Model lost from faulty pack

[Tony Smith 7]

I still find it odd that modellers are so anti battery boxes. I have loads of equipment in regular and rough service which relies on them, including SOLAS approved maritime life saving equipment. It really only seems to be modellers who are so concerned.

 

To my mind the comment above "you can't surely use the poor quality of manufacture to discredit the basic idea?" applies equally to battery holders. Just because some are poor, doesn't mean the whole idea is poor.

[Martin Harris - Moderator]

It's very unlikely that a simple accident involving a smaller model would have its claim invalidated as no illegal act would have been committed. The cover is for a claim made against you as the result of you or your model causing damage to a 3rd party due to your error or negligence.

 

I think one thing to consider when flying >7kg models is the legal position of ignoring the advice from the BMFA and (IIRC) CAP 658 not to use battery boxes.

 

Whether or not you believe that they are generally acceptable, in the case of any fault being discovered involving a battery box, it might be used as evidence against the operator of a model involved in an incident having properly satisfied himself that the flight could be made safely. It would then probably be your responsibility to prove that the BMFA/CAA advice was flawed...

 

If the case was made, then the insurance could possibly be invalidated due to the illegal nature of the flight.

Edited By Martin Harris on 01/07/2011 21:50:56

[Tony Smith 7]

CAP 658 has nothing to say about battery boxes, only a recommendation against dry batteries for airborne use (but apparently fine for transmitters).

[Martin Harris - Moderator]

That's not quite how I'd interpret the following from Chapter 6 Flying Radio Controlled Models 1 General which I've just checked:

It is recommended that you use welded or soldered re-chargeable battery packs in your radio control equipment.

Granted, not quite as strongly worded as the BMFA advice:

when fitting Nickel Cadmium (Ni-Cd) or Nickel Metal
Hydride (Ni-Mh) rechargeable batteries to
equipment designed and sold to take dry batteries,
always ensure that the cells are soldered or welded
into packs and that the packs are either hard wired
or wired through a plug and socket into your
transmitter and receiver systems. Do not rely on the
spring type battery contacts in battery boxes.

I suppose that you might argue that you're not fitting the packs to "equipment designed and sold to take dry batteries" but I think you'd be arguing against the wording rather than the spirit of the advice and could still be on sticky ground if claiming your installation was fit for purpose.

[Former Member]

[This posting has been removed]

[Martin Harris - Moderator]

Can't really see any benefit in a series circuit without balancing taps but I suppose it gives the contacts a polish each time you do it!

Edited By Martin Harris on 02/07/2011 00:31:14

[Tony Smith 7]

I'm no legal expert, but my take is that CAP 658 is advice drawn up by the CAA to help people stay safe and legal. Sort of like the Highway Code in that it's not necessarily a legal requirement to follow it's advice, but you'd be very unwise not to do so and might well be held to account if your non-compliance was material to an incident.

 

BMFA handbook is essentially a club's recommendation to its members. Very much lower in terms of authority. For example a non-member would not even have access to this information, so could certainly not be judged negligent for not following it.

 

I guess Eric's comments support my opinion, which is that there is absolutely no evidence that a reasonable quality battery box is less suitable than a reasonable quality pre-made pack. There's no evidence to support a witch-hunt against battery boxes as being a more important safety issue than say cheap servos or poor airmanship.

 

It would be a shame if real hard facts like this get buried under club policies etc, which are not based on actual evidence. I suppose that's why I'm not a great club person. I prefer to determine the true facts, make my own judgements and stand by them. That's not really any different from other areas in life, or even in other aspects of aeromodelling.

[leccyflyer]

Posted by Tim Mackey - Administrator on 27/06/2011 19:23:41:
Not my picture, but this shows what I mean - note the large hammerhead iron, I still have mine and use it frequently for such work. Puffin models amongst others stock them.

That looks like a very similar iron that I use, with the same hammerhead tip.

 

My cell alignment jig is a homemade one fabricated from aluminium angle and scrap wood, with a couple of high quality rubber bands- does the job perfectly.

 

There seems to be a premise running through this thread that seeks to downplay the advice from BMFA not to use those battery boxes for airborne use, and to ignore the slightly less explanatory, but still perfectly clear, advice from CAP658 to not use them. Something to think about.

 

If you have to plead a special case for ignoring such advice then it might be a good idea to have all of one's ducks in a row, retained with a wrap of good quality tape, and with an outside covering to prevent ingress of moisture.

 

Even then one might expect that an opposition lawyer would take every opportunity to point out that doing so was a bit quackers.

[Lee Smalley]

Well you guys use them I will stick with the welded packs so I am unlucky enough to need the bmfa insurance it will not be an issue I have to worry about

[Tony Smith 7]

There seems to be a premise running through this thread that seeks to downplay the advice from BMFA not to use those battery boxes for airborne use, and to ignore the slightly less explanatory, but still perfectly clear, advice from CAP658 to not use them. Something to think about.

