Is there a minimum distance to be maintained between the propeller blade tips?
I built a quad (x config) with:

1400kv motors
30A esc's
10x4.5 props
11.1v 1250mah 20c lipo

And it seldom can hold hover, it keeps yawing to the left. I checked the receiver test in the FC (im using a kk2 from HK) and all the sitcks max and zero properly but when i take off it keeps yawing to the left. Any clue why?
I tried messing around with the PI gains but that didnt seem to help.

Another issue is that when i reduce the throttle just a little bit, the quad falls really fast and i have to bump the throttle up way high to avoid a nasty crash    . This happens all the time, the roll and pitch controls and sensitivity is good just the automatic yawing that make it hard to fly. I tried trimming it too during flight, it helps a bit till i land, then again when i take off it starts yawing again.

Could there be a minimum distance requirement that causes this?
Could it be a transmitter problem (I am using a 4 channel flysky ct4b)

The frame I built myself, the distance betwen prop tips is 2.5 inches.

Any help would be really appreciated.



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First of all, your battery is too small for the quad to get a good flight time. I would recommend buying a 2200mAh or similar if you want to fly for long. A pic of your quad may help.
For the yawing part, have you calibrated the ESC's? If not then that might be the cause.
As for the falling part, every quad does that. You need to bring your throttle stick down a bit and then when it comes down you up it a bit. Doing this will help it decrease altitude slowly. Also, you can try applying pitch to the quad for descending.
Last, what is the arm to arm(diagonally opposite sides) disance of your quad frame? I have seen that configuration mostly with 450 size frame.

Which firmware on kk ?

1250 mah only? I use 1250mah 3s just for lights and video transmitter 😐. You are using 30A ESCs and 1400kv motors. Which motors are they? Yellow one from Amazon? Increase the battery dude.. Take 3500mah. And you should take note of your total weight, thrust generated by each motor. Weight should not increase much such that motor can overheat or even burn.
It keeps yawing to left? Check the centre of mass, weight must be equally maintained. Seems like software problem. PM me I will help you. 😊

Quote from: Inv3nt0r on June 10, 2016, 01:20:07 PM
It keeps yawing to left? Check the centre of mass, weight must be equally maintained. Seems like software problem. PM me I will help you. 😊

Bro centre of gravity only affects pitch and roll and not yaw.If its not balanced, it drifts in a certain direction and doesnt yaw.  This is atleast what I have noticed

Since it is a custom built frame, the yaw issue could be because the arms/ motors/ motor mounts are not perfectly level. Try checking them with a spirit/ bubble level.

Yaw issue could be a million things. Like mentioned above, check for twisted motor mount, miss-aligned arms.
The distance between the prop tips will not cause the yaw issue (afaik). It is more common to propwash.
Is the yaw mix set correctly in your transmitter? Try reversing the mix.
Is the gyro calibrated correctly? What props are you using? Slight difference in pitch value could also be the reason (common issue while using cheap props). Also check for prop balance.

Quote from: Darshan for multirotors on June 10, 2016, 02:24:04 PM

Quote from: Inv3nt0r on June 10, 2016, 01:20:07 PM
It keeps yawing to left? Check the centre of mass, weight must be equally maintained. Seems like software problem. PM me I will help you. 😊

Bro centre of gravity only affects pitch and roll and not yaw.If its not balanced, it drifts in a certain direction and doesnt yaw.  This is atleast what I have noticed

Bro, I know. I just said that as usual. As SK said, the level may be wrong. Because of it, flight controller make some motors spins faster to make aircraft level. This can cause aircraft yawing sometimes. And that levelling could be by wrong placement of components or unbalance in weight.
To the OP, can you post any video? Such that we can see actually what is happening and can tell what's the problem.

Sorry for the late response, wifi was down.



Here is a pic pf the quad, also the rotor to rotor distance diagonally is 44cm.

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Quote from: Darshan for multirotors on June 10, 2016, 11:25:39 AM
First of all, your battery is too small for the quad to get a good flight time. I would recommend buying a 2200mAh or similar if you want to fly for long. A pic of your quad may help.
For the yawing part, have you calibrated the ESC's? If not then that might be the cause.
As for the falling part, every quad does that. You need to bring your throttle stick down a bit and then when it comes down you up it a bit. Doing this will help it decrease altitude slowly. Also, you can try applying pitch to the quad for descending.
Last, what is the arm to arm(diagonally opposite sides) disance of your quad frame? I have seen that configuration mostly with 450 size frame.

If you mean throttle calibration... Yes, I have done it. Didnt help even when i repeated it to make sure.

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Quote from: SK1701 on June 10, 2016, 05:19:26 PM
Since it is a custom built frame, the yaw issue could be because the arms/ motors/ motor mounts are not perfectly level. Try checking them with a spirit/ bubble level.

