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MISCELLANEOUS (cont'd) But now let's assume the rules permit ANY motor: I would look around for one of about the same size and RPM, but with greatly increased resistance ... suppose I locate one that had an R value of 4 ohms, and that I set it up with 13 small cells. The current would be 3.25a (A = V/R = 13/4), and the power input 42W (13v X 3.25a), the SAME as the standard motor! Would it be competitive? Yes, the climb rate would be the same, but the RUN-TIME on the 50 mah charge more than DOUBLE! (3 ampere-minutes/3.35a = .92 minutes, or 55 seconds) It is my prayer that this expanded explanation of charge-allotment will serve to clarify the numerous advatages offered for a simple and inexpensive beginners' free flight electric event.
Ron St. Jean
March 2006 |
November 2006 -- an update: Bench tested a 24 volt motor and PROVED the correctness of principle above ... BUT a new insight came. It is NOT necessary to restrict the event to just one specific motor IF the number of CELLS in the battery is limited, to say 4 - 6 cells! (The 24v motor, when run on 6 cells did not develop enough power to cause a 5 ounce model to climb! But it ran OK with 16 cells, enough to run it far longer than 2 minutes.))
Ron St. Jean
10 Watkins Way Yerington, NV 89447 USA 775-463-2751 |