
Motors Calibrated
Motor Rotation Check
X Quad Config
Quad Arms Properly
No Heating Issues in ESC
Acc. and Gyro Calibrated

I have made one prototype before also and it flew perfectly with the default settings.

Now i am facing vehicle take off issues. The escs are delivering current bursts making the quad wobble and loose control. Hardly lifts off the ground properly. I have checked all solder joints with multi_meter and have no connectivity issues in Power Distribution Board all the way to the receiver.

I have made multiple erases and reconfigured the entire settings as well on the board and still get the same flight issues.

Can you help me with that ?

Regards,
K.Raghavendran

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #1 on: June 16, 2018, 05:20:05 pm »
Is the FC mounted upright with the arrow pointing forward (ESC connectors on right side)?

Does it fly well once in the air so it is only a takeoff issue?

It looks like you have selected X quad config?  Make sure that Stabilization->ZeroTheIntegralWhenThrottleIsLow is ENABLED.  Take off quickly after starting motors.  "Jump" up to knee high.  Do not move any stick except for throttle until it is in the air.  Take off from level ground, not hill side.

Balance props.  Unbalance beyond a certain amount can cause crazy flight.

If still having a problem, make a video (camera not on quad) so we can see what it looks like.

Zano64

  • *
  • 5
  • From OpenPilot to LibrePilot
Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #2 on: June 16, 2018, 05:45:41 pm »
I had a similar problem when one of my propellers was not properly screwed on the axis.
If that can help


Envoyé de mon iPhone en utilisant Tapatalk

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #3 on: June 16, 2018, 07:14:01 pm »
Dear TheOtherCliff,

CC3D is facing forward(arrow) from me the way it should be.
No flight, No Takeoff, ie, very very unstable.
Stabilization->ZeroTheIntegralWhenThrottleIsLow is ENABLED.

Edited by Cliff: use youtube.com links so they will work in forum


This is the link for a similar drone i made and it worked very well with the same settings.

https://www.instagram.com/p/Bd9F2PmhzFO/?taken-by=stemrobotechnologies

Please let me know if any other information/screenshots/vidoes that i need to send to solve this issue.

Regards,
K.Raghavendran



« Last Edit: June 16, 2018, 07:31:00 pm by TheOtherCliff »

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #4 on: June 16, 2018, 07:35:41 pm »
Are you sure that you have the ESCs plugged in the correct connectors on the FC?  The correct props on the correct motors and the motors spinning in the correct direction as pictured on GCS Configuration->Vehicle page.

What ESC protocol are you using (Output page)?  Using [email protected] will cause this unless you detune the PIDs.  Don't change the PIDs.  Use a better protocol, like PwmSync or [email protected]
https://librepilot.atlassian.net/wiki/spaces/LPDOC/pages/12058743/ESC+Calibration

In this video are you moving the sticks at all?

Video wasn't clear.  What happens if you do not touch roll/pitch/yaw at all and just blip the throttle stick up enough to get it off the ground?  Either it does "instant flip" (gets upside down without really leaving the ground) or it actually gets up in the air a little bit and you have cut the throttle by then and it falls and lands right side up.
« Last Edit: June 17, 2018, 04:38:45 am by TheOtherCliff »

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #5 on: June 17, 2018, 05:31:56 am »
ESC are plugged in the right way according to GCS.

1C        2 CC

4CC        3 C
_____________________________

Motors Spinning just the way they should.

_____________________________

1045 Props on 1000Kv motors

_____________________________

ESC protocol  :  [email protected]

_____________________________

roll/pitch/yaw are not being moved at all, just throttle, and it should lift off properly.

What you see in the video is 40% throttle, constant, and the esc is acting all improper as if its not getting continuous current.

Battery health is perfect, checked it with balance charger.

_____________________________

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #6 on: June 17, 2018, 06:34:35 am »
Quote
1C        2 CC

4CC        3 C
This is not good enough.  From this you have the spin directions and props correct, but we still don't know if they are plugged in the correct connector.  NorthWest motor must be connected to ESC connector #1, NE must be connected to #2, SE must be connected to #3 and SW must be connected to #4.  Verify this before going any further.

I never saw it actually get off the ground.  Does it instantly flip over, or just drift badly?

Also, you could try it on Rate mode in case you did Accel calibration incorrectly.

Also, you could put on a heavy coat to protect your arm, and try to "fly it in your hand" in Rate mode at low throttle settings.  This is dangerous so you must be willing to do it.  If you don't want to, that is OK.  When I do this, I grab it from the bottom in a place where I can grab tightly without damaging it.  It will either try to twist out of your hand at much higher throttle than you select on throttle stick (be ready to instantly stop the throttle), or it will be happy and stable and will resist you trying to force it to bank / twist it with your hand.

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #7 on: June 18, 2018, 08:15:57 am »
Hi, sorry for the delay in reply. Was out travelling with family.

Q:ESC connector #1, NE must be connected to #2, SE must be connected to #3 and SW must be connected to #4.
A: Image in the attachment. I am 100% sure i have connected them properly.


Q :Does it instantly flip over, or just drift badly
A : It mostly drifts badly. Has issues taking off the ground. Motors are pulsing instead of continuous PWM output.

Q: Rate mode in case you did Accel calibration incorrectly.
A: Accel. is calibrated properly. Flight data GUI shows exactly what i am doing to the drone. Left right forward and backwards are mimicked exactly as it should.

I have not tried it in rate mode yet. Ill post the results in an a couple of hours.


Input : I am also attaching image of my my zmr250 kit flying very well with exactly same settings settings.

Thank you for your valuable inputs.

