Peter Beeney

Regarding the control surface flutter, Martin, the is main reason I spend a bit of time on the control geometry first is to try and make the movement of the surface as secure and as rigid as possible in an attempt to help prevent it getting into a wobble in the first instance. In very general terms the types of model that might be likely to suffer control surface flutter, such as fast WW2 fighters etc. fortunately lend themselves to this sort of tinkering, in terms of generally requiring reduced throws. I’ve personally never owned a model that has experienced any flutter, but I have seen, (and heard!) it happen a few times, and indeed I was flying someone else's model once, the first flight of a Spitfire, when the dreaded buzzing started and within seconds it had taken the complete rear half of the fuselage right off! On another occasion, an Acrowot this time, the fin and tailplane were found to still be hanging by the (plastic) clevises, themselves still intact and attached to the servos, when it finally came to rest in the top of a small apple tree. With respect to the screw type connectors I do admit there are some types I probably wouldn’t use from choice, they seem to require some careful assembly to make them work properly; as I said, for me the correct size servo arm hole is a good start. Also I don’t use choc. blocks as push rod connectors, just electrical connections; I use a good brand, after all a strip of each size will last a very long time. But again, I will agree that you have be careful, some of these are made of what appears to be a ‘brass lookalike’ material, about one grade up from hard plasticine, and if you are a bit over enthusiastic when tightening the screws it’s possible to split the body underneath. Re: your OP, I do find it quite remarkable that these retaining screws can slacken off in such a short period of time. Although, as you say, if this does happen frequently then an alternative fixing is certainly the best idea, as this would always be an area that a pilot was always wondering about, to say the very least! Also I learnt a long time ago not to rely on anything someone else says anyway, particularly beginners. Way back a new learner assured me he was on a particular frequency, but as it happened he wasn’t; later we had a near miss, another mate at the patch came to me with a little glitching problem which was the frequency clash, but no harm done fortunately; since then I’ve never bothered to even ask, I just check everything myself first… And just to add a rider to that, in those days my tx, a MPX, had a built in frequency scanner so I also made a point of checking transmissions with that as well. On one occasion I did find one tx xtal that was clearly marked as 62, when in fact it was transmitting on 61. We only discovered this because the owner couldn’t get his radio to work, though. But a pair of incorrectly labelled crystals could eventually indeed have some interesting repercussions… For me there are other rather more important areas of safety; receiver battery integrity and particularly their electrical connections for a start. I’ve nothing personal against the fuel tube clevis keepers at all, either, but I’ve never been that convinced that in the event they make a lot of difference to the security of the clevis anyhow; I prefer to just use a good quality clevis and insure that it’s properly snapped shut. Fly Safe.. PB

Just to add a another view in favour, I’d always use these connectors in preference to any other, with Z bends being the last in line. Although to be honest, I’ve never really had any trouble with any connector when they are installed correctly. I like the Great Planes screw connectors, and I always start by trying to the geometrics as accurate as I can, creating the shortest servo arm and longest control surface horn, but of course that’s not always possible if you want maximum surface movement. This means I have to decide which servo arm hole hole I’m going to use and I have a set of small drills to make the hole exactly the right size to accept the connector spigot. The Great Planes connectors have both a metal star washer fixing and a separate plastic washer, I use the plastic washer. As always, I’ve done my own primitive security checks on these, basically with a tommy bar and a pint of Guinness for extra beef, and I soon concluded that even if the holding screw is only pinched up it will hold sufficiently well enough without the pushrod moving to start to distort a standard Futaba servo arm; and then from there I also concluded that if there are strong enough forces going on within the model to start to bend said arm a slipping connector is the least of my worries! And as Denis Watkins remarked, they are so convenient to use into the bargain… Along the same sort of lines, once upon a time I did have a bit of a meddle with the ‘keepers’ on the quick links, with some quite surprising results here, too. I can certainly remember David Boddington making some very cryptic comments (from experience) about using fuel tube keepers on metal (or plastic) clevises years ago, something I also implicitly agreed with at the time. But then I always was a bit on the perverse side, I also use choc. blocks to make electrical connections in model planes… So for and against; as usual in the modelling world, probably best to just use the methods you are entirely happy with. PB

