3GX Question

[the-borg]

Hi all

I have recently upgraded my fly bar 500 to an Align FBL system (not DFC) with a 3gx controller running V4 of the software with the default settings.
In the hover its nice and stable and does wander not but in forward flight I keep having to input small amounts of back cyclic (up elevator) other wise it fly's into the ground its not drastic just very annoying and the faster the forward flight the more back cyclic I have to put in.

The C/G is correct so I don't think its that.

Any suggestions would be grateful.

[sparky 2]

Are you sure the swash was level at mid stick during setup and you've not accidentally put some trim in since ?

[the-borg]

Are you sure the swash was level at mid stick during setup and you've not accidentally put some trim in since ?

Yes I use the 50 in and 50 out as per the Video's on YouTube and I have the sub trims disabled on my DX8.

[coolice]

Hey Buddy.

Sounds like you might have some trim in the elevator axis in your stunt mode, as this model was flybarred are you still using the same transmitter model memory just adjusted to suit the new FBL setup?
If yes, I'd suggest starting with a blank model memory and going through the setup stages again to make sure you don't have any trim/mixes hidden in the Tx settings.
.

[the-borg]

Hey Buddy.

Sounds like you might have some trim in the elevator axis in your stunt mode, as this model was flybarred are you still using the same transmitter model memory just adjusted to suit the new FBL setup?
If yes, I'd suggest starting with a blank model memory and going through the setup stages again to make sure you don't have any trim/mixes hidden in the Tx settings.
.

I used a completely new model memory.

[sparky 2]

Hope not teaching you to suck eggs I meant more the mechanical set up not the zero set up in your tx is the swash mechanically level when your tx is at mid stick

[coolice]

Yes I use the 50 in and 50 out as per the Video's on YouTube and I have the sub trims disabled on my DX8.

Hey Stuart.

How have you levelled the servo arms while in DIR mode so that they are 90 degrees to the servo at mid-stick?
While you cannot adjust your sub trims when outside of DIR mode, you will have had to use them during the bench setup to set your servo arms to 90 degree's with the collective/throttle stick in the mid stick position. Usually 2 out of the 3 eCCPM servos require some sub trim to level the arms, especially as the Trex500 use's single arm horns rather than round disks which can be rotated until the control ball hole is 90 degrees to the servo.
.

[the-borg]

Sparky Very happy to be told how to suck eggs I just grateful for the help.
I will recheck the swash plate is level at the mid point.

Ian incorrect terms here on my side when I said Sub Trims were disabled I meant the Trims on the TX sticks.
When I setup the servos so the arms so they were at 90deg I use the Sub Trims (servo centre) to do this.

[tourerjim]

Odd...? my 500 with v4 is perfect & agree with Ian (coolice)

Hey Stuart.

How have you levelled the servo arms while in DIR mode so that they are 90 degrees to the servo at mid-stick?
While you cannot adjust your sub trims when outside of DIR mode, you will have had to use them during the bench setup to set your servo arms to 90 degree's with the collective/throttle stick in the mid stick position. Usually 2 out of the 3 eCCPM servos require some sub trim to level the arms, especially as the Trex500 use's single arm horns rather than round disks which can be rotated until the control ball hole is 90 degrees to the servo.
.

[Slobberdog]

The 3gx will wonder if you have any end point adjustment in the radio, it's what caught me out a few weeks ago,

[jessdigs]

Hi all

I have recently upgraded my fly bar 500 to an Align FBL system (not DFC) with a 3gx controller running V4 of the software with the default settings.
In the hover its nice and stable and does wander not but in forward flight I keep having to input small amounts of back cyclic (up elevator) other wise it fly's into the ground its not drastic just very annoying and the faster the forward flight the more back cyclic I have to put in.

The C/G is correct so I don't think its that.

Any suggestions would be grateful.

The only 3gx advice that I can give is to remove the 3gx and try to get £35 for it, or place it on a table, and shoot it with this: Then buy a V-bar. I removed ALL of my 3GX (5 in all) and installed v-bar or v-bar clones. It changed my life.

[the-borg]

The only 3gx advice that I can give is to remove the 3gx and try to get £35 for it, or place it on a table, and shoot it with this: Then buy a V-bar. I removed ALL of my 3GX (5 in all) and installed v-bar or v-bar clones. It changed my life. [ATTACH]73981[/ATTACH]

Thanks for the input I'm sure there will be those that agree and some that don't

[Gunnergolly]

Thanks for the input I'm sure there will be those that agree and some that don't

Just take your time setting up the 3GX, make sure your mechanical setup is good and it will work just fine ...

The 3GX i have on my TRex 500 is flying really nice, my only complaint is that the tail stops could be a little crisper when stopping abruptly from fast pirouettes .... other than that i'd say it's a capable unit that can certainly out perform most peoples abilities.

[Grumpy]

The borg,

Double checking the mechanical DIR set up would be the fist thing to do, but if that all checks out the 3GX does have a collective to elevator pre-compensation that should be able to fine tune out what you are experiencing. As I read it the nose is dropping when you increase collective in fast forward flight, if so elevator pre-comp should help (reduce pre-comp I think).

[coolice]

Hey Buddy.

The above pre-compensation can be linked to a similar behaviour, however older firmware's had a slider that was labelled at removing elevator porpoising during fast forward flight, on the newer versions it's labelled to correct the model in the elevator axis on vertical ascends and descents where large collective pitch changes are made.
If you're flying along and making large adjustments to the collective pitch angle, then this will help, but it seems like you are experiencing the nose tucking under when the collective is at a relatively constant point to maintain forward speed, so the above is cancelled out.

Just re-reading your first post, you mention this is a converted Trex 500, so what main blades are you using?
In my experience I found the smaller models definitely saw a fix to any fast forward flight porpoising when using dedicated flybarless main blades, as they are that little bit heavier and weighted better to suit it.
The original non-FBL blades are lighter by comparison and thus more twitchy as a result, fitting the slightly heavier FBL blades adds more centrifugal induced stability to the rotor disk and helps the FBL unit fly straighter.
I remember having a similar problem on my old 450 PRO with 3G, in fast forward flight it was like the model was following a roller coaster track and different main blades were the fix on this machine.

If someone in your club has a similar sized model with FBL blades it might be worth asking if you can try them on your model.
.