 

Well bear in mind that the thread started off with people complaining about lost models due to failed welded or soldered packs. Maybe those wouldn't have happened if the modellers had used battery boxes.

 

As for BMFA advice, no I don't value it on this particular subject as it is contrary to my own experience both in aeromodelling and in other areas where battery holders are standard practice.

[leccyflyer]

Posted by Tony Smith 7 on 02/07/2011 19:38:18:

There seems to be a premise running through this thread that seeks to downplay the advice from BMFA not to use those battery boxes for airborne use, and to ignore the slightly less explanatory, but still perfectly clear, advice from CAP658 to not use them. Something to think about.

 

Well bear in mind that the thread started off with people complaining about lost models due to failed welded or soldered packs. Maybe those wouldn't have happened if the modellers had used battery boxes.

 

As for BMFA advice, no I don't value it on this particular subject as it is contrary to my own experience both in aeromodelling and in other areas where battery holders are standard practice.

The OP merely illustrates the benefit of rolling your own, rather than trusting someone else to do it.

 

Comparing poor quality, substandard packs with battery boxes that are neither designed for the job, nor recommended for the job by the national body, and the governmental organisation that recommends "best practice" as it would be defined, should push come to ouch, is counter productive..

 

A possible compromise would be to strip the heatshrink from suspect packs in order to inspect them or better still, for manufacturers to use clear heatshrink, facilitating proper visual inspection.

[Malcolm Fisher]

I have followed this thread with interest, particularly as I have had "proper" welded packs fail and have also used battery boxes in gliders for a number of years with no problems. Somehow I had missed this recommendation in the BMFA handbook, so have been operating outside the guidelines. Recharging has always been done by removing the cells from the box and using a mains charger designed for charging such cells rather than using the usual supplied charger which comes with a radio set.

It has also already been said that this is a recommendation, not a legal necessity.

Personally I can't see a problem as, after all, the final connection IS reliant on the spring contacts in the plugs and sockets we use, and that includes high capacity batteries used with gold plated "banana" plugs for electric power trains. Could these not also fail?

My earliest radio set came with a battery box for dry cells for the reciever and used dry cells which I soon swapped for rechargeables which were far more expensive in those days but safer in my mand as I knew they were fully charged before setting out for a flying session and one never knew what the state of dry cells was. Replacing them for every flying session was even more expensive in the long run as well as being wasteful,

Five of the transmitters I have use spring connectors, and two of these are only a couple of years old. I know there isn't the same vibration issue with a transmitter but they can be dropped or knocked and that could cause a loss of continuity of the electrical supply.

Malcolm.

[Peter Beeney]

Tony @ 09:40:19, - I can certainly identify with your post. I’d agree 100%. As a small club our few rules are based on the operation of the members safety and likewise of anyone nearby, we have an adjacent footpath to one side, plus other walkers and infrequent cars on a made up track on the other. The strip end abuts onto the track. Any adjustments to, or any thoughts about any new additions to these rules, are fully discussed and then accepted by a majority vote; and hopefully then are as crystal clear and as simple as possible. If some of these procedures deviate from the BMFA recommendations, then so be it. I have always considered this, and, if necessary, would be prepared to justify my actions. If I failed I’d have to cross that bridge when I got to it. We are in it just for fun, but at the same time some of this activity is capable of causing really serious harm in an unguarded moment.

I don’t think there is any great desire in aeromodelling to use battery boxes. It was simply that Josip mentioned these, as they are approved for aeromodelling use in Austria, and maybe elsewhere. In the UK they are approved for some Safety Equipment, I’ve seen this and Tony also mentioned it. Indeed, I have a sneaky suspicion that if we could see into the matter, we might find that that the CAA themselves have approved these items for use within the aero industry, perhaps even in a higher risk situation than model flying.

If we talk about circumstances involving lawyers, what would be the reaction if someone was flying with the approved welded battery, but for what ever reason the plug pulled out of the socket. Let’s say the battery was insecurely fixed in the model, moved around and the plug and socket was unable to support the weight of the battery. The consequences of that then involved a lawyer, and I’m sure he would soon be looking at Article 138 and many other angles, too. Then just how long would it take to find someone qualified to say that this was negligent on at least two counts, firstly the battery wandering around on it’s own, and then the unrestrained power connector. Just how long does it take to convince any interested parties that with no power there is no control…. However, this is all hypothetical anyway, it might never happen; but if it did, I’d bet my last brass farthing that within seconds there would be a BMFA Safety Note out saying that these items should be latched or in some other way restrained.