Geoff Sleath @03/03/2016 11:05:43 Yes indeed Geoff, I think it may well be possible that my charger is not being quite honest, but I’ve no way of really knowing. I’ll find someone with an internal resistance capable charger and try some comparisons, that might give me some indication. I’ve just tried a brand new straight out of the box nano tech 1000 3S and that came back with 16 - 20 - 22, total 58. After I’d charged it, 569mAh, I re-tested, 21 - 17 - 20, total 58. Then I switched off the charger supply and disconnected the pack, re-connected and re-test. I did that 5 times in all, the figures all stayed very similar but they gradually ticked down at each reading, I didn’t anticipate that, the main total readouts being; at start: 58 then 56 - 55 - 54 - 53 - 50. So what is going on here? Is it the battery, or is it the charger? This at least gives consistent readouts, if nothing else. However, if these are incorrect I’d tend to ignore them, better to have no information at all rather than false, perhaps. This stuff does seem all a bit sophisticated just to fly a model aeroplane; at what point do you actually do the readings, for instance? If I owned a known proven meter I’d only check it at the fully charged point anyway; l’d have thought there’s little point in any other; the resistance increases as the pack becomes further discharged so if I inadvertently checked at the fully discharged point I might be tempted to junk a perfectly serviceable pack… Of sightly more immediate concern, to me anyway, is a black-bag pack I’m looking at at the moment, the subject of another thread. One cell of three collapsed to zero, suddenly and without warning; ok in isolation, maybe, but is it all on it’s own? I’m now beginning to wonder… PB

Very briefly, the result of a re-run on the Overlander pack, as @02/03/2016 19:04:05. In the first instance, this lump had been dormant for quite a while, so I just topped it up to make sure it was fully charged and then consequently got the odd readings. I’ve now recharged it, taken the IR, discharged and retaken IR; as before. Readings this time after charge = 10 - 16 - 9, total 35. Discharge = 1969mAh. then 36 - 40 - 41, total 117. So the pack is now acting more or less normally, I guess, I think it’s possible the lay up had confused it. However, I still think I’d need to spend a fair amount of time juggling with these internal resistances before I could really make any sense of them. I think I’ll just carry on as before, that’s generally waiting ’til the model needs a bump start to get going, and then I’ll treat it to a shiny new box of watts… And from what I’ve noticed about other regular electric flyers at the patch, that’s exactly what they all do, too! PB

One technique used in the battery industry to examine a cell’s internal resistance is to give it a quick squirt of AC across the terminals and measure the resultant impedance. This can be done with the cell in service if necessary, I believe, and is far quicker than a standard capacity test discharge/charge cycle. This probably is reasonably simple, too, I once saw an article in a mag. with all the info. on making a cheap and cheerful DIY unit, for testing small consumer cells, but I didn’t study it at all. My charger does measure cell IR so I thought I might try and get it to work. I tried a brand new Turnigy nano-tech 3S 1300mAh 45-90C discharge High Discharge pack; and it’s also marked ‘matched’. All readings in milliohms. Fully charged the reading were 17 - 19 - 13, total 50. Discharged, capacity came back as 1220mAh at 1amp rate, 21 - 24 - 20, total 65. To get a comparison I found an old Overlander 3S 2200mAh SuperSport 30 -50C. Charged 34 - 36 - 36, total 106. Discharging the capacity yielded 1958mAh at 1.4 amp rate; and then, get this, an unusual little anomaly maybe: lower readings, 24 - 25 - 27, total 75. To check this is actually true, I’m repeating this exercise again. This pack is still serviceable after considerable use, although not flown for a while, it will fly a Riot, but only in learner mode really, it’s now just lethargic and a bit. Then I hung four random packs on, all 4S, a couple of Turnigy Nano-Tech 2200mAh 35 - 70C discharge, matched. These have all done a fair amount of hard service, mostly flat out down to flat, I tend not to consider their wellbeing at all. All fully charged and ready to roll again. The figures came back as 7 - 5 - 5 - 14, total 31. Second 17 - 12 - 13 - 9, total 51. Then a couple of Zippy Compact, 1800mAh, 40C series High Discharge rate, 25 - 25 - 25 -25, total 100. Second 26 - 27 - 24 - 26, total 103. I have to say that I’m not quite sure as yet how I can draw any form of meaningful results at all from this lot. I just fly the pack until it obviously is not worth bothering with anymore. Although it only takes a second or two to check it out I still don’t think I’ll be scrapping any packs on the advice of the internal resistance screen any time soon. Also my charger is only a consumer item, so there are no guarantees as to how accurate it is, but the charging/discharging operations seem to be well within acceptable limits, so I’ll accept these figures at face value, too. Back with some more worthless rubbish later… PB

