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Member postings for Keith Miles 2

Here is a list of all the postings Keith Miles 2 has made in our forums. Click on a thread name to jump to the thread.

Thread: Help! Can't charge my Lipo
11/07/2020 22:57:36
Posted by Mike Blandford on 11/07/2020 22:12:22:

Keith: I use audio reports so don't need to look at the Tx while flying. Most are enabled by a switch so I can turn them off. The one item I find most useful is capacity used. That way I know how much battery is left.

Mike

Again, fine, if you have a suitably capable transmitter, or are willing to buy one!

11/07/2020 22:44:56

David, sounds very good indeed as long as you didn’t over-discharge the Lipo! Unlikely if you have a working voltage cut-off in the ESC, something which is probably best not tested in the air! As far as I am aware, if this cuts in, the motor should stop but leaving just enough power for the receiver and servos to get you back to terra firma!

A point about battery capacity checking, something which has come up in this forum in the past. The capacity check facility is a bit of a misnomer because it is, in fact, measuring voltage and, as such, is not as reliable or accurate as monitoring the amount of charge (mah) that you put back into the battery after a flight. There is no means of measuring capacity directly whatever you might hear to the contrary.

On battery care, and opinions may differ, I would say keep no less than 25% capacity in reserve in order to extend the life of your batteries, more if possible. Discard any Lipo with any cell at 3v or less. Never charge Lipo cells above 4.2v (correct charger setting will prevent this). Use “Balance Charge” for all multi-cell Lipos. Do not store Lipos discharged. Do not store fully charged Lipos for more than a few days but use the “Storage Charge” facility of your charger (it is there for a reason). And Lipos are not dangerous if you treat them with due respect and care!

Oh, and warm, or cool, components are fine. Hot ones aren’t!

Happy landings!

Edited By Keith Miles 2 on 11/07/2020 22:50:08

Thread: Flaps. Servo speed.
11/07/2020 21:35:58
Posted by Richard Clark 2 on 11/07/2020 18:47:03:

Perhaps surprisingly I've never flown any Cessna, nor been a passenger in one.

As for the flap to elevator compensation moving the elevator fast when the full amount of the 'slow' flap part has not yet arrived at the mixer so is not yet 'known' by it I don't see how that can happen.

Did I say that or are you quoting someone else? Sorry if I misunderstood.

In my case, I have yet to use a mix, so can’t comment on that at all. First impressions suggested that I might not need it. A club mate has a Hangar 9 Cirrus and I asked him for advice on this issue before I test flew my Super Chipmunk. He doesn’t use a mix either.

Thread: Help! Can't charge my Lipo
11/07/2020 21:21:42
Posted by Mike Blandford on 11/07/2020 16:06:00:

You haven't mentioned what radio gear you are using. Many modern radios include telemetry back from the model. With suitable sensors you can get the flight pack voltage and the motor current displayed (and even spoken). This may well avoid the need for a wattmeter. I have one, but haven't used it for a long time as I use the telemetry.

Recently I've started using FrSky Neuron speed controllers with FrSky radio gear. The Neuron has built in sensors and sends voltage, current, RPM, capacity used and temperature back.

Mike

Telemetry is all well and good if you are prepared to buy and fit the necessary sensors or the type of ESC you describe to each and every model and it can be fully justified as opposed to it being just a fancy and unnecessary additional gizmo.

Each to their own, but I also prefer not to have too many potential distractions when I’m flying! I prefer to pay attention to what I and the model are doing rather than be tempted to pay undue amounts of attention to the transmitter.

Also, for some, a wattmeter, being a universal device, is simpler, perfectly adequate and probably more cost effective especially if you only fly models that are already set up or fitted with the recommended components which should not need in-flight monitoring.

Beginners are also better off with simplicity than complexity, in my view.

11/07/2020 14:28:12
Posted by David Ramsden on 11/07/2020 10:48:18:

Thanks again Simon and Richard. I flew IC powered r/c and slope soarers in the 70's and took up slope soaring again just recently. This is my first electric set up.

