Small G-T5 tweaking guide

[swalko]

My small tweaking guide :

!This is only small tweaking guide based on my G-T5 practice in my TDR, assumption is a carefully readed and understand of G-T5 and AC-3X manual!

In comparison to AC-3X the G-T5 have some new setting, these settings are very important, then the AC-3X manual is not enough.

At first, use gentle values (best is to use default). Set total gain on TX to 60%. Try it in hover. With default values it is possible that your model will be lazy. If is all OK, switch total gain to 100%. Helicopter will be more responsible and more locked. If all is OK with 100% total gain you may start tweaking:


Tweak only one parameter on same time!



Tail:


P:
Set P as high as possible without fast tail shaking in hover. If tail is shaking fast in hover it is HIGHLY overgained, turn P 5 points down until fast shake disappear. If the tail is not shaking fast in hover you are still not done. Now you need to test and listen you tail in more conditions:

1. Fly heli in forward direction on the back and immediately go into fast climb and on higher side do piruette. If you hear buzzing sound from tail in this maneuver decrease P 3 points and test again. If is all OK, go to tail P test 2.
2. You need to test P gain in straight fast fast forward flight. If you hear buzzing sound in FFF decrease P 2 points and test again.
3. At the end you need to test P gain in FFF turns. If you hear buzzing sound in FFF turns decrease P 2 points and test again.

I:
Do pirouettes in forward flight, increase I until pirouettes are constant. Windy condition is good for this test. When the pirouettes are constant do not increase I more.

Tail stick dynamic:
Set this to value when you are contended with tail stop response (not tail stop sharpness). It is possible that in this step will tail bounce on stops. I have on my TDR in 3D good stop response with value about 35.

D-Sense:
In comparison to AC-3X this is new settings and is very useful. Test tail stop sharpness in fast pirouettes. If the tail will not stop sharp increase D-Sense 5 points until tail stop will be sharp.

DMA pitch:
Set this settings to value when the tail will stay in its direction without kicks to any side on hard collective punchouts.

DMA cyclic:
Set this settings to value when the tail will stay in its direction without kicks to any side on elevator tick tocks.

When DMA pitch and DMA cyclic values are set by procedure above, it is still needed small tweaking of both values by doing some flips, rolls, loops at various speeds and the tail must stay in its direction without noticeable stick input (only small stick corrections will be needed). Watch for DMA pitch and DMA cyclic values because these may be set to positive and negative values.


Cyclic:


P:
Set P as high as possible without fast aileron and elevator shaking in hover. If aileron or elevator is shaking fast in hover it is HIGHLY overgained, turn P 5 points down until fast shake disappear. Now you need to test and listen your main rotor in FFF and FFF turns. If you hear buzzing sound from main rotor in FFF or FFF turns decrease P 3 points and test again.

I:
Do stationary flips and rolls. Increase I until flips and rolls are constant, do not increase I more.

D-Sense:
In comparison to AC-3X this is new settings and is very useful. Test main rotor stop sharpness in basic stops and stops from stationary flips. If the heli will seesaw after stop increase D-Sense 5 points until stops are sharp and without seesawing.
With too high value heli will seesaw after stop and may oscillate too. If is this case set D-Sense to value when the stops are best and tweak Feed forward settings.

Feed forward:
With too high value you may get seesawing after stop. I test this in middle part of flips. If flips are nice clear and without seesawing i am done.



When you are done with all points in this guide it still may be needed to do small tweaking of some values depending on the helicopter mechanics and your flight style. Some parameters influence flight characteristics of other parameters, then you need to find right balance between these settings.

[Stolla]

Great stuff i'd like to add my quick, lets call it "before you start tweaking guide" as it may save you some time in the setup.
My quick tips are
1.) Get geometry right, use this link http://www.vstabi.info/en/node/667 and follow the online geometry link at bottom.
2.) Make sure you do the setup with 100 percent overall gain then lower afterwards for testing as this influences your total cyclic travel. do overall gain adjustment on tx gyro menu, remember as per manual this changes both cyclic and tail gain as well as affect cyclic throw
3.) Set up min and max pitch in setup under pitch value, you can use subtrim and atv here to get center and min max the same
4.) Set up max cyclic throw in setup 6- 8 degrees, this is only a reference point for the control loop and not a limiter against binding Dont use atv or subtrim for cyclic in tx!
You dont want to lower this value too much as manual recommends higher to speed up D value if you have to lower too much follow steps in pt 5
5. ) When out of setup swash should not bind if the geometry is correct, if it does you have the option to lower each individual servos throw or moving in a position on the servo ball link, if value is small adjust servo throw but keep in mind limiting range also lowers servo resolution so ideally do the ball.
Once these steps are followed you should have an ok setup for the first flight, expect to add dma values on bigger machines with stronger motors.

[HeliBenj]

Great guys, nothing to add on setup and tweaking, only answers to general questions:

- Yes you can use last port in the unit to connect battery or BEC. It is connected to the power bus.
- Total gain: this is optional and allows you to affect both cyclic and tail gains in flight. It can be tied to a flight condition switch to have more gain with lower headspeed and vice versa. It will affect both cyclic and tail overall gains proportionnally. You can also use them at first to get in the right ballpark gain wise. If you use satelites / sbus and a 6 channels radio you lose the opportunity to use the 7th channel as total gain but you can still tweak gain in the unit. Normal receiver and 6 channels have been reported to work
- Sensor vibration filtering parameter is reversed and wrong in the manual, meaning 1 is the most amount of filtering, 5 is the least.

