I have bought new heli from hobby king
Helicopter - HK 450 MT
Analog Servo - 900
Gyro - Hk401
Motor  - 4000KV
Battery - 2200 30c
ESC - 40 Amp
Balde - Fibre Glass
KDS model 7x transmitter

In tx i set the gyro gain to 40.(If it above 10)
When i move the rudder stick to left the tail assembly is moving to boom side then stays their and is not coming back to center position. same when stick is moved to right(away from boom and stays their).

When  the gyro gain is 0 then its running fine.ie; when the stick is left(or right) its moving away from center and when stick is center tail is back to middle position.

Is that any error? Also i cant hover the heli .. the tail is slowly rotation to anti clockwise. If we are giving gyro gain still its rotation .. what could be wrong ..

1.  If a beginner (possibly you?) have assembled this, make sure the blades are fitted right and they are rotating in the right direction. 

2.  Then you give left rudder stick, the HEAD of the heli (not the tail) should move to the left (looking from behind the heli towards its nose).  To achieve this, on most helis, the slider should move right.  If this is not working right, REVERSE the rudder channel (usually channel 4 for many brands) in YOUR RADIO.

3.  By the same logic, when you move the head of the heli to the right holding the tail in one place, the slider should move along with the head to the right, due to the compensation issued by the gyro.  If the slider is moving to the left when you move the head to the right, then REVERSE the direction on the GYRO unit itself (not in the radio!).

4.  You should do your settings with rate mode preferably with about 48 gain, and then switch to heading-hold with a gain of 35 before flight (that is the simplified method, the rigorous method involves testing in rate mode itself). Rate mode and heading hold mode gain numbers depend on the radio to some extend, there is extensive discussion here on this subject, just search.

As a general comment, try to download and see the Finless Bob setup videos from Helifreak.com (search this forum for details).

Anvar.. what ever you told is correct with my heli.. every thing is running fine... but still drifting... might be gyro is loose inside..i dont know
The one what you told abt baldes... i have a doubt on it... main rottor blades might benot aligned... let me go through it ..

In some descussion some experts told that the power of the motor power is so high(4000KV).. with 11T pinion. Make it to 10T or reduce the power to 3500KV to make working for hovering. I had ordered one 3550 kv motor... its on the way.

Next reply is, with HK 401 gyro we need high speed servo(analog or digital). 900 servos are a bit slow.. so making it some precise tail servo will compensate those issues.

I did not realize that you did not use a proper tail servo (a high speed one).  That is a crucial factor in tail performance.

A high power/rpm motors is not a problem, as long as you use the right pinion AND/OR you adjust the throttle curve accordingly.

I am facing a similar problem on my Belt CP...actually its tail is behaving very unevenly ( I dont know wot word to use)......after lift from the ground it have sudden jerks ....in its tail..i dont know what could be the possible reason...if I keep the gyro knob at centre (0) then its jerks are more frequent but as I reduce its gain (-) they become less frequent ....

  what is the problem?

It would be great if you can post a video.  Tail behavior is a combination of a bunch of things, and seeing the actual problem helps big time.

Will comment further if you are unable to post a video.

+1

Hi Arvind,

If you are using the stock Esky Head lock gyro and stock Esky tail Servo then the settings on the Gyro and the Tx are as follows:-

Keep the Delay at 50% on the Gyro pod

Keep the gain on the TX at 11'o clock considering Zero/ center is 12'oclock and the tail should be fine.

BTW sudden tail jerks are also a feature of the ESC when the batt is raching the cutoff voltage the ESC starts giving out tail jerks as an indication to replace battery. so make sure your battery is always charged.

A video will definately help pin point the issue.


Thanks
Hellyflyer

Thanks,  ....Anwar and Amit.

My heli flying skills are of a toddler and I am in Pre-pre school of heli flying so shy of shooting my crashes....However now "How not to crash" is my current learning.... ....(will learn flying after this).................other reason I always fly alone...so no one to keep the camera...seldom my son and wife accompany me, then only I can ask her to shoot.

 ...You were right Amit ...some minor problem with gyro settings, I adjusted and now its hovering fine, no more sudden jurks  .....

hi here is the video of hovering. you can notice the sudden tail kicks..what is the possible reason, although reduced very much but still its not balanced .