GY401 help with drifting tail

[wichet]

Hi i am using a GY401 on my 450se v2 with a digital s9650, the thing is that the tail drifts very slightly and slowly during the hover to the left i am always having to bring it back round with right rudder. Can someone advice me on this, have i got my gain to low in the tx or have i mist something. Gain is set to 65% HH in tx, this seems to work as there is no bouncing back and forth from the tail.

Thanks in advance

Darren

[gazza]

Have you set it up mechanically in normal mode first mate? Hover the heli into wind in normal mode & adjust the servo position on the boom or shorten/lengthen the tailrod until it hovers with no drift.

Land the heli & adjust the limit pot for no binding, then unplug and plug in the lipo. Let the gyro initialize then flick whichever switch you use to select between HH and normal modes into normal mode then back to HH mode 3 times in quick succession with the switch finishing in HH mode.
The switch flicking tells the HH mode the new neutral position.
Adjust the gain up until the tail wags then back it off just until it stops.
If you end up with a high gain figure like eg 80-90% before it wags bring the rudder pushrod out a hole on the servo arm..I think around 55% is a good figure for this size heli.

[Sieze2]

Finless on Helifreak says there is no need to mechanically set the gyro up with a heading hold gyro, mainly becasue in doing so it limits the tail pitch slider in one direction, therefore reducing the overall usable slider Range of motion for the gyro to use.

I don't profess to be a gyro expert, but I do see his point. And yet lots of people set the gyro's up mechanically in rate mode, so there must be something to it?

PS Wichet the drifting should be sorted by switching between HH and rate 3 times in rapid sucession (as Gazza states). (start in rate and end in heading hold). I have had this problem myself and that fixed it - a nice easy fix to a problem (unusual with RC heli's), now if only I can get my head round why it is better to mechanically setup in rate mode !?

[gazza]

We had this debate at our club with some setting up in rate mode & some not.
The obvious advantage of not setting up in rate mode gives you equal throw on the pitch slider, but I'm not sure that the gyro & servo aren't being overworked using this method??
I'm sure someone on here can clear it up The rate mode method works for me so I tend to stick with it.....

[Made2Fade]

now if only I can get my head round why it is better to mechanically setup in rate mode !?

Well for 1 it makes ya tail servo/gyro not work as hard in HH mode. If you dont set up in rate mode then when flying in HH the gyro will always be looking for that refrence and adjusting. Will probably make the lifespan better in the longrun. I think thats the theory behind it anyways summit like that. I set all my helis in rate mode first and have never had a problem with any of the gyros on them. Doesnt matter about equal throw anyways as it has to work harder on one side to compensate for the engine torque etc. You can use atvs in HH mode to adjust if it piros one way faster than the other.

Lee

[wichet]

Thanks for this, I have my tail set in the centre for equal through, if i was to set it up for rate mode which way do i have to set the tail. more right rudder or more left to compensate

Darren

[gazza]

More nose right offset is needed mate..Appprox 7 degrees on the tail blade.

Thanks for this, I have my tail set in the centre for equal through, if i was to set it up for rate mode which way do i have to set the tail. more right rudder or more left to compensate

Darren

[Made2Fade]

Right rotating helis would be more left rudder (nose will go right on the heli). Im unsure exactly how much on that model heli but its a trial and error thing to get it perfect anyways. Just remember when you have finished setting in rate mode to flick the gyro gain switch a few times so that heading hold remembers the centre position like Gazza said.
Hope that helps.
Lee

[Made2Fade]

If you fold the tail blades in then looking from the back of the heli they should point to the right slightly.
Lee

[wichet]

Much appreciated