[Stolla]

good info to add, also something else to add if you wanna adjust dma under pitch and cyclic see which way nose move against collective and cyclic input in flight, when adjusting dma in setup you will see how increasing the values will make the tail respond to pitch and cyclic input, so let's say on a normal tail rotation where nose will rotate to the right when tail leading edge bite towards the boom, when you pitch pump nose swings to the left then go to dma in setup and from zero pitch increase pitch, make sure the value you add will now provide, nose right input to the tail, I.e. bite towards boom, same when going negative from zero pitch, follow same procedure for cyclic, negative and positive values will determine the direction of the tail compensation, once out of setup this will also show as, usually nose right input on pitch and cyclic inputs, if your tail provides left nose input , leading edge biting towards boom you want the opposite compensation i.e. ma stratus etc

[superflY851]

Nice Tweak Guide.

One thing i would like to add is to set your radio to mechanical mixing and not 120deg swash mixing. This had me stumped when if first plugged it in because none of the servos were moving correctly. The GT-5 unit does all the servo mixing.

[Stolla]

Yep that's ivery clear in the manual, it 's important before working with this unit that a person read the manual and understand the terms, also study the ac3 x manual then following the abovementioned guides it will all come together. Please don't take offence but if I may suggest we keep swalko's thread to the unknown or unclear issues to prevent a runaway thread, more like an addendum to the manual

[superflY851]

Originally Posted by Stolla

Yep that's ivery clear in the manual, it 's important before working with this unit that a person read the manual and understand the terms, also study the ac3 x manual then following the abovementioned guides it will all come together. Please don't take offence but if I may suggest we keep swalko's thread to the unknown or unclear issues to prevent a runaway thread, more like an addendum to the manual

But anyway, let's hope they revise the manual to make things a bit more clear and in order.

[Stolla]

I believe we will get some better understanding as the unit becomes more familiar,
Something i'm unclear about is the overall gain against white and dark background, i see on my gyro settings i can have 100 percent against both backgrounds but dont see any difference in the reaction of the sensors, are there any literature on this?, i would have though one is heading hold and other rate but then sensors should react differently in rate compared to hh.

[NitroAl]

I can tell you from first hand experience that in flight your heli will be extremely unstable and you will have no piro comp if the background is not black!
At first I thought I had a geometry or setting issue that did not meet the requirements of the control loop and altered many settings over 6-8 flights to no avail. It was only when Rexxigpilot mentioned the background that the penny dropped.

[Stolla]

Great, so let's assume then white background is rate mode

[swalko]

Originally Posted by NitroAl

I can tell you from first hand experience that in flight your heli will be extremely unstable and you will have no piro comp if the background is not black!
At first I thought I had a geometry or setting issue that did not meet the requirements of the control loop and altered many settings over 6-8 flights to no avail. It was only when Rexxigpilot mentioned the background that the penny dropped.

Are you sure? From the beginning i fly G-T5 with black gyro gain number on white background and i do not noticed anything you wroted. On the ground G-T5 always behave as HH gyro independently on the gyro gain number background color.

[Stolla]

I found the same result the tail would be in rate mode as it would hold with a lot of piro comp one direction but then wipe out comletely the other i wuld not fly it against white background, Soon i had it against black it was a different machine

[Stolla]

Some more tweak tips, if you want similar to more agility in vbar, rather adjust feed forward than the ail, el values in setup, once these are in the 8 deg range going to far can cause cyclic wipe out. This happened to me at 127, now back to 100 and also feedforward at 100 and much better, i'd say about even with 100 -105 on vbar agility, off course geometry has to be in spec to comapre values
Although ail el values will give you faster roll and flip rates it does nothing to make heli more agile through piro flips etc, here feed forward is the ticket.

[swalko]

Originally Posted by Stolla

I found the same result the tail would be in rate mode as it would hold with a lot of piro comp one direction but then wipe out comletely the other i wuld not fly it against white background, Soon i had it against black it was a different machine

Thank you, i will try it and report, may be it solve some of my small troubles .

[swalko]

I may not noticed that troubles because i had perfectly set tail on my TDR in rate mode in the time when i used CGY-750.

Funny thing is that piruettes with VStabi was newer so constant as their are with G-T5 and my current setting . I noticed only two problems, my tail is not holding well in hard flips and kick to sides (i was not able to tune it with DMA) and from time to time depending on the tail settings my tail will drift slowly.

If you are right, after gyro channel reverse it must hold like hell .

[swalko]

Small guide update:

P/I/D-Sense needs to be in correct ratio.

With incorrect P/I ratio you may get overgained effect (fast wag) in FFF. If your heli in aerobathics feels undergained (spongy feeling, seesaw on hard rate changes, bad pyros, ... ) and in FFF you will get overgained effect (fast wag) or nose pitch up, this may be the case. Try to find correct P/I ratio and then raise P/I in correct ratio and try to find settings with crispiest feeling on sticks.

[vintcs]

is there a guide for the correct ratio?

[swalko]

Originally Posted by vintcs

is there a guide for the correct ratio?

No. This ratio depend on helicopter mechanics and setup.

[seemore74]

Can one of you GT5 Gurus do a video of setting up this unit with all that you have found out about this unit to date? I think that if you are lucky to use default settings & your heli flies great or close to great then your'e ok but if not then it the nightmares start. If you end up with mechanical limit problems ect then it starts to get tricky as adjusting throws ect will affect something else so if a video can be done on proper setup also touching on some of the possible problems and how to deal with them then that would be great.