MattyB

Withdrawal from a market generally means products are no longer available there - nothing I have read indicates that is the case for HH in the UK at this time. Ultimately it is their right to supply the UK in whatever way they deem most efficient and effective; the only thing that customers who do not like the shutting of the UK offices and the potential knock on effect it may have on CS is to vote with your £££s and buy competitor products.

Posted by Denis Watkins on 26/03/2017 14:41:11: If you chuck that thing of a hill Jim, it could be the last time that you see it. If you ever go for powered flight, PM me for onfield instruction 30 miles from your location Sorry, that is complete nonsense. Have you ever flown slope? If so you would know that no aileron model with zero dihedral will go further than a few feet on the venturi of a slope before needing correction. In the hands of a beginner it is more likely to land 6 inches in front of him because it is not trimmed correctly than drift off into the distance. Jim, a quick Google led me to this thread on this very forum with the following info on Basildon Moor... Posted by JohnA on 12/11/2009 17:16:14: Baildon Moor is used for slope soaring. West (slightly North/west) facing slope is above shipley glen, just north of caravan site. Not greatest slope and there is power lines running diagonally across it, but has a great big flat landing area with minimal boulders. You need a permit to park up on moor but there is a small layby on the Elswick to Baildon road with a path running up to the slope. North facing slope is by the car park at the "summit" of the Baildon to Hawksworth road. Small cliff edge slope but can generate a lot of lift in right conditions. Beamsley Beacon used to be used (above the back road from Ilkley to Bolton Abbey) not sure these days but it is very rocky. ...so all you need to do is wander up there the next time there is a 5-12mph westerly or northerly wind and introduce yourself to the locals. Have them check out your plane and one of them will probably test fly and trim it for you before giving you a bit of instruction. Welcome to the slope brotherhood!  Edited By MattyB on 26/03/2017 16:06:11

Posted by Charles Pic on 24/03/2017 12:40:51: If more current is being drawn from one pack than the other, wouldn't the voltage of that pack want to reduce more quickly, leading to a balancing current travelling from the other pack (since they are joined in parallel with low resistance cable?) in other words, while joined in parallel, the load must be shared between the batteries in proportion to their capacities, as capacity defines how quickly the voltage decays while current is being drawn? In principle you are correct, but the condition of the batteries and ability to deliver current is significantly different you can have issues, especially if you are discharging to a low SOC (i.e. less than ~30% left in battery at the end of the flight).

Very very nice Andy! It'll never do a 30 second free flight round Edlesborough school hall though...

Agreed. If you sat down and added up all the charge and discharge time and compare it to the pre and post flight routine in IC I concede there would be more time spent on "care" tasks with electric. Electric though is almost "maintenance" free in my experience - in 7 years of electric flying I've only ever had one component go bad (a £7 motor whose bearings failed; I replaced the whole thing, it was easier and cheaper!). By contrast there are far more "lifed" components in IC (fuel tubing, plugs, pump diaphragms etc) that will require ongoing maintenance / cleaning / replacement to keep an engine operating reliably. As you say (in non-catchy longhand), "you are responsible for your decisions and cannot blame someone else when your decision is not successful"...! Edited By MattyB on 23/03/2017 16:57:33

Posted by Rich2 on 21/03/2017 19:35:49: PS - Despite using almost exclusively cheapo motors I have never had an electric motor do this either... haha! yes, but batteries require regular maintenance, and the issues you mentioned for IC are one off's. I have never maintained a lipo in my life! I just charge em, use em then discharge any spares I didn't fly back to storage. Does the last step count as "maintenance"? I don't think of it like that, but I suppose some people might. If you do though you should many more similar tasks associated with IC that don't apply to electrics (charging glow sticks and starters, wiping down the model, removing fuel from the tank, applying after-run etc).

There might even be local clubs who see there membership numbers fall if the facilities at the NFC are better than the club ones; little or no weekend flying may be a deal breaker for many though. Edited By MattyB on 23/03/2017 13:05:34

That email had already been posted on page 4 of this thread. Edited By MattyB on 23/03/2017 10:57:28

They do not even have to be of the same capacity - just the same cell count and a similar C-rating.