I’ve only ever seen battery boxes in 4 off AA and 2 off AAA sizes, so I’d say that it’s most unlikely models over 7 kg will be ever be using these anyway. I’m sure the operator would prefer to use something a bit more substantial.

leccyflyer, - I’m not entirely sure that battery boxes are ‘neither designed for the job‘ because they are made to contain cells; to perform as a series constructed battery; and other organisations approve them for this very function, certainly to operate in conditions equally as stringent as model planes. Whilst comparing them may be counter productive, although I’m not quite sure why, as I said before, the good quality cells in the box are much better than the unknown welded pack that fails; and that seems to be happening with depressing regularity. To take positive steps to try and avoid a potentially dangerous situation seems to me to be positively productive. If these boxes are used in Safety equipment I’d have though that at the very least they would be given a careful check over at the design stage, and maybe some performance tests too, I shouldn’t wonder. I’m sure they are proved to be more than adequate, so I’d just love to see a valid explanation as to why they would fail when used in a model aeroplane.
I certainly agree about stripping the shrink-wrap etc. Some manufactures do use clear plastic, Vapextech, see my photo, but there is a piece of card over the connections. Here you can see the onslaught of rust, which must have taken some considerable time to build up. It’s probably is not an immediate threat to an open circuit but it’s definitely not good and I think it does indicate that the pack is considerably older than the purchaser thought it was. Yet another hazard facing the unsuspecting pilot…...

Now we want a sell-by date printed on to go with everything else!

PB

[leccyflyer]

Peter

 

The reason I say it's counter-productive is that there has been a clear, definitive, statement made in CAP 658 and in the BMFA handbook. Whether that is right or wrong, in a technical sense, isn't really all that relevant. It's out there and, in the event of an incident, taking actions that are contrary to that advice would be something one would not really want to be having to justify.

 

The number of such guidelines is relatively small, given the complexity of the hobby, so acting directly against them is something to be embarked upon with a lot of thought.

 

I will say this though, there appears to be a trend to make the BMFA handbook ever more complicated, with advice given on every little thing under the sun. Some of these have not, in the past, been shown to be particularly well thought out. There is a risk that, in attempting to provide a comprehensive guidance, we are painting ourselves into a corner.

[Bob Cotsford]

Well said Leccy, some of the technical recommendations in the book seem to be based as much on hearsay as technical knowledge, or one size fits all philosophy which doesn't always apply.

I'd take a guess that the battery box recommendation is based on two factors, one being that lower quality spring contacts can't cope with the vibration of IC models terribly well, the other being the spate of low end sets in the 70s and 80s that came with cheap and nasty battery boxes.

For the average flyer a welded/soldered pack is generally a safer bet.

What was it about guidance of wise men and obedience of fools? The hardest part is often assessing which group you belong to in any particular case.

[Tony Smith 7]

Some sense written there. In essence its clubs, rules and courtesy. Not really safety in itself more a matter of going along with someone else's rules, which were drawn up with the best of intentions, even though you may not quite agree.

 

If we can't bring ourselves to do so, then find another club.

 

What I don't agree with, is the idea that one club's rules should be taken as some sort of authority outside the context of their membership, especially when nobody can explain the foundation for the rule. (I'm discounting the TV remote control comment that always comes up)

 

I think there's just a sort of temptation to think that if something is written out in a well structured manner, then it must be true. We see that in sailing where some people believe that the "Boat Safety Scheme" is some sort of authority. It is, but only in the context of Inland waterways and especially canals. Compliance with some aspects would seriously compromise seaworthiness of a sea going vessel.

[Former Member]

[This posting has been removed]

[Lee Smalley]

If you decide to go against the recommendations of the bmfa handbook then that is your choice, but in the event of anything happening just don't moan If the insurance people don't want to know, let's face it they take any opportunity to not pay out as it is! In my experience

[Former Member]

[This posting has been removed]

[Lee Smalley]

all that is in the BMFA hanbook is recommendations, only the extract from the ANO are law

[leccyflyer]

The thing is that CAP 658 - which is the official set of recommendations issued by the CAA with regards to model flying - would be taken as indicative of best practice - whether a flyer was a member of BMFA or not.

 

CAP 658 states

 

It is recommended that you use welded or soldered re-chargeable battery packs in
your radio control equipment. Dry batteries may be adequate for use in transmitters

but their use in airborne battery packs is not recommended.

 

Now, that is a recommendation. However. if you choose to ignore the recommendation and anything goes wrong, as a result of ignoring that recommendation, you had better have a very good reason for ignoring it, and be able to justify that. "I've always done it that way and never had a problem until now" is not likely to cut it as a very good reason.