fb3, I’ve always used a 2V lead acid as a glow driver, back in the early days it was a wet cell, but only because I had access to them. Then the Cyclon SLA came on the scene, the original Hawker Siddeley variety were excellent, I suspect the one you’ve just binned may have been one of these. But the present ones are still pretty good, and I just connect them with a standard length clip-on lead; and, just like you, I’ve never blown a plug, either. Again, way back when I traded with John D Haytree I always used Fox plugs, and they were always labelled 1.5V. Just for idle tinkering, once upon a time I gathered up a motley collection of 8 different plugs and tested the current flow at 2V. No two were the same, and they varied from 2 amps to 5.1 amps. This means they do rather like a bit of poke so I consider a low resistance source SLA to be a worthwhile investment. Then I left one connected in the clip for half an hour, just to see what would happen; it was still glowing bright orange, (8Ah cell), which is what I like to see. By this time the clip was almost glowing, too! Actually, this is probably the worst case, when the plug is tightened in the cylinder head this must act like a heat sink and therefor the plug element is only ever going to be slightly cooler. Over the years my glow clip has also started other pilots sometimes reluctant engines; I think it probably burns any neat fuel and oil residue off the element fairly smartly… I simply charge mine with the standard lipo charger, although set to lead acid of course, but particularly in the winter I occasionally raise the voltage to about 2.6V for a while with my bench supply unit to insure it’s kept well fed. SLA cells do tend to show a noticeable dislike to being kept for long periods in a discharge state; but I guess you already know this anyway. If you had 2.3V supply you could keep it permanently ‘floating’ across this, it keeps it in really good nick. Good Luck with whatever you do in the way of a glow driver… P B

Ian, It’s certainly very likely the battery needs a little encouragement, (or maybe a bit of a kicking, depending on your point of view!). Recharge it and see if it’s any better, it may indeed take a couple or more cycles. Without knowing any details of the capacity and charge/discharge rate etc. it’s difficult to forecast precise charge/discharge times but it sounds as though it should be better than this. Not a good idea to fly until you are really certain of the battery, I do know for certain sure this ‘sleepy’ new battery syndrome has resulted in the total demise of at least two brand new aeroplanes; which is why one of the little pieces of advice I’ve advocated for a long time is that all brand new receiver packs are well checked out before any air time because in both cases the batteries later proved to be right up to spec. Good Luck! PB

With the greatest respect, I can’t help but think this may be becoming a little overstated. According to my reckoning, (which may well be wrong!), looking at the case of the 1 amp discharge current, if the faulty cell resistance is (say) 1 ohm then 1 watt is being dissipated as heat. If the current was as low as 200 milliamps then the heat would be 40 milliwatts. Thinking about it, I’m not quite sure if it’s possible to actually reach any combination of current and resistance that would start to become problematic. On a discharge curve, that is.. Further to this point, I can say that I have discharged scrapped packs at a higher rate of knots, the interesting point has never been the pack, rather more the components used to make a load. When these start to gently glow you know you’ve got a good ‘un - as ken a might say! I wouldn’t generally stray far from this potential pyro demonstration when it’s on, but generally speaking it’s not long before the pack is running right out of puff anyway; and as it’s heading straight for the bin there seems to be little point in trying to consider it’s feelings… And I also now have to qualify all this by saying that I do recognise this is all at my own personal responsibility and risk and should definitely not be taken as any form of instruction or advice on discharging batteries!! As it happens just this minute I’ve been given another scrap pack, this is a 3S, 3Ah, ‘Wild Scorpion’ pack, no less! I don’t know it’s age, but it does imply that the charge rate is 10C, that’s 30 amps, so it may be a fairly up-to-date little warrior. The negative end cell has suddenly gone flat, 0.6V, that seems to be a fairly common failing. I suspect that it’s developed a short between the plates. I was going to going to lob it, but I’ll have a little fiddle about later and see if I can get some sort of handle. I never usually bother with stuff like cell resistance as it happens, so this might be a chance to see if I can come up with some meaningful figures. Meanwhile, where did I put that box of Swans … PB

