450 Building my first! - Align T-Rex 450 Pro V2 3GX

[stokke]

Sundays, gotta love'em!
Woke up today, got in the shower, stuffed down a loaf of bread and sat right down at the "build station"

Continued the wiring today.

As you can see, I have not followed along completely with the instructions (or Tony's video's for that matter).
I left out mounting the 3GX-unit so I'm able to set the connectors before actually mounting the 3GX in place.
I believe this spares me much trouble, and would advise this method to everyone mounting a 3GX-unit or a receiver for that matter.

Unit in place with double sided tape.

Wiring nearing completion. Only the wires from 3GX to RX to go.

Before mounting the Receiver I made sure the connection with my transmitter still was OK. It was!

Feels good to add this model to the Tx

Fastened the Rx with more of that thick double-sided tape I got yesterday.

Rx mounted.

Satellite mounting.

Wiring complete.

Almost forgot to attach the links for aileron and pitch. LOL

Along with the great tape i bought yesterday, I also got some Velcro to use for by battery mounting.

Since I have used a zip-tie on the ESC, I went ahead and fitted one Velcro-piece above, and one under to make sure the battery sits flush along the bracket.

Battery in place with strap. That strap which was included with the kit barely is long enough to reach around the battery. I think I will replace the strap at a later point with a longer one.

Canopy rubber mounts.

OMG! OMG! OMG! Feeling like a kid again!!

Put on the blades. I see the nuts provided are some sort of lock-nuts, but I added some thread lock anyway.

SWEEEEEEEEEEEEEEEEEEEEEEEEEEEEEET!

New and old.

After a short solo celebration, I removed the canopy and proceeded to power up the electronics. Put the 3GX in so-called "DIR-mode" (Direct control mode, controls not affected by the 3GX system). This is achieved with holding the small button on the device while connecting the battery.

I had to reverse the aileron-servo, after that the swash responded correctly to my stick input.

I noticed at mid sticks, the rudder pitch slider is not centered. I'm not sure if this is correct, please advise on this.

I also put on my pitch gauge, and the pitch is way off. I had about -20 degrees on low throttle, and about +9 degrees on high.
Also at mid stick, the swash is clearly not level.
I will now commence to research the setting up of the swash and head, but any input on all of this will be much appreciated!

I'll come back with another update later tonight.

 

[stokke]

OK. I was quite excited in my last post, and was in a hurry to get things flight ready
I forgot that there are more pages in the manual after the build part. LOL.

Been reading some more now, and I see most of my questions are being answered later in the manual.

 

[sterlingh]

That looks so cool. Great job. Biting at de bits for mine to get here.

 

[heli-maniac]

the tail slider will reset after you do the gyro set up you will have to power down and back on for it to adj.

 

[stokke]

There were a few screws and parts left over... I sure hope none of these are supposed to be on the bird!

I have been reading up on the centering of the pich slider:

I checked the servo was at 90 degrees to the tail, then started to tweak the tail servo.
I do believe this is called end-point adjustment.

On my first check the servo started to bind at about 60% left, and 65% right.
So according to this new information, I knew the link had to be adjusted.

While in the setup for servo travel, I held the stick max to the left, then trimmed until I could hear the servo starting to buzz, then trimmed back one or two % until the buzzing stopped. Then the same procedure for stick right.

After adjusting the link sometimes back and forth, this was the closest I could come to perfect center. Note that I could have gotten it even closer, but then I would have to turn the link a half a turn, and that is not an option as the "A" on the link is supposed to face outward.

I trimmed it down to an even 60/60%. This so the rudder will have even speed both ways.

In addition to listen to servo-buzz, I of course visually checked that there is no binding at either end of the pitch slider.
Under the entire process, the system was on, and sticks were at center position.
Now, the pitch slider is at center - good as gold

 

[Tony]

Actually you should not use end point adjustment in the Tx to do the tail, it will mess up the gyro settings. There is a menu in the gyro where you can set your end points. You enter it by powering up the heli, then pushing and holding the button until it goes into setup mode. From there I will have to refer you to the manual lol. Mine is in a box ready to head to meet my T-Maxx or I would pull it out and check on it. But from what I can remember, you need to leave the travel at 100% and adjust them in the gyro. Let me know if this confuses you lol.

