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-!!/

Quote from: Rahulvyas on April 28, 2013, 06:15:11 PMNex robotics? :O They are not a good store to buy RC stuff. the prices are super costly.

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

Quote from: Abhishek Goudar on April 29, 2013, 12:41:50 AM
I had emailed them. But did not get a response.

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