I think you have it about right on the reverse charging idea, Allan, in all the the tinkering with cells that I’ve done over many years I’ve never been able to establish any cases of this happening whatsoever; although it’s perhaps easier to explain the mechanics of the thing rather than the chemistry in the first instance. The situation as I see it is that if the lower voltage cell is charged up to say 1 volt with the the pack in the discharging configuration it would simply discharge again with the good cells, the current flow is only going one way. The same thing also applies if this cell manages to charge up to 0.5 of a volt; or only 0.00005 of a volt… actually the merest suspicion of half of a gnat’s whisker of charge will just instantly discharge.. so the nett result of all this faffing around really means that (in my opinion at least, anyway,) the flat cell can never even begin to become reversed charged, in any sort of battery pack, anywhere. Back in the dawn of pre-history I did a number of primitive experiments on batteries and other r/c radio equipment to try and verify some of the theories I didn’t understand that were circulating at the time. Amongst them I tried to reverse charge nickel cells by charging them in reverse but I never succeeded in even getting a millivolt of charge to stick. Indeed, what actually constitutes a reverse charge anyway? There must be some minimum voltage and capacity it has to attain to qualify as being reversed charged. This, of course, is certainly not to say it can’t happen, however. Maybe someone can take a pack and reverse charge it, just like that.. I’d not be in the least surprised. Certainly wet lead acid cells can occasionally take a degree of back-to-front working, I have seen this for real. In one particular classic case one cell was connected the wrong way round in a large battery and was in operation for some period of time. But it did cause persistent odd unexplained problems and after poking around for a while we discovered this maverick little scallywag. We changed it, - live, incidentally, which was always an interesting procedure in itself, it always got the adrenalin flowing nicely - and after much kicking around later it proved to be virtually unharmed; and it rectified the faults into the bargain. Much the same as the nicads that I was sometimes very ‘vigorous’ with. They always seemed to bounce back ok without batting an eyelid… Re: Tony’s OP, I’m often given packs to dispose of, and I just discharge them to 3V/cell (and a bit lower on a suitable nimh setting) on my charger and then short them out for a while. To all intends and purposes 3V is pretty flat anyway, and I’ve personally never had the slightest cause for concern. I take them to the local civic amenities site and when you see the myriad of different packs in the disposal bins there I guess that probably the biggest percentage most likely will still have some charge on them, at the very least. A modern battery recycling plant must surely be able to deftly handle everything that is thrown at it. As with others on the tread, too, I think the salt water theory is not at all good as I’ve always reckoned that the landfill contamination awareness arising may have been partly responsible for the declining fortunes of the nicad in the past, as it happens. I don’t have that many really green credentials, but I’d definitely considerer pouring possibly contaminated waste down the the drain not to be one of my brightest ideas. Just another random interpretation of events… PB

Dick, With the greatest respect, but I think that watt hours are indeed a measurement of power, not energy. It’s a convenient way of stating what power is available, or what has been used. For instance, your electricity bill is measured in kilowatt hours, it’s how much power you’ve used, but you might not have used it at the rate of one kilowatt per hour. I’m now going flying for a while, back later this afternoon to continue, perhaps… PB

I think you have to consider the principles on which an electric motor operates to understand the power consumption of said motor. With regard to 3S and 4S packs, for cells of identical capacity, say 2.2Ah, a 3S will contain 2.2Ah x 11.1 volts = 24.42 watt hours, a 4S becomes 2.2Ah x 14.8 volts = 32.56 watt hours; thus a 25% increase. Now it simply depends on the operator how he wishes to use the extra power. PB

