A mysterious incident

[Erfolg]

I am also sure that the probable cause of the incident is closely related to motor failure.

 

On reflection, I also have experienced a ESC issue when pulling a very high current from my flying wing. It was inadvertent, due to trust in the data sheet and not using my Watt meter. It was hot enough to melt and shrink the protective shrink wrapping.

 

So in my case I have had the ESC shut down to abuse at least twice. I have been lucky to date, in that my models survived, whichhelped in pointing at the probable cause.

 

It is easy to point a finger at the electric systems. Yet in my case, I left no head room, by doing so operated to near the limit. In the first case it was due to normally doing a -30 sec motor run, then +15 minutes of gliding. This allowing the motor to cool. It was the constant running, in search of either height or a thermal that pushed the motor passed the limit. The second was laziness, not doing the sensible checks (watt meter).

 

Although not a particular fan of Spektrum, I recently saw a model being flown low down, near to a mile away. I know because I helped in the retrieval and it was a long drive. The model only went in because the modeller eventually could not see what it was doing. It was one of the very cheap Spektrum sets.

 

I do feel we are all to quick to blame equipment of all makes, particularly the very low cost equipment for failures. Whereas most blame lies with us modellers, generally in some form of abuse. Yet it do recognise that equipment does fail, even if it is eventually.

[Chris Bott - Moderator]

There must have been thousands of successful electric flights without any issues whatsoever. I don't think we suddenly have a reliability issue.

 

I can add to the debate though that I did once see an ESC after an EDF motor seized. In this case the ESC had been so hot that all the solder had melted and all the components had floated to one end of the board!

[Tim Mackey]

Can anyone confirm an email address for BRC hobbies?

I have an old one in my address book, ( [email protected] ) but I note their website continues its tradition of hiding any readily visible means of contacting them via E-Mail !

[leccyflyer]

Sorry to read this, but at lest she looks repairable.

 

My boy's Ripmax Spitfire, killed by a radio malfunction, was rather more badly damaged and on stripping the covering off, the wing was completely shattered.

 

That was an AR500 as well. Total loss of control. Model failed to go into failsafe and hit the ground with the motor running. AR500 sent back to Horizon and was replaced FOC, "for customer's peace of mind" by an AR600. Before that I was quite content with my several AR500s, now, not so much.

 

Is there any chance that the motor could have been caught up on impact and overheated then?

 

I've seen motors burn out in an arrival when the pilot failed to close the throttle soon enough and the stalled motor has burned out, or blown a fuse even, in the olden days..

[Tim Mackey]

Well I shut the throttle as soon as I realised I had no control - so I don't think so.

I have, as relayed in an earlier post, thoroughly flight tested the receiver in another model, and can find no fault - so Im reasonably happy that this was not the cause.

Of course, as I also often say, its a bummer, but frankly, no system is guaranteed, and its a risk we all run with every flight.

[PatMc]

Posted by Tim Mackey on 03/09/2011 13:23:01:

Can anyone confirm an email address for BRC hobbies?

I have an old one in my address book, ( [email protected] ) but I note their website continues its tradition of hiding any readily visible means of contacting them via E-Mail !

 

I get emailed their latest offers from [email protected] Although it's obviously meant as an outgoing only address it's possible they may respond it.

The latest info is that the shop is closed today & Friday 10 Sept because they are preparing for the Catton Park show.

[leccyflyer]

Posted by Tim Mackey on 03/09/2011 14:02:20:

Well I shut the throttle as soon as I realised I had no control - so I don't think so.

I have, as relayed in an earlier post, thoroughly flight tested the receiver in another model, and can find no fault - so Im reasonably happy that this was not the cause.

Of course, as I also often say, its a bummer, but frankly, no system is guaranteed, and its a risk we all run with every flight.

Yep - the AR500 in the Spitfire had previously had dozens of flights without a single problem, and Horizon could detect no problem - but still replaced it FOC. IIRC the AR500 has now been replaced by the AR600 anyway.

 

None of my other AR500 receivers have ever had a problem either but my confidence in them is severely dented.

[Tim Mackey]

Posted by PatMc on 03/09/2011 14:10:20:

Posted by Tim Mackey on 03/09/2011 13:23:01:

Can anyone confirm an email address for BRC hobbies?

I have an old one in my address book, ( [email protected] ) but I note their website continues its tradition of hiding any readily visible means of contacting them via E-Mail !

 

I get emailed their latest offers from [email protected] Although it's obviously meant as an outgoing only address it's possible they may respond it.

The latest info is that the shop is closed today & Friday 10 Sept because they are preparing for the Catton Park show.

 

Cheers PatMc I'll try em both

[Peter Beeney]

Erfolg @ 12:20:42 and Chris @ 12:36:11. Yes indeed, I’m sure all this is perfectly true. It’s only the odd rogue flight that makes the headlines, as always. As Chris says, perhaps as many as 99% of electric flights are perfectly acceptable, so I guess that by and large we are the right track. But, by the same token, it would be very difficult to estimate exactly how many small incidents there are, these never get reported anywhere. We have a number of electric flyers, proportionally the same as any other club, maybe, and there always seems to be some little thing going on, some question being raised about something.

