Tom T Posted September 24, 2011 Share Posted September 24, 2011 Hi everyone, On the fine glorious day that it was today, if you forget about the 20mph winds, I thought id take the trusty trainer (nitro) to the FMFC for a spot of flying (which was amazing as I got off buddy) a whole days flying without a single problem, fault or defect and I was using a Spektrum system, hmm.... how didn't anything go wrong? Anyway, after arriving home the wind had dropped and I thought id take the PZ SU-26 (electric) out for a flight across the fields, after a few flat spins, snap rolls, loops, knife edge and anything else sport like I thought id send it vertical with a few twists, but after id reached the top and pushed hard right rudder for the descent, the electric motor decided to dead stick (still had every other control). Fortunately I could land it safely (ditch it) in the stumble field without any damage. I took it inside to fix it/find out the problem, but nothing seemed to be wrong, everything was working fine again! It is not my radio as I've done checks and had a whole days flying out of it with the Trainer. I wanted to know if anyone else has had this problem and could tell me how I can fix it or if its just a silly mistake that i'm making (i.e not enough battery life). Just to add I took it out again after and it did the same but on take off. Thanx Tom Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted September 24, 2011 Share Posted September 24, 2011 tom--have a go at resetting the model up again......reprogramme the controller... ken anderson ne..1..... electric dept. Quote Link to comment Share on other sites More sharing options...
Tom T Posted September 24, 2011 Author Share Posted September 24, 2011 Ok thanx, I will try that Is it common for electrics to dead stick? Quote Link to comment Share on other sites More sharing options...
PatMc Posted September 24, 2011 Share Posted September 24, 2011 Tom' it's very uncommon for electric motors to fail when the battery has enough life in it. What motor, prop, battery & esc were you using ? What low volt cut-off mode have you set ? Quote Link to comment Share on other sites More sharing options...
Tom T Posted September 24, 2011 Author Share Posted September 24, 2011 Hi PatMc Battery: 3.7v 150mah lipo Motor: 8.5mm cordless motor Prop: 130mm X 70mm ESC: Not sure, sorry I had been flying it for 4 minutes so maybe it was getting tired? Tom Quote Link to comment Share on other sites More sharing options...
PatMc Posted September 24, 2011 Share Posted September 24, 2011 Tom, I hadn't realised it was such a small model. I don't have any personal experience of them but I've seen them being flown at indoor meetings.It sounds like you just ran your battery down to the low volt cut off point (LVC). The LVC is to protect the battery against over-discharging which could permanently damage it. Most larger ESCs give the facility to select the type of LVC that suits the model but I don't think yours will. For electric gliders it's common to have the motor cut immediately the LVC point is reached . For sports models the ESC is usually set to reduce the power as LVC is approached so that there's some warning & the model can be landed ASAP but still with some power. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted September 24, 2011 Share Posted September 24, 2011 Two possibiliies occur to me: 1. Thermal cut out on the ESC. 2. UBEC kicking in. The trouble with both of these explainations is the statement - "I took it out again and it happened on take off"! I think Ken's idea is a good starting place - re-programme the ESC and try again. Just give everything a good once over befor you fly it again - particularly all connections - not only pushed home but secure - and turn the motor over to check the bearings feel OK. BEB Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted September 24, 2011 Share Posted September 24, 2011 Tom the symptoms do sound like an empty battery. Or at least that the battery volts were going low enough for the speed controllers LVC (low Voltage Cutoff) to operate. The battery would then recover a little when the load was removed, so would work again briefly until it happened again. Have you been used to getting longer flights than that? If so then maybe the battery is near the end of it's life, or for some reason it hadn't been charged completely. Quote Link to comment Share on other sites More sharing options...
Tom T Posted September 24, 2011 Author Share Posted September 24, 2011 Thanx Everyone, I will restart it all and charge battery to full again and try. PatMc: Yeah I know. I just brought it for the garden, I fly nitro at a club but i needed something to help me not go rusty during the week. Also its good fun, because I can chuck it around and not really care. Tom Quote Link to comment Share on other sites More sharing options...
Olly Giles Posted September 24, 2011 Share Posted September 24, 2011 i think low voltage cut off. If you still had radio link then it wonr be anything wrong with it. The PZ gear wil pulse the motor as its running when it is getting close to LVC as a warning. Quote Link to comment Share on other sites More sharing options...
Alan Randall Posted September 24, 2011 Share Posted September 24, 2011 I doubt that a SU26 would fly on full throttle much at all when flying indoors and would probably turn in about 10 minutes flying. Full throttle out side flying doing aerobatics would probably run the battery down much quicker to the LVC point. We have also found that after a seasons use, the single cell lipos can loose their staying power and the duration is much reduced.. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted September 25, 2011 Share Posted September 25, 2011 Posted by Biggles' Elder Brother - Moderator on 24/09/2011 20:22:10:Two possibiliies occur to me: 1. Thermal cut out on the ESC. 2. UBEC kicking in. The trouble with both of these explainations is the statement - "I took it out again and it happened on take off"! I think Ken's idea is a good starting place - re-programme the ESC and try again. Just give everything a good once over befor you fly it again - particularly all connections - not only pushed home but secure - and turn the motor over to check the bearings feel OK. BEB You can always tell when the petrol heads chime in on leccy problems eh UBEC kicking in ..... LOL Quote Link to comment Share on other sites More sharing options...
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