 

[stokke]

Actually you should not use end point adjustment in the Tx to do the tail, it will mess up the gyro settings. There is a menu in the gyro where you can set your end points. You enter it by powering up the heli, then pushing and holding the button until it goes into setup mode. From there I will have to refer you to the manual lol. Mine is in a box ready to head to meet my T-Maxx or I would pull it out and check on it. But from what I can remember, you need to leave the travel at 100% and adjust them in the gyro. Let me know if this confuses you lol.

Thanks again Tony. I have read about what you're referring to, and will follow up on this.
It's good to be done with the build, but I'm starting to realize it's not going to fly immediately.

But this is my situation as of right now, please read carefully if you plan to help:

The swash is not level, the elevator seems to be sitting a bit higher than PIT and AIL.
On the early pages of the instructions it states; "sub trim is not to be used with 3GX flybarless setup".
Later on it states; "While in DIR mode, adjust swash and sub trim". < WTF?

Yesterday I put the 3GX in "DIR", and started to adjust sub trim to get a level swash. I do not have a swash leveler, so I just eye-balled it.
After getting the swash level, I put on my pitch gauge. I'm getting 0,7 negative pitch on mid sticks. < WTF?

As of this moment my plan is:
I will remove the sub trim and lengthen the AIL and PIT links one turn each.
This might level the swash with little or no sub trim.
If the pitch is still off with negative 1 degrees, I will lengthen the pitch links with one turn each.

Another thing; The servo horns are not perfectly 90 degrees at mid stick, maybe off by 3 - 6 degrees. Is this a concern?

I'm at work right now, so I won't get back to my bird yet anyway.
Please advise if you can.

Thanks.

 

[Tony]

Subtrim is fine in DIR mode to get the servo arms to 90º to the links, but after that you should never have to touch the trim tabs. Just make sure the swash is level.

 

[stokke]

Subtrim is fine in DIR mode to get the servo arms to 90º to the links, but after that you should never have to touch the trim tabs. Just make sure the swash is level.

So when the arms are 90, the swash should be level.
And if the swash's not level when arms are 90, the links should be adjusted?

Thanks, Tony.

 

[Tony]

You should adjust the arms so they are 90º to the links, and make sure all of the links are the exact same length. If all of that is done, then the swash should be level. If it's not, then there is an issue somewhere.

 

[murankar]

this is where the swash leveler comes in or the zip tie trick. There are a couple vids on the zip tie method on you tube. Your tail if it set up like a standard non 3GX gyro then yes you use the gyros end point adjustment to set your throws. If you have to trim the tail find out what direction you need to trim. Instead of trimming it adjust the linage length so that it centers. I think I am having a brain fart moment on how to adjust the length. It should make its self clear as you tweak the length.

I got mine set so I have zero trim using this method and in a few days I will have my new gyro to see how solid it is. Time to rtfm on the new gyro.

 

[stokke]

There are a couple vids on the zip tie method on you tube. Instead of trimming it adjust the linkage length so that it centers.

I have checked out the zip-tie trick, will do this when I get home today.
Regarding the tail pitch, I did do what you describe. Just fiddled around with it at I gradually understood it.
Now it is as mechanically centered as possible. Will remove the rudder-trims from my Tx, and go through the 3GX end-point adjust instead.

Thanks, Matthias!

 

[murankar]

No problem, took me a few weeks to figure this out. wanted to save you some time so you can fly soon.

 

[stokke]

Starting out, I connected the GYRO/SENS-port from 3GX to GEAR on the Rx.
I found I had to switch the wire from GEAR to AUX2 on the Rx, as the instructions state ch5/GEAR is for governor, and ch7/AUX2 is for gyro.

AUX2 is to be used as Gyro-port on the Spektrum AR8000 receiver.

Started out to level the swash, and adjust pitch. Swash not so level. Radio at mid sticks.

Had to take off the anti rotation bracket so I could see the elevator servo (and get to it if I had to make link adjustments).

Elevator servo as 90 as I can possibly get it.

To get a point of reference when 90'ing the front servos, I placed the "pitch reference bar" on top of the servos.

