Is it possible the Spartan Quark killed my HSG-5084MG?

[flydude]

PRIL250:

I see you have the combo on your 400, what Tx are you using please and can you let us know the EPA on your GYRO Switch (for switching from RATE to AVCS, otherwise known as GAIN switch or GYRO on/off)?

I ask because all this tailservo heating thing started a long while back, Futaba 6EX Tx and Futaba 617FS Rx - I had my EPA set for that switch (switch 5, Ch 5 GAIN) to +50% (on) and -50% (off) with a futaba GY401 & Futaba digi tailservo (s3154? I forget) - the tail was never totally solid so I upped the endpoints to 100% and dropped the gain from 64% to 32% - that worked ok for a while then that servo heatsiezed

So for the last 2 years I have been trying to find the perfect solution for the tail using whatever parts I could afford -- then I found this thread on the same day my new parts arrived (which were more expensive compared to the usual) so will be re-installing the old stuff tomorrow instead of flight testing my new kit - I'm very impressed as you can imagine

Can the GYRO switch endpoints affect servo operation? that is the last thing I am not sure about regarding this situation

Tomorrow I will reset those endpoints and test every servo I have with the Quark

many thanks for the support - back soon
FLyDuDe

[pril250]

Originally Posted by flydude

PRIL250:

I see you have the combo on your 400, what Tx are you using please and can you let us know the EPA on your GYRO Switch (for switching from RATE to AVCS, otherwise known as GAIN switch or GYRO on/off)?

I am using a DX7 and AR700. I use the Gear switch its range +/-150, gain +44% for HH mode and -44 for Rate.

I ask because all this tailservo heating thing started a long while back, Futaba 6EX Tx and Futaba 617FS Rx - I had my EPA set for that switch (switch 5, Ch 5 GAIN) to +50% (on) and -50% (off) with a futaba GY401 & Futaba digi tailservo (s3154? I forget) - the tail was never totally solid so I upped the endpoints to 100% and dropped the gain from 64% to 32% - that worked ok for a while then that servo heatsiezed

So for the last 2 years I have been trying to find the perfect solution for the tail using whatever parts I could afford -- then I found this thread on the same day my new parts arrived (which were more expensive compared to the usual) so will be re-installing the old stuff tomorrow instead of flight testing my new kit - I'm very impressed as you can imagine

Can the GYRO switch endpoints affect servo operation? that is the last thing I am not sure about regarding this situation

The gyro switch end points have no effect on the servo but the gain does make it work harder in the extreme it is so hard it feedsback on itself which is the well known tail wag. What end points you are using for the rudder though, they have some bearing on things, like piro rate.

Also if the tail slider is binding at the end of left/right travel that can lock up the servo which will certainly contribute to it heating up. I suggest you get hold of a volt meter and check the voltage supply to the servo as well.

Tomorrow I will reset those endpoints and test every servo I have with the Quark

many thanks for the support - back soon
FLyDuDe

Hope that helps.

[flydude]

Thanks for that - rudder EPs are no prob I know how they work - was just always intrigued about that switch and the effect it might have on the power going to the servo

I'm afraid after today's tests it would seem I got a bad 5084 it will be replaced immediately by the align DS520 - I see they have been ideal for lots of people with quarks

Will let everyone know the moment it gets here

cheers
FLyDuDe

[flydude]

OK so I got 2 savox SH0257's on the way and received (from heliguy.com - uk) their new kid on the block, ACER-LAB D12-MG Digital Servo -- atthe price, £13.00 ea I can't argue and have had nothing but joy from their lower end range - £5.00 for ACER-LAB A8-SG which I use on planks which can handle 6v are a pleasure

ANYhow, the Savox are still coming soon so I hooked up the D12-MG and rattled the sticks, and swung the tail for 3 minutes straight..

