Hello everyone,
I am trying to build a quadcopter for my final year project. I had problems taking off. I approached one of the forum veterans, Ashta Murthy and he was able to debug it and quad flew for a bit, but still unstable. I tried to fly it today and i could see that it tended to drift a lot. I tried the roll, yaw and pitch settings, to no avail. I am herewith uploading a video about my experiment.
Later i noticed that motor no. 1 (in X configuration) was at a lower rpm and wasn't generating any thurst as compared to the other motors. So i switched the motor and esc, i notice that the motor wasn't the problem, but the esc wasn't as hot as compared to the other three esc's. Please advise me as to the inherent defect.. is it the esc ? or the gain settings of the FC board ?
here are the specs of my quad.
Hobbyking i86 Multi-Rotor Control Board
N2822 1800Kv Brushless DC Outrunner Motor
Quadrotor 49.5cm Diameter Frame
20Amp BLDC ESC
8x4.5 inch (20x 11cm) Pusher and Puller Propeller







Please help me out

you could have uploaded a flying video... And i hope its not that stable because of the high kv motor.. you could have choosed a 1000kv motor... What is the Frame size? 450? try uploading a flying vid so that we can help you further...
All the best...

@Arun Sir : Thank you for your reply sir. Sir the quad hasn't taken off till now every time i increase the throttle a little more and it trips viciously.. Curtsey of which i have suffered four broken props. Any little increase in throttle as you can see and the quad trips.
The frame size is 49.5 cm in diameter.

Few things that you can try, but first: when you have quad flipping on one side, test on BED or any soft surface. So that you save props from breaking.

Play with trims, and see if you get any improvement.
As you thought may be one of the motor is faulty or may be it has some dust, so interchange motors and try.

Do this:
If you quad is flipping on left, that means the motors on right is strong and on left is weak. So interchange one motors from left to right and vice n versa. You can test like this, you might see some improvement.

If changing motors does not improve anything then maybe ESC is dead or may be some issues with it. Now interchange ESC, same was as you did for motors.

I hope above helps, keep us updated.

@Satyagupta sir: Sir, thank you for your speedy reply. I tried the above mentioned procedure sir. I played around with trims a lot. But everytime the same arm ( the one bearing motor 1 in X configuration ) either drags the quad or fails to take off. I interchanged the motor to arm 2 and it worked fine. However the motor which was on arm 2 when connected to arm 1 esc, failed to produce thrust. Should i conclude the the esc is dead ? If so would another esc from a different manufacturer sync with the existing ones ? ( A hybrid combination )

This may sound strange but is it possible to, through certain manipulation or mixing of trims, deliver extra thrust to individual motor and in doing so compensate for the slow rpm ?

Not directly but you can apply huge amounts of subtrim to combat the problem. Which radio are you using? Your front left arm is malfunctioning right? Subtrim your channels this way:
Elevator down trim (to pitch up)
Aileron right trim (to roll right)
Keep on increasing these trims until the quad lifts up. Mind you, the quad will not be that stable dynamically..

Post some pictures of your quad.

@ arun.sreelakam : Theoretically higher Kv motors makes multirotor more stable as they react to changes faster. Smaller props make for less momentum and therefore less time to change speed. But this leads to reduced efficiency, and in some cases of improperly balanced systems, more vibrations.

@LastRites: Thank you for your advice. I am using Turnigy9x mode 2(v2). If i subtrim the elevator down, wouldn't it increase the flow to the back motors and increase the pitch down ? Cause yesterday i noticed that in order to increase the trim on the left arm, i increased the roll towards left and elevator up. HOwever the amount of throttle to the left lower arm was huge and it tended to dominate, thereby again tripping. Also i have reversed the elevator the roll channels, so i guess the trims too are reversed.
One more thing, would another esc from a different vendor, provide the same stability ?
Thank you again

http://www.rcindia.org/multirotors/new-kk-2-0-%28-lcd-%29-board-wont-arm-!-help-!/



I'M HAVING THE EXACTLY SAME ISSUE !!!! ( though the tilt is a little lighter )

still no solid help yet

Getting a different brand may not work at all. I think the ESC is fine. When you pull on the elevator channel (pull it down), the nose of the aircraft should go up, i.e. , it should climb, or in the case of mutirotors, go backwards. It is conventional to have two same coloured arms towards the direction of flight, when you have the quad x-configured. Yours looks like its set up for + config. Have you set up the wires accordingly for the x config? And the position for the DIP switches needs to be checked too.

Isnt the quad bit too fast? I dont think it would be stable with so high kv motors.
Well still it would be good for aerobatic flying.