I like the idea of a watt meter. Can I use my multi meter(?) and if so how, or, is it better to buy something more dedicated to the task - maybe something that could connect into the Deans connectors? Do such things exist?

Thanks

David

Ah, so not a complete beginner, then? Welcome back! Sorry if I told you anything you know already!

I doubt that your multimeter will be of much use, in this context, unless it has a high current capability and substantially sized cables!

For the average electric model you will be measuring tens of amps, at least, at full power e.g. 500 watts on a 3s battery equates to a current draw of 45 amps and 500 watts on a 2s battery would be almost 68 amps.

And bear in mind, as already mentioned that it would take about six minutes to totally flatten a 1600 mah battery at a continuous current of just 16 amps and similarly, a 2900 mah battery would be totally flat after six minutes at a continuous current of 29 amps. It is not good to discharge a Lipo more than 75% and not good to fly a model until any low voltage cut-off operates!

For current measuring, you could use a clamp meter although decent ones are not cheap.

Yes, such things as wattmeters do indeed exist (available from model shops or online) but you might need to solder on your own preferred connectors to suit your set up or make up adaptor leads (with appropriately current rated cable) as required. Electric flight does have more complexities than IC or non-powered gliders and slope soarers. Connector types are numerous and soldering equipment and skills are an inherent part of it. And it doesn’t end there as you are already discovering!

The wattmeter’s primary role is to ensure that you are obtaining maximum efficiency from your power set up as well as ensuring that you do not pull more current than the components and the wiring will withstand and a very easy way to create overload, and possible fire, is by fitting a prop of greater diameter or pitch without monitoring the increased electrical load!

A ready to fly model, however, should not need such checking if left as it is, unless of course, a fault is suspected so you might not yet need to buy a wattmeter at this stage.

 

Edited By Keith Miles 2 on 11/07/2020 14:31:42

Thread: Flaps. Servo speed.
11/07/2020 12:34:05

I fly full size, too. Cessnas have powered flaps with gradual deployment. Pipers are manual with instant deployment. In practice, I find any pitch change is easily controlled in either case as you tend to both feel it and see it and then compensate with elevator automatically before re-trimming.

Of course, you have no “feel” with a model, so I suppose it depends on how much pitch effect a given amount of flap has on a particular model (and you probably won’t know that until you try it) and how much correcting pitch trim is required.

For my first, and currently only, flapped model, I opted for “book” setting and slow two-stage deployment using the timer on my DX9 purely to allow maximum reaction time to make any necessary pitch correction. I’ve only flown it a few times so the experiment continues. Thus far, I have found that I can comfortably control the model with just power and elevator without adding trim or needing a mix.

I suppose, as with other things, it ultimately comes down to personal preference and Tx features although I suspect that gradual flap deployment might be generally preferable on a model, notwithstanding the possible difficulty mentioned if an elevator/flap mix is desired.

Thread: Help! Can't charge my Lipo
11/07/2020 11:16:13
Posted by Bruce Collinson on 11/07/2020 10:15:38:

David,

I was where you are four years ago. Some of what I have learnt, partly the hard way, might help.

On balance (sorry) I think it wasn’t totally unreasonable for the retailer to direct you to the widely advocated method of reviving a low cell by zapping a NiMh charge into it, I’ve tried it, with initial success but ultimate failure.

A few points.

Learning from other people’s mistakes is certainly good advice and in that context.....

It was (sorry) a mistake, and arguably irresponsible, for a retailer, especially, to advise a “widely advocated” as opposed to a manufacturer approved method of charging a Lipo. As you said yourself, you tried it, and failed, presumably, and perhaps luckily, without injuring yourself or causing damage, so your support of the retailer, in this case, seems somewhat contradictory.

