Andrew McKelvey 1

Someone somewhere thinks there is validity in being able to measure cell resistance, my question is what do you do with the answer, no one has gone near an answer yet

The video I watched showed typical resistance values for a new battery 4 cell of between 6 and 8 micro ohms, shown on the charger per cell, so adding them together is more than 20 micro ohm so that would write off a new battery so I took it as a value for each cell of over 20 would be enough to write off a battery of cells. My chargers don’t calculate the cell resistance, probably because they are circa 10 years old and reasonably cheap.

DickW I think I may have found an answer on the t internet, There is a dc test to calculate battery internal resistance, open circuit voltage (OCV) with no load, followed by the second reading with a load; Ohm’s law calculates the resistance value (voltage difference divided by current equals resistance).= internal resistance. My guess would be the higher the load current the more accurate the result? I also found a video of a guy explaining the in’s and out’s of lipo’s, not sure his qualifications but he sounded like he knew what he was on about. His take on it was New battery’s of various capacities return an resistance of below 10micro ohms and continue to be usable up to 20 micro ohms and any thing above that should be retired. I normally use a 12v 60w headlamp bulb to discharge any unused lipos back to storage voltage (actually x2 to increase the current) The effect of the higher internal resistance reduces terminal voltage under load, the prop spins slower and causes more heat to be generated in the battery which makes it hotter and thus not what we want. This has taken most of the day so now I need to test my older lipo’s, thanks for the input guys

I didn’t fly for about three of those due to the pandemic so they where stored with a storage charge and never abused before hand. I have one of those data loggers that got a write up in RCM&E a few years ago and have used that, my charger will only discharge at a few amps, I was hoping to emulate a real life situation and pull about 40A and see what that did to voltage etc but apart from giving me some electrical values how does that equate to how good the battery is? I have only ever binned one battery that puffed up severely, they seem to get demoted to powering hand drills etc but discovered that Li-On cells from laptop packs do a good job there after the ni-mh and ni-cads pack in. Requires surgery with a dremel but at least keeps then out of the landfill.

I have just reinvested a healthy chunk of money in buying some new li-po batteries in the belief that the old ones I have may no longer be up to it. aka 4cell 3300mAh 60C as compared to the same with 20C and being about 6 years old or more. The comparison using my wattmeter with fully charged batteries in my plane setup gives nearly a 100 w difference , ie a difference of about 6 - 8A draw at full throttle and the older battery being about a volt or more down on the new one. I know this is down to internal resistance of the battery which has worsened with age and I could do comparison checks of my older battery's against new one but I am reluctant to do a load of testing with an 12x6 prop wizzing round at full chat just to provide the load plus the wind factor isn't good in the model room. The questions! 1 How do you test an battery for capacity and obtain comparative results 2 If you manage to compute the internal resistance of said item how do you determine a pass or fail 3 Is there a method or a bit of technology I can use that will mean I am not holding down my plane and applying full throttle and trying to read the numbers on my wattmeter. Your thought please will be gratefully received, I have more than enough electrical test equipment to do the measurements I just dont know what the results mean other than the old battery makes the plane unflyable and the new ones make it a pleasure to fly.

I have a HP Envy 4500 think it is about 4 years old now, bought it in Currys, it is combined inkjet printer scanner copier and prints double sided A4 is wifi enabled so you can print direct, via a network or has a printer cable port and for the money was/is a cracking printer cost about £49 and there are newer versions available that has the same functions. Never had an issue with it and setup is a doddle. The downside, depending upon how much printing you do the combined 301 colour and black cartridge pack are around £26 and buying them singly significantly bumps the price up, a 301 Black cartridge is about £19, you can get an XL version but I have never used one, the tri colour lasts longer than the black because I don't print a lot of colour. The upside of this is you can use the printer in single cartridge mode, a setting deep in the software so if your black runs out at an inopportune moment you can still print, single cartridge mode I think it's called.

Over the weekend I had reason to go looking for some information and thought I know I'll go and look it up in the magazine to check. Well, I tried every permutation of login id customer number and password and whatever I had and gave up in the end. Just spoken to a very helpful lady on the end of the helpline who now informs me I need a Digital and Print subscription to get access to the Digital Archive, I did explain I have used it before and that was under mytimemedia now we are with a new company mortons we have to pay and extra £12 a year to retain that facility. So, if you like me wondered why you can't access the Digital Archive or even read this month's mag online like what you used to do it's because you like me only have a Print subscription and not Digital and Print subscription. I don't know what I think at the moment, and I am erring on the side of caution because I don't want to make any hasty decisions but in recent months, I haven't been that taken with the content of the mag and since losing a couple of contributors who were key to my enjoyment the whole thing leave a sour taste.

