Bladerunner

Been a while, but just read it all. Nice summary. Regards

Posted by Steve Hargreaves on 25/11/2011 11:17:26: Or indeed just charged as a single pack....??   My eldest has a 1/10th scale electric buggy powered by a 3300mAh 6 cell sub C pack of NiMh.....his little brother will get one tomorrow for his birthday....(Ahhhh!!)   My question relates to charging the batteries.....as they will obviously want to race together then both batteries are likely to need re-charging at the same time........my charger is cabable of delivering the power to charge both packs but I was wondering if I should charge them in parallel as a 6 cell 6600mAh pack or in series as a 12 cell 3300mAh pack.   Or should I just charge the packs individually & separately.....my concern is that they may be in different states of charge when removed from the cars.....   Both batteries are the same make & capacity & similar age/usage....   Your thoughts as ever would be most welcome.... You should charge NiCd and NiMh chemistry cells/batteries in series because they have a negative delta-V(voltage reduction) once fully charged; if you charged them in parallel this would result in one cell or battery "hogging" all the charge current as its voltage reduces relative to the other. When fast charging it is especially important to charge in series as the effect is more pronounced and it could lead to overheating and cell damage. Slow charging at a current rate of 0.1C(1/10th of battery capacity) for 14Hrs to 16Hrs will generally result in a fully charged and balanced pack. In this instance the cells are able to cope with the relatively low heat dissipation which results once fully charged, allowing all the cells to fully charge without damage.  Ideally follow the manufacturers recommendations. Be aware that fast charging in series could lead to overheating and damage anyway if the cells happen to be significantly unbalanced. Cells in a battery pack should be of the same type and capacity. Never leave charging batteries unattended, check them periodically.  Regards.    

Posted by Bladerunner on 19/09/2009 12:17:19: I fly FASST (but not fast) so curious about new Futaba gear. Nice features but looks cheap - as opposed to minimalist Multiplex or iPhone™. Does this Tx mean the FF7 days are numbered? Probably not at that price Edited By Bladerunner on 19/09/2009 12:17:53 In the end it felt better in the hand than it looked and cost less than anticipated. So naturally had to have it  

Posted by Andy Harris on 08/03/2010 20:29:32: Schottky Diodes would have a lower drop at @ 0.4V  Agree with this  Just to add to earlier discussion: Technically the use of diodes is the better option (if you can live with the diode voltage and dissipation losses) as it provides source isolation in the event of a source failure. Semiconductor diodes are exceptionally reliable and robust devices.   There are other more complex active solutions but probably beyond the scope of our needs.    Regards  

Posted by AWM on 14/02/2010 10:02:58: Ah... the consensus seems to be that the benefits of 2.4Ghz outweigh the extras on the FF7. I fly mostly glow engines, fw and a heli. This year I am tryng an electric plane and have read there is no countdown timer on the 6EX. So I have a little clip on timer, I can use. Problem solved.   Or should I sell both and get a FF8 2.4Ghz... No!!  Stop it!!   Yes, do that   

Posted by Fred Schofield-graham on 27/02/2010 18:48:54: My transmitter has not been changed in any way and I do not like the idea of modifying it as I do not have the electrical expertise to do this, so I feel my original posting has not been answered.                                                                                                                                                                                                                                                                                                                            still confused Fred Well if you'd like the damp squib version: Using Lipo's are at your discretion - manufacturer only recommends NiCd or NiMh for that transmitter. For the purpose of warranty (and possibly insurance) if something were to happen, you may regret using that there Lipo. Don't mess about, get an eneloop Tx pack and never think about it again. Alternatively: It's a hobby, do what you like and forget about it  

Posted by Bladerunner on 26/02/2010 17:21:08: Agree with the advice you've been given. If you research it, there are one or two variations on the theme but they all have the requirement for an initial rich fuel setting. Its surprising how rich you can set a 4 stroke and still run it (clouds of smoke!). One more thing: once you've finished the initial run-in as per instructions, the most important adjustment you can make is setting the low speed needle correctly. Makes the world of difference to the way the engine handles. As has been pointed out this applies to ringed engines in general. Most modern 4 stroke engines are ringed with few exceptions, so I tend to place them all into that category. 

