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HomeAircraftHelicopterHelicopter Main Discussion › Aliron glitch !! UPDATE 👍
03-28-2015 02:40 AM  3 years agoPost 41
Cobra 46

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Cambridge il usa

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I wonder if static charge is getting built up by CF rotor blades and then to the frame and Heli through the main shaft . Any time you have plastic and air and partials flowing fast over and around it , it will build static ! This is why we ground PE (polyethylene) natural gas pipe ,
it's a large potential for ignition with blowing gas .
Ever use a big shop vac without a ground plug on the cord ?? It will shock you when sucking up dirt or dust .

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03-28-2015 02:53 AM  3 years agoPost 42
Cobra 46

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Cambridge il usa

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Got you EE. thanks
I really forgot how much I hate chasing a problem in the radio ! Lol
Thanks for the help guys. I flew my spare jr 550 tonight with no issues ,
So I would say it's not the radio for sure. I am going to replace servos one at a time and then the reciver . both Helis are wired the same way and routing . I just had a thought can a lipo do this ??? I used lipo #1 in the problem Heli and lipo #3 tonight in the spare Heli !!

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03-28-2015 02:55 AM  3 years agoPost 43
TMoore

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Cookeville, TN

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All I will say is that every 2.4 Ghz system deals with static discharge differently, some better than others. Many of us have seen and as Dave pointed out earlier in his post, shaft drive machines are typically not the culprit but we have seen belt drive machines create havoc for certain users. Looking at this situation through the shrouded eyes of an Internet forum is very smoky and nothing even remotely close to actually being in front of the machine when it happens. The only thing that I would suggest is depending on the orientations of the TX and RX antennas at least try to keep the TX antenna polarized vertically unless you are using one of the dual antenna TX's where there is really no control over that situation. If your TX antenna allows orient it straight up 90 degrees to the ground and then try to visualize where the model was during the point in the maneuver where you can see the glitch or bobble. Visualize where the antennas are relative to you and see if there is a way to improve that condition.

Delayed Response Operator Not Engaged
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03-28-2015 04:15 AM  3 years agoPost 44
dkshema

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Cedar Rapids, IA

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When I say "common-mode" the static potential is present on the main batt. positive, also.
Are you SURE you're an Electrical Engineer?

The majority of helis on the market today use carbon fiber frames, a conductive material. There isn't going to be much in the way of static charge buildup that will cause any operational problems.
-----

Helis with plastic tail cases and/or painted/hard anodized tail booms, AND BELT DRIVEN tails MAY suffer from static discharge -- and its attendant spark.

-----

With a plastic tail case or a painted/anodized tail boom, the tail pulley and shaft are insulated from the frame and the front drive pulley. The front end of the boom is also usually well insulated through the use of a plastic tail block and through the paint or anodizing.

As the belt contacts and leaves the pulleys, they generate a high potential static charge (triboelectric charging by separation). As the charge builds up to a high enough voltage, that potential can create a spark, as the dielectric strength of the surrounding air is exceeded. You get a conductive path to an adjacent, lower potential surface.

There are a few videos out there showing the discharge occurring at the front end of the tail boom, near where it enters the frames, with the spark terminating on the case of a tail rotor gyro, or perhaps a receiver.

Plastic and painted/hard anodized aluminum are non-conductive. The idea behind grounding the tail rotor shaft to the frame is that you provide a low impedance path from the tail rotor shaft and its pulley, to the frame, so that no excess static charge can build up, and therefore, no spark occurs.

I don't believe I have ever heard anyone talk about "common mode static electricity" till now. And static charge present on the positive terminal of the battery, too? Last time I checked, the impedance of a battery (voltage source) is extremely low, as in a few milliohms. That would be between the positive and negative terminals. You're NOT going to have any static charge voltage differential between + and -.

Only a FEW helicopter designs have been prone to static discharge events, and the problem ONLY occurs in helis with belt-driven tail rotors. It's a rare event. Dry air is a contributing factor, and we see a lot of that in the winter.

Grounding all sorts of stuff in the airframe to your battery is not a useful or productive effort for all helis. It may be required for those few belt-driven tails prone to static build-up and discharge.

-----

72 MHz (as well as the the 27 and 35 MHz) radios of days gone by were quite prone to interference from the electrical noise generated by loose metal to metal contact. This was not static electricity, by the way. Loose mechanical connections or dissimilar or corroded metal connections form non-linear electrical junctions, which act as unintended "diodes" or mixers. Add some nasty oil with bits and pieces of fine metal particles, you have a fun dielectric in the mix. When these devices are excited by sufficient level of one or more signals they generate intermodulation products.

I used to demonstrate this quite easily by simply dragging a small screwdriver tip along the cooling fins of my motors on planks. I learned real early in this hobby, as a young lad, NEVER to use a metal clevis on a throttle connection.

I also fought the metal to metal gremlin in a Schluter Heliboy that took down every radio I threw at it...AM, FM, and even PCM, Airtonics, Futaba, and JR. The culprit turned out to be a sharp burr on a stamped metal pitch change mechanism at the base of the rotor shaft. Found the burr, filed it off, and voila, the Heliboy was cured.