Max Z I don't suppose you have the script and a schematic available that you could send me. I have an Arduino ready to program and hook up..

I just thought that proportional speed control would be a bi product of using off the shelf speed controllers with radio control, just a bit more refined than on off. I have made up a battery with Li Ion cells from a redundant laptop battery three in parallel each side which is about 3.3v and I charge it with one of my multi chargers at 6 and a bit volts both banks of cells are in series and it works well, I have only recharged it once and have had the bulldozer all over the house a lot better than the old U2 batteries as I seem to remember

Thanks for the replies guys, I am in a much better position in understanding what I need to do. At the moment the control is on off via a couple of levers which are effectively change over contacts. I need to find out how much current the motors draw but as it was power by 4;U2 cells 2 each side it isn’t going to be a lot. I need to do a bit of experimentation with one of these mixers or even a couple of brushed esc connected to a receiver and see if something like a v tail mix will do it but I definitely have more idea now Thanks. I would have thought that the esc’s being proportional the voltage applied is also proportional so even a six volts i can limit the volts to about three, I am running it off 2 Li Ion cells at the moment which are 3.4v without any problem.

I have an old Marx-A-Power Bulldozer which I am planning on installing some radio control to drive it. At the moment it has two brushed motors of 3v one for left track and one for right track with independent control. I require my control to drive the vehicle forward backward and steer. I would like proportional speed control, it is either on or off at the moment, my guess is that those of us that have tanks and other tracked vehicles have a solution to the problem but I don’t know what it is, is there an esc that will do the job, do I need two esc’s, do I need a mix in my tranny to drive two channels, how is it done. Any info will be great fully received to point me in the right direction. I could quite easily design something and then find a solution of the shelf. I want to keep the 3v motors if I can so as to be reverse any mods I make.

For some inexplicable reason and actually reading this thread helped enormously, I think I am sorted...doh!

It would seem my browser was logging me into the forum or I hadn't specifically logged out yesterday

The main forum screen shows I am logged in as Andrew Mckelvey 1, I didn't log into the forum site specifically so I don't know if my browser logged me in or there is some sort of pass thru authentication. I am using MS Edge on my laptop Last evening when I tried this and then tried posting I got an error telling me my email address is already in use?

Early Bird This morning I have logged into the Main Site and got a banner which said I had logged in successfully using my id Andrew Mckelvey 1, however when I go to subscriber services I get the screen you posted. I then have clicked on forum which is how I got here.

Early Bird Yes when I go to Subscriber Services I do get the screen you showed Martin Harris I used my forum ID Andrew McKelvey 1 to log into the main website and that has worked, so the daft question is why with two separate systems am I using my id for the forum to log into the main site, not very intuitive...

After three hours messing around I am still not sure I'm doing this right. Yes I have logged into the forum but when trying to login to the main site and I go to subscriber services it wants me to sign up, I already has a subscriber number and it is in my login details. I am not stupid I did IT support for 15 years but really, this new site to me is untested, and all the problems should have been ironed out at acceptance testing or a big article on the home page on how to rectify these issues, I have changed my password six times today and I am still not sure what my credentials are. Not Good

Gordon, I completely agree this isn't a new problem, it probably coincides with a change that the web developer has made to the site, I raised a new thread because I thought that in the intervening months / years some thing would have been done to correct the issue and I may have missed it, I am not on here daily.. As far as I know support for Flash Player stops from this month so all those web pages that support flash have had to be changed for some thing that is supported, security and all that, did the old viewer run on Flash, I don't know but something has changed that we can't correct at this end, but to re-iterate there are web sites out there that have secure content that you can view without the hassle we have to endure.

The problem described above is a problem with page coding and how the browser reads the html code, not really some thing we can fix at our end, so must be some thing the programmer / developer has implemented, It may just boil down to incompatibility in browsers after all the developer should test his code against all known browsers or make explicit mention that not all browsers work. The point I was making is that there are viewers out there like Amazon Kindle Viewer which will allow you to see secure items and will remember what page you are on and at what magnification you prefer to read at and repaginate the pages accordingly and do it across a whole library of available items, even if the settings are different for each book/magazine. After all that's what cookies are for! In my view it shouldn't be to difficult to give us a viewer that satisfys the user experience rather than getting what the developer wants to give us. Edited By Andrew McKelvey 1 on 09/10/2020 13:34:06

Do I assume that with no replies that no one has any thing good to say about the online viewer and that the digital subscription is not fit for purpose?

