401 & DX7 ISSUE

[madmick]

Hi to all,
I've had a problem with my 401 Gyro for sometime, and tried to live with it but I thought that I'll ask if someone has had the same problem.

ITS when I have the heli hovering the tail moves left by its self every now and again so I have to compensate for this movement the Tail dose not waggle around so I guess that the Gain is just fine. IT just moves to the left, its really starting to bother me,

I've gone over Bob's 401 Vid's time and time again, and the only thing that I'm not shore about is do I have to set Gain for HH mode went I setup the tail or not. Or the setup the Gain in the DX7 for gyro?
I have found that my Trex600 which is stranded out of the box except for a upgraded tail, that the belt might be to tight which puts strain on the bearing and that in turn might make some sort of nose which upsets the Gyro?
I'm just guessing as I've heard that Gyro's are sensitive to all sorts of nose and Its acting like there's something Wrong.
The Gyro is mounted on top of the Tail Case and the wires run down in side the frames right behind the Main Gear, if it helps I'll put in a Pic to show what I mean.

[HiroboFreak]

The wiring looks fine, provided it's not tight as tension on the wires can transfer vibration to the gyro.

We've had a few issues over here in Oz with 401 gyro drifting when paired with some JR/Spektrum radios.
It basically comes down to the Tx centre signal causing conflicts.

Firstly, ensure you have initialised correctly, (HH startup with NO movement).

If this is all OK & still drifts, then add a bit of subtrim to rudder (channel 4), no more than 5 units of subtrim are necessary. Switch off Rx & Tx & fully reinitialise the gyro system as per normal procedure.

This will alter the centre point voltage slightly. If the drift is worse, change the subtrim units to the opposite direction. Switch off & reinitialise the gyro system again.

I'm aware that this goes against all HH gyro theory but that's what we have found the fix to be. ;)

Remember that because you are reinitialising, the gyro doesn't know you have added a small amount of subtrim. It's calibrating the new centrepoint.

Let me know how it goes :)

[madmick]

The wiring looks fine, provided it's not tight as tension on the wires can transfer vibration to the gyro.

We've had a few issues over here in Oz with 401 gyro drifting when paired with some JR/Spektrum radios.
It basically comes down to the Tx centre signal causing conflicts.

Firstly, ensure you have initialised correctly, (HH startup with NO movement).

If this is all OK & still drifts, then add a bit of subtrim to rudder (channel 4), no more than 5 units of subtrim are necessary. Switch off Rx & Tx & fully reinitialise the gyro system as per normal procedure.

This will alter the centre point voltage slightly. If the drift is worse, change the subtrim units to the opposite direction. Switch off & reinitialise the gyro system again.

I'm aware that this goes against all HH gyro theory but that's what we have found the fix to be. ;)

Remember that because you are reinitialising, the gyro doesn't know you have added a small amount of subtrim. It's calibrating the new centrepoint.

Let me know how it goes :)

I've moved the Gyro wires from one side to the other so they run down the frame by themselves so there's no interference from servos wries or from any bearing, I'll fly the heli tomorrow and see I'll let you know.
Thanks for all info.

[madmick]

Hi HiroboFreak,
Just a stort note to let you know that I tryed out the the tail problem,
it still drift's a little but only when I'm in hover and move side to side. so I think that I'll put up with it as I cart seem to get it any better its no where as bad as it was.
Thanks again for all the trouble you've gone to.