I am thinking of switching one of my last Spartan VX1n's to a new Spirit pro or a Spirit II (all my other heli's have Spirit FBL and MKS servos and working great)
The current heli, a Synergy E5S, has all newer BK Servos but I remember a while back Thomas had mentioned a compatibility issue with these servos.
Has there been any updates to address this issue, anyone using the BK servos with their Spirits?
would like to hear some feedback.
Thanks in advance.

I am running BK BLS-8002HV cyclic servos on a gas heli with success. I had a BLS-8005HV on the tail for a while, but switch to a MKS servo when trying to solve a tail wag, but the BK and MKS tail servos both gave me the same results. Note that on this heli everything is powered by a 2 cell Lipo, so if the BK servo issue is related to ESC power, then my experience is no help.

On this gas heli I did have a BK BLS-8002HV and a BLS-8005HV servo that developed jittery issues, not related to Spirit, and were replaced successfully. Because of this quality issue I now choose MKS servos for new builds.

Thanks for your reply FrankFuss
I may PM Thomas to get his professional opinion.

I tried with 2 BK servos and had no luck always a tail wag I use Align tail servos and no issues at all .

BK servos are all compatible, but it seems there is high fault rate of the internal electronics/mechanics and/or at the same time it is very sensitive for any electrical interference. So it all depends on how the cables are mounted, what ESC is used, what motor is used, what frame is used, etc.
So the same servos could work well on one model while for other it is enough to touch them by finger and they could start jittering on its own.
To be even more strange, you can buy same servo and it will stop. Or not.

I am afraid we can't do anything about it. We were contacting BK many years ago, they received our units for testing and from this moment they stopped to reply.

There are many satisfied users but also the rest. I believe the latest servos are much better in this sense.

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Spirit System developer

Good reply, thank you for your input Tomas.
Going to take what you said into consideration
Much appreciated

i have the Kyles stacy edition bk cyclics on my spirit and they work just fine, the tail servo though i had to sell on as i coudn't tune out the tail wag no matter what settings/gains i changed, put a futaba tail servo on it works just fine, hope this helps

Thanks Jay23
That is exactly what I am going to do, I have a spare Futaba tail servo.