David Davis Posted February 25, 2019 Author Share Posted February 25, 2019 Gangster please have a look at the post I put up at 10.55, the first one on this page. The cause of the crash was a break in the black negative wire. Each of the cells registered at least 1.4 Volts but when the wire broke there was obviously no electricty to power the receiver, hence the crash. As to why the wire broke in the first place is another question altogether. On a more amusing note I have for several years awarded a prize at our New Year's Eve Dinner, " La Prix Si Leger Comme Un Prune," (As Light As A Plumb" don't ask!) to the clubmate who has destroyed or damaged more models than any other member. This year my clubmates have suggested using a points system: 20 for a total wreck, 15 points for a model just about repairable, 10 points for an easier repair, 5 points for a fleshwound! So far I'm winning hands down! Quote Link to comment Share on other sites More sharing options...
extra slim Posted February 25, 2019 Share Posted February 25, 2019 what a shame, and a broken wire I guess can happen to all of us.. battery/switch etc.. So much is spoken of Nimh care etc... but as someone has already pointed out, it isnt about cycling, monitoring how much goes back in etc etc... (although these can be useful).. it is about how the battery copes under load.. and other than a fairly basic load checker I'm surprised more hasnt been done in this area.. and also understanding IR.. as many chargers now will give you a reading... but trying to obtain a rule of thumb as to what is too much is nigh on impossible!!.. I'll stick with Life packs and have done for many years now. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted February 25, 2019 Share Posted February 25, 2019 Game of blood. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted February 25, 2019 Share Posted February 25, 2019 "and other than a fairly basic load checker I'm surprised more hasnt been done in this area" What is it that you think hasn't been done? Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted February 25, 2019 Share Posted February 25, 2019 David, as the copper wire in the negative wire is broken, have you cut through the negative wire near the break (it's scrap anyway)? Possibly you will see lots of black wires instead of nice shiney copper coloured ones inside the insulation? I found an old NiMH battery of mine in a storage box in the my garage, the negative wire was a bit stiff and 'crunchy' when I bent it. Black wire corrosion. I wasn't planning on using that old battery anyway! Quote Link to comment Share on other sites More sharing options...
gangster Posted February 25, 2019 Share Posted February 25, 2019 David. Sorry I missed your 10.55 post this can happen when you get lots of input. But this is scary did the broken wire cause the crash or the crash break the wire. More investigation methinks. Maybe a new switch. further to the delta peak issue I was re reminded of an annoying feature of so called intelligent chargers. They will not charge a dead flat battery Just got my Futaba 8j to go flying and guess what switched on and battery flat. Swapped battery and went to charge the dead one with the makers delta peak wall wart. Had to put a tiny charge in from elsewhere before the charger realised it was connected. A common phenomena and I probably have 20 ways of putting a tiny charge in. But what a situation a flat battery on a bit of kit and unable to start a charge. Mayby if I had left it but I doubt it. Anyway good luck David and hope you get sorted ok Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted February 25, 2019 Share Posted February 25, 2019 Posted by David Davis on 25/02/2019 13:08:27: On a more amusing note I have for several years awarded a prize at our New Year's Eve Dinner, " La Prix Si Leger Comme Un Prune," (As Light As A Plumb" don't ask!) to the clubmate who has destroyed or damaged more models than any other member. This year my clubmates have suggested using a points system: 20 for a total wreck, 15 points for a model just about repairable, 10 points for an easier repair, 5 points for a fleshwound! So far I'm winning hands down! David, "plum", not "plumb"! Edited By brokenenglish on 25/02/2019 13:50:37 Quote Link to comment Share on other sites More sharing options...
David Davis Posted February 25, 2019 Author Share Posted February 25, 2019 Posted by brokenenglish on 25/02/2019 13:50:14: Posted by David Davis on 25/02/2019 13:08:27: On a more amusing note I have for several years awarded a prize at our New Year's Eve Dinner, " La Prix Si Leger Comme Un Prune," (As Light As A Plumb" don't ask!) to the clubmate who has destroyed or damaged more models than any other member. This year my clubmates have suggested using a points system: 20 for a total wreck, 15 points for a model just about repairable, 10 points for an easier repair, 5 points for a fleshwound! So far I'm winning hands down! David, "plum", not "plumb"! Edited By brokenenglish on 25/02/2019 13:50:37 Quite so Brian, I stand corrected. As for whether the broken wire caused the crash or whether the wire broke in the crash, I lean towards the former explanation. Two of my clubmates who witnessed the event said that I had no control once the engine stopped. I am not the best pilot in the world but given a dead stick situation I feel that I have the ability to right the model and to glide it into a landing, but when there's no power to the receiver... Quote Link to comment Share on other sites More sharing options...