-----

Static discharge is a force to be reckoned with on electronic equipment. As an avionics hardware designer, one of the common required qualification tests all avionics is required to pass is an "ESD" test. The unit being tested is powered up and and put in its operational mode. The unit is then zapped multiple times, in multiple places, with an ESD gun -- at 15 kilovolts. The unit has to play through the discharges without interruption or unexpected behavior.

-----

But back to the problem at hand. As this helicopter uses a SHAFT drive, it's NOT going to have a static electricity build-up/discharge problem. The behavior that usually follows an ESD hit on our electronics is not just an annoying glitch on a single control function. It is usually a catastrophic result, as the discharge disrupts the processors in the RX and/or gyro, causing a full system reset in the air. That ain't pretty.

2.4 GHz radios ARE quite susceptible to ESD created by static discharge.

If the OP isn't using a ferrite toroid on the ESC to RX connection, this would be the time to install one. Get as many turns on the toroid (donut) as you can...the more you get, the better this will work. ESCs output quite a bit of electrical noise that if they find their way to your power and/or ground signals, can wreak havoc with today's processor based systems.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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03-28-2015 04:24 AM  3 years agoPost 45
EEngineer

rrProfessor

TX

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every 2.4 Ghz system deals with static discharge differently
I'll bet...and I bet none of them want any static discharge as you mentioned......

All I was trying to explain was that without having continuity between the "frame assy, et al" and the main batt. negative....the avionics "ground" is isolated from the "frame assy" and the main batt. negative.

This situation can allow such "static build-up" to cause the arc-over that you described.

And if a separate "static" ground wire is routed....from the tail rotor pulley....through the boom...attached to the frame/boom attachment bolt...and then to the aluminum motor mount...(like Mikado and others describe)

And then routed from the motor mount to the main batt. negative connector on the ESC.....the avionic systems will always be at the same "static voltage potential" as the whole frame assy....so an arc-over doesn't happen....and there's a separate path from the tail to the main batt for static than the avionic ground.

I was taught this is the "single point ground method"....

I cannot account for the myriad of methods that people come up with.....I do what has worked consistently for me.

I think we're pretty much in agreement with the "VdeG" effect on a belted tail heli....the only question is extending the "anti-static" wiring to the main batt. negative.

Hope Cobra's issue is just due to a servo going "cruddy"....easier to address....

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03-28-2015 05:03 AM  3 years agoPost 46
EEngineer

rrProfessor

TX

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There isn't going to be much in the way of static charge buildup that will cause any operational problems.
I disagree...where is any static that has built up discharge to?

The static spreads out all over the whole heli.....like the static on a toy balloon does(the classic case of static generation...in my generation...).
as the dielectric strength of the surrounding air is exceeded. You get a conductive path to an adjacent, lower potential surface.
I agree....but what about the dielectric strength of the ground wires insulation?
72 MHz (as well as the the 27 and 35 MHz) radios of days gone by were quite prone to interference from the electrical noise generated by loose metal to metal contact.
That's what I meant...and I corrected my "rubbish"...
The unit is then zapped multiple times, in multiple places, with an ESD gun -- at 15 kilovolts. The unit has to play through the discharges without interruption or unexpected behavior.
Yes, a quantitative test...but isn't the mechanically case routed to it's PS input...rather than "willy nilly" connected to the internal PCbs and such?.....Single Point Grounding....case and internals are at the same "static voltage potential"....
it's NOT going to have a static electricity build-up/discharge problem.
Are you sure, TM?....I've heard that the main rotors spinning through the air builds up static....and that would be distributed over the frame....
That ain't pretty.
ESD is a big issue....my bench employs anti-static mats, wrist-strap, etc....
2.4 GHz radios ARE quite susceptible to ESD created by static discharge.
I totally agree with you....IMO, any electronic systems are....
ESCs output quite a bit of electrical noise
I also agree with you....have spectrum analyzer "captures" that demonstrate such.

And, so do external SBECs...again my spec-an captures....

A specific....the Kon internal SBECs exhibit a series of harmonics that can coincide with the "passbands" of one's FBL cntlr's MEMS gyros....almost all gyros are made by Invensense

By using the toroids, I have spec-an data that demonstrates the "suppression" of these harmonics....that can interfere with the gyros.

So, I'm a really big fan of using such toroids...given my situation.

And, TM, with regards to the OP....it could perhaps be some sort of interference to the FBL.

These kind of issues can be very difficult to correct.

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03-28-2015 05:11 AM  3 years agoPost 47
EEngineer

rrProfessor

TX

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I wonder if static charge is getting built up by CF rotor
It is....but perhaps you have a "glitch" servo...

Swap out, if you can, and isolate the issue....

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03-28-2015 05:15 AM  3 years agoPost 48
EEngineer

rrProfessor

TX

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TM, pardon for the point-counterpoint....

So many issues....