The pitch servo required the most sub trim: 42+
Elevator sub trim: 18U
Aileron sub trim: 10R

Is any of the above values considered very high?

After 90'ing the servos, I used the zip-tie trick to level my swash.

Got out my fancy pitch gauge

Mid sticks. Waaay off.

Please have a look at my "monitor" values (mid sticks):

Had to lengthen the AIL,ELE,PIT links three full turns. Then I got the magic number at mid sticks.

Max high THR/PIT stick.

Max low THR/PIT stick.

Please look my values over and give some feedback if you will.
As far my knowledge goes, this is as good I can get it.

As per now: Swash is level. Servos are 90 at mid sticks. Pitch is 0,0 at mid sticks.

 

[murankar]

to put the blades at 0 pitch at md stick you would need to adjust the the two long linkages that go from swash to blade grip. the adjustment you made is for fixing the difference in +- pitch at full travel of stick. Basically if you have +11* of pitch at high stick and -9* at low stick then you would adjust the three servo to swash linkages.

Sorry to end so abruptly but I have to go report to formation.

 

[stokke]

Basically if you have +11* of pitch at high stick and -9* at low stick then you would adjust the three servo to swash linkages.

Thanks for checking in Matthias.
Well I am just now in the process of doing some adjusting in the swash menu of my Tx. I'll post the results in a bit, but I think I'm on the right track.

 

[stokke]

I have been fiddling some more with the set-up.
I have decided to stick with the previously mentioned servo set-up, and have been following the instructions to adjust the pitch.

This is what I have done so far:

I went in to my transmitters Swash menu.
The "factory default" settings were:

AIL: +60
ELE: +60
PIT: +60

This gave about 16 degrees both negative and positive collective pitch. Which is way to much?

My NEW settings:

AIL: +62
ELE: +60
PIT: +34

This gave +9,5 positive, and 9,2 negative collective.
It gave 10,2 positive cyclic.

Please advise if you see any problem with this, or have any concern about any of my other settings.

ON ANOTHER NOTE:

I went through the 3GX flybarless set-up, and everything was looking good.
Then I proceeded to set up the rudder gyro. When setting end points of the rudder servo, the instructions state to push left until I reach the end-point (DU'UH). But while doing this, then returning stick to center, the servo does not follow - it just continues to press on, and of course binds up (heavy buzzing).

Tried to do this several times now, but same problem.
At my first try I had set some gyro sensitivity values in the Tx, but on a later try I had set all Tx gyro sens-values to zero, still same problem...
I would like to note my Tx has 1% left on rudder all the time, seems the stick just settles there (the spring returns the stick to middle when letting go).

Hope this makes any sense.

 

[heli-maniac]

the AIL and the Ele should be the same and you will want to get the blade pitch close to 12degrees

 

[Tony]

If I remember correctly, if you are using v2.1 firmware, you want 8º of pitch in either direction on both the aileron and elevator. And 11º of pitch for collective.

 

[stokke]

the AIL and the Ele should be the same and you will want to get the blade pitch close to 12degrees

You mean my swash menu should look like:

AIL: +60 instead of: AIL: +62
ELE: +60 instead of: AIL: +60
PIT: +34 instead of: AIL: +34

(AIL+ELE values same?)

I guess you're talking about col. pitch. The instructions state to have about 9° (favoring stability over agility).

Thanks, Jesse.

If I remember correctly, if you are using v2.1 firmware, you want 8º of pitch in either direction on both the aileron and elevator. And 11º of pitch for collective.

I did not flash my unit yet, and still use the V 1.2.
I did NOT check pitch on elevator. Guess you just rotate the blades 90° (blades 90° off the frame), then tilt elevator back to measure pitch on elevator?
Will flash my unit after I have successfully gotten the bird in the air - then do the set-up over again.

Thanks, Tony.


Continuing.

I had a problem with my left stick (PIT/THR/RUD) not outputting the correct RUD-signal when at mid stick. The stick is spring-loaded, and is supposed to go RUDDER-center when letting it go. But my RUD-channel outputs 1% LEFT when the stick is not touched. I FIXED this by going in to my controller settings, and did a calibration. Now all outputs are correct, and my rudder is outputting 0% at mid stick (AS IT SHOULD).