Vbar setup outside the control loop

[Thunder Fighter]

Hi guys,

Just finishing the setup of the Vbar on my E5s before the maiden tomorrow and the numbers are not very optimised for the Vbar control loops.

I am getting 62 for my collective to give 12.5 degrees pitch and 70 for cyclic to give the 8 degree set point. Now the arms I am using are not the factory arms but are 20mm spacing the same as the stock ones so should not be the issue. The servos are MKS X8 HBL 860's and the geometry of the links looks pretty good with the front links being very slightly angled inwards and back but you have to look hard to see they are not exactly vertical.

I would normally move the servo holes inward a hole to be able to get the Vbar into its normal control loop and not loose so much resolution from the servos but I am wondering what everyone else who runs Vbar is doing?

//Dennis.

[Richard Rollins]

Hey Dennis,
I need to completely understand your question is that on Collective your getting +/- 12.5 both sides of 0 at 62 and to get 8 on the known Cyclic number at 70? If that is the case I would go fly, run the optimizer (fly like you want to fly) on the head for a few min and land turn off the optimizer and if all is good go fly. I always run the optimizer for the head and the tail my first flight with a new vbar setup. Mr Mel also put out a video on running the optimizer. Hope this helps.
One more thing, IF this is your maiden, Do a normal maiden flight before you go tweaking the settings and running optimizers, make sure the gains are good etc.

[curmudgeon]

I am using the stock Synergy CF cyclic servo arms with a VBar Silverline with Pro firmware.  These are my VBar numbers:

Collective:  "87" yields +12.8°/-12.8° range
Cyclic 8° at "89"
Cyclic Ring at default "85" yields +13.2°/-13.2° (+/- 0.2° discrepancy) for both elevator and aileron.
[/font]

[Thunder Fighter]

Hey Dennis,
I need to completely understand your question is that on Collective your getting +/- 12.5 both sides of 0 at 62 and to get 8 on the known Cyclic number at 70? If that is the case I would go fly, run the optimizer (fly like you want to fly) on the head for a few min and land turn off the optimizer and if all is good go fly. I always run the optimizer for the head and the tail my first flight with a new vbar setup. Mr Mel also put out a video on running the optimizer. Hope this helps.
One more thing, IF this is your maiden, Do a normal maiden flight before you go tweaking the settings and running optimizers, make sure the gains are good etc.

Yes that is what I am getting. Sorry, just realized I wrote 70 for collective set point when I meant cyclic set point, I will edit and fix that.

While the optimisers can help, the servo resolution is well down so the setup is not at all optimal. I will be flying it as is for the maiden, I was just surprised that it was so far out of the green zone of the Vbar. Of course the Logo 600 I grabbed the Vbar off was setup with 100 collective and 100 for cyclic, not surprising when it is designed by the same manufacturer but I can normally get my Goblins right into the Green zone by following the standard setup arm length instructions.

I am using the stock Synergy CF cyclic servo arms with a VBar Silverline with Pro firmware.  These are my VBar numbers:

Collective:  "87" yields +12.8°/-12.8° range
Cyclic 8° at "89"
Cyclic Ring at default "85" yields +13.2°/-13.2° (+/- 0.2° discrepancy) for both elevator and aileron.
[/font]

Those are much better numbers and I would be very happy with that setup, my cyclic ring also at 85 and maximum elevator/aileron are about the same as you are seeing with no binding. I guess you are not running the MKS servos. I can only surmise that that is where the difference is coming from, I did read for some of the MKS servos they had a greater rotational throw than normal, not sure if this applies to the X8 but that would explain the difference, I will have to do some research on that.

I only plan on putting a few easy packs through it tomorrow to run the gears and dampers in, so it's not that important for now, but I may grab another set of arms and move the arms into 17.5mm and see what that gives me.

Btw: this is being setup as my F3N Competiton machine so near enough isn't really what I am after.

//Dennis.

[Chris Sexton]

The X8 servos might have less internal resolution in the gear train meaning you need to move the balls in from 20mm. The stock arms work on 90% of the servos but I have had to use aftermarket arms on some. I would seek out a ball spacing that gives you more ideal values.


Sent from my iPhone using Tapatalk

[Thunder Fighter]

I picked up a set today that will let me come in a couple of mm, that should get me back to the green zone. If I have time I will put them on and redo the setup tonight. It flew ok today with the lower resolution, but I will optimise it before doing any more tuning.

//Dennis.

[Thunder Fighter]

The new horns brought the settings up to 70 for collective and 80 for cyclic, probably still not ideal but I think I can live with these settings. All setup and ready to try today.

//Dennis.