extra slim Posted February 25, 2019 Share Posted February 25, 2019 Hi Nigel, I meant for such a critical component of any airframe.. and a very common power source.. I would have imagined a product, which allowed folk to enter in the parameters of their model.. i.e. number and nature of servos.. analogue/digital/ 9g, retract servo, the battery type, and capacity.. and the product would reproduce a simulated example load within +/- parameters.. and give a green or red light!!!..whilst at the same time being able to indicate that if you had a 2600mah Nimh memory or whatever, and IR reading of X would lead to you performing a simulated load or throwing it in the bin or putting it back in the model as it is fine.... we are left to the power of google to try and suss out what's what.. with all manner of opinions... and from my experience.. folk tend to say "arghh thats all too complicated.. I just buy a new one".. which isnt really a full proof method. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted February 25, 2019 Share Posted February 25, 2019 I think I see where you're going. But. If I'm honest, I think you've got a MOAS request there. And you can't really tell what the battery is like without doing a full discharge. A simple gadget such as Denis linked to, is enough for confidence checking at the field. Plug in, green or red light - fly if green. The other factor is, pick the right battery. We could do 'rules of thumb' for that, given a certain servo setup, easy enough, I guess. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 25, 2019 Share Posted February 25, 2019 I saw this thread and my first thought was that it must be from one of my clubmates. On Saturday, a friend took off and flew a circuit or two with his Cougar funfly. As he was lining up with the strip, all control was lost and the model took the straightest route to the ground. We held a post mortem and I noticed that slight pressure on the switch would disconnect the receiver battery - this seemed the most likely explanation and as damage was not terminal, the model would be rebuilt with a new switch. Imagine my surprise when in conversation with another member (incidentally a regular forumite) later in the day, he mentioned that before I'd arrived at the club, he'd lost his Cougar funfly to a faulty receiver switch! What are the odds on that! ...and a lesson to all. Quote Link to comment Share on other sites More sharing options...
John Robertson 3 Posted February 25, 2019 Share Posted February 25, 2019 David Davis - As regards "... Nice model thought the Fun-Fly was, I've too many incomplete models and unstarted kits in the workshop as well as a couple which need small repairs so I'm going to concentrate on those before entertaining the idea of building another Fun-Fly …", hopefully you won't be working on the STOL Mk2. It's a purely selfish thought on my part as I still cherish the thought of another French trip in the motorhome, as in: David Davis 24/07/2018 08:03:32 3205 forum posts 535 photos Is it the one in Ossett, West Yorkshire John? I have a complete fuselage and tailplane for this model in my garage, I only need to build the wing but I've too many other calls upon my time! If you can get yourself over to the middle of France you can have it for free! and the associated reply. Just a thought! Quote Link to comment Share on other sites More sharing options...
David Davis Posted February 26, 2019 Author Share Posted February 26, 2019 One thing I forgot to mention was that after the crash yesterday a flock of six storks flew over the flying field at low altitude. There were two models in the air at the time but these were electric powered and the birds didn't seem to mind a bit, besides the pilots deliberately flew away from them. The storks then roosted in a dead tree a few hundred metres way from the flying field, disposing themselves in the tree like numbers on a clock face. Picture below sorry I cut the top a bit, it was taken into the setting sun. Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted February 26, 2019 Share Posted February 26, 2019 Super photo! It sure beats the latest rtf foamie posed on the front lawn... Quote Link to comment Share on other sites More sharing options...
Former Member Posted February 26, 2019 Share Posted February 26, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted February 26, 2019 Share Posted February 26, 2019 Posted by David Davis on 25/02/2019 08:23:54: a I normally get quite annoyed and upset with myself when I crash a model, especially one I've built myself so I don't know why I feel so positive. Then again, there has been a new lady in my life since 12th January. I expect that has something to do with it! Edited By David Davis on 25/02/2019 08:27:12 .. hello david...you mention that you have a lady in your life,storks visiting etc....you'll be collecting daises next....the models will be going on the back burner......have fun.. ken anderson...ne..1.....stork and daises dept. Quote Link to comment Share on other sites More sharing options...