NO HEAT...... ANYWHERE

NOTHING NADA ZILCH

:thum bup:

FINAL CONCLUSION:

After all the testing with the Quark and 5084 I have come to think that the servo can't really live up to the advertisers claims and handle more than 4.8V, or maybe most of them do and I have simply read a lot of 5084 heating issues and got a bad one myself - my conclusion after all this is that the 5084 is going back to the shop to be EXCHANGED for a different servo ( I hesitate to use this type again- ever) and my gut feeling is that this little Acer D12-MG is going to kick serious butt coupled to the Quark (considering how good the Quark's rep is when everything works)
I also think the Savox are going to be good too

Job done - the end result is that I wouldn't personally pair the HiTech HSG5084MG with ANY gyro never mind the Quark - and still can't believe how hot it made everything after 1 minute of mild work - lucky me I still have my ESC & Rx in one un-melted piece

Oh - I would recommend a thorough bench test for ANY new gyro or servo installation

ANGELOS:
I feel it's only fair to have a good test of this combo (Q + 5084) and if you guys get heating issues, if not removing it from the Quark compatibility list completely, at least get some sort of warning written in there

I shall post the maiden when the rain goes away, really looking forward to this 'Spartan' experience - so far this gyro is looking GOOD

All the best

FLyDuDe

[pril250]

Glad to hear you are getting somewhere now. Good luck with the maiden when conditions allow

Let us know how the Acer D-12 performs and later the Savox SH0257 works out.

[flydude]

HEY HEY the maiden with the Quark gyro + ACER D12 Digi servo was FANTASTIC - I was well behaved (hover only) as my test park is small -- dropped a bit on gain - 35% to 24% as I had some wag, but punch-outs and switching to Idle-Up etc produced NO drift on the tail, HOLDS LIKE A ROCK -- all this time trying to find the perfect combo for the tail & NOW I have it WOOHOO

Unfortunately I will NEVER use the 5084MG again, for anything, in fact I will probably not consider HiTech servos for my builds at all - ACERs are the way to go IMO

Hail to the Quark Gyro it is DEAD EASY to set up

Now for the BIG park next and some proper flying, full report of that and the switch to the SAVOX servo will be here soon

I HAVE A PERFECT TAILCOMBO WITH NO HEAT BUILDUP ANYWHERE - Man I am SO pleased

all da best
FLyDuDe

[pril250]

Since reading this post I have been keeping a close eye on this combo which I also use. The bench test does not produce any significant rise in temp on the servo but it does come back quite warm after a 7min flight. Can't say I am happy about it and may consider going back to the DS3500g which I had replaced FOC after developing a fault.

[flydude]

If I were to hazard a guess I'd say that not all, but maybe a good percentage of the 5084MGs might have a problem (& I got 2 bad ones in a row) - there are enough posts on the net - however if yours is behaving OK it should probably continue to do so..

Please bear in mind my futaba s3154 killed my last heli with the same problem but was fine for the first 30 flights or so - then it just overheated and seized (during the first hover of the day) yes I tried to auto it but it smacked a streetlamp on the way up to auto-altitude - and it was spinning like mad

... damn


If I were you though I'd change it tomorrow - the acerlab D12MG is CHEAP - no I don't work for them
or just reinstall that DS3500g if you trust it

More news soon
FLy

[Steve Evans]

Originally Posted by flydude

Please bear in mind my futaba s3154 killed my last heli...

Just read through this thread and I found myself remembering my S3154 which was hailed back in 2007 as a wonder servo by some, but many others reported it burning out, see HERE. Mine managed half a battery's worth of test hover before frying. The fact is that tail servos have a very, very hard time. Apart from the pulse width (typically 1520us) you must also consider the frame rate. For an analogue servo this is 67Hz, whereas digital servos use this pulse width at either 250 or 333Hz. The higher refresh rates make a servo work a lot harder and it was generally advised with the S3154 to run it in analog (67Hz) mode or 5V, but digital (250 or 333Hz) mode and 6V was a BAD idea.

To blame the Quark for these failures is, quite frankly, ridiculous. Sure it may ask a lot of a servo, but that's because it's doing it job.

Angelos is absolutely correct; you HAVE to trust the datasheet, and then taking the worst case figures for everything. Somewhere between the engineer writing the datasheet, and you, the customer, there is generally a department called marketing which loves to say what it thinks you want to hear and isn't generally that reliable, so don't trust "product summary" type waffle.

The 5084 is probably absolutely fine connected directly to a receiver where its getting analog compatible inputs (unless you're using a high speed Futaba rx :-) ), but perhaps a heli tail is not where it's at it's best?

