Drift problem with a 611?

[mak24seven]

Not much chance of flying today where i am unless you like flying in a gale but anyways last night was super calm so just thought i'd have a play with the 500 in the garded and do a few tweeks, I,ve always had a bit of tail drift problem on this heli when it enters the vertical position the tail will not hold stright and seems to kick out 10 - 15 degrees (401 ) so i put a 611 on it to see if it would be better, it is better but still does it, anyway back to my origanal reason for posting, the gyro has been set up so everything works properly, gain 38, no binding, set up in normal mode for the hover ect ect but last night with it being so calm i just thought i'd see how solid the tail held in the hover in normal mode, up into the hover it sat perfect for 10 seconds then slowly started drifting to the left then stoped and went the other way 20 degrees and continued to go back and forth :-(, sorry for the long post but how the hell can i set the gyro up for a hover when its going back and fourth, i'm thinking this must be a tail issue but any thoughts and sugestions welcome

[Made2Fade]

I take it when you swapped gyros that you didnt touch the servo? Why dont you try a diffrent ball position on the servo arm just to see what happens? Could give ya an indication to the problem or even fix it.
Lee

[mak24seven]

Lee the servo has been changed along with the gyro, it now runs the 611 tail servo, i'm guessing the mechanical gain is about right with the ball on the servo because at 40% gain it will fast wag in certain moves but at 37-38% witch is the sudgested ball park figure its fine.

[Made2Fade]

just wondering if you'd played with it thats all. Wonder if its something related to the heli and not the gyro itself?
Lee

[mak24seven]

Thinking the same, there's a rook of play in the tail hub, if you grab the tail blades they move up down and fore and aft but every one knows about this and no one's said its an issue, dont get me wrong the thing flys fine and i can correct the tail moveing as i flip but its just odd it wont keep a constant tail lock in the hover ( in normal mode) without drifting from one side to the other, in heading hold it's ok but i was just curious as to this movement, no worries maybe i'll find out why one day. :-)

[robgt]

Does it hold reasonably still in rate mode?
If it's far enough out in rate mode it will drift in heading hold.

Cheers,
Rob

[mak24seven]

Does it hold reasonably still in rate mode?
If it's far enough out in rate mode it will drift in heading hold.

Cheers,
Rob

Thats just it, i've always set em up in rate mode, hovered, tweaked, hovered tweaked ect untill it hold's perfect then just flicked between the 2 modes to set tail nautral and away we go but in rate mode it difts left 20 degrees then right 20 degrees and so on, a perfect hover albeit from 1 side to the other so there's no point in adjusting the tail push rod unless it carried on turning in one direction.

[robgt]

so there's no point in adjusting the tail push rod unless it carried on turning in one direction.

True!
Check every setting in your Tx related to the rudder to make sure there's no trim or sub-trim on that servo/channel.
If it does the same thing on the 401 and the 601, that suggests to me that it's mechanical rather than electrical.
If you have used different servos, it's unlikely to be the servo at fault - unless you happen to have two servos that are on their way out?

Detatch the rod from the servo and make sure you can easily push the rod to move the rudder linkage to it's extremes of travel with no force required at any stage to keep it moving - i.e. it moves freely throughout the range.

If all that is sound - make sure the gyro's themselves are mounted firmly and are not able to sway at all - also make sure nothing is hitting them inflight (canopy for example).

Final thing is, if it's a regular slow wag side to side throughout the flight, the gain could be too low?

Beyong that... I'm not sure what you could look at!
Cheers,
Rob

[Rodsport999]

Hi mate,
The 611 will drift slightly in AVCS mode unless you use a small amount of subtrim to correct it, it did mention this on some paperwork i got with my 611 but i cannot find it.
Put the gyro in to HH, if the servo drifts adjust the subtrim until it stops (should only be 1-2 points).
Cheers

[mak24seven]

MMMMMM! The gyro pads are perfect, there is no binding wot so ever on the mechanical tail linkage set up but that would be hard to acheive any way s as there's only 2 push rod eye's 2 go through and the gain is spot on at 37 (indicated on the amplifiyer display) as 40 gives me a fast tail wag in some manouvers, basicaly wot i have hear chaps is a perfectly set up gyro and mechanical linkage set up but when hovered in rate mode it lifts perfectly into the hover then slowly moves to the left stops then slowly moves back to centre then to the right then stops then back again, i guess this is just one of those posts you read and think mmmmm! must be something he's done wrong and will pass without ever knowing the true problem but hey, thanks for your input guys i'll chalk it down to this hobby being one learning curve after another :-)

[mak24seven]

Forgot to add the 611 set up on my night is perfect (robbed it for the 500) so maybe it's got something to do with the slop in the tail set up of the trex 500?