hurricane 550 tail drifting

[miladyazdi]

ok so I have been fighting with the problem and I cant solve it so lets ask here.

I have the hurricane 550, everything stock with the GY401/s9254 servo. I have set the tail mechanically so everything is 90 degress. Subtrims, endpoints etc etc are all set at neutral. Then I take it up in a hover in normal mode and set the tail pitch so it almost doesnt drift and flip to HH. Is this the correct way to do this? In normal mode when the tail stick is in neutral the pitchslider is not in the middle, more to towards the hub, is this correct?

In HH the tail drifts a little to the right no matter how much I set the pitch for the tail in normal mode. I start at 80 % gain in HH and it wobbles, but as soon as the wobble stops about 76% gain the tail drifts. Any suggestions? What have I missed, my last hurricane the tail was rock steady but this one refuses. Also, the tail fin shakes alot in flight. Could the tail not holding have to do something with this issue and why is the tail fin shaking? Thanks for your help!

Regards

M

[kkwait]

You have to set it mechanically in normal mode so the tail is steady, and then you can switch in HH.
If you trim it in normal and then switch to HH, it will drift... because the HH neutral is not the same as it was when you turned the heli on.

[miladyazdi]

yes I do set it in mechanically in normal mode and hover it in normal mode and turn the ball in or out until the drift stops in normal mode. So I have it set in normal mode and then switch to HH and the tail drifts. could it be the belt is too loose or tight? I'm lost ....

M

[miladyazdi]

ok so there are 3 different characteristics on the GY401. The one with a red light (HH) flashing light (what is this?) and no light (which I guess is normal mode).

In what of the above 3 phases do I set the tail?

M

[Graeme67]

The fact the tail fin is shaking suggests either something is out of balance or not running true. Check you blade tracking - this can certainly shake the heli if it's not right, check main blade balance, mast running true, TR spindle, and try a new set of tail blades. The 401 could be having problems due to the vibrations?? I'd clear this up first.

Cheers
Graeme

[kahn10]

and to give you somewhere to start....tail shaking side to side - tail blades.tail shaking up and down -main blades

[mjdee14]

If the fin is shaking, then most likely that vibration is being transmitted to the gyro and it will cause the servo to move.

http://www.helifreak.com/showthread.php?t=82309

take a look at the above thread...it's what I did to stop the vibs.....

I traced mine mostly down to the gaui hub...and I was using the thrusted hub. it had worked well for many flights then started vibrating causing servo movement.

also try tightening or loosening the belt and see if that changes the vibration any.

[helvetic]

ok so there are 3 different characteristics on the GY401. The one with a red light (HH) flashing light (what is this?) and no light (which I guess is normal mode).

In what of the above 3 phases do I set the tail?

M

flashing light means incomming signal from the receiver, NOT neutral position !
So, if you switch to HH, the red light must shine, no flashing!

Just try this one: Switch to HH, and then turn on the power. Don't use the Normal Mode. The Heli should stay, no drifting. Red light is on, no flashing.

[kahn10]

there's a good 401 set up in bobs vids......but basically start her up in hh mode.once gyro's initialized(stopped slow flashing and constantly on) flick it into normal mode then set your tail up to hover mechanically with no trim.once you've got her hovering straight with no input for the tail bring her back down and switch bec off.turn hh back on transmitter then turn bec back on.a rapidly flashing light means your 401's confused......

[miladyazdi]

yes I know a steady red light is HH, was just wondering what the flashing light is (not he one before initializing to HH, but a constant flashing light). I guess that doesnt mean anything.

Kahn10, that is exactly the way I have done it but no matter how much I correct for the tail to be straight in normal mode is still turns to right which means I have almost no space for left rudder on the control surface. Hmmm this is confusing

M

[kahn10]

if its constantly flashing and more rapidly than the flash when you turn it on its got an issue or can't find neutral.go thru your transmitter and make sure you have every sort of programming involving your tail/gyro inhibited

[miladyazdi]

no it is not constantly flashing, I have it in HH, that is with a red light, that I'm sure of. The thing is I can not get it in a way that it wont drift in normal mode. If it drifts to the left I turn the ball one turn and try again. Then it starts to drift to the right ...

[miladyazdi]

anyone?