Regards,
K.Raghavendran



« Last Edit: June 18, 2018, 08:20:32 am by K.Raghavendran »

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #8 on: June 18, 2018, 11:27:13 am »
What is your battery C rated at?  2200mah for 4x 30amp probably won't have the required discharge rating and the ESC's are probably cutting out

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #9 on: June 18, 2018, 12:39:45 pm »
What is your battery C rated at?  2200mah for 4x 30amp probably won't have the required discharge rating and the ESC's are probably cutting out


2200Mah, 11.1V, 30C but thats what the sticker says, once i peel of the sticker there is another white sticker hidden inside, that reads;

1800Mah, no C rating provided.

Note : These are for the same battery. Something fishy done by the vendor perhaps.

Please check attachment.

Q: What battery rating would you use to fly the f450 frame, on 1000Kv motors and 30A*4 esc.?

Regards,
K.Raghavendran

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #10 on: June 18, 2018, 01:03:47 pm »
Somebody correct me if i'm wrong.......
A 30C 2200mah battery, if i'm following the equation correctly will only give you up to 66 Amps continuous draw  (C rating times batt capacity in Amps,  E.g. 30 x 2.2=66A continuous draw).

So if you have 4x 30A ESC's, you need a total of 120A which your 2200mah 30C battery is only going to give you half of. Plus you need a little more over the 120A to power your FC and receiver etc.

If you want a 2200mah battery, you'll need one with a rating of at least 55C.    You'd be better off with an 1800mah 3s with a 75C rating, this will be lighter than a 2200mah battery too.
« Last Edit: June 18, 2018, 01:55:24 pm by Rickolas »

f5soh

  • *****
  • 4465
    • LibrePilot
Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #11 on: June 18, 2018, 02:03:23 pm »
Escs are 30A max rated but current from motor never reach 30A on this setup but something around 15A at full throttle.
A 30C 2200mah battery is enough.

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #12 on: June 18, 2018, 02:36:39 pm »
A 30C 2200mah battery, if i'm following the equation correctly will only give you up to 66 Amps continuous draw  (C rating times batt capacity in Amps,  E.g. 30 x 2.2=66A continuous draw).

So if you have 4x 30A ESC's, you need a total of 120A which your 2200mah 30C battery is only going to give you half of. Plus you need a little more over the 120A to power your FC and receiver etc.

If you want a 2200mah battery, you'll need one with a rating of at least 55C.    You'd be better off with an 1800mah 3s with a 75C rating, this will be lighter than a 2200mah battery too.

Yes indeed, never thought in such a way. But i have seen many videos on the internet with the same battery config. and they are able to pull of flights with 6-8 minutes of flight time. But i will definitely try with a high C, or high Mah(30C) battery to match up the equation .!!


Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #13 on: June 18, 2018, 02:51:11 pm »
Escs are 30A max rated but current from motor never reach 30A on this setup but something around 15A at full throttle.
A 30C 2200mah battery is enough.


Wow, Thank you for such a great/logical answer.

So according to the calculation;

a) 30C * 1.8A = 54A;    (1800Mah bat.)

Current Required : 15*4 = 60A;

b) 30C * 2.2A = 66A;  (2200Mah bat.)

Current Required : 15*4= 60A; therefore the cut-off at one esc.

am i right now ?

Regards,
K.Raghavendran

« Last Edit: June 18, 2018, 06:43:04 pm by K.Raghavendran »

Re: CC3D _ F450 _ Very Unstable Take Off & Flight
« Reply #14 on: June 18, 2018, 08:16:54 pm »
If you have ever "over discharged" the battery, then the battery may be bad and that may be your problem.

The recent question for you is whether battery has enough power to hover.

Hover power is much less than max power.  A guess is that 10A x 4 = 40A should be enough to fly.

I have many such models and I usually fly them with 3300 20C or larger which also has max current of 66A.  A 2200mah / 20C battery should work well enough to hover.  Even a good 1800mah/20C should fly, but at that point, it is not good for the battery and you won't get as many flights before the battery is too old.

You list 30A eBay ESCs.  If they have stock firmware, you MUST set the settings correctly.  It is better to flash different firmware such as BLHeli or SimonK, but stock firmware will work if the settings are correct:
- Low Voltage Cutoff to the "disabled" or "NiCad" setting
- Slow startup OFF (or fast/normal)

One test to make is to run it without stabilization and see if motors run smoothly and with plenty power.
- take props off (really!)
- transmitter not needed
- connect USB to PC and quad
- go to GCS Output page
- click all 4 boxes ("Link" column, right side) to link sliders together
- plug the battery in, in addition to USB (FC may reboot and you may need to redo the Link step)
- click Test Outputs
- click one slider
- now you can use mouse (drag slider), or keyboard left, right buttons to slowly move the sliders
- keyboard Home key stops them and End key is full throttle, practice these...
- put props on
- put a heavy coat on to protect your arm
- grab quad tightly by the bottom
- slowly increase throttle (I use keyboard arrow keys, just hold it down to do it quickly)
- you don't need to test full power, just plenty power to hover and for say 20 seconds
- press Home key to stop motors, or just hold down left arrow key is safer, because pressing End key is full power
- Uncheck the Test Outputs box and do not save settings as it reminds you that you could.

Is it smooth and does it have enough power?

If other model flies fine, you may try using those settings.  (Save settings first so you can go back.)  Export from one model and import to the other.

Buy you some LiPO alarms, set to 3.6v (per cell, it measures individual cells) and leave one attached to balance connector during flight.  This is good advice to always follow.  It will tell you when your battery is low or if too old to supply enough power.
https://www.ebay.com/itm/1-8S-Lipo-Li-ion-Fe-Battery-Low-Voltage-Meter-Tester-Buzzer-Alarm/202276236708
« Last Edit: June 18, 2018, 08:53:50 pm by TheOtherCliff »