David Davis Posted February 26, 2019 Author Share Posted February 26, 2019 We're both far too old to be of interest to the storks, but you're right, there's been less aeromodelling going on in recent weeks. That said, I took her to the flying field a couple of Sundays ago and she enjoyed her day out. Edited By David Davis on 26/02/2019 09:28:12 Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted February 26, 2019 Share Posted February 26, 2019 pleased for you both David……. ken anderson....ne...1..... happy dept. Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted February 26, 2019 Share Posted February 26, 2019 Couple of things, first up I dumped nimh years ago, bought some of the last nicads from overlander then, when they started declining, went to life batteries, have never had a battery problem since. This was for both rx and tx btw. My seagull blade had a faulty switch and I've subsequently renewed all my old fashioned switches and replaced them with HD type, such a small cost really against the potential loss of a large amount by comparison. Generally speaking two 1100 mAh life batteries are about the same weight as one 2000+ mAh Ni** chemistry battery and, tbh, I've never used more than 60% of the battery capacity in a long afternoon of flying. (one for spark and one for rx; in my nicad days I would recharge between flights but don't bother with the life cells) One word of advice, the budget JR servos (591s ?) won't take more than 5 volts for a few minutes without letting the smoke out, futaba budget (148, 3001, 3003, 3004 fp 26 ? )seem to have no problem at all with life on load voltage. FWIW hitec servos have no problem either. Edited By Braddock, VC on 26/02/2019 12:30:48 Edited By Braddock, VC on 26/02/2019 12:31:46 Quote Link to comment Share on other sites More sharing options...
David Davis Posted February 26, 2019 Author Share Posted February 26, 2019 Thank you Braddock. I still have several new Eneloope batteries still in their plastic bags and will use them before going over to LiFes which the general consensus deems to be superior. I only use HiTec servos. And thank you Ken. This is a particularly happy period in both of our lives. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted February 26, 2019 Share Posted February 26, 2019 Posted by David Davis on 26/02/2019 12:47:01:... And thank you Ken. This is a particularly happy period in both of our lives. and long may it continue so David Quote Link to comment Share on other sites More sharing options...
Jon H Posted February 26, 2019 Share Posted February 26, 2019 I am currently giving the 9 year old 3000mah (or 3300, i dont remember) nimh pack in my la7 its health check. I fully charged it on saturday and after 5 months idle it only self discharged by 1700mah. I then left it until today and now its getting a discharge/recharge at my normal 500mah. its been discharging since 8.30am and its still going. So far Its given me 2700mah back and has .6v left to drop before the cut off so it looks like it is in good health I just have to check all the others now, which i wouldnt mind so much were it not for the fact that it literally takes all day! A small price to pay to ensure the health of the pack though so thy will be done Quote Link to comment Share on other sites More sharing options...
Nigel R Posted February 26, 2019 Share Posted February 26, 2019 Jon, discharge at 1C, it will give a better idea of the internal resistance. Batteries of all sorts can still hold a good capacity but be a bit useless at holding up terminal voltage when it comes to pushing out the amps. Although worth noting, at rates around 0.1C you should get 100% of marked capacity out of the discharge (or very close to). "going over to LiFes which the general consensus deems to be superior" LiFes have their own set of issues. The low discharge nimhs are a solid, well developed technology. YMMV. Edited By Nigel R on 26/02/2019 14:20:51 Quote Link to comment Share on other sites More sharing options...
Jon H Posted February 26, 2019 Share Posted February 26, 2019 I always do everything at half an amp with my Nimh packs. There is no need to batter them more than that as there is no way i am drawing more than half an amp continuously while flying. Even if i was the evidence is that i can fly for most of the day! In the past i have rejected numerous packs that failed this test. I failed a 2000mah eneloop last week as it only gave me about 1400 back from a full charge, then took 2100 back in, only to return 1400 ish again. With a knot tied in the lead it was certified as no good to fly. In any event the numbers are in and i got 2943 out of it. Assuming we see about 3000 back in again its good to go. Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted February 26, 2019 Share Posted February 26, 2019 Posted by Nigel R on 26/02/2019 14:18:17: Jon, discharge at 1C, it will give a better idea of the internal resistance. Batteries of all sorts can still hold a good capacity but be a bit useless at holding up terminal voltage when it comes to pushing out the amps. Although worth noting, at rates around 0.1C you should get 100% of marked capacity out of the discharge (or very close to). "going over to LiFes which the general consensus deems to be superior" LiFes have their own set of issues. The low discharge nimhs are a solid, well developed technology. YMMV. Edited By Nigel R on 26/02/2019 14:20:51 What are their issues, Nigel? Quote Link to comment Share on other sites More sharing options...
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