one month ago I have completed my first 250 qaud bulid. But i couldn't fly happily because it drifting and i couldn't recognize it.Now,in past two days i noticed,it going Right side when i increase the throttle.

I have already centered roll,pitch,yaw values to 1500. 
I have calibrated ESC balancing props.
I Used subtrim function to center the channels.
didn't touched trim buttons.
I have flysky Fs-th9x 

one thing i found strange many time when i start power on transmitter and quad and checked with cleanflight,i found,above three  channels vary from 1495-1505,whereas i already centered all three channels.So, I put Rc & Yaw deadband 10. but my problem still occurs.

Try dropping RC deadband to 5. Make sure your COG is correct. You can adjust your accelerometer to compensate for drift with stick commands. It's explained very well here.

(20-Jun-2017, 04:02 AM)RENOV8R Wrote: Try dropping RC deadband to 5.  Make sure your COG is correct.  You can adjust your accelerometer to compensate for drift with stick commands.  It's explained very well here.

Thanks for the video   I will drop RC deadband to 5.And COG is correct.

(20-Jun-2017, 04:36 PM)ANUJ300 Wrote: Thanks for the video   I will drop RC deadband to 5.And COG is correct.

By way of explanation, the reason RENOV8R says you should reduce your deadband to five is that the deadband you specify is applied to either side of the centre value. So a deadband of five covers the range of variation that you saw.

You don't mention what flight controller you are using (very important information!), but some are more susceptible to vibration than others.

If there is a lot of vibration in flight (from poorly balanced propellers or motors) it can lead to errors in the flight controller's idea of where level is.

In your case though, I find it suspicious that you say your quad drifts to the right when you increase the throttle. That's quite strange. It almost sounds like a difference in thrust between the left and right hand sides of the quad. The motors are all the same? All bought at the same time? Props all from the same order?

It could also be that the accelerometer calibration wasn't done with the quad perfectly level. When calibrating, the frame is what should be perfectly level. This compensates for the way the flight controller is mounted in the quad not being perfectly aligned with the frame. In the end, it's the craft that needs levelling and not the flight controller!

Yes i know that,the range of variation showing in Roll,pitch & yaw,that value should be apply on the RC & Yaw daedband.But sometimes my receiver shows more variation than i specified in deadband.

And I have Sp3 racing deluxe fc.I didn't enable the barometer and magnetometer yet.

I already added o ring between fc and mounting screw for shock absorption.And I think flight controller is perfectly  mounted on frame. 

last time i calibrated accelerometer at the level -Roll 0.3 & Pitch 0.9(added screenshot).is this level is good for calibration or it should be 0.0 both,at time of calibration? 
May be they are not leveling at 0.0,because i added some soft foam in quad arms for smooth landing and avoiding crash.

Yes, you should put your quad on a flat surface and shim it to get as close as you can to 0.0 on both axis before you calibrate

As I earlier mentioned my quad is drifting right,i checked at cleanflight/receiver tab, in preview section.My quad was also rotating right side smoothly. Have a look at this video-



Then I re-calibrated my transmitter sticks,re-adjusted subtrim(for centering at1500),and re-calibrated accelerometer. Again i tried to fly but it going to backward   ,then checked at cleanflight/receiver tab... ....Please,have a look at this video

Unfortunately, the way the model moves on the receiver tab doesn't take the deadband settings into account. In your first video, the channels are centred slightly above 1500 and just below 1500 in your second video. This explains the movement you see in the model.

Your deadband setting will work properly when you are in the air.

Trying to keep a quad perfectly still as it hovers is incredibly difficult! There will be some drift in one direction or another depending on wind. How does the quad fly when you get moving?

(30-Jun-2017, 01:25 PM)unseen Wrote: Unfortunately, the way the model moves on the receiver tab doesn't take the deadband settings into account. In your first video, the channels are centred slightly above 1500 and just below 1500 in your second video. This explains the movement you see in the model.

Your deadband setting will work properly when you are in the air.

Trying to keep a quad perfectly still as it hovers is incredibly difficult! There will be some drift in one direction or another depending on wind. How does the quad fly when you get moving?

Thanks for reply  
  
In last two flight when i increase throttle slightly, quad was moving to right side.Again i calibrated the transmitter stick and also accelerometer then quad was moving to backward. 

I will try to upload the video tomorrow ! Please stay connected! I really need help

I know it is difficult to keep a quad stable in the air and there will be always some drift in any direction.But in my case when i raise throttle it drifts or rolling to right direction continuously until i low throttle stick or move the AILERON stick to opposite(left).

now,when i move the AILERON stick to opposite(left), Quad move to left or Roll to left but(here was another problem) it continuously moves to left whereas i already i released the aileron stick.

One strange thing I found that when i move right side stick(Aileron & elevator) up,down,left,right ! they never again goes to center position,whereas they was at 1497-1503.
I mean, AILERON & ELEVATOR at the position of 1500(1497-1503).
            then i moved the AILERON stick to left side then,it returned to 1492.Again i moved the stick to right side it returned to 1508 .
 it also happens with ELEVATOR stick


so,I am guessing there is something  wrong with my transmitter stick. Ok! I will tomorrow upload the video of flying quad

You're in rate mode (acro). That's how it works. When your copter is in rate mode, the pitch and roll sticks command how many degrees per second the craft should rotate, clockwise or anticlockwise. When the stick is at centre, it means don't rotate and maintain your current attitude. The yaw axis works in rate mode regardless of the selected flight mode.

If you want to fly in a self levelling flight mode then you need to go to the modes tab and set up an AUX channel with a two or three position switch from your radio so that you can select different flight modes.

With both Cleanflight and Betaflight, if you don't explicitly select a flight mode, then the default is rate mode (acro).

The radio's sticks not returning to centre properly is something that can happen, especially on cheaper radios with poor quality gimbals. It could also be that the tension on the sticks is too high or that they forgot to dab a little petroleum jelly (Vasaline) on the joints and binding surfaces of the plastic parts of the gimbal's mechanics.

Either you fix the gimbals, get a better quality radio or sweep the problem under the carpet with the ten point deadband you need to tune out the poor gimbal. The price for just covering up the problem is less precision when the controls are centred.

In reality, unless you spend time trying to get a perfect hover, this kind of problem isn't even something you would notice in forward flight with self levelling flight modes.

I already configured the three position switch-N for acro, ID1 for angle mode and ID2 for horizon mode.I tried all three modes and i didn't found any improvement. 

If my transmitter gimbals are defective,then I am planning to buy a new transmitter- FrSky ACCST Taranis Q X7 2.4GHz 16CH Transmitter