I also agree with Erfolg, and I also think it is a mixture of reasons why these things go wrong. In one case I saw a battery that had been hot, one cell so much so that the heatshrink had melted and appeared to have become part of the metal casing! Needless to say, that cell was a bit naff, but when I replaced it the pack carried on completely unperturbed. Demonstrating the outstanding quality of some items, perhaps? The pilot had no comprehension of just how much current he was trying to extract from the battery! 4 by 600 brushed motors and goodness only knows what sized props. So there is some sort of moral here, tiresome as it may seem, you really do need to study the calculations first. A totally inadvertent incident.

Then there was the ESC that totally exploded in a shower of sparks and exited out through the side of the fast foam model it was in. There was absolutely nothing left of the ESC in the model. It was pretty impressive at the time. It’s a wonder that the model didn’t go on fire anyway. The inrunner motor was on full song right up to that moment. The pilot was striving for every last ounce of performance, it most likely had a 4 cell pack when it should have been 3 cell perhaps, but it was worth the cost of the ESC just to see it. The pilot was very philosophical, but he now uses sensible sized controllers! So that was not quite so inadvertent, I think the poke and hope principle, (I know it well!), was in action here, unfortunately the ‘hope’ link became rather disconnected! Again, it might pay dividends to do the sums!

Recently there has been a third failure, a beginners Wot4 foam-e that had done a number of flights, took off, a quick climb to height and then started to quickly lose power. By the time we nearly arrived back at the strip the ESC was well alight, a mass of flames. I know this is how it happened, I was flying it. Bog standard set up, as supplied, I think this is just sheer unadulterated poor quality equipment, Ripmax instantly replacing the ESC for a bigger capacity version, without a quibble; and this would seem to verify that view. I don’t think this could have been easily foreseen, particularly by a beginner, unless you had sound prior knowledge.

So we have a goodly mixture of different types of occurrence, and awareness, I suspect that all the little happenings will fall near one of these little brackets.

Just a thought, but I’d say a good study of the subject might be a big help when it comes to electric flying.

PB

[Peter Beeney]

Sorry about the post, I think we have a hiccup on the site. But it might be more widespread, I’ve seen one other unrelated site reporting apologies as well.

PB

[Tim Mackey]

I have written to BRC, and we will see what response I get.

I'm certainly not buying another EnErG motor, and have gone for an E-Flite ( well pleased with the few I have used to date ).

Just ordered the Power.15 from one of my favourite online retailers ( Model Shop Leeds ) @ 16:14 hrs, and at 16.20 I get an Email confirming receipt of order.

16:32, another E-mail states " Order dispatched by MS"

Cant beat that ..especially on a Saturday afternoon.

Getting back to the damage, I have repaired the top hatch, and cowl, and am now thinking that I may just use threaded studding as per many other motor installations I have done, and simply attach the studding to the main firewall a few inches back from the original ply motor box.

I'll simply cut off the remains of the ply box, and then after sorting out thrust lines and final prop shaft position, fit the cowl back to suit.

Shall wait for the motor before continuing.

[Tim Mackey]

Posted by Peter Beeney on 03/09/2011 16:34:10:

Sorry about the post, I think we have a hiccup on the site. But it might be more widespread, I’ve seen one other unrelated site reporting apologies as well.

PB

 

It reads fine, if a little small

[Peter Beeney]

Yes Tim, exactly so. I can’t log on to the site at all in Firefox, Opera says that the pop up paste box is prevented by a mysterious incident and I have to go all round the mountains to post using Safari. By which time the print has much reduced in size and also changed fonts!

I think I shall go flying instead, at least I can crash everything there in relative style….

PB

[PatMc]

Posted by Tim Mackey on 03/09/2011 16:41:38:

I have written to BRC, and we will see what response I get.

I'm certainly not buying another EnErG motor, and have gone for an E-Flite ( well pleased with the few I have used to date ).

Just ordered the Power.15 from one of my favourite online retailers ( Model Shop Leeds ) @ 16:14 hrs, and at 16.20 I get an Email confirming receipt of order.

Tim, I think you might find that EnErG & Eflite are differently badged versions of the same motors. I have a "Tornado" motor, at one time sold by Overpricer, that is identical but for the purple anodised finish.

 

BTW I've just a quick read through most of the thread. You found that all three winds are open cct - that doesn't sound to me like the motor was the prime cause. If it was the motor I would expect only one wind to have burnt out with possibly some signs of overheating to the other two.

Edited By PatMc on 03/09/2011 19:40:10

[Tim Mackey]

I didn't know that they were the same - although I must say that the E-Flites I have seem better quality, smoother finish etc.

I suspect that the O/C on all windings may also be due to the very poor soldering of the lead out wires...as shown in an earlier picture.

TBH, I was more concerned with eliminating the radio as prime suspect, and in my mind at least, I think I am there.