You can have fast quad quads with much lower Kv motors. The speed depends more on the power to weight ratio than Kv of the motors. You use lower pitched props with faster motors..

@LastRites: Thank you again for your reply Could you please elaborate on which wires you are referring to. Also all the other three motors are generating considerable thrust. But the one in arm 1 isn't generating almost anything. Very low thrust. Is it supposed to be that way ?

Abhishek did you use the ecalc.ch ?

@Rahulvyas: Thank you for your reply. I tried to use them. But I had bought this combo from Nex Robotics. They haven't given any specifications of motors or the ESC apart from the ratings. ecalc.ch demands the name of the manufacturer for the motors.

Nex robotics? :O They are not a good store to buy RC stuff. the prices are super costly. I compared it.
well, if you have bought it. Ask the support to tell you all those details.

I had emailed them. But did not get a response. Could anyone suggest an alternative ? How can i judge if an esc is not functioning ?

i was searching for ESC's on this forum. Would these esc's serve as a good substitute

http://www.rcindia.org/for-sale/stock-clearance-!!/

if there is anything more than super or "insanely high" then you can give that tag to them too

I had mailed them in July 2012 about bad packing and shipping still no response. When you call them they say for technical issues please drop a mail

@Abhishek, those ESC's are good. i think its issue with ESC. Did you tried interchanging the ESC? that might help you to get hold of issue.

Hello Everyone,
I am exhilarated on account that my quad took its maiden flight today (also its maiden crash  ).
Turns out it was the burnt esc that caused the rapid tilt and occasional tripping over. I bought these four new esc's from Mr. Pooyan, and everything worked just fine . I would like to convey my regards to everyone for their valuable feedback and guidance Thank you all.
However , The quads a little  unstable and tends to drift. Is it possible to achieve hovering capability on the i86
?

Since the i86 has gyros only, you will not get super stable hover.
But you may solve the drift issue to an extent by reducing the vibrations caused by the unbalanced props or motors.

Last Rites : Thank you for your reply. I have also bought a kk V5.5 board from Satyagupta sir. I believe it would provide more stability. Would that be better ?

well you should have bought kk2?

@RahulVyas: Yes I have I will try to incorporate it. Hopefully will achieve better stability. The manual on the hobbyking website seemed a little elaborate. Could you please redirect me to a better multimedia or written material Thank you for the support again

@RahulVyas: Lightening fast Thank you

welcome
sometimes internet goes mad

Hello everyone, here is a video of maiden flight of my quad. Also, The doesn't seem to descend down gradually when i reduce the throttle, instead tends to fall.
I suffered a crash on the third take off. Again the esc in the arm one was burnt. I noticed that soon after the crash, one of the wires from esc to the motor was disconnected. Is that the cause for the esc to be burnt or was it the crash landing.
Could you please suggest a way to stabilize the quad for hovering and altitude hold. Thank you. I will be trying KK2 board when the replacement esc's arrive.
Thank you all

It flies nice mate. Keep it up. Just need bit practice and it will be handy.

Looks good Abhishek, little more practice and you are good with it

you quad is in + mode of x mode?

@Dharmik: Thank you sir

@Satyagupta: Thank you sir. The Quad is in X configuration sir.

Abhishek try to hover your quad at one place.. I can see its not in control and landing hard...

Like this

nice arun b bhaiya

Thanks rahul....

@Arun sir: Sir, thats pure serenity. Sir, which control board are you using ? Any suggestions for hovering ? And sir as i mentioned earlier, on one flight the quad crashed and i saw one lead was open, the esc was burnt again in arm one. Any idea about the defect

Abhishek cal me arun
And I am using the kk2 with v1.2 and some pid tuning...
Now hoverng is all depends upon the stability of the quad, As in my reptile i need to do more cg adjustments but yours is a cross frame and no need of that... Make sure there are no vibrations and the quad is placed parallel to the ground.
Now increase the throttle and slowly and trim untill the drifting is minimum...
Now lift up the quad and try to keep it hover in a spot by using all the three controls simultaneousl, You will succeed..
And about the esc, You sure This motor can handle a 8" prop and keep the A below 20? as it is 1800kv?
I doubt that

@Arun : I recently upgraded to 30 A esc and the props were adopted as per the results of the online calculator. I will incorporate the kk2 board.. and try to adjust the trims..

Never worry about the board.. KK2 is a good fc but still All others can also do the job just fine...
you just need to build it properly... An unbalanced prop will make massive drifts...
30A is just fine i think..