Going a bit off song here, so apologies, but with regard to house fires it does seem as though the humble plug-in-the-wall-socket types of battery chargers are now frequently in the frame for this, too. I’ve noticed recently that the latest culprit is the rechargeable e-cigarette… it seems the chargers for these may have caused a few house fires. There surely has to be a touch of irony in here somewhere… or a moral, perhaps. I guess that relatively speaking these fires are few and far between, but because there must be so many of these types chargers in use at any one time, such as phones and other toys, it seems rather a lot. Many of these have their own built in fuse holder, which is a good start, but others don’t, which I think might be a potential fire risk. When you plug this into the socket the only protection now is the isolating device covering the ring main, be it fuse or circuit breaker etc., and I’m not entirely sure this strictly conforms to the regs anyway, as it happens. Therefore a full instantaneous short circuit in the charger could result in a brief current of at least a few kilowatts flowing, perhaps enough to cause a few sparks popping out. Or in other cases the charger might just get hot over time, maybe eventually enough to self ignite. I personally think this situation is best avoided if at all possible. So, as I said recently in a similar thread, rightly or wrongly, I would obtain a good quality two outlet adaptor, one with a built in fuse holder, and then use a 1 amp fuse. Not always that easy to come by, but our local 99p store always has them, (very versatile!), and you can also buy them here. 1 amp may seem a bit delicate, but the fusing factor of a wired fuse is 2, so a 1 amp actually blows at 2 amps, and at 230 volts that’s still the thick end of half a kilowatt anyway. Plenty to get an electric fag well lit up, I reckon, even in a howling gale! Now at least the charger is covered by a low current fuse, so at least it does stand a chance in what I do admit is the unlikely event of a fault developing. But it can happen, a friend nearly had his house alight, and although it was for a slightly different reason, there was absolutely no doubt that it was a seriously faulty wall-plug charger, together with the lack of appropriate fusing, that caused it… PB

Spikey, It might well be be your problem is the fact that the blanket controller contains some diacs and triacs. These are used in controlling mains power, such as light dimmers etc. They are fairly prone to causing main-borne interference, and to combat this they would probably have interference suppression circuits built in. However, maybe the manufacturer has been a bit minimalist in providing these filters, only just what is required by the regs because it all adds to the cost; normally, I suspect, it would be sufficient, though. Your clock radio is also going to have a high input impedance, and because these two supplies are so close together in the extension lead the interference is able to occasionally trip the input to the clock. Does the clock only go off when the radio isn’t on? As suggested by Dave Hopkin, a filter of some sort, extension lead or plug in, might well do the trick. Mains interference can cause problems, we had a few head scratching moments some years ago, when I was working; and, oddly enough, it certainly wasn’t always the worst trace that showed when checking the mains with an oscilloscope. One case involved walking around the locality for a fair distance until we found a small unit printing tee shirts… …using thyristor controlled ovens! But this was hardly visible on the ‘scope trace. A colleague also had some problems at a very sensitive site, the culprit being a local factory with some massive mains contactors that crashed in and out. He eventually solved it by using UPS’s (Uninterruptible Power Supply) where necessary. In this case, they were simply acting like large filters. But as switched power supplies became more popular this was the complete answer. PB Apologies, my answer is a bit late. Glad you’ve cracked it!

Jack, I have a colleague that runs a four stroke with exactly your arrangement and his has been ok; but having said that he’s never had an incident of engine detonation to test it. When the engine is running normally the prop nut will constantly be tightened by the engine’s motion, it will never become undone, but if it stops suddenly, (cause - detonation!), the energy in the fast moving prop will cause it to unwind, often in quite a spectacular manner, it can fly forward a fair distance at speed. Also engine starters, when they are in good form, can spin off the prop because the starter is trying to undo the nut, again at fairly high speed and usually across the pits area; but this can apply to two stokes as well. So it’s quite important to makes sure the prop nut(s) are as tight as possible in the first instance. One small point, detonation will only generally occur when the engine is running near/at flat out. Thus it really is seriously a good idea to never ever stand in front of a running engine under any circumstances, that is your good self or anyone else. A locknut, of any sort, probably helps, but it’s still no guarantee, I’ve seen one instance where the clinch type lock nut, as in photo 1, was taken straight off as well, just as if it wasn’t on, and I’ve heard of other similar cases. And there was a case reported that someone was quite badly hurt when he was standing in front of a running four stoke. He open the throttle and ‘bang’, the prop buried itself in his thigh, and the spinner cone made a hole in his chest. This was a few years ago, now. Therefore provided I always took note of my own advice, and that’s not always a certain thing I have to admit, I would be quite happy to run your installation as it is. I believe Laser engines have a wedge shaped combustion chamber, which very much helps to prevent detonation; and I suppose in theory that the prop could be thrown off if the throttle was shut quickly enough. But for a variety of reasons the engine progressively slows down, so I’d think this an unlikely event; although it might happen with electric motors in some circumstances. PB