Is not the acc bubble and the gyro bubble on the kk2 to serve this purpose? Both these bubbles are level.

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Quote from: Darshan for multirotors on June 10, 2016, 11:25:39 AMFirst of all, your battery is too small for the quad to get a good flight time. I would recommend buying a 2200mAh or similar if you want to fly for long. A pic of your quad may help.
For the yawing part, have you calibrated the ESC's? If not then that might be the cause.
As for the falling part, every quad does that. You need to bring your throttle stick down a bit and then when it comes down you up it a bit. Doing this will help it decrease altitude slowly. Also, you can try applying pitch to the quad for descending.
Last, what is the arm to arm(diagonally opposite sides) disance of your quad frame? I have seen that configuration mostly with 450 size frame.

The battery may be small for it, but I am kinda focusing on attaining a stable flight first before using a bigger battery.


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Quote from: Inv3nt0r on June 10, 2016, 01:20:07 PM
1250 mah only? I use 1250mah 3s just for lights and video transmitter 😐. You are using 30A ESCs and 1400kv motors. Which motors are they? Yellow one from Amazon? Increase the battery dude.. Take 3500mah. And you should take note of your total weight, thrust generated by each motor. Weight should not increase much such that motor can overheat or even burn.
It keeps yawing to left? Check the centre of mass, weight must be equally maintained. Seems like software problem. PM me I will help you. 😊

These are the ESC's



Battery I will upgrade once stable flight is achieved.

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Quote from: Voice of deaf on June 10, 2016, 12:17:41 PM
Which firmware on kk ?

I scrolled down to version on the board and got the following:

HW Ver 2.1.x  (does that mean version 2.1? And what is the "x" for?)

FW Ver 1.19S1 Pro
Steveis

Does that help?

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The gyro/ acc bubbles only tell you that the FC is level relative to how it was calibrated. I meant that you should use a spirit/ bubble level, or even an inclinometer app on your phone to check that the arms are perfectly parallel to the ground and that the motors are mounted correctly relative to the arms as well.

It says 2.1.x as the kk 2.1 and 2.1.5 both run the same firmware. 1.19S1 is the latest firmware Steveis released for the kk and flies well even on defaults so that is most probably not your issue.

Quote from: SK1701 on June 12, 2016, 05:32:25 PM
The gyro/ acc bubbles only tell you that the FC is level relative to how it was calibrated. I meant that you should use a spirit/ bubble level, or even an inclinometer app on your phone to check that the arms are perfectly parallel to the ground and that the motors are mounted correctly relative to the arms as well.

It says 2.1.x as the kk 2.1 and 2.1.5 both run the same firmware. 1.19S1 is the latest firmware Steveis released for the kk and flies well even on defaults so that is most probably not your issue.

Ohh, okay, got it. The gyro and acc bubbles are only for the FC relative to how it is mounted. I will do as you suggested and post the results here...... as soon as it stops raining outside :-)
Thanks for your input.

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Mechanical tuning/trim
couldnt elaborate.

1.250 X 20 = 25 A, the reason it cannot lift off maybe because the battery cannot provide enough amperes to fly the quad, I once say a guy using DJI 980 kv motors on a hex frame with DJI props (self tightening) and on full throttle it didn't even budge because even he was using a fairly small battery...

Yes rathi u r right 25amp is the amperage ur lipo is giving right now thise chinese golden motors surely take more than 15amp at full throttle juss calculate with 10amps x4 -40amps so ur lipo is insufficient to provide powrr and that may be the yaw issue juss get a new lipo that may solve ur prb rcm has 15% off on lipos for limited time grab some lipos

Boss just increase the battery. Atlest 2200mah 20C would help. 1250mah 25C is like asking 2 year old to pilot a plane.

your premise is reasonable... solve the yaw first and then get a larger battery . the rest is just noise and clutter.


towards solving the yaw issue .... "voice of deaf "  has got it the closest

tilt one or more motors against the direction of yaw.  a couple of degrees will do.

the concept is similar to a tricopter tail servo.

please ensure first that your props are rotating the correct way ... the front left hand one should go CW

Quote from: saikat on June 13, 2016, 08:21:41 PM
your premise is reasonable... solve the yaw first and then get a larger battery . the rest is just noise and clutter.


towards solving the yaw issue .... "voice of deaf "  has got it the closest

tilt one or more motors against the direction of yaw.  a couple of degrees will do.

the concept is similar to a tricopter tail servo.

please ensure first that your props are rotating the correct way ... the front left hand one should go CW

Thanks saikat, will try tilting the arms by a few degrees and then see how it flies.

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