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03-28-2015 05:29 AM  3 years agoPost 49
dkshema

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Cedar Rapids, IA

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Carbon and metal frame helis are made from conductive material, unlike the rubber or latex balloon. The heli is made up of conductive static and dissipative materials. Charge will not build up as on the balloon. There is simply no need to rigorously ground your various electronic items to the airframe or power ground. It is a waste of time and effort in most cases.

As for avionics, grounding, and ESD, it is apparent you do not understand large integrated systems consisting of hundreds of individual LRUs (avionics boxes) connected by miles of wire, powered by multiple sources, both AC and DC, in many cases using the airframe itself as the ground reference. Effective ESD control is not quite as simple as your single point ground.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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03-28-2015 05:38 AM  3 years agoPost 50
EEngineer

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TX

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Charge will not build up as on the balloon. There is simply no need to rigorously ground your various electronic items to the airframe or power ground. It is a waste of time and effort in most cases.
Disagree...but to each his own....

I always "rigorously" ground....so as to avoid these issues.

Has never failed me.....

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03-28-2015 05:55 AM  3 years agoPost 51
EEngineer

rrProfessor

TX

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Anywho...think we got off topic.

This issue is to help Cobra solve his aileron glitches.

Static has been thoroughly discussed...

Perhaps it's a servo goin' south....

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03-28-2015 06:18 AM  3 years agoPost 52
EEngineer

rrProfessor

TX

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it is apparent you do not understand large integrated systems consisting of hundreds of individual LRUs (avionics boxes) connected by miles of wire, powered by multiple sources, both AC and DC, in many cases using the airframe itself as the ground reference. Effective ESD control is not quite as simple as your single point ground.

You couldn't be more wrong....and as such, I now realize your viewpoints with regards to anything I post that you don't agree with.

Are and are claiming to be the only one that has such experience?
ESD control[quote]

Starts with you handling IC's without being grounded. As you are claiming....

ESD 101...."grounding"...to prevent ESD...

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03-28-2015 06:22 AM  3 years agoPost 53
EEngineer

rrProfessor

TX

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Effective ESD control is not quite as simple as your single point ground.
What designs have you personally implemented to counter this issue?

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03-28-2015 06:29 AM  3 years agoPost 54
Cobra 46

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Cambridge il usa

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I swapped out my Aliron servo. Will fly sat am.
No toroid ring on it by the way. The Heli was a combo kit and that's how I flew it , the first 40 flights were event free ..this all started after it sat awhile this winter Let u know how it goes sat

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03-28-2015 06:31 AM  3 years agoPost 55
EEngineer

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TX

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Hope it goes well, Cobra...

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03-28-2015 06:47 AM  3 years agoPost 56
EEngineer

rrProfessor

TX

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As for avionics
You don't have an O-scope nor spec-an, do you?

How can you come up with your conclusions without having the proper test equipment to back up your claims?

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03-28-2015 11:38 AM  3 years agoPost 57
icanfly

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ontario

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ya know, after dealing with damn static resets sending my servos to their extremes within a minute of flight on several occasions, if I didn't add silicone lube to the tail belt(s) on more than one belt tailed heli thereby instantly crashing my heli in quick order as was the case last Monday aft, I've had to learn the hard way. Mondays static jolt cost me several hours of repair to a frame and shafts and a brand new set of blades completely destroyed and not 5 minutes old. This time the static was obvious because the tail belt was definitely rubbing the cf boom before I caught it AFTER the heli was smashed to the ground, sure it depressed me. I have my rx parked on the tail block but raised the antennas up by a cm with tripled up mounting tape now (tip, make a wedge and mount the sat/rx so the antennas are furthest from the heli).

the way I see the problem speaking from experience, if there is a static problem on one of the antennas then the glitch should reset the rx/sat. What I've learned is to DISTANCE the antennas from the belt and nearby cf/plastic by about a cm and more when possible. For the most part this has worked in resolving much of my problems regarding static, lube the belt before every flight/session also. I have no grounding wires to mention.

Yes cf and plastic have an electric field to them, felt it at a plastics manufacturing factory where fresh parts in a box caused my pant leg to pull into it when I walked past, what you can't see can hurt you.

additionally, if you go through the servo by pushing down on it while you move the tx stick associated with it's movement it might feel rough or skippy/notchy, then it's a servo in need of closer inspection.

remember, kis,

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03-28-2015 11:39 AM  3 years agoPost 58
dialarotor

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Traverse City, Michigan

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Kudos to Horizon Hobby service
Sent in my well used and yes dropped once DX8 for tuneup.
They replaced a tweaked flt mode switch, found a missing tension screw, something with the antennae, and even copied all the models on to the SD card for me. NO CHARGE in less than 9days. Just the return shipping.
Thank you Horizon Hobby Services.

RapRexSynLogo Pilot

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03-28-2015 11:46 AM  3 years agoPost 59
icanfly

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ontario

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back to the glitchy flight problem, please read my last reply for clues

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03-28-2015 01:52 PM  3 years agoPost 60
Cobra 46

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Cambridge il usa

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I read it and I never tried holding the servo like that. I will do it Thanks EE me too !!

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