Abhishek your motor can use only 7x3 prop with 3s...
See the attached file... And using more than that may burn it...

@Arun Sir: Thank you again Thanks a lot.

Nice build.PID values seems to be the only culprit.
regards
Pankaj

@The Hobbyshop: Thank you for the compliment. I will do good to stabilize it.

Hello everyone,
Since this quad build, I have been meaning to build one more, with a custom frame and if possible include altitude hold and provide hovering capability. I have a few spare esc's with me. 20 amp. Which motors do you all think will be suitable for giving thrust sufficient  to lift a GoPro and may be a 5000 mah lipo. Thanks in advance.

I think 1000kv 2836 will work okay.
or you can use 2212 920kv

Using 20A with 2836 is risky... it is rated Max amp as 18 but still 30A is the safe range for a 300+ w motor...
And as you are planning for a go pro also...
Still sticking with 20A then need to go for lower kv motors with 15A Max current or so..
May need to use 4s lipo...


Sent from my Canvas using tapatalk 2

Good to know that your quad now gets up in the air, Abhishek.
I suggest you use some foam/thermocole to protect the lipo as well as to serve as a good landing gear.

what about 5010 360kv? which is super efficient .

@Rahul and @Arun : Thank you for the info
how about these ?

http://www.hobbyking.com/hobbyking/store/__41878__Turnigy_Aerodrive_SK3_2822_1090kv_Brushless_Outrunner_Motor_AUS_Warehouse_.html

http://rctimer.com/index.php?gOo=goods_details.dwt&goodsid=858&productname= with 10x4.7" props and 3S
or
http://rctimer.com/index.php?gOo=goods_details.dwt&goodsid=847&productname= with 11x5.5" props and 3S.

Better than the aerodrive one. The above motors are built for mulitrotor purposes only! and rctimer is a good website

@veloci. Thank you for the tip :-) :-) i  have made the amendments :-)

Everyone, is it necessary to have GPS and auto pilot for altitude hold. ? Or are there other means to achieve greater stability and hovering :-)

with reference to greater stability, cheapest solution is u need rapid escs = simonk flashed escs, flash your escs . then u can run at double the gains settings from before which will make your quad super stable given that everything else is working properly.

edit- gps is overrated(not saying its not important). look for all the little places that can help u improve stability.

video attached as example why u need simonk.(not my video, but thank you maker of it) .

No, GPS is not necessary for Altitude hold. GPS is required for position hold.
GPS will make it more stable.

@pravesh: thank you for the info :-) :-) pardon me i am a noob. But with reference to flashin, ill need a programming card, what significance does the simonk have here. ?

@Rahulvyas: as always lightening fast :-) wouldnt absence of position hold cause a drift sideways. ? :-)

u dont need programming card, you should search the internet a little more if u dont want to stay a noob forever, everything is there to learn from. now spoon feeding is not possible(at this age).   google simonk flashing. all your answers are there. we are all nooobs. u want stabilty simonk has given u option, it makes your escs run at above 450hz. and u can pump up your gains settings, try running your quad with high gains on stock esc and watch it wobble to death.  

edits. quads etc will always drift, its a part of rc to control it. air turbulence, wind etc etc, gps counters all this and keeps quad in one place. but that is positoin hold not stability

edit-ps. u need barometer for altitude hold.

I wish I could flash my plush 25As, but its too difficult for Plush to be flashed.

altitude hold means, holding in a certain level/ height. it dosnt mean position hold.
If you add position hold feature(GPS) it will be more stable.

For that you need a FC which supports GPS. I ordered Arduflyer.

my new quad from http://www.quadkopters.com/
 

@ pravesh. Thank you for the info :-) i will do good to stick to it :-)
@ Rahulvyas. Thank you again.  :-)

Seems like old thread, but I post it anyways I been experiencing some drifting in my first quad ...

QuadCopter PID tuning process going on and observed pitch axis behaviour as goes: when I increase throttle (in small intervals) then quad bends little one side but then recovers and get itself level. And when I decrease throtttle (in small intervals) then it get bend other side, recovers and get level. Leveling process taking few secs. Also bending is proprotional to amount of throttle I apply in one time. But once level it respond well to radio sticks, have been fighting  this problem from quite some time then I decided to go ahead and ask on forums and here I am.

(my ques: why it is taking time to level it and why quad bending with inc/dec throttle & how to correct) 


Thanks

CG not in the center?
If so, on opening throttle, the lighter side will accelerate faster, causing tilt, till corrected by self levelling action...

Center of Gravity? I think it is check some pics

Also self leveling action happening slow like in 5 sec or so