It is also not reasonable for a retailer to fail to immediately offer a refund for, or replacement of, goods that are clearly faulty, as supplied, especially relatively volatile Lipo batteries!

As I alluded to in an earlier post, any deviation from a manufacturer’s advice or instructions puts us in experimental territory and we only have ourselves to blame if the experiment fails or results in a serious incident.

11/07/2020 10:06:14

David, just echoing what Richard has said, if you are new to model flying, I would not recommend trying to teach yourself, it is likely to end in tears, and possibly not just yours! Also, flying in close proximity to housing or the public is also not to be recommended and might, in fact, be either illegal or in breach of local bylaws, or both!

I am assuming that you are also aware of the new CAA regulations regarding registration of both model aircraft and pilots, regulations which have come about as the result of the Gatwick “drone” incident?

If not, you NEED to be before flying ANY RC model aircraft!

10/07/2020 20:16:15
Posted by David Ramsden on 10/07/2020 19:34:05:

Thanks everyone.
Simon - I might be wrong but I don't think my charger displays the individual voltages of each cell during and at the end of charge (bear in mind this is my first time using any Lipo charger). It did though show the pack voltage during charge which I monitored.

I have just ordered one directly from Overlander.

To be fair to Wireless-Madness, they did sound reasonable on the phone and they've not hesitated in recommending a refund. On balance though (and being a cautious sort of chap), I'm not impressed with their advice. The amount of experience amongst forum members must be immense and you are all kind enough to give free advice (which I have followed on this and other questions). Thank you all very much indeed.

That’s what we’re here for, well, mostly!

Many things might be, or are, debatable but battery characteristics are established science and if you deviate from official instructions regarding their use you put yourself into experimental territory even if you have expertise and know what you are doing!

If you have no individual cell check facility on your charger, or even if you do, I can only again highly recommend a battery checker. They are not expensive but very useful for quickly and easily checking your batteries. And on that point, though some will disagree, be particularly wary of Far Eastern suppliers (of anything!) on E-bay and, preferably, buy from a reputable model shop or supplier who will provide you with a genuine article, not a clone, and a likely more reliable and professional customer service! You can probably add a checker to your Overlander order. Check their website and give them a call. And, no, I don’t work for them!

And finally, as well as this forum, there is plenty of information for beginners online regarding Lipos and electric RC in general which will provide you with a great deal of very useful basic knowledge about the hobby and the components used. Hopefully, you will be in a better position, then, to take a more informed view of advice received and to judge the possible motives that might be influencing it!

P.S. Just checked and Overlander still do a decent checker for £14.99. Add a Lipo bag and the optional temperature probe (if you don’t have one) for your charger and you will have all of the basic safety factors pretty much covered! Oh, and DO read all instructions!

Edited By Keith Miles 2 on 10/07/2020 20:48:49

Thread: Has Your Club Made Any Decisions Regarding The Coronavirus?
10/07/2020 19:29:18
Posted by Denis Watkins on 10/07/2020 17:08:59:

The lads have to test negative before every meeting Keith

Or they cannot play

They also have a strict " bubble " regime, all agreed months ago

Lucky them, if that’s the case.

Bet, though, that there are more than a few frustrated people who might consider themselves more worthy of the same attention and opportunity to be regularly tested.

Thread: Help! Can't charge my Lipo
10/07/2020 17:25:41
Posted by David Ramsden on 10/07/2020 16:16:25:

The battery in question is outdoors and Wireless-Madness have asked me to "Open a Returns Case" on Ebay. They will arrange for Hermes to collect it from me.
Dee from Wireless-Madness just told me on the phone that people on forums are often over cautious with regard to Lipos and that packs with a low voltage cell can usually be recovered and thereafter work fine. He said between 1 in 100 and 1 in 1000 overlander batteries are like this and once recovered (by the process they talked me through) are fine.

That advice seems directly contrary to all the advice I've received on this forum.

As a complete novice, it is baffling to be confronted with this situation with my very first battery and charger. I am sending the battery back but obviously I still want one!

