Servo chatter & buzz - HK Raven 990 DLG

[Tony Kenny]

As my experience makes it a lot less likely I'd buy an ARTF from HK again, I'd have hoped that the relationship based on money would make them listen. But, one voice among many.

However, this has been a learning curve that I otherwise wouldn't have experienced, so there's a positive side too.

[Dave Bran]

Firstly, nearly all my HobbyKing sourced ARTF are running with the originally supplied servos, despite LOTS of use, some of it five years plus. This includes some very fast and very nervous/aerobatic machines putting high loading on them. There simply in my extensive experience is NO hard on link between HK ARTF and poor servos across all their output. What if anything they do not do is QC bought in product before sale well enough.

The Gening servos I mention above as rubbish were sold to me by a reputable respected UK seller along with foam glider plane kits.

Reminds of many years ago when I bought a multi charger lead that when I checked before use was shorted! When it went to the suppliers "warranty checker" the reply to seller, copied to me, said "this product was so bad it could have been made by DYS" (DYS at the time were selling lots of budget servos via UK sellers, ones I had tested and rejected long before)

What I do is to release links and check the hinging is not too stiff and work it manually for a while, part slitting if really required on the thicker foam hinge lines. I then set the throws/end points so no end binding and run monitor on the Tx for at least ten mins per servo (NOT a servo cycler which usually over travels surfaces)

With regard screw type wire ends (EZGrip, etc), I have many in use over more than ten years. I do not use threadlock and have NEVER EVER had one loosen, though that does not stop me checking under the assembly checks and maintenance that many seem not to do. To "ban" screw type fixings blanket fashion is "safety overkill". NO system is free from the need for checks.

[Martin McIntosh]

Sorry Dave, but I stick to my guns regarding the screw on links. These are only fitted because it makes it easy for the manufacturer/user to adjust and are cheap. Maybe OK on small electrics but they do not stop there with them. The vibration from an i/c motor will cause the screw to bed into the wire thus releasing it. I was once asked to get the retracts on a Hangar 9, 91 powered Mustang to work for a club mate. Guess what they supplied at the servo end? On that tack I have many retract equipped models which use grub screws to hold the legs. No matter how much heavy duty Loctite is used the stresses cause the screws to bed in to the wire legs and become loose, same to a lesser extent with control linkages. You would never see them used on better quality stuff, large scale models, aerobats etc.

Martin

[PatMc]

Posted by Martin McIntosh on 27/12/2017 19:26:35:

Got to comment on some of this. Firstly, ditch those screw on connectors and fit good, freely operating ball links. As former club safety officer I banned these from anything other than light indoor models because there is nothing to stop that screw from coming loose in time.

If I you were to tell me that I wasn't allowed to use them I'd thank you for expressing you're opinion but since my own opinion, based on experience differs from yours, I'd carry on flying with them in place.

[Tony Kenny]

Crikey, between this and my LiPo thread, I've managed to stat 2 simultaneous arguments!

Personally, these connectors never "feel" secure to me, no matter how hard I tighten the screw,it just doesn't feel 'solid'. I'll fly with them at first, but ultimately, I'll replace them with something that 'feels' better to me.

Whichever I use, my policy is to check ALL connectors, control surfaces etc, in fact a full head-to-toe inspection of the aircraft before every single flight. That's just my brain wanting a solid routine so nothing gets missed. (although distractions can happen and then things do get missed!)

[Ian Swadling]

I have found that when a servo is buzzing, and stops when you tap the relevant stick, or control surface, that something is binding in the control run. Fixing the binding usually fixes the issue. Unless the servo is faulty, in which case the only place to fit it is in the rubbish bin!

[Tony Kenny]

Thankyou, the problems seems OK now, but waiting for the right time to get out and try it in the air.

Broken servos, I tend to keep them just in case I get a similar one strip a gear, then I can enjoy a fiddly 3D puzzle! I did the same with a Rx that failed range checks, handy for bench testing (is labelled most clearly so I don't put it in a model by mistake!)