Posted by Ash on 11/02/2010 06:38:01: Ok fellas this could leave me looking like a bit of a tool. I'm in the market for a new 9 or 10 channel transmitter of the 2.4ghz variety and I understand how the futaba fasst method works but i was wondering how the dsm2 method works. My understanding so far is that when the transmitter is turned on it will select two unoccupied say 1 and 2 and transmits on channel 1. If channel 1 is interrupted it will switch to channel 2. What I would like to know is if it will then select channel 3 as a backup or what happens if 1 and 2 both get blocked.   Also if you respond to this thread and you use a 9 or 10 channel transmitter please list it below your response. It works "on a wing and a prayer" This 2.4G stuff is all good.

Agree with the advice you've been given. If you research it, there are one or two variations on the theme but they all have the requirement for an initial rich fuel setting. Its surprising how rich you can set a 4 stroke and still run it (clouds of smoke!). One more thing: once you've finished the initial run-in as per instructions, the most important adjustment you can make is setting the low speed needle correctly. Makes the world of difference to the way the engine handles.

Posted by Stephen Grigg aka bw on 10/02/2010 18:07:14: Put a 4th model in last evening and it is getting a lot easier and quicker.After my first forays I seem to be advancing qiute well.This evening will be spent looking at setting the model up as the last 2 additions will need this.If I can get the gist of things before I go to the field itll make things a lot easier.Although it has received high approval at the field none of them know how to work such a sphisticated modern technological contraption.I think most of them would be happier if Id arrived with a Bang Bang kit or Fleet Tx,which incidently I have seen used at our patch. Grin, glad you got it working. I just bought one of these myself and its shaping up to be a fine bit of kit. The menu structure is actually quite good once you get the hang of it. I've dabbled with touch sensitive devices (they're everywhere now) so that was not a problem for me. Like the clean design and layout of the unit. Been through the manual and played with it a bit - next thing is to get it programmed. I have to say its functions and facilities are a big step up compared to the 7C (which is also a nice Tx). Funny thing: when I first saw the 8FG I thought it a bit odd in terms of comparitive design and placement within the Futaba range, but as I read up it began to grow on me and when I first held it...done deal! It feels light in the hands and nicely balanced. The more time I spend with it the more I like it - never had that with another transmitter  

Posted by Romeo Whisky on 05/10/2009 19:26:50: Like you David, I log all my flights, but I do it in order to monitor the battery cycles and record each flight time by model and the mAh taken on recharge every time each of them is charged.  The data is useful for monitoring the number of cycles achieved and any deterioration in performance over time.  Batteries are serious business (and cost) in electric flight!  I was attarcted to the Elektro-Trainer as soon as I saw it, but my main issue with it is the price.  In Europe it seems to come with the servos fitted as well as the motor and ESC for about the same price.  I know prices have gone up but £130 for a foamie even including motor and ESC is OTT, and I feel maybe the price is inflated to cover the extras (FlyCam holder, floats etc) which I don't want!  The price, together with the rumours about its weak nose and failing motor mounting have knocked it off my wish-list.   There is much better value to be had out there.  If you think the E-Trainer S is heavy on the wallet, check out the Mpx Acromaster! Did'nt stop me from getting one though - just had to see what all the foam bashing was about

Posted by Phil B on 04/09/2009 21:32:03: Is the only advantage of a four stroke motor the sound it makes. Or I am i missing something. ( i suspect I am)One big advantage of 4 cycle is that they respond quite linearly to throttle input - relative to small 2 cycles which tend to be a bit "peaky".

