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Old Apr 26, 2012, 06:20 PM
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Chattanooga, Tennessee, United States
Joined May 2003
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Unless that