3GX rudder endpoint adjustment advice?

[hedge]

Ive been looking at trying to set my tail perfectly. I centered the tails slider mid shaft as recommended by Align for v4.0...



They say A=B. In order to get this exact I used a piece of paper. I marked the slider hub where it goes into the recess upto the bearing (This is a 600) so I knew exactlky how deep the recess was (or at least there abouts)

Below is my rather shoddy photography showing the equal space.





While the angles of photos may seem to show poor measurement they are near as damn accurate.

So all this equates to uneven throw travel left = -61 travel right = 91.



Should I worry?

The reason I am looking at it is because I lost the tail at the bottom of a fast backward loop which caused me to crash and so I want a perfect set up. 3 odd years into the hobby and I still dread anything to do with gain and tail adjustments - its just a black art.

Cheers for any help or advice.

Paul

[KevDavies]

Id dis regard the instructions regarding the tail with the V4, i think this is where the issues with the tail come from on that version.

In RATE mode hover the heli and adjust the tail linkage so it will hover as close to hands free as possible. DO NOT add any trim, do it all mechanically with the link rod.

Once it will hover best you can get it in rate mode, reset your end points in the 3gx, and then flick into heading hold and set the gain.

This will give the best results with the tail. this is how I set my 3gx unit up and the tail worked fine. Yeah it was on a 450 but the procedure is the same no matter what size heli

[hedge]

Thanks Kev I will give that a go.

[dannyboy123]

Did you get your tail servo perfectly at 90 degrees?? I find the centre of slider by moving the control rod to one limit and put a mark on the rod where it meets the clamp/slider on the boom. Move the rod to the other limit and then measure from the clamp to your mark, if it is 20mm make a mark at 10mm, then adjust the ball link at the servo end so that at 90 the rod has the 10mm line lined up. Do this and you should have equal travel both sides. Hope that makes sense

[hedge]

Thanks Danny, if you go the the screen I've shown above, using your method does that result in equal travel, left, right numbers?

[dannyboy123]

It should be close, the numbers dont need to be exact, but I think I got about 75 73. the numbers need to be over 50 I believe or you are using the wrong hole on the servo horn.

[hedge]

Thanks Danny,

Did you apply these changes ?

[dannyboy123]

I didnt know about these changes tbh but I didnt get a problem with bounce back anyway.

[dannyboy123]

How did you get on with the endpoints? any better?

[coolice]

Hey.

From experience with the 3G/GX, I wouldn't run the outer hole on the tail servo arm. If anything I've found running one hole in over the Align manual recommendations works best, the slight decrease in transition speed is offset by the ability to run a higher gain value giving a better hold.

Kevdavies is right, since the release of V4 the tail setup on the 3GX has changed. We need to now employ the old way of setting the tail up, which is to trim the tail in rate mode, adjusting the tail pushrod length to give a hands off hover in rate mode, before going into heading hold mode and having a good tail.
Combine this with removing all the delay within the PC software, choosing large or small heli delay as required and then letting the 3GX time out on it's own without pressing the rubber button. There is a bug in the software which doesn't save the value if you press the button as you'd expect to do.
This setup then reduces/removes the bounce back and over-shoot seen on the tail with quick stab tail commands.
.

[dannyboy123]

Cheers Coolice I am proved wrong again, haha
Do the end points still need to be over 50 for the 3GX to recognise the end point?

[coolice]

Cheers Coolice I am proved wrong again, haha
Do the end points still need to be over 50 for the 3GX to recognise the end point?

Hey buddy.

In all honesty I don't think there's right or wrong, it's just that as Align improve the 3GX the methods that worked on past firmwares then do not work so well on newer versions.

I don't know of a specific value as such, but have had problems setting tail limits of the servo horn is too long and not allowing enough control steps, in which case you cannot set the limits within the 3GX.
Myself I've always ran a shorter tail servo horn within reason to still allow adequate pitch on the blades, but to allow me to run a higher gain.
I know some gyros, one in particular is the CSM SL720, demanded a longer tail arm to work right.

This latest firmware from Align seems to have had all the parameters increased almost, which has increased performance. I'm running the currently unreleased V4.1 and the tail setup has remained from V4, requiring a rate mode setup first.
.

[dannyboy123]

Cheers for the Clarity Ian, you keep me right

[hedge]

Thanks for joining in Ian. The reason I started exploring ideas was two fold first up on 3.1 I lost the tail at the bottom of a backward loop, this made me decide to upgrade to 4. Now with 4.0 set with the servo horn ball in one from bottom and the tail set up in rate mode for hands off hover the tail was bouncing really badly (Trex 600n DFC). However having read other posts from you on RR I think perhaps it was two things,

1) slow head speed, I was in normal mod eats about 1900 HS
2) the gyro rudder gain in the sw was standard at 70

So looking at what you posted I'll revert back to the third hole in the servo, set the heli up in hands off rate mode, drop the sw rudder gain to 50 and run the HS at 2050.

i should get time this weekend to try this out, if you can think of anything else please let me know.

thanks for your help.

[coolice]

Cheers for the Clarity Ian, you keep me right

Thanks for joining in Ian. The reason I started exploring ideas was two fold first up on 3.1 I lost the tail at the bottom of a backward loop, this made me decide to upgrade to 4. Now with 4.0 set with the servo horn ball in one from bottom and the tail set up in rate mode for hands off hover the tail was bouncing really badly (Trex 600n DFC). However having read other posts from you on RR I think perhaps it was two things,

1) slow head speed, I was in normal mod eats about 1900 HS
2) the gyro rudder gain in the sw was standard at 70

So looking at what you posted I'll revert back to the third hole in the servo, set the heli up in hands off rate mode, drop the sw rudder gain to 50 and run the HS at 2050.

i should get time this weekend to try this out, if you can think of anything else please let me know.

thanks for your help.

Hey Guys.

You're very welcome, always happy to help when I can and as we know the 3GX is not a bad performer once setup.

Head speed does play a big part of the bounce, I was alerted to this from another club member and he was correct, the higher the rpm the better the stops. But this is to be expected as the tail will be turning faster and so generates more thrust to work with.
Are you referring to the Rudder Lock Gain within the software at 70%? Yes, out the box this has always been too high, I'm surprised Align haven't reduced this stock setting to 50% for out the box use. This has always been too high even on the 3G and 3GX.

Keep me posted on how you get on, I'm confident you'll have a benefit when combining all the changes. It will be worthwhile making the tail changes first and trying them on your current head speed and then winding it up a little more to check the effects.
.