Gavin Livsey Posted February 3, 2011 Share Posted February 3, 2011 Evening, I'm looking for guidance on whether to fit a normal or heavy duty switch harness to my YT Mustang. I'm operating a total of 8 servos, seven standard and one high torque, so should I go for a heavy duty? I don't suppose current draw would be huge as ordinarily I'll only be using throttle (1 standard), elevator (1 high torque) and ailerons (2x standard) with a touch of rudder (1 standard) at any given time. What do you reckon? MTIA Gavin Quote Link to comment Share on other sites More sharing options...
Yobyid Posted February 4, 2011 Share Posted February 4, 2011 I guess that a bit more info is needed. So....what's the specs of the two switches that you're considering? Can you post links to them? Quote Link to comment Share on other sites More sharing options...
Bert Posted February 4, 2011 Share Posted February 4, 2011 When Mick Wilshere gave a talk at our club he said that the switch was a proven weak link in the system. He only uses the heavy-duty switches. Bert Quote Link to comment Share on other sites More sharing options...
Gavin Livsey Posted February 4, 2011 Author Share Posted February 4, 2011 Yobyid, That's exactly the problem. I have been unable to find any info on the differences between a standard harness and a heavy duty one. The only blurb is that the heavy duty one is for high current applications such as when using digital servos or ,presumably several, high torque servos. Safest option I think as Bert says is to go for a hd one. Quote Link to comment Share on other sites More sharing options...
Yobyid Posted February 4, 2011 Share Posted February 4, 2011 Hi Gavin If weight, size and even cost aren't a problem then I'd also suggest the HD one......to be on the 'safe side'. HTH Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 4, 2011 Share Posted February 4, 2011 My 2P worth. Except for very large applications, I doubt very much that the current capacity of a standard switch would be insufficient - one only has to look at the wire gauge used on the average receiver pack etc to relaise that the contacts in a standard switch harness should easily carry the currents involved ( which are a lot less most of the time than a lot of folk predict ). Whats more likely to an issue is the physical construction quality of the switch - irrespective of size, some of the cheaper ones are pretty flimsy - I know because I have stripped some of them and checked! What is needed is a good firm spring and proper maximum contact surface area of the components. We use a slide switch as it has natural self cleaning "wiping" action in use - but if this is too easy to slide, then it could soon fail, electrically or physically. Also cheaper ones tend to be poorly encased, with small crimps, with gaps around the unit which could easily let in dirt and so on. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 4, 2011 Share Posted February 4, 2011 I'd go with Tim on this. Calculations of the work done by the servos, including estimates of efficiencies etc., predict vey low current draw even in surprising "high demand" applications. This tends to be borne out by how little recharge an inflight battery needs even after a busy day's flying. Finally, I seem to remember Tim doing some actual experiments (the best sort of data!) and again showing that the current draw, even when a servo is supporting a substantial weight, is much smaller than you might expect. But the problem is not the current, its the crummy nature of the average standard R/C switch which, if you disect it, you'd be amazed that it works at all! That being the case in a larger model, that can carry the slightly higher weight wihout even noticing it, I'd go for the HD switch ever time, simply to get better mechanicals, not so much greater current capacity. BEB Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 4, 2011 Share Posted February 4, 2011 HEREand HERE ( page two even has video evidence of tests done )And finally.... plugs, and leads etc..... Quote Link to comment Share on other sites More sharing options...
001 Posted February 4, 2011 Share Posted February 4, 2011 How about one of the Multiplex safety switch series that are not mechanical, fail safe electronic switching Quote Link to comment Share on other sites More sharing options...
Gavin Livsey Posted February 4, 2011 Author Share Posted February 4, 2011 Tim/BEB, Thanks, as usual what you say makes sense. I was having similar thoughts regarding the amount of juice taken out of an RX pack the other week as, having just replaced some standard 700mah packs with ones of double the capacity during my winter maintenance programme, I noticed that even after a very busy flying session I was only putting less than 200mah back in. Just as well because I have just returned from my LMS having requested a heavy duty switch to find that they've actually sold me a standard one, albeit a Futaba branded one. I'll stick with this. Thanks again Gavin Quote Link to comment Share on other sites More sharing options...
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