Trex 450 / align gpro rudder movement - RC Groups
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Feb 14, 2016, 03:30 PM
Registered User
The Flying Pig's Avatar
Discussion

Trex 450 / align gpro rudder movement


In the final stages of setting up my Trex 450 dominator 3S ...

Puzzled by this:

When I move the rudder stick the rudder moves to its full travel before the stick, by the time the stick reaches about 3/4 of its movement.

This happens when on the bench, I've yet to maiden it yet.

Any thoughts?
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Feb 15, 2016, 11:45 AM
Registered User
Black_Angel's Avatar
Quote:
Originally Posted by The Flying Pig
In the final stages of setting up my Trex 450 dominator 3S ...

Puzzled by this:

When I move the rudder stick the rudder moves to its full travel before the stick, by the time the stick reaches about 3/4 of its movement.

This happens when on the bench, I've yet to maiden it yet.

Any thoughts?
Try shorter servo horn ?

BA
Feb 17, 2016, 03:41 PM
Registered User
The Flying Pig's Avatar
I'm using the shortest servo horn already.

It's actually a dead zone on the rudder servo - the rudder servo stops moving once my transmitter stick is about 3/4 of the way left or right.
Last edited by The Flying Pig; Feb 17, 2016 at 05:01 PM.
Feb 17, 2016, 05:31 PM
Zippy Puffer
2Doggs's Avatar
That's an entirely normal behaviour for a tail gyro or FBL controller.

On a 450, the servo arm should be about 7mm. In the Gpro, tail limits need to be 70 - 100 or so, and the left and right limits are often different.
Feb 17, 2016, 05:37 PM
Registered User
The Flying Pig's Avatar
Thanks for the reply.
Why is it 'normal behaviour'? Why does the servo run out of movement, before the transmitter stick is any where near its full limit?
Feb 17, 2016, 05:44 PM
Zippy Puffer
2Doggs's Avatar
Because moving the stick requsts a yaw rate, rather than a deflection. In flight, you will sstill get a higher yaw rate at full stick deflection than at 3/4.
Feb 17, 2016, 06:00 PM
Registered User
The Flying Pig's Avatar
Thanks.
Being mostly a fixed wing flyer and new to FBL not having a servo respond as I expect unnerves me.

So, if this is normal, I'm almost ready for the maiden flight.
Feb 17, 2016, 06:17 PM
Zippy Puffer
2Doggs's Avatar
Good luck! The Gpro has some "beginner" settings, that keep things stable and calm, so you might use those initially before hotting things up.

Hope you get some decent weather!
Feb 19, 2016, 11:23 AM
Registered User
A 450 dominator as a first CP heli? Man, you are brave. lol
Feb 19, 2016, 12:00 PM
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The Flying Pig's Avatar
No, not my first - I've been flying a 250 for years.
I'm new to FBL.
Feb 19, 2016, 11:13 PM
Registered User
Quote:
Originally Posted by The Flying Pig
No, not my first - I've been flying a 250 for years.
I'm new to FBL.
Oh, okay. I also have a 250. I love that thing. Mine is a pro DFC and it's a fast and twitchy little hornet. Flying that little guy made me a much better pilot overall. When I fly my 450, it feels so floaty and buttery smooth. You should be fine after flying a 250 for that long. I have a blast with the dominator in Realflight. Huge difference with 6S.
Apr 24, 2016, 04:15 PM
Registered User
The Flying Pig's Avatar
Have finally had a chance to fly my 450.

About 10 flights in, am loving it.
Jun 05, 2016, 12:13 AM
Registered User
I have 6 flights on a 450L 6s , first heli , after much time on Phoenix RC simulator. Tail in hovers is about all my little heart can handle , but I am loving it!


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Jun 15, 2016, 09:15 PM
Registered User
#tail wag on the 450L Dominator. I lowered the Rudder gain on the Gpro, until the helicopter was sluggish around the vertical axis. Did some digging around on the inter webs, and found read that sometimes the wag could be reduced by moving the link to the inner most hole on the servo control arm.

Also, I scrutinized my Align instructions, and discovered that the manual suggests placing the link on the inner hole on the servo arm. Guess where I placed my link? of course, on the outermost of the 2 holes. Needless to say, I corrected my error, reset the Gpro settings to default and will take the heli out on a calm day to see if the wagging goes away.

It pays to read carefully
Jun 22, 2016, 02:25 PM
Registered User
Quote:
Originally Posted by 2Doggs
Because moving the stick requests a yaw rate, rather than a deflection. In flight, you will still get a higher yaw rate at full stick deflection than at 3/4.
This is such a simple, intuitive and correct answer. Nice to read a short but elegant reply.

I am thumbs-upping you right...*now*!

I have never really thought about what controls that rate. Would expo slow down the movement or would you adjust rudder travel to reduce the distance traveled relative to time?