Posted by Mal Quelch on 16/06/2008 11:18:00: Hi again Timbo. So your figures are for 'realistic'  current draw and that is amazing, 0.5A Peakcurrent !  it was the place of measurement that would have helped initially. As for I/C flying   I guess the word motor must have confused me! I know I should have checked but everything seems to be electric these days  !! And as you were using A123's in your WOT4 a separate rx battery is a must,  unless you use very well timed flights due to the low discharge voltage possible from these cells and the abrupt cut off associated with them. Once again-truly amazed! Mal On the Ripmax 4-Cell monitor I have, its 4.3V-4.4V for lowest Red LED and 2nd Red LED and 4.7V - 4.8V for 2nd Green LED and 1st Green LED.

I fly FASST (but not fast) so curious about new Futaba gear. Nice features but looks cheap - as opposed to minimalist Multiplex or iPhone™. Does this Tx mean the FF7 days are numbered? Probably not at that price Edited By Bladerunner on 19/09/2009 12:17:53

Posted by Lima Hotel Foxtrot on 26/08/2009 20:06:05: Hi, I just took delivery of my shiney new FF7 and am wondering if it is worth charging the TX battery pack that came with it.  I have swapped over the (greater capacity in mAh) battery from my old radio set and the FF7 works fine, but should I do anything with the supplied battery or just leave it alone? If I do so, will it just decay and die? Have a weird memory fit? Do nothing? What if I cycle it once? Any thoughts? Thanks,LHF.  I always maintanance charge my spare packs at least every 3 months. Allows me to monitor their condition and keep them in a ready state. NiCd is not too bad in storage, but standard NiMh is very sensitive to long periods of storage (i.e. permanently loses capacity). I'd perform an initial formation charge (overnight trickle charge / 1/10C for 16Hrs) at least.

Posted by Steve Hargreaves on 17/06/2008 09:50:00: Hi all....back to the fray after a few days "working" & blimey a few interesting comments there....  Just for the record Timbo is correct this was an IC Yak.....typical club model, 52" span, 5 standard analogue servos 60 4-stroke power. The battery had been fully charged with a dedicated NiMh charger (interesting article there Timbo...) the night before & had put in about 500maH if i recall (which is about right from previous experience....a flying session....a couple of weeks in the shed & then a charge before flying) & the battery is 12 months old. I take the point about the accuracy of the monitor....who knows what green light number two means in terms of voltage but I would hope that it is at least relative (ie bottom red is a considerably lower voltage than top green). More testing needed methinks but sadly I don't have a variable DC supply to see what voltage each light represents. What I can do however is put a constant load on said battery using my charger/cycler up to 1A & see what happens....I will try this & report back. Personally I think LiPos & a regulator are the way forward & when my fleet needs new batteries this is what I will do. The main attraction to me is the way LiPos hold their charge. Recharge when you get back from a session & they will still be ready to fly several weeks later...no way I would chance that with NiMhs. I'm amazed that no-one yet offers a "box" containing a Lipo, suitable regulator & cut off circuitry for if the voltage of the LIPo drops too far (if you'd left the radio switched on say)   New post to old post...you could also try sanyo eneloop as a direct replacement for existing AA packs. Hold their charge for months, no regulators required and directly compatible with existing NiMh charge gear. I've tested these and they have good load performance too  

Posted by Steveflys on 10/08/2009 00:18:49: Sorry to read about your problem with your pulse.  I've owned mine for about a year now and have flown it extensively without a single problem, in fact so many people have commented on it and have gone on to purchase one.   I've got an OS 91fs in mine which provides it with more than enough power, I'd have thought that a 1.25 was a bit overpowered, in fact Hangar 9 have just announced a larger version for that very size.   Just a thought.   Steve I'm still assembling mine. Went with a Saito 100 for the reason you mentioned and also to keep the prop diameter below 15 inch due to ground clearance. Also performing the usual artf mods (fuel proofing, extra glue, nuts and bolts, etc) to make its more robust. Nice looking plane this xt60.