[Mikej]

I'm not using a 401, but have 2 550's one with a Telebee and one with the Gaui 210 gyro, what I do is set the tail using in rate mode so that it will hold steady without drifting (by adjusting the length of the links on the rod) this is so the with the rudder at neutral I have no trim or sub-trim. When I then flip into HH I usually need a few clicks of trim to get to a non-drifting heli.

Not sure if thi shelps at all, but it seems to work for me. Out of interest how much gain do you have set for rate and HH ???.

Cheers,
Mike

[miladyazdi]

this is exactly how I do it. So its OK to trim it in HH to get it not to drift, I thought that was a NO NO.

In normal mode my gain is 40 % and in HH I start at 80 % and go down until the tail doesnt wag but the tail drifts, I could probably trim it so that it wont but as I stated above I thought trimming is not good???

M

[Mikej]

I'm not really sure to be honest - works for me :):)

I though that there was something that you could do on a 401 to tell it that the way that you had it trimmed was the new "neutral" - isn't it flick between HH and rate 3 times very quickly - or am I hearing voices again ??

[Mikej]

This is pinched from another area - but this is what I was thinking about ....

"If you read the manual on the 401 you have to set the neutral in rate mode thats what I think they call it. So basically in rate mode you adjust your linkages to get a stable no drifting hover. Then you land unplugg and replug and boot up in HH mode. Or during hover have one of your toggle switches set for one position rate and one HH and in hover once you set the neutral. Quickly toggle between the settings a couple times and end up in HH. That will set the neutral. And if your using Spektrum don't forget to rebind. And the light will also blink when your applying tail input."

Seems brave doing it whilst hovering and I thought that it was 3 not twice - perhaps a 401 manual will help

This is what the 401 manual says

"•Rudder neutral signal memorization methods
[Method 1] When the gyro power is turned on, the transmitter rudder signal
automatically received at that time is assumed to be the neutral signal and
is memorized. The gyro is normally used in this state.
[Method 2] Rapidly switch the transmitter sensitivity switch between the
AVCS and normal modes at least 3 times at a 1 second or shorter internal,
then set the switch to the AVCS mode position. The monitor LED flashes
instantaneously and the rudder signal is memorized. If the trimmer was
moved during flight, the memorized neutral position can be updated to the
current neutral position by repeating this operation. When performing this
operation, land the model and hold the rudder stick in the neutral position."

This sentence "If the trimmer was
moved during flight, the memorized neutral position can be updated to the
current neutral position by repeating this operation."suggest that trimming in HH mode is OK ??

[ukgroucho]

If you look on RCgroups on the mini helicopter section I documented 401 setup a LONG time ago... it was a sticky for a couple of years and then they decided to un-sticky everything. Anyway.. search on my user name and 401 and you'l probably find it.

The objective of setting rudder neutral in rate mode (non-HH) is NOT to get a stable hover in HH mode. Rudder neutral is helpful to the gyro because it helps understand where it needs to return the tail slider to to stop yaw... at least in a stable hover. Setting rudder neutral correctly will tune the setup for best performance but is not essential to get a stable tail during a hover in HH mode. You can set rudder neutral mechanically if you wish... I prefer to use sub-trim in rate mode because it enables the tuning of rudder neutral to be performed without messing up the throw of the tail slider one side or teh other. If you've carefully set the limit on the 401 to get maximum throw then it seems a little pointless to mess that up playing with trying to set up a mechanical rudder neutral... I've had this debate with a number of people who maintain that you must set up mechanically, all I can say is that Futaba document using sub-trim to set up rudder neutral in the 401 manual.. they do it for a reason.

You never (EVER) add trim / sub-trim to the rudder with a 401 in HH mode. This will cause a blinking LED and a continuous drift as the 401 will interpret this as a continuous input requesting the nose to turn.

You don't say if you are using a Spektrum radio (DX7..). If so then it is essential that you rebind the receiver after you complete setting up the rudder neutral.
- Set up rudder netral (in rate mode, using sub-trim to get stable hover).
- Power off, flip Tx to HH setting and rebind.

If the LED is stable on the 401 then it's in HH mode with no rudder input... if it drifts then most likely cause is vibrations. Did you remember to put a rubber pad under the 401? If so then you can try adding a second one.