401 gyro problem

[jamiesawyer28041978]

Hi guys got my self a brand new 401 gyro today delighted only problem is the tail is hunting badly , tryed the gain max in both directions every where else but no good.I think I read a previous tread with something about moving the push rod connection on the servo arm in a hole , will this help with it.

All replys much appretiated

[nightstalker]

What servo do u have running with it?

[jamiesawyer28041978]

Hi there night stalker Ive got a hitec hs 5475 hb digital is that ok
It on a rappy 30 v2 and the tail servo is on the boom with a carbon push rod direct to tail push rod.

Thanks for reply

[nightstalker]

That is very slow 0.23sec, how far out on the horn is the rod? and have you tried adding any delay??
Dont run in with the DS set to on as thats for fast servos

[jamiesawyer28041978]

MM that might help turning it off , ill try that tomorrow and ill check the delay. Ill post back tomorrow and let you know if there is any change. The connection is on the second hole out from the middle of the servo .

[nightstalker]

Ok that's ok for starters you might find you will have to go to full delay being how slow that servo is, if you still get a slight wag move the rod in and go higher with the gain.
But to be honest you will need at one point to get a better tail servo as that's gonna let you down later when you really need a good holding tail

[HiroboFreak]

For starters, check your tail pitch system is moving freely.
Any stiffness or binding will cause a wag/hunt.

Once you have the tail pitch system nice & smooth then start worrying about your gyro settings.

The "gain" setting in your radio affects the wag in a hover.
A slow wag - gain too low. A fast wag - gain too high.
A 401 with fast servo won't wag until the gain is very high, but you will reduce the life of the servo.

What radio are you using?
This will help me to give you an idea of what gain to run.

The "Delay" dial is used to stop hunting at pirouette stop when using a slow servo.

ie: do a few pirouettes with stick at full travel & stop abruptly.
If the tail hunts, increase delay setting.

If you are using a super-servo like the 9254 (0.06sec) then set delay to 0.

If your servo is a "DIGITAL SERVO" , set the DS setting to "ON" . If not, leave it off.
The DS setting has nothing to do with how fast or slow the servo is, it has to do with the framerate.
Analog servos run at a lower framerate than digitals.
If you run an analog servo on the DS setting you will damage the servo.

Good luck.

Regards,
Dennis.

[HiroboFreak]

This is the procedure that I use when setting up tail pitch travel.

Set your gyro to normal mode during this procedure.

Disconnect your tail push rod from the tail pitch slider.
Move your rudder fully one way,
move the pitch slider fully in the same direction,
compare the tail push rod ball link position with the pitch slider ball.
Do this on the other side as well.
Keep increasing the limits in the Gyro until
the tail push rod matches the full stroke of the tail pitch slider.
This method ensures that you do have maximum tail pitch slider throw.

It is vital to keep the left & right limits at the same value.
Move the tail servo on the boom and adjust the tail push rod
length to get the end of the tail push rod into the centre of the
tail pitch slider throw.

You want the left/right limits to be at least 120,
this prevents over working the tail gyro and burning it out.
The higher the limit the more granularity the gyro has to work with,
which means it's maths are more accurate,
which reduces over corrections and oscillations.

The following tips are specific to the Futaba 502/601/611 Gyros

Set the gain to 37%

With the rudder in the neutral position,
switch between normal mode and heading hold 3 times,
you will see 3 or 4 stars in the gyro amp module,
this means the centre point has been calibrated.

Set the gyro to heading hold to make it idiot proof
(we never use normal mode in flight).

Many thanks to Nigel brown for this procedure.

Keep in mind that your rudder end points/atv's in the TX adjust your pirouette rate, NOT pitch slider travel!

[jamiesawyer28041978]

Hi there i have tryed switching the digital servo off but no difference there so its back on , the hunt seems more pronounced with the engine reves . Each time it misses a beat the tail wags so on and so fourth till its time to land cos its getting out of hand ( prang coming ) . Ive also tryed eliminating this but it sounds like the engine is over reving . Ive moved the servo push rod in one hole and im going to try it again to see how that is . Not holding my breath on that one but we will see . Let you know how im getting on in a while.

Regards Jamie

[Ade_Law]

tails are tricky little gits if you dont get the right servo/gyro combo and as thus true tail servos are very special beasties.

you have a choice...

1) buy a 9254 and it will just work if setup correctly on the bench.

2) mess around trying different servo horn lengths and different amounts of delay on the 401... realise that its never really going to work very well and buy a 9254

Ade

[jamiesawyer28041978]

cheers for that info but I was hoping it was going to work for at least a couple off weeks so that the wife might forget when I spent the last money on heli bits . But I do know deep down there is only one route for this but surely a normal digi will work for the time being , had a 148 working the tail before.Exsperianced nothing like this tail wagging till I got this 401 gyro

[jamiesawyer28041978]

Moving the servo push rod in did a big difference to the tail wagging not fully gone but very flyable , thanks for all the help . Will ,buy a faster servo in a week or so and up grade the rest to I think while im at it.