Posted by andy watson on 04/08/2009 14:47:55: Running with extra nitro will give more power and let the engine run cooler.   By choice I tend to buy duraglow 10% nitro, which the engine runs very well with.  I did once have to buy some 20/25% nitro, and to be fair the engine seemed to love it, but generally I would say the extra price wasn't worth it.  A trainers very design will stop you wringing the maximum performance out of the engine.   If the engine is running fine then stick with it as it is.  (this is generally the best bit of IC advice you will ever be given ) That is good advice. Put another way: engine problems are directly proportional to the amount of needle twiddling taking place

Posted by Brian Cooper on 19/08/2009 21:09:03: Posted by Bladerunner on 19/08/2009 19:50:11: Posted by Brian Cooper on 18/08/2009 17:27:46: Just use Prosynth.    Job done.     B.C.  And that has how much oil in it as per OP's query?...  Don't know.  And don't care.   Frankly, we don't need to know.   eg: I have never asked for a chemical breakdown of ingredients before I refuel my car.   All we need to know is the fuel (Prosynth) works....... and wow, it works extremely well. Engines run faster, cooler, last longer and stay clean.  In other words, it does what it says on the tin.   B.C.  Cool, I'll not try it sometime. I was told when I started out in this hobby never to trust fuel with unpublished mix ratio's - snake-oil, manufacturer-warranties and all that Hard to unlearn actually.

Posted by Stephen Grigg on 19/08/2009 00:09:01: A "smoking "Mentor Grasshopper No that'd be S&M (Smokin&Multiplex for the prudish)

Posted by Brian Cooper on 18/08/2009 17:27:46: Just use Prosynth.    Job done.     B.C. And that has how much oil in it as per OP's query?...

Posted by David Ashby - RCME moderator on 17/08/2009 11:01:40: There I was up at 5am yesterday to chat to Jamie and Diggs on the ATTF R/C podcast show, have a listen here or download the show from itunes. We had a great chat comparing the scene in the UK and USA amongst other things.....great fun  oh and before anyone says, I meant B-50 not B-29!  Quite enjoyed that

Posted by Martin Harris on 18/08/2009 10:18:47: There does seem to be a convention emerging with Deans connectors.  All packs that I've encountered with pre-attached Deans have had the positive terminal aligned across the width of the connector. As to difficulty soldering Deans, I simply drill 2 holes in a lump of wood to take the back end of a spare connector and stand one in them.  Plug in the one you're attaching and use "high" silver content solder with a large enough iron and they are a doddle! However, I have found that using ordinary electical multi-core solder with gold plated connectors can be trickier. I use the same trick with the bullet connectors - I have a block of wood strategically drilled for several different sizes... The older lead and tin based solder (for specific electronics use) is easier to use as the melting temperature is quite a bit lower and it flows nicely. Probably won't be available much longer due to Rohs requirements though. Besides the health benefit, I console myself with the fact that silver is a better conductor

Posted by Timbo - Moderator on 18/08/2009 08:45:16: The Lander EDF units are high performance fans, but at a cost of course - after all, as they say, you dont get 'owt for nowt. The current draw on these fans is, I believe, around the 50A+ mark and even on a 3300 pack thats quite high - especially if they are not high C rated ( you dont mention the C rate ? ). They are also working this hard all the time, with little or no let-up, so you may have simply just pushed them so hard that they have lost some performance.1) Did you balance charge them after wards, and check each cell? 2) what capaciy was returned to them during charging, and3) what was the terminal voltage of each cell? I am finding more and more these days that the flightpower packs are not as good as they used to be I heard the same thing, but apparantly the new eon-x packs are longer lasting. Specs seem good too.

Posted by Steve Hargreaves on 19/07/2009 14:06:37: SC motors would normally be around 1.5-2 turns out on the needle......start her up & let it warm up at a fast idle for a couple of minutes....tune for max revs & check it still holds its revs with the nose pointing vertically then open up the needle about 4-5 clicks....you may need to adjust the idle needle to get a good tickover/transition.   If you have an expert on hand get him to show you...4 strokes have a less easily defined "peak" than 2 strokes so its a little bit harder to judge....a lot comes down to experience I'm afraid.... As you say, and thats why a tacho is very handy on 4 strokes. Helps find peak quite accurately and helps to reference prop performance. Edited By Bladerunner on 18/08/2009 10:55:14