Steve

[pril250]

OK, twenty flights or so down the line, Quark+5084MG on 5.1V servo is toast No crashes, nothing dramatic the tail started a constant but not violent wag not affected by gain. Landed her, servo a bit an the hot side and moving very very slowly to stick input.

I guess this servo does not hold its own with the faster gyros. Will be sending it back for a replacement. My trusted JR DS3500G that was replaced for free is going back on there

[Steve Evans]

Sounds like the 5084MG does indeed find life as a tail servo overly stressful!

Steve

[pril250]

Will see what MSL have to say about this tomorrow

[flydude]

PRIL250 glad to hear you got it down in one piece after the failure

Typical -
you got: 'nothing dramatic the tail started a constant but not violent wag not affected by gain. Landed her, servo a bit an the hot side and moving very very slowly to stick input'

I got: 'Heat sieze, violent piro, hit lamppost, exploded into small bits' -- ah well...


Some have tried to explain or excuse the 5084 which is decent of them & probably deserved by HiTech - but it was simple for me:

it was supposed to do something, spec sheet claimed it would, datasheet says differently
some of them do work, some don't
it therefore should work as some of them prove to do but this seems to be subject to 'luck of the draw' --- suggests an ongoing occasional problem in manufacture??

result - my heli has too much time and money invested to take the chance, there are too many other proven products at better prices - so I'll skip the HiTech

Best
FLyDuDe

PS my Rex is all trimmed out now so it's 'massive field & plenty speed' time next weekend yeeha!

[pril250]

Sorry to hear that. Keep away from them in the future. Someone said on another thread that there is no way a servo the size of your cyclic servos can take care of your tail with a MEMS gyro in charge.

[flydude]

I'd like to hear opinions as to what the best servo is for the job - from pro to our level

anybody?

this little Acer D12-MG is still working great but like I said I have been polite to it so far - that will end soon

[xatled99]

Just as a data point, I bought a 5084MG last June. It worked great for over a year, but a few weeks ago, it started blowing out during flips, so I replaced it with a s9257. I was driving it with a gy401 at 5V and I have Heim Joint's chinese weights installed.

What is the "normal" service life of a tail servo (or a [flybarred] swash servo, for that matter)?

[flydude]

PLEASE run some benchtests on it to check for overheating...? Might go a long way to prove the theories, does it run hot or what?

FLyDuDe

[xatled99]

FWIW, I mounted the 5084 in a vise, hung a 1lb weight off the horn (about 1/4" radius, so 4 oz-in of torque; probably too low to be realistic), and fired up ye olde servo cycler. After a few hundred cycles, I measured it at 130F with an IR thermometer.

[Rookiepilot83]

Originally Posted by Angelos

The 5084MG is rated for 4.8V operation only (second line in spec): http://www.hitecrcd.com/product_file...135/5084MG.pdf

A high end gyro like the Quark will demand from the servo to keep up with constant and rapid position changes throughout the flight. If the servo runs at higher than rated voltage it will most likely overheat and cut out as you have experienced. Another very common problem that usually goes unnoticed is faulty bearings in the tail blade grips which may appear to run smoothly when bench testing but lock up with the centrifugal forces when the rotor is turning.

-Angelos

I just downloaded a "General Servo Manual" off of Hitec's web site <http://www.hitecrcd.com/support/prod...vos/index.html> and here is what Hitec states in regards to voltage range :

Voltage Range
All Hitec Servos can be operated within a 4.8V-6V. range.
Only the HS-50 operates exclusively with 4 Nicad cells ( 4.8 volt ).

This would lead me to believe that the HSG-5085MG servo can be safely operated at 6V, or am I missing something . I have a 450 Pro that I'm running at 6V with a UBEC that is soldered into my ESC so I would like to stay at 6V if possible. However the servo resource guide on Spartan's website says NA under the 6V category on the HSG-5084MG servo and that coupled with testimonials of these servos frying at 6V makes me very reluctant to install mine and run it a 6V. I'm currently using a HS-5065MG Digital on my tail and as my skills improve its just not going to cut it. Has anyone had any success running the HSG-5084MG at 6V?

[raptorheli2]

in there lies the confusion-even hitec seemingly don't know as their own documentation differs.

cheers