Posted by The Wright Stuff on 22/03/2017 12:53:34: As far as I'm concerned, this whole argument just boils down to personal requirements, and value of time versus money. As Matty says, it is good to have factual information, from reliable sources. However, how that information is then used by individuals is largely down to whether the return (longer life) on investment (the time spent) is worth it to the individual. Yep, completely agree - if all I had were low C rated 3S 2200s or under I would not worry so much, but once you move up to the big 6S packs at £60-100 each then caring for them suddenly becomes a lot more important!

I have no problem with charges being levied for usage, but after the initial novelty of visiting the National Centre wears off is anyone outside the immediate locale going to bother? That is the challenge the BMFA has in the early years. Further development is reliant on funding generated by the centre itself, but with not much more than a runway and a basic campsite why bother travelling when most members have a perfectly good local facility at their club they have already paid for? I would like to be proved wrong, but I can't see it generating much revenue outside of event days. That means the lions share a of cash in the early stages will need to come from events, donations, bequests and grants (though the BMFAs own independent study indicated grants will be very hard to come by unless the centre can be proved to boost economic development in the area). Edited By MattyB on 22/03/2017 19:44:58

Posted by john stones 1 on 21/03/2017 19:49:26: Cheap shot dragging Adrians ? misfortune into the thread, his installation n maintenance are the envy of many scuze me for getting puffed about it Nothing of the sort - did I say anything about it being a maintenance issue? My point was things can go wrong with any power system, and you need the right knowledge (sometimes quite specialist knowledge) to fix or avoid such problems. Personally I find electrics to be simpler and easier to troubleshoot, but if I had a lifetime of IC experience under my belt I would probably think the opposite. YMMV. Edited By MattyB on 21/03/2017 20:07:32

All power systems have their pros and cons. Battery usage and care can seem like a pain I agree, but then when I look at this and other forums there seems to be a far higher variety of issues with IC than electric (plumbing issues, carb problems, blocked/dirty pipes, tank positioning etc) - that variety seems to make it harder to troubleshoot any issues that do occur. PS - Despite using almost exclusively cheapo motors I have never had an electric motor do this either... Edited By MattyB on 21/03/2017 18:30:54

Now that is a top quality thread title typo... Eddy, if you give us some more details on the model (span, weight etc) we may be able to help. Was Speed that original 600 geared or DD? Edited By MattyB on 21/03/2017 17:00:07

Comments embedded below... Posted by Chris Walby on 21/03/2017 14:48:34: IMHO so just fire away, but my comments are based on my experience. No difference if you store lipos partly charged (above 25%) or fully charged to total life Posts on this topic always go this way; those that believe in discharging to storage can quote lots of evidence from the likes of the electric car and renewable energy industries, but those who say that's incorrect only ever quote from their own experience. When I read a citable source proving scientifically there is no loss of cycle life or increase in IR from storage at elevated SOC I will happily eat my words, but til then I am believing the likes of Nissan and Tesla who have millions invested in the technology. It is also interesting that everyone I meet who uses really big, expensive batteries and/or use them at very high C ratings keep their lipos at elevated SOC for the minimum amount of time; this is very evident if you read the Batteries and Chargers forum on RCGroups. Those whose biggest battery is a 3S 2200 are much more inclined to store at full charge for convenience. Cycling lipo's will shorten their life be it in use or discharging from full to storage, what is important how fast/hard the charge or discharge is....the closer to the C rating the less cycles you will get out of them in total life span. Right, which is why discharging to storage does very little damage to a lipo - the C rating is very low, no real heat gets generated so there is next to no negative. Storage at elevated SOC though causes anode degradation and dendrite growth, both of which have an impact on capacity and IR. In extreme cases batteries have been known to short out internally from dendrite growth, not something you would want in your house I am sure. The safety aspect is the #1 reason I do not store my batteries fully charged - 4x fully charged 6S 5000s in close proximity has an awful lot of energy inside at full charge. I have lipos that at are very puffy and have reduced less than 5% of total capacity...knackered I think not I have lipos with less than 50 cycles, just as puffy as above and have reduced by 30% capacity...u/s in my book Advice - take a look at the lipo for physical damage, if it is dispose of it and if still performs in capacity and discharge capability the keep going whether its puffy or not. There I totally agree - just being puffed does no mean it is by default U/S, similarly not being puffed does not mean it is performing well. Puffing is however an indication that the pack should be treated with caution moving forward and monitored carefully on charge and discharge Questions Who would store a lipo at +60C for over 3 months...really! get real Those are the results of a scientific experiment, and in experiments you push the boundaries to see what happens. Sure, no-one is likely to do that, but it does show the impact of temperature on the internals of the battery in an extreme environment. Okay if you store them in the fridge, then take it out to fly, then put it back in the fridge what effect does the thermal shock cause to the life span of the lipo... Ever tried discharging a cold lipo.. it can result in catastrophic cell failure & who said its only IC's that dead stick! The OP posted about the effects of storage at elevated SOC, not temperature. I am inclined to agree that storing in the fridge is not necessary (at least not in this country), but look at the numbers at 25C - if stored at full charge the battery capacity could be degraded by up to 16% vs. if it had been stored at 3.85V/cell. Edited By MattyB on 21/03/2017 16:56:57 Edited By MattyB on 21/03/2017 17:15:24