I have two laptops both HP Pavillion one an i5 the other an i7 the i5 is 10 years old and the i7 about 8 years old, both top end in their day. The Blu-ray Disc on the i7 has failed twice now once under warranty, I don’t use that laptop with any dvd drive now as I rarely need one. The i5 laptop is my main one runs Windows 10 all my seasoned software runs under 10, I have three copies of Autocad 2010, 2012, and 2019 all of which run ok, I prefer 2010 and the reason I use the older laptop is because of AutoCads licensing arrangements now, I can’t get it to register even though I have all the correct keys on the newer one. Both have 8gb memory and neither have ssd. The i7 ran like a complete dog after a recent windows update, 5 minutes to boot up etc and it transpired windows had swapped the Radeon screen driver for an Intel one, which the hardware didn’t like. Both would be described as top end gaming laptops, the i7 came to me via a staff purchase scheme and cost circa £1500 drip fed over 36 months, the other cost £40 via an auction of office equipment in my local sale room.  I also run a home use copy of Microsoft Office 2016 on the i5 and 2009 on the i7 just because that is what my employer used and it cost the price of the cd-rom and packaging, £15 both work under Windows 10 without fault and the office packages from the web also, so I have never found any software incompatibility with 10 I couldn’t fix, I have always thought 10 to be more backwardly compatible with software, however a bit more finicky with hardware due to driver issues, the hardware manufacturers don’t update drivers for old defunct hardware that the public hold onto. What ever you buy is a lottery, so you need good support, you need to spec the thing to do what you want, I have a raspberry pi which will browse the internet and read my email and cost £25. Pick your spot in the market place and shop around, the latest gizmo isn’t always best, although we all like to boast about it. You would be hard pushed to find a laptop without camera usb and WiFi these days and if you do they’ll be dirt cheap because no one wants them. Edited By Andrew McKelvey 1 on 07/10/2020 11:24:09

For reasons I won't go into my copy of the magazine gets held up at the door because of my wife's Corvid restrictions, it could contaminate me. I have over the last few months been viewing the latest magazine via the subscriber page on the website but find the viewer very poor. I have looked at numerous posts going back to early 2019 of subscribers bemoaning the quality of the viewer and I too have had issues. I normally want to read the magazine last thing at night while settling down in bed by using my iPad but the constant zooming in a out to read the text does not make it an enjoyable experience, even on my desktop computer Windows 10 with a 21" monitor it isn't that good. I have no problems with things like Kindle viewer and PDF viewer I have bought more than a few books to read during lock down on my iPad and the quality of viewing is excellent. I even tried pocket mags thinking my subscription may let me get at the mag but no joy. I was thinking of going to a digital subscription but if this is the quality of the viewer, I won't be, am I missing some thing is there an add on I'm missing, how can I improve my viewing satisfaction, this seems to have been complained about for a long time now so surely there is a solution.

I tend to use old bicycle spokes which are about 2mm, or just less so I’m not limited to 300mm, run a threaded die up it and you can have a thread both ends, nylon clevises don’t seem to care whether it metric or ba, you just need to source some old wheels. The bent end is good in servo horns you don’t need keepers! You can join the ends using 5 or 10amp electrical connectors (chocolate blocks) if you don’t want to go to the hassle of rethreading, annealing the end helps with cutting new threads Edited By Andrew McKelvey 1 on 18/08/2020 10:58:10

I was beginning to wonder where my copy was, my subscription according to the website expired last month but as I pay quarterly I see it is now October so my guess is I am ok their. However I did discover I can read the current mag online through the subscriber pages so I have had a good browse all ready, just would rather have copy in my hands to flick through and the print is bigger!

Basically I have gone for this as a design looks like most other wings I've ever seen. I have gone for 11 wing ribs with 45mm gap at the root (3 off) one actually sit over the fuselage, the gap is 65mm otherwise, they are all 3mm ribs with 6mm cap strips. It is D section sheeted leading edge with 1.5mm shear webs, spars are 6mm balsa. I haven't decided on aileron construction because it isn't stock size 48mm. Also I haven't made my mind up to make it two piece with a joining tube or one piece, its about 620mm each panel. I have also redrawn the section and gone for a 14% depth S8035 section, the idea was to go thick because I didn't want a ballistic missile just something that potters about, but would pull the shapes but nice and slowly. A sort of cross between a Wot4 and a Ripmax Jive if there can be such a thing, however I haven't got the resources to test every little change, spose I could make a thick one and a thinner one! I am surprised there isn't more science to this design malarky just seems to be preference and what has gone before and it's if it looks good it should be ok Any thoughts Edited By Andrew McKelvey 1 on 06/07/2020 17:16:02