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    Would anybody like to comment on the following please; FW F4 90 mm has 130 AMP esc (fitted 4075/1250 KV), FW Yak 130 90 mm has 150 AMP esc (fitted 4075/1390 KV), both planes are 8S. Yak esc is fitted in the wheel well out of airflow, max amp draw is 98, max volts are 32.7. The Yak esc is unreliable and needs to be replaced. Question is why would I buy a 150 amp instead of buying a 130 amp which is a lot better priced? The only difference I can see is the RPM as a consequence of the KV. But considering these planes are made to a price, I don't see the manufacturer putting in a 150 amp when a 130 amp would be satisfactory. Am I missing something? Your thoughts would be appreciated. Thanks in advance.

  • #2
    Hello M1110 ,
    What your missing is most likely that your unaware of the electrical engineering science that supports the power factors designed in these aircraft.
    As you noticed/commented, the YAK has a higher rated amperage ESC because the kV's that it's motor has is much greater than that of the F4.
    Power factors are not a simple linear factor but are exponential.
    For every increase in RPM, blade count or blade diameter the power required is increased at exponential factors and with those increases so do the amperage requirements of the ESC.
    If you don't trust what the manufacturer has designed, then you need to own a power meter if you are going to be experimenting with power factor changes.
    Actually, owning a power meter as a basic support tool is probably a good thing to have by any modelers that fly electric power.
    The GT Power is a good one and well worth the $25 investment.
    Best regards,
    Warbird Charlie
    HSD Skyraider; FlightLine: OV-10, Sea Fury; FMS 1400: P-40B, P-51, F4U, F6F, T-28, P-40E, 1700 F4U & F7F, FOX glider; Freewing: A-6, P-51; VQ: P-39; Dynam: ME-262, FW-190, Waco; ASM A-26; ESM F7F-3; LX PBJ-1 EFL CZ T-28, C-150


    • #3
      Thanks OV10, 150 AMP it is.