Pete, With respect, but I think that 5lb is actually 80 ounces… 70oz weighs in at 4lb 6oz - and to be utterly ruthless I measure the wing span from the wing root to the tip. I suspect in your case the given 48 inches is the total measurement right across the bottom of the wing. I’m sure the fuselage does contribute to the lift but I ignore this, then I know exactly what the wing area and consequently the loading is, at least. Any extra lift will then be a bonus. So if the fuz is a couple of inches wide I’d call one wing 23 inches span and double it. I always measure everything because I’m always interested in the wing loading; and occasionally models differ from the dimensions given. I can remember that one model, I think it was a trainer type, the span was given as 65 inches but it was actually only 60, however you measured it; that could now start to make a difference to the loading; and if the were other errors, such as the estimated weight they could be cumulative and then this could give some slightly false data. Small, low wing war bird style models with high wing loadings are always going to be ‘interesting‘ to fly. We flew off a tarmac runway for years, so with care models would invariably get in the air, which was perhaps sometimes a bit unfortunate because on more than one occasion I did wonder if I was going to get it back down again in one piece! I’ve just read Pat’s post, and I think I can align exactly with that. I use to watch and talk to some aerobatic lads, they flew larger models but even so the lengths they would go to to reduce weight, especially at the back end, were quite remarkable. PB

Pete, Having had some experience of this sort of aeroplane over the years, I’d tend to say this looks like it might be a bit of a handful, to say the least. Hazarding a very rough guess that the average wing cord is in the region of eight inches, at forty eight inch span and six pounds in weight that gives it a wing loading of thirty six ounces to the square foot! If it gets off the ground powered by a 25, which in itself might prove to be a minor miracle anyway, it will probably fairly fast…… but only when it’s going down a steep hill! Everywhere else it will tend to appear to be grossly underpowered; in my view anyway. With this sort of wingspan I’d consider that 4lbs, or maybe a bit less is a reasonable weight; and powered by a good 46 on a 10 x 7 or perhaps even an 8, it will fly fast, with a good vertical performance for really big loops and wingovers etc. But even then you do need to keep the relative speed up at all times, I certainly wouldn’t want to fluff around for a second on a landing approach, say. It’s ok to play around at the stall at height, it’s the incipient wing drop when you’re very close to the ground you want to try and avoid. Good luck. PB

You might try sending Century a friendly sort of email, Craig, explaining what’s occurring, I’m sure they will understand the fault, whatever it is; and then as they did with us, they might agree to send you a new one. You certainly can’t lose anything by it at least … Electronic equipment does sometimes fail on switch on. You’re unlikely to make it malfunction in a crash, a knock won’t hurt it unless it’s physically damaged. But judging from the number of failures overall that I’ve seen in the past it’s possible the quality control may have been missing a few checks here and there, although that may now be improving. Good quality solid state kit these days is ultra reliable and can also operate for a very long time. Taking a simple linear voltage regulator that costs only a few pence as an example, short of a close encounter with a hammer, or a deliberate high voltage overload, forward or reversed, you cannot break it……and it will probably tick away doing it’s thing almost to infinity. As I’ve said before, being cynical, I often wonder if the model trade in general is probably not that much concerned about the odd mishap or many… Good luck. PB Edited By Peter Beeney on 19/12/2014 21:57:22

We had a spot of hassle with a Riot used for training, although this was a slightly different MO. The motor would just occasionally stop and start in mid flight and in a completely random manner. I thought at first it was indeed the motor that was faulty, but a substitution check proved it to be the ESC. I emailed Century with the exact details and they instantly replaced it FOC, the new item was back the next day. It also cured the fault. I’ve found that substitution is often the quickest way of finding these gremlins, and it sounds to me as though your aggravator isn’t going away any time soon. But I also do appreciate that’s very easy to say when I’ve got some odd kit just lying around, such as two Riots for a start. When things like this happen for no apparent reason I’d tend to think maybe something has gone a bit u/s. Although I might just try swapping the throttle servo over with one of the others, just to make sure that the throttle stick/channel is actually operating and hasn’t become isolated in some way. Or even checking for the right memory, perhaps… Good luck. PB