Who would you go to for a good overlander 2900mah 3s by mail order?

Firstly, if you what you say is true, I would get a refund and never again seek advice from Dee or Adam or, perhaps, anyone else who works for Wireless Madness! Perhaps they are aptly named?

”Over cautious”? No. Scientific fact that when a Lipo cell discharges to 3v or less, the internal chemistry deteriorates. This is also the case with batteries in general but Lipos require particular care as the chemistry is more volatile. This is widely understood within the model flying community and I am baffled that a company would embarrass itself and potentially damage its business by providing such poor, and potentially dangerous advice, especially to a beginner! Then again, they might not have tried it with an experienced flyer!

If you remain unsure, there is plenty of information on line about Lipos and not necessarily associated with any retail business! It is a common mantra that Lipos require a Lipo dedicated charger. Period. Multi-chargers are set up to suit specific individual chemistries and have inbuilt safety features for each individual battery type. Charging a battery, or attempting to, with a charger/battery mismatch is not only misusing both battery and charger but could be dangerous in addition to invalidating the warranties of both!

Do you have to have an Overlander 2900? If so, or you just want to keep things simple for now, you can order direct from them via their website. In fact, as long established suppliers of batteries, with a pretty good reputation, you could even ask their opinion of the advice that you were given by the aforementioned duo, especially the bit about recovering the occasional low cell (that 1 in 100 or 1000) rather than the alternative of simply returning it to Overlander for a refund or replacement!

The choice of possible alternatives to an Overlander 2900 might be a little baffling at first, as you probably need to consider similar dimensions and C ratings, for starters and, as in all things, whilst expensive might not mean best, cheap might not be good either and, again, opinions can vary about various makes!

Welcome to the jungle!

Edited By Keith Miles 2 on 10/07/2020 17:43:07

10/07/2020 15:55:02
Posted by Keith Miles 2 on 10/07/2020 15:22:31:

If you want to see what can happen when you mistreat a Lipo, you will find a number of clips on YouTube!

P.S. Oh, I see someone has since posted such a clip!

Not only did he do it twice, he didn't put a door on his 'fireproof' cabinet.

Dumb or what?

Richard Clark, yes, indeed!

And I had edited my post before seeing your reply.

There are “professionals” and “enthusiastic amateurs” and some of the latter might claim to be the former!

Edited By Keith Miles 2 on 10/07/2020 15:57:08

10/07/2020 15:22:31

Agree with others.

NEVER take chances with any LiPo!

Cells should be balance charged and kept in balance for a reason and once any cell has dropped below 3 volts it is likely to have already suffered damage and should be discarded.

Furthermore a Lipo cell should NEVER be charged above 4.2 volts and any significant voltage differences between cells is also something to be very wary of.

And NEVER use any setting on a charger other than the correct setting for the battery type and cell count/voltage!

A good battery and charger and correct use of both will avoid potential dangers!

I would also suggest that you get yourself a battery checker. Plenty of choice. Pocket sized and more convenient to use than a multimeter.

If you want to see what can happen when you mistreat a Lipo, you will find a number of clips on YouTube!

P.S. Oh, I see someone has since posted such a clip and having watched it, and despite claims, in the clip, that the victim is a “professional”, human error cannot be ruled out especially as this was, apparently, his second such experience! My view is that if Lipos are inherently dangerous and unpredictable they would not be on sale! 

 

Edited By Keith Miles 2 on 10/07/2020 15:25:53

Edited By Keith Miles 2 on 10/07/2020 15:47:28

Thread: Has Your Club Made Any Decisions Regarding The Coronavirus?
10/07/2020 14:31:43

A related issue, albeit slightly off topic.

Anyone watching “Match Of The Day” might have just cause for wondering if a certain group of people have been officially exempted from following or complying with government advice and, if so, why? Other than the absence of spectators, it looks like business as usual to me and in the seemingly complete absence of any criticism within the media or by politicians.