Posted by David Hall 9 on 21/03/2017 14:58:53: I lashed up a discharger for my 3s batteries from a car bulb and one of those cheap discharge warning devices,,,,now to use it.. Thanks. It just makes it all a bit of a push having to charge ALL my batts before an outing, but worthwhile for longer LiPo life, I guess. Thanks for the detailed info.... It is possible to create a much more advanced discharge rig relatively cheaply from commercially available units - I am going to finish off my 300W setup tonight, and will post some pics in a new thread when I do. This combined with a high wattage PSU powered charge setup means I can charge all the batteries I need for an afternoon's flying in ~45 mins and discharge any leftovers afterwards in a similar time safely and simply. Edited By MattyB on 21/03/2017 16:30:42

Yes, the low C rated lipos are much less likely to puff due to storage at elevated SOC, so probably not worth worrying about on that pack. LiFes are even better in that regard though, although their very flat discharge curve does mean it's difficult to set the low voltage alarm.

Bruce from RCModelReviews (tests on his site and Youtube channel), and a personal test I did of a friends DSM2 RX about 6 or 7 years ago after he experienced a brownout - sorry, I can't remember the model number. As I stated above not all Spektrum DSM2 RXs exhibited high reboot voltages, only a subset of the early ones. Edited By MattyB on 21/03/2017 13:58:14

Here is a good page from Battery University on the subject - a quote from halfway down... "Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling. Table 3 demonstrates capacity loss as a function of temperature and SoC."

Yes, leaving Lipo batteries at a high SOC (state of charge) is bad for them and will cause premature death; despite some naysayers in the hobby world who will tell you this is incorrect there is tons of real world evidence from industry (particularly electric cars) showing this effect is real. The premature swelling problem seems to be more prevalent with the higher C rated packs that have more of the gel component in their construction. If you want the very best life from your packs you should discharge any unused packs to storage level (3.75-3.8V V/cell) asap after use unless you intend to use them again within 24-48hrs. I do this with all my batteries except the very smallest ones, of which I keep a few fully charged for impulsive parkflying (they are cheap enough not to matter). As a result I seem to get very high cycle lifes out of my packs, though to be fair I do not push them as hard as some power users using them in EDFs, multi-task gliding etc. More discussion in this thread... Edited By MattyB on 21/03/2017 12:50:32

Posted by Nigel R on 21/03/2017 10:44:59: "But is not Matty saying that the RX works to voltages where the the servos are dying from lack of volts. " But not so with the original DSM receivers; therein lay the problem we were commenting on. They would brownout at a relatively high supply voltage, so I understand. Correct - the DSM and some first generation DSM2 RXs had brownout voltages in the 4.1-4.2V range. That proved well within the window of vulnerability if using an aging 4.8V pack as the power supply for high power/large numbers of servos. Coupled with slow re-acquisition after reboot it did cause losses, but these issues have long since been addressed by Spektrum in their newer products (any RX purchased from 2009 onwards should be fine).