John, As I said, I’m not into powerboxes, but I don’t think it’s a case of the PowerBox not recognising battery chemistry. The led monitor is recognising very small voltage drops across the pack as the servos operate when you stir the sticks. You suggested you might use extension leads to couple up the new packs; unfortunately this doesn’t really help the situation, either. Somehow you need to find out exactly what the magnitude is of these drops, as in actual volts, using a voltmeter, and what part of the circuit is causing them, although I’d perhaps consider that it’s unlikely that it’s now actually the cells themselves; so it might be that the unit itself is suspect. Just one other thing, the Hextronik display is dual function, LiPo and LiFe, the switch between the two is a tiny touch confusing, and if you get it wrong it can tend to seriously lead you up the garden path for a while… however, I’m sure you’ve already made sure this is correct on your device… This probably doesn’t get you much further on, I’m sorry to say, it now needs a spot of tinkering with to crack it, I guess. PB

John, On the face of it, it would appear that your power box is perhaps trying to tell you that your batteries are beginning to show their age, is that a possibility? One way you might be able to check it out is with one of these. They are certainly cheap enough, and from our experiences really excellent pieces of kit. Simply remove the powerbox connection from the rx, plug one battery straight in with the Hextronik monitor, you can use a Y lead if you’ve no spare ports, wiggle the sticks and see if this still runs up and down the leds. If this is the case then the odds are that the batteries are suspect, or if it now remains in the solid green the powerbox might stand a coat of looking at; plus the wiring, switches and everything else in the circuit as well. I’ve never considered PowerBox, I’ve never really seen any advantage in using one, but I would think that the led part of the indicator is just a voltmeter, with a scale over maybe just one volt; so by definition it will monitor and thus indicate very small changes. All circuits have resistance, and as current flows through this resistance the voltage is proportionally dropped across it. Batteries inherently have very a very low resistance, and therefore low voltage drop, Life’s are particularly good, which is why they are able to deliver high current rates without the voltage becoming too low. Also, of course, it allows you to recharge at relatively high current rates. A battery failure is caused by it’s internal resistance going higher, sometimes due to age, maybe this is beginning to happen to yours, so this is why it’s possible that it’s causing these voltage fluctuations. I personally wouldn’t have a problem with this particularly, I’ve seen it before, usually with nimh cells, and in the event it’s not been a problem. However, after reading your pasted instructions relating to this box of tricks……It looks to me like a bit less of the PowerBox and a bit more of the Pandora’s Box… Some chargers now are able to read the internal resistance of cells but of course you would have to know what it should be in the first instance. And the degree to which it safely deteriorate, if there is one. This could be a little bit confusing. We’ve been using Life receiver packs now for some time, and so far they’ve shown an exemplary performance, although there has been a report or two about some failures. Maybe the straight answer is to just buy a couple of reputable packs and try them. I personally would not be entirely convinced that LiPo packs, in this situation, would be any particular advantage. Good luck! PB

And at least one manufacturer, I think it was Kontronic, at one time produced an ESC, (for planes), that would drive a brushed or brushless motor, as I remember it just sensed which type you’d connected it to, two or three wires. PB PS Brushed motor also AC. Edited By Peter Beeney on 09/12/2014 11:22:35

Because in some ways they may be similar, it may be interesting to compare the Max Thrust Riot pulling potential with this one, the Riot uses an 850 kV motor and a 12 x 6 plastic flexible propeller; and generally, I believe, a 3S 2200 mAh battery pack; also a 40A ESC is part of the power train. The motor is probably rated at around 300 - 350 watts, or 25 - 30 amps x 3S. The model’s AUW is 3lbs and that gives it a wing loading of between maybe 13 - 14 per square foot, although this is only an intuitive guess on my part, though. Another stab in the dark, too, if perhaps the prop reduces the kV to around 750 rpm, then on a 3S, 11.1V, this gives it a straight and level speed of around 45 mph. Which could explain why the Riot’s gait does occasionally seem to be a touch on the leisurely side, but by the same token it has more than enough power for beginners struggling to tame it. By flying it in the gentlest of relaxed manners I managed to eke out 14 minutes of flying time on a 2200, including a glide down from height, but normally I limit each battery to 10 minutes. So on that basis I’d consider that by comparison a 10 x 6 on a 960 kV will be positively spritely, requiring plenty of judicious use of the throttle stick to enable the Meadow Skipper to fly in a manner fitting to it’s lineage, normally very sedately I would think. Relating to the ESC and the amount of current flowing I have a model which came with the kit installed already to go, as many models now so do. When I did a little check on this I found the supplied black plastic prop takes the current above the rating of the supplied ESC; however, this has now done many flights, and has never once shown any signs of distress. The ESC slides into a slot cut into the foam, which on the face of it does not seem like a good idea at all, but there an air inlet at the front of the slot so that air is forced in over the unit rather than round it. And that I think if it’s possible to arrange one of the more essentials requirements of electric flight, a good draught of air through the fuselage to keep the temperature within reasonable limits. Heat is the big killer of most things electrical, if they can be cooled sufficiently enough, and to do that sensibly it could be important to get the air to flow in the right places, many devices can be overloaded without coming to any harm. Incidentally, Pat, just to be a mite pedantic on my part, a watt meter is an ammeter is a voltmeter. Simply because an ammeter is a voltmeter…. PB