It hardly sends out a consistent message to the public, nor does it help to combat the conspiracy theorists or the persuading of the irresponsible and the selfish.

Perhaps it’s a cricket preferring Tory government conspiracy to kill off footballers?

Thread: Returning after a 20 year absence!
30/06/2020 15:38:51
Posted by Rogeo1983 on 29/06/2020 23:25:57

I had the carb put through a cleaner, heated it and it freed up. But as soon as it cooled it seized again. Ill use the new engine, and keep that one for parts.

That is very, very strange!

I gather, from your previous posts, that you used this engine in the past and that, presumably, it was previously okay? Carb barrels are not usually such close tolerance items and I’ve never heard of barrel expansion or shrinking manifolds! Ruling out corrosion, the only other thing I can think of is ovality in the manifold or barrel but unless you know somebody with the relevant measuring equipment, it might have to remain a mystery!

Would love to know, though!

Good luck with the rest of your project(s)!

Thread: The great i.c. / electric finger chopping debate
23/06/2020 13:39:38

Just been reading through some “incident” posts as suggested by JD8.

Whilst equipment has improved since most of those posts were made, it hasn’t changed my view, but rather confirmed it, that EP, due to its very nature, has a much greater chance of suddenly bursting into life causing an accident and certainly requires much greater vigilance and care in terms of setting up the Tx and Rx.

And as for powering up, setting up or testing a model indoors (not exactly practical with IC!), with the propellor fitted, why take such a risk?

And nothing in this thread should be viewed as part of the traditional EP versus IC debate, or as a competition, but rather about simply fully recognising the very real dangers of each and applying the appropriate safety precautions to each.

23/06/2020 11:17:53

Perhaps another appropriate summarising phrase would be “familiarity breeds contempt”?

22/06/2020 23:15:35

JD8,

I’ll have a look at that but I was also thinking in terms of compiled statistics, a bit much to ask perhaps, though.

FlyBoy3,

A fellow club member made a similar point about lockdown boredom to me, earlier, which brings me to.....

Hello, Dave,

I trust your intentions were entirely honourable (said he, with tongue slightly in cheek) and I totally agree with your long awaited summary!

In my view, there is also a difference between safety features which address, or attempt to address, inherent electrical, mechanical or design issues and those which, similarly, might be more about addressing human factors.

At a more serious level, MCAS was primarily a technical intended solution in respect of the former whilst, at the same time, largely eliminating the latter, and we saw what happened there.

I remember an old truism from the back of an England’s Glory matchbox (remember those?) which read “It is human to err, but to really foul things up requires the use of a computer” or words to that effect.

K.I.S.S.?

No, not you, in either sense!

Edited By Keith Miles 2 on 22/06/2020 23:21:35

22/06/2020 20:17:03

Without wishing to appear combative or morbid, I would be genuinely interested to know more about accidents in general, both involving IC and EP.

Notwithstanding the issues associated with personal reputations or embarrassment, some form of reporting system could be very useful to all of us and I’m wondering if this has ever been an idea that has ever been put forward either within clubs or more widely.

Just a thought.

Edited By Keith Miles 2 on 22/06/2020 20:20:12

22/06/2020 17:30:17
GPosted by David P Williams on 22/06/2020 17:19:50:

Yep, drifted too far. I promised myself I wouldn't feed the troll, but I got sucked in.

I think “troll” is a rather unkind exaggeration in this context.

Threads often drift for reasons other than malevolence which the word implies.

And to get back on topic, in my view, and with no disrespect to the OP, I’m not sure that there would be much mileage in the original question, anyway, as both technologies will easily take your fingers off if you’re not careful. The only difference is that it should be easier to see one coming than the other!

At least a rattlesnake will usually warn you before it bites and as result of its inbuilt programming!

Edited By Keith Miles 2 on 22/06/2020 17:55:55

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