Delta Whiskey Posted March 11, 2010 Share Posted March 11, 2010 Just thinking as I was driving my car this morning, has the idea of charging flight batteries from using the engine somehow, ever been explored? The obvious questions might follow to this, like why, extra weight disadvantage etc, but with today's modern electrics would have thought this could be possible? And if it was, next we would then want longer lasting Tx batteries, larger fuel tanks to keep us in the air longer, and the will and concentration to last longer ourselves so perhaps not a good idea after all !Edited By Delta Whiskey on 11/03/2010 09:54:51 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 11, 2010 Share Posted March 11, 2010 Well technically of course its perfectly possible to generate electrical power from the engine. I would have thought the problem would be "cleaning it up" to use for charging given how fussy modern batteries are if you try to optimise their charging rate. If we assume we're using NMh then charging for a flight pack is usually 0.2amps or there abouts - meaning it takes about 6 hours to charge a 1200mAh set at optimum rate. But I doubt they'd actually last 6 hours - so because of optimum charging conditions it might not be possible to replace the charge as fast as its being used! Even though the engine could easily generate the power to do it would be sub-optimum for the batteries to use all that available power as a high charge rate. Anyway with 2400mAh packs available is there really a benefit? I can't fly long enough to run a pack that size down anyway! BEB Quote Link to comment Share on other sites More sharing options...
Delta Whiskey Posted March 11, 2010 Author Share Posted March 11, 2010 Very True BEB, I did say it was a silly idea as I wrote it....just wondered. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted March 11, 2010 Share Posted March 11, 2010 DW Much easier to charge whatever from the car you're driving . Ne'er mind -carry on thinking ! Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted March 11, 2010 Share Posted March 11, 2010 take into account the losses in driving a generator, the losses in the regulator circuits, and then the internal losses in the cells themselves and I think you are on a hiding to nothing. Much more efficient to just drive a prop directly from the crankshaft. I'd imagine diesel-electric trains are efficient (if they really are) only because the diesel can be run at max efficiency rpm at all times. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted March 11, 2010 Share Posted March 11, 2010 Bob Yep! A bit like a variable pitch prop in a way but done through torque converter transmission .Some gains & some losses Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted March 11, 2010 Share Posted March 11, 2010 PS Worked as an engineer for a while on an oil rig where constant rpm was required by 4 SNACME 3650 HP diesels (French train power plants at the time ) at a consistant rpm to drive generators as the main power source of the rig at the required frequency . Think I'm off thread again Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 11, 2010 Share Posted March 11, 2010 Hi Bob, if you're talking about an electric powered mode then hell yes no chance. The inefficiencies in the transformation from mechanical to electrical energy would simply overwhelm you. But I understood that DW's suggestion was just for toping up the Rx battery pack - not power batteries - hence my assumption about them being NMh's BEB Quote Link to comment Share on other sites More sharing options...
Delta Whiskey Posted March 11, 2010 Author Share Posted March 11, 2010 I was 'talking' about topping up RX batteries with the idea of not just for longer flying, as I already mentioned it has too many negatives to be of any use, but also for less charging time down for example at a whole day at the patch. I fly IC and electric and to keep flying them all day, a good charging cycle is needed (one battery at a time for me), and for the IC not be be part of this, was the basis of my thoughts. Ok I would presume they would discharge (Nimh) faster than they could be charge, but maybe with the right electronics, the electricity generated from the engine could power the RX or servo's thus maximising the time of the flight pack. Anyhow no worries, totally not practical, just wondered that all ! Quote Link to comment Share on other sites More sharing options...
Brian Parker Posted March 11, 2010 Share Posted March 11, 2010 You just need to couple a second brushless motor between the main brushless motor and the prop and wire it into the flight pack as a three-phase alternator. If you ignore efficiency losses you will have perpetual motion. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 11, 2010 Share Posted March 11, 2010 Mmmmm, Anyone spot the flaw in this argument! BEB PS Be good if you could do it though wouldn't it! Quote Link to comment Share on other sites More sharing options...
Chris Channon Posted March 11, 2010 Share Posted March 11, 2010 Hi all, Micron do an airborne charger to top up the flight pack on ic engined models. Not actually attached to the engine but is driven by a small prop. Regards Chris. Quote Link to comment Share on other sites More sharing options...
Ultymate Posted March 20, 2010 Share Posted March 20, 2010 This has been done by Sullivan not sure if it's obtainable in the UK Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted March 29, 2010 Share Posted March 29, 2010 Would be interesting to keep the ignition battery topped up on a petrol motor..... Quote Link to comment Share on other sites More sharing options...
Boots Posted January 3, 2011 Share Posted January 3, 2011 yup it been done, the sullivan genesis, 4.8v @ 800ma. From the pictures it looks quite good, bet its not cheap !! Quote Link to comment Share on other sites More sharing options...
John Privett Posted January 3, 2011 Share Posted January 3, 2011 And not a new idea either. I read about the Sullivan Genesis (or something remarkably similar) in a modelling mag a good many years ago - I'd say certainly 10 years ago, maybe even 20? Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 5, 2011 Share Posted January 5, 2011 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Ian Jones Posted January 5, 2011 Share Posted January 5, 2011 Found this: #F-SLN662: Sullivan Genesys - White StrobeOur Price: £37.99 http://www.wheelspinmodels.co.uk/car/item/F-SLN662-Sullivan-Genesys-White-Strobe__8430/ Quote Link to comment Share on other sites More sharing options...
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