 

[Peter Beeney]

 

Yes indeed, Eric, I’ve only ever seen these two sizes in our local Maplins, and because I’m not really interested at all in battery boxes, other than for experimenting and testing purposes, I’d taken very little notice. All my packs are home brew soldered together efforts, and they’ve never ever been the slightest trouble. But I do appreciate it’s not every one that can do this, and most folks have to rely on the standard issue. Having now had a quick check, it looks as though there are in excess of 30 different types and up to about 9 different sizes. So we are really well catered for, if necessary. As it so happens, as I need to renew in the future I shall change to LiFe types, the A123s, they really are reliable, easy to use and even less effort to put together. Again, if necessary, you can easily customise your installation exactly how you want it.

Personally, I think this battery box discussion is the very least of our worries. It’s the condition of some the commercials packs, and the problems that some people have charging, the installation techniques, or lack of them, in some cases, and the unlatched plugs and sockets, to name but a few, are what I consider rather more pressing issues. Invariably, if there is a power outage it’s something like this that’s caused it. However, if the battery box topic is highly important then I’m quite happy to accept that, but I’m not sure that I will ever be concerned about it, I suspect that relatively very few people indeed use them. But, in the event, I wouldn’t have a problem with that, as I said before, I’d be much more interested in what was put in them.

Continuing down this theme, when yesterday at the field a foamy trainer suddenly lost all radio control, it occurred to me how things are changing. When I assembled my Keil Kraft model out of the box and built a warp into the wing, or put too much dope on, that was one thing, but now the model is ARTF and the only things left to assemble are the electrical bits. In this particular case I’m told it was a piece of excess heatshrink on the connector that the owner had soldered up that had jammed in the battery/ESC bullet connection and caused an open circuit. Fortunately, the model made a very sedate glide down and a perfect landing.
It seems to me that I see a number of broken electric models, frequently due to rx power loss. Is this my imagination and it’s just us as a small group anyway or is there a common thread running through here? And if so, is is down to a whole variety of reasons or just one or two re-occurring situations? Maybe it’s perfectly acceptable but I’d thought that the system should be more reliable; after all the expected MTBF (Mean Time Between Failures) on some of today’s electrical equipment can be measured in hundreds of years now, I believe.

With regard to the insurance this might be a very vague grey area if push ever came to serious shove. On the other hand, it might be very robust. I’ve had assurances in the past, from both Graham Lynn and Manny Williamson, that the insurance is good, even if you are breaking the law you are still insured. It has also been said, thus far, the insurance has always paid out on any claim….
It struck me as a little odd, when recently it was stated that there has been a sudden rise in the number of claims, particularly to motor vehicles. There are the same number of members, which by and large I’d have thought are the same people, year on year; and the flying and car parking procedures cannot have changed that much. Or maybe they have. On the other hand, with my cynical hat on, I did wonder if it might be that someone thought that it might be a good chance of getting some damage repaired that might not actually have caused by a model aeroplane…

We have a really really legal beagle in the club, now retired. He refuses to be drawn on any of this stuff, as he says, he only speaks when he gets paid for it. However, he is unequivocal about the fact that any dispute would be settled in court, if necessary.

I think if we sat around too long thinking about the implications of what we were doing, and whether we were strictly within the rules and guidelines, and can we justify this and that, I think we’d just give up and go home. There is not enough time to be able to both fly and read the handbook these days…

PB

[Steve W-O]

How long does it take for a 2.4GHz RX to initialise and start receiving valid signals (ie valid outputs to the servos) after power up?

[Tim Mackey]

I think we have drifted off topic here Steve

However, the short answer is - it varies from type to type. Also, remember that correct initialization also requires the Tx to have found, acquired, and secured free channel(s) before it and the rx talk to each other. On some of my spekky receivers , this can take several seconds.

[Steve W-O]

Posted by Tim Mackey - Administrator on 04/07/2011 21:19:57:

I think we have drifted off topic here Steve

However, the short answer is - it varies from type to type. Also, remember that correct initialization also requires the Tx to have found, acquired, and secured free channel(s) before it and the rx talk to each other. On some of my spekky receivers , this can take several seconds.

 

 

 

 

It may appear off topic at first.

 

However, I have a spring loaded battery pack in my plane, making a perfect approach, when suddenly turbulence smacks the wheels down hard. The angle the pack is mounted at, in relation to the bounce of the aircraft, compresses one spring, causing the pack to briefly go to zero voltage.

 

Now my plane is at a low speed, low throttle, nose high attitude while I wait for the receiver to come online.

 

Of course it has never happened, and no doubt could be shown to be impossible. And of course the bounce could have caused a welded pack to come loose.

 

Any accident is only one event away from occurring.

 

The choice experienced people make, and the consequences, if any, of those choices is up to them entirely.

 

I just hope that any new flyers reading this thread make the wise and correct choice for their circumstances.