Come in Here 3GX.?

[tourerjim]

Very strange but here goes! my 450 pro has developed a aile to tail drift, she fly's perfect until about 1 min of battery is used then she starts with a slight tail drift becoming stronger such that by time ive done 4 mins she has a very strong left aile to tail drift.
3GX is fitted inverted under main shaft, ive already tried 2 pads, adjusted gain pots in all direction played with parameters, settings at the moment are perfect so no faults there.
I have the sh257mg savox servo's & all the setup is with digi gauge.
The strange thing is when I was on v1.2 had no probs with drift but did have cyclic behaviour in hover but since going v2 she been perfect all week, ive got to have done getting on for 30 odd flights in the week then yesterday afternoon done about 9 packs when the fault started to happen on the final 3 lipo's so didn't take to much notice of it, then today on the first pack she started doing again so sat her on the level then looked at the swash & its nice & level so im assuming ive got vibes but cant find thing wrong.
Im been reading on others having drift problems but I think this is be caused in a different way!
I've been a 3g boy since they first come out so its not down to lack of experience so what do you think can be the cause.?

[Gaui-Deanoo]

is your tail set up correctly in rate mode so there is no drift? maybe the gryo is trying to compensate for itself? and as the pack dies it hasn't got enough power to compensate. other possibility is maybe you have a dying servo on your tail that is sensitive to power regulation?

just back track the basics first, check mechanical setup is good, then check servos, then voltage regulation, then maybe rebinding/reprogramming the 3gx will cure it, hope you find out whats wrong buddy

[Gixxer]

Or maybe vibrations are taking hold?

[Delarado]

I have the same thing, ive still not managed to kill it off. Hovers just fine at take off. After a few loops and inversions its almost like you have a few clicks backwards on the trim on the cyclic (Which i do not, ive checked!)

[coolice]

Hey.

My thoughts are that if there was a setup issue, then this would be present from the start of the pack until the end. As it's come about with the V2 upgrade it's also concerning and that it creeps in part way through a flight it points to something else, vibrations have and always will be a possible cause, but recently there has been talk of the BEC voltage being a possible cause.

You can have a bad upgrade, the upgrade process has been known to cause problems and this has been traced to a bad download fron the internet.

On your ESC what voltage do you have coming out of it? I would guess you're running 6 volts to the servos to maintain the required servo spec, which means you are already good, but is this votage being held nicely of is it flutuating greatly?
Is it possible you could try another power supply into the 3GX and fly the model?

Setting up the tail in rate mode I only did so on the bench to set zero pitch on the blades and then let the heading hold of the gyro control the tail, as not many use rate mode anymore and so having a trimmed tail in rate mode isn't so critical.
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[Delarado]

I havent done any tail setup in rate mode? I set my tail up in the 3GX software and then put my gyro at 71% and its fine. Do I need to do something else?

I don't have any other means of supplying power to the servo's unfortunately. Im using the stock 70A align ESC though and I haven't changed any of the parameters regarding voltage. Ive bought a new set of every bearing in the bird to fit today to eliminate vibrations too... will feed back!

[coolice]

I havent done any tail setup in rate mode? I set my tail up in the 3GX software and then put my gyro at 71% and its fine. Do I need to do something else?

I don't have any other means of supplying power to the servo's unfortunately. Im using the stock 70A align ESC though and I haven't changed any of the parameters regarding voltage. Ive bought a new set of every bearing in the bird to fit today to eliminate vibrations too... will feed back!

Hey buddy.

The norm was to setup rate mode so that the tail would stay still in the hover, this normally meant adding a few degree's pitch on the tail blades to compensate for the torque reaction on the model. The downside to this is that it biased the tail throw more to one side and made having equal tail throw for left and right more difficult, if impossible to obtain. So the current school of thought changed to just use rate mode to set the tail pitch slider in the middle of it's travel to see zero pitch on the blades and then adjust to get maximum tail throw either side of this centre.
However some gyro's do still benefit from the old fashioned way of setting a hands off hover while in rate mode, the CSM SL760 is on of these gyro's for instance. But the Align's don't seem to be bothered either way.

As you are using the stock Align ESC I would say it's BEC output will still be at the manufacturers defaults, which will be 5.5 volts output, which means you are not getting the best out of your servo's for use with the FBL unit. Also, as with main motor power supplies, the higher voltages work more efficiently and in turn it's thought reduce load on the BEC.
I would cycle through the ESC options and make sure the BEC output is set to 6 volts.
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[Delarado]

I'll give it a go mate, thanks! Will that make my servos quicker? Shouldnt affect flight time right?

Ill report back on the state of my bearings when i remove. So far i've tried moving the 3gx from top shelf to bottom and flipping it around (So the front is the back and vice versa, to see if i then got forward drift)

I did not, so I think its something else not mechanical with the 3gx unit at least. Its either link setup on the head or vibrations or something else funky.

[coolice]

I'll give it a go mate, thanks! Will that make my servos quicker? Shouldnt affect flight time right?

Ill report back on the state of my bearings when i remove. So far i've tried moving the 3gx from top shelf to bottom and flipping it around (So the front is the back and vice versa, to see if i then got forward drift)

I did not, so I think its something else not mechanical with the 3gx unit at least. Its either link setup on the head or vibrations or something else funky.

Hey.

Yes, servo's will be quicker and torquier so might need gains lowering to compensate, but flight time should still be the same. The BEC is actually working harder to reduce the voltage to 5.5 volts than it will to 6 volts and will actually not be wasting so much unused energy as more is being used.

Near the top, above the boom clamp is known to be quite a high vibration area and so moving it down will always bring about better results. There is the age old debate about the benefits of having the gyro directly below the main shaft for the tail rotor atleast. The cyclic gyro's would need to be along the roll and flip centre lines.
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