Exactly so, Phil, I fully concur; but I’ve also occasionally centred both props and backplates if necessary when I’ve not had anything else suitable to hand by carefully wrapping insulation tape around the shaft until it’s an exact fit. Very important to cut all the excess width off with new sharp blade though, so that it’s not compressed at all. This lash up may not be to everyone’s liking, but it’s always worked perfectly for me. For a nice neat fuel filler tube installation a fuel line shut off clamp is the bees knees. Fixed to the side of the fuz with a small screw, it works like a dream! PB

ceejay, I’m also worried about that full up elevator, too, it’s simply done in an attempt to get off the floor at at all, due to the spongy ground and very slow moving model; it just about manages to stagger into the air. This is indeed why I’m saying I do it carefully, I had one or two practical lessons about flick rolls on take off in the early days when I bought my first proportional radio, around 1970; and I’ve been diligently practising hard at avoiding this caper ever since… and, so far, the ‘yank it off’ technique has been successful every time. I quite agree about the scale like take off for scale models, but this one is only an ancient hack Uno Wot, and it won’t be a big loss if I break it anyway. As it happens, I’ve usually found scale models like Spifires and others are often something of a pussy cat when taking off and flying, but there can occasionally be some interesting exceptions; although perhaps it’s invariably the small short coupled biplanes with lots of eager power and a propensity to attempt a torque roll whilst still on the ground that can really captivate your full attention. I certainly try not to zig zag models while taking off, simply by moving the sticks as necessary, slow, fast, or whatever, to keep it going in a straight line. Some model stats; only for interest, really. It came with a 10 x 6 prop, which I thought was a bit OTT, so I changed it for a 9 x 6 ACP. This turns at 12.5k, so a potential speed up to 70 mph; and indeed once it’s flying it is quite nice and lively, so I reckon that together with the rather precise landing approach required this will be just the ticket for improvers wishing to start turning up the wick a modicum. OS spec the motor for 0.84 bhp at 18000 rpm, these sort of revs might be a bit tricky to achieve, but I may well try other props, if a 9 x 5 will spin at around 14.5k I’ll still have more or less the same sort of speed but perhaps a little more inspiration to get off the ground quicker; and if I consider the standard rule of thumb that says to allow 10% extra for unloading in the air I haven’t lost very much at all. Electrical power is supplied by what now must be a rather ancient 4 cell 800 mAh nicad, which has probably seen better days, but is still around 90% capacity. After 3 full length agile flights, 20 min each?, I’ve not timed them yet, it’s down about 200 mAh. The tank is the square blue fronted Slec type, is that a 9 oz? So all in all, and in answer to the Paul’s OP, I’ll join the consensus of opinion and say practise + practise makes perfect. But once you have full confidence and you’ve got the right prop on the motor which is on full song, on a tarmac runway into a gentle headwind you’ll be able to nip off so fast it won’t really have time to swing about; and you’ll then be wondering what all the fuss was about… PB

Yes indeed, and with the greatest respect, I think I might also take the slightly different view, too. A motor runs fastest at it’s unloaded speed, then any load applied, such as a propeller, will cause it to run slower, the speed becoming directly proportional to the load. This in turn enables more current to flow, thus producing more torque and compensating for the speed loss. This results in there being just one point on the power output curve where the motor is producing it’s maximum power, this can be established by testing with a dynamometer, unfortunately these figures seem to be very infrequently given in the specs. A motor’s most efficient running point on the curve, (not normally max output), is usually quite close to the no load speed. This implies we are just talking about permanent magnet brushless motors of course, PB