Extreme Aileron / Rudder Movement on Initial Bench Test

[DavStr]

Hey guys - I've just completed my bind with the Aura 5 Lite / Lemon Satellite receiver to my Radiomaster TX16s. I had the Spitfire Master Series on the bench, hooked up the control surfaces, powered on and when the receiver bound to the controller the Rudder travelled to the extreme left and one of the Ailerons pulled downward to the point where the servo wanted to pull the aileron off. I remove the Y harness, tested again and the same thing happened.

This is my first build from scratch - the step by step process has really been amazing and helpful thanks to the great videos from FT - so this is new territory for me.

Thoughts?

 

[Merv]

...Thoughts?

It could be you need to remove the servo arm, center the servo, then reattach the arm.

 

[CrshNBrn]

I'd second Merv's advice. A servo tester is a cheap, handy tool useful to centering the arms on a servo- its worth picking one up for your upcoming builds. Enjoy your Spit (once you get everything figured out)- I've built several and they fly great (until I crash them).

 

[Piotrsko]

Stoopid question: are the trims centered in whatever part of the transmitter they reside in?

 

[quorneng]

I doubt the trim could cause such extreme servo travel.
You can't assume the servo has been truly centred at the factory so as Merv suggests it is essential to ensure any servo is "centred" and the servo arm then positioned accordingly.

 

[Merv]

Centering the servo is totally dependent on it’s orientation when installed.
The factory simply can not know which direction you are going to install a servo.

 

[DavStr]

The servo arms are all centred, both pointing inwards as per John’s build video. The strange thing is the other aileron sits motionless upon power up (normal) and the problematic one powers up and does a hard 90+ degree movement. It would move more if the aileron would allow it.

 

[DavStr]

I removed the servo screw for the problematic aileron, powered it up, allowed it to centre itself, screwed the control arm back into place and voilà. The servo centred itself. NOW ... and this is where the Noobie error gets compounded ... I have another servo buried in the fuselage that controls my rudder that needs to be centred, meaning I have to remove my wing assembly which I so readily glued into place thinking I was good to go. NOTE TO SELF - centre all of your servos BEFORE you glue them into place and BEFORE you close up all the compartments where they are situated. My next post should be on how to properly remove already glued on parts so that you don't make a total mess!

 

[CrshNBrn]

I removed the servo screw for the problematic aileron, powered it up, allowed it to centre itself, screwed the control arm back into place and voilà. The servo centred itself. NOW ... and this is where the Noobie error gets compounded ... I have another servo buried in the fuselage that controls my rudder that needs to be centred, meaning I have to remove my wing assembly which I so readily glued into place thinking I was good to go. NOTE TO SELF - centre all of your servos BEFORE you glue them into place and BEFORE you close up all the compartments where they are situated. My next post should be on how to properly remove already glued on parts so that you don't make a total mess!

If it makes you feel any better, most of us have been there. Nothing worse than cutting into a brand-new build to try and re-center a servo. Chalk it up to a teachable moment and try not to repeat the mistake, right?

However, before you start cutting foam, can you see if you can center it through your transmitter servo sub-trim settings? Give that a try first.

 

[Bricks]

If it makes you feel any better, most of us have been there. Nothing worse than cutting into a brand-new build to try and re-center a servo. Chalk it up to a teachable moment and try not to repeat the mistake, right?

However, before you start cutting foam, can you see if you can center it through your transmitter servo sub-trim settings? Give that a try first.

Problem with using a bunch of subtrim is you loose throw in the direction you subtrim it. Best practice is not use any subtrim and if so just for slight difference if servo cannot be centered mechanically.