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    Use 3s or 4s ?

    My very first BL plane is taking shape and would appreciate your advice on lipo configurations and esc limits

    The plane is a Phoenix EP trainer, 1330cm span and 1 to 1.2kg flying weight. The motor is a 980kV max 280W outrunner spinning an Aeronaut 10.5 x 6 prop. ESC is a Hobbywing P30A.

    I currently have 2 packs of 2s 2000mAh 15c lipos, each used for less than 4 cycles in EP boats.

    Would it be wise to connect the lipos in series and run 4s 2000mAh with this motor and esc? Or would it be better to buy a new 3s lipo and run a less aggressive voltage? Would the amp draw on 4s fry the esc?

    I've tried a static test using a single 2s pack... temps were cool but the thrust may not be enough to achieve a good rate of climb.

    Many thanks

    If in doubt - add more horsepower!

    #2
    You can control the amp draw on 4s by using a smaller prop, thus keeping amp draw within limit. However, I think the on board bec of the esc might have to work quite hard when powering servos for a 1.3m plane. 280w motor on a 1.2kg plane with 1.3m wingspan might be a bit weak. If you want to fly it slow, it might work, but otherwise, you really need to follow your signature, add more horsepower

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      #3
      Thanks BZ... you really got me there with the horse power thing

      I might try a 9x6 and do some static testing to see if the esc can cope. Is a 4s set up commonly used for planes or do people tend to use 3s (i.e. does a 4s set up have a history of frying esc's)?
      If in doubt - add more horsepower!

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        #4
        If you want to go 4s, you must have a matching esc. I.E. a esc that is designed to work with 4s. Most of our esc today can work happily with 4s if you do not use/stress the bec in the esc and keep within current limit.

        3s or 4s depends on your personal preferance, end of day, what you want is the watt. Its just like using a 2s 15A setup or a 3s 10A setup. Both will be about the same if proped correctly at similar efficency. I think the Watts is more important. It is not uncommon to use 4s or more, just not common on those smaller electric planes that most of us fly. Anyway, a 1.3m electric plane is also not very common around here. . I think doing your batt in series to form 4s with a connector might be a good idea. At least then you know that your battery is good for 14.8v 30A, which is over 400w of power.

        At that size, you might actually want to consider going nitro, way cheaper than electric.

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          #5


          dunno if its worthed calculating until SOOOOO precise... sharing the information (maybe old) for explorers!

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            #6
            Thank you very much gentlemen... very helpful advice and info

            I've seen ESC specs being quoted with BEC enabled and disabled... now I know why, so thank you. The motor calc will be very useful but I need to be in the office before i can download it (I use Mac at home ).

            Ok, looks like I'll have to do some prop shopping next week... here's the current state of the plane minus the prop and spinner. BTW, she is designed to use stardard servos on aileron, elev and rudder... so your point about stressing the BEC is well taken

            ... and YES, nitro is my preference ... but must also have an EP in the hanger for those days when I just wanna fly for 15 mins down at the local park

            If in doubt - add more horsepower!

            Comment


              #7
              When and where do you want to maiden. I have a Delta WIng to try out.
              Gone Gas...but Petrol went UP !!!
              now burning NITRO !!!

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