Posted by Steve J on 20/03/2017 19:27:20: @MattyB While I agree with most of what you say, I must pick you up on a couple points. Only the earliest Spektrum receivers had a slow signal reacquisition time. The problem was fixed by the Quick Connect firmware which was released early in 2008. The fix was simply for the receiver to record the frequencies that the transmitter was using and check them first on boot. The lower voltage limit for most Spektrum receivers has been 3.5V (i.e. the input voltage for a 3.3V low dropout regulator) since the first DSM2 receivers (AR7000 3.5-9.6V, AR8010T 3.5-9V). Yes, I am well aware the slow reacquisition was eliminated long ago, hence why it titled that section "Hangover from 1st generation protocols and power sensitive / slow rebooting RXs". Re: operating voltages for Spektrum, 3.5V may be the stated minimum on their TXs but many do better than that - this 6100E gets down to 3V before it fails. It was not always so, but despite the fact they don't quite match FrSky (who go down to ~2.8V) it's still good enough IMO to dispel the persistent "Spektrum Brownout" excuse from the early days when their reboot voltage was 4.1-4.2V. Edited By MattyB on 20/03/2017 20:22:30

Nigel, I have no idea how they have addressed it in the end - you clearly have more knowledge than me. What I can tell you is that everyone (including Spektrum) now seem to have now got their RXs to the point that they only reboot at voltages below those that most servos cease to respond. I am guessing, but given that's the case I doubt they have integrated anything in software to deal wit the brown out conditions - they have just concentrated on minimising the chances of it happening by reducing the minimum voltage of operation, and rebooting and reconnecting faster if a reboot does occur. Even so it remains critical to think carefully about how you power your RX and servos nowadays, especially if using big digitals that are current hungry.

Posted by Frank Skilbeck on 20/03/2017 16:41:09: Posted by Martin Harris on 20/03/2017 16:16:28: I generally agree but it's interesting that you've highlighted how misinformation can be perpetuated by repetition of half truths and rumours... The Jeti sticks have, to the best of my knowledge, remained the same design and materials since release and hundreds (thousands?) of transmitters appear to survive their flying sessions with their sticks intact. The only broken sticks I've heard of have been subject to physical abuse - including one transmitter that I witnessed being dropped onto a stick - which was replaced for free by the manufacturer with the circumstances being explained! It was discovered that in the two instances abroad that I'm aware of, one had been kicked immediately prior to the failure and the other had been transported roughly in a case with the supporting padding removed... It wasn't rumour but it was addressed by Jeti and they strengthened the sticks. But similarly some of the early Multiplex Profi's had a centering arm break (sub-supplier changed the materials apparently) but mines been fine and it isn't treated gently!, also there were some reports of centering spring breakages on some Taranis Txs. Yep, as Frank says above Jeti have stated they strengthened the sticks after reports of breakages in the early days for the DC/DS-16. They claim they have been tested to 40kg of load which may be the case, but whether they failed through mis-handling or a manufacturing defect nobody really knows. In my book I would still say letting them out of the door like is an error on Jeti's part, as something like a stick on such a premium product should be thoroughly over-engineered to avoid a failure - doing so has essentially zero consequence to weight or price. Edited By MattyB on 20/03/2017 17:12:50

Posted by Peter Christy on 20/03/2017 15:45:47: MattyB: An excellent summary! However, as one of those who came to the hobby before proportional control was actually available - analogue or otherwise - I feel duty bound to point out that we *had* to install our equipment carefully! Reed and relay receivers (some had as many as 12 relays on board!) had to be mounted "just so", and with as many as seven wires going to each servo, heaven help you if your wiring was not tidy! Yep, I have seen some of my Dad's old 7 wire servos in a dusty "archive" box at the back of one of his cupboards, and by all accounts they sound like temperamental beasts! I am sure that in those days installs were done with extreme care in order to give the best chance of success. Those installs were certainly not the ones that led to complacency in the 2.4 era!