[steve mildoon]

Lost my plane today, flew it on wednesday at the local club all went sweet as a nut, today fueld it up,pre flight check etc, took to the air and all was fine, about 2 mins into the flight it rolled on its own and then went virtical as thou ide rammed the elevator back, then it went into a downwards roll, i corrected it as i needed to land asap, it didnt respond and flew off into a tree where now only the fire brigade could recover it, well im well miffed as i cant recover it to check it out, can only think of two things, interefernce or duff receiver, tx is still fully charged.

[Tim Mackey]

Hard luck Steve....

However, I think the summary of my rather long investigation and posting should be that its all to easy to blame the receiver, without conducting a thorough test first

[Tom Wright 2]

Sorry to hear of the Spit prang Tim ,sounds like a ubec would have saved the day .

[Tim Mackey]

Its nearly finished and ready to go again Tom - not sure about the UBEC TBH, Im afraid it may remain one those unsolved mysteries....the ESC shows no signs of distress at all, so Im still not really sure of the cause - other than I dont think it was a receiver issue.

[Tim Mackey]

Posted by PatMc on 03/09/2011 19:39:41:

Posted by Tim Mackey on 03/09/2011 16:41:38:

I have written to BRC, and we will see what response I get.

I'm certainly not buying another EnErG motor, and have gone for an E-Flite ( well pleased with the few I have used to date ).

Just ordered the Power.15 from one of my favourite online retailers ( Model Shop Leeds ) @ 16:14 hrs, and at 16.20 I get an Email confirming receipt of order.

Tim, I think you might find that EnErG & Eflite are differently badged versions of the same motors. I have a "Tornado" motor, at one time sold by Overpricer, that is identical but for the purple anodised finish.

 

BTW I've just a quick read through most of the thread. You found that all three winds are open cct - that doesn't sound to me like the motor was the prime cause. If it was the motor I would expect only one wind to have burnt out with possibly some signs of overheating to the other two.

Edited By PatMc on 03/09/2011 19:40:10

 

They dont look remotely like the same motor - the E-Flite has a much higher quality feel and finish about it, its heavier ( which is a shame - but then probably as result of higher quality ) however, I did have a little noseweight on the model with the lighter EnErG motor, so this will be eliminated, and the Lipo can always sit a little further back.

BRC have requested that I send it back, so we will see what transpires.

[Steve Hargreaves - Moderator]

Sorry to hear about the Spit Tim....these unexplained crashes cause sleepless nights don't they....?

 

Just thinking aloud here because I really don't know but is it actually possible for one of our brushless ESCs to "short out" via the motor connections? As I understand it a typical brushless ESC will look for back emf pulses to keep everything synchronised. If it doesn't get these (which it wouldn't if the motor windings went O/C or shorted together) wouldn't it go into fault mode & shut down?

[Tim Mackey]

No worries Steve, she will be finished and ready to defend the nation by this evening

I don't know is the honest answer, but maybe one day, I may just pick a sacrificial unit and find out

As I have subsequently tested the Rx ( and Tx for that matter ) and found all to be well, I was just trying to deduce the cause form the evidence I have.

A burned out motor, and what certainly appeared to be a total lack of response to the sticks.

The ESC checks out good, as does the BEC output, so it may well remain an unexplained incident.

For some more peace of mind ( but that's debatable actually ) I have fitted a different motor, of good known quality, separate switch mode UBEC, and a twin AR6200 receiver.

After all, I really dont want another crash with this model to identify that one of those items was indeed the culprit..

The original rx will stay in my 46" foamy slope soarer wing.

[Tim Mackey]

Posted by Tim Mackey on 02/09/2011 18:12:00:

The AR500 passed with flying colours. I flew it way way out - certainly much further than it was when the incident occurred yesterday evening at the flat field site. Not a flicker of any problem at all, full connection and control at all times. Then it was flown in closer and joined in the combat - at least that would also likely show up any dry joints / hidden arial breaks etc...and after a few hits, and some very troubled arrivals - including one so hard that the wing itself broke in two... no problem found at all. Some strapping tape later, and she was thrown out again, and fought on for another hour or so flying. All rock solid.

My faith in the receiver is restored ( and it somewhat rules out any transmitter issue also )

 

So, what was the cause??

 

What evidence I have is that the motor is dead, and appears to have overheated .

 

1) Do people agree with that ?

( Chris, the overheating may well be the reason that solder has sprayed around the windings...that was sort of what I was suggesting myself )

 

2) Did the motor overheat in flight, go dead short and overheat the ESC causing thermal shutdown of the BEC ? Ill take the ESC out of the model, and check for any signs of heat damage.

 

3) Anyone have anything else to suggest?

 

Certainly the quality of the wiring is suspect to say the least, and I shall contact the supplier to see what they have to say. It will be a good test of their service levels.

PS: I have changed the thread title, as it is unfair IMO to blame the radio on the evidence so far.

Edited By Tim Mackey on 02/09/2011 18:13:57

 

 

It took a while, but BRC contacted me today and have refunded the cost of the motor, which the manufacturers have admitted was faulty. Result

Incidentally, the Spit is flying as well as ever - if not even better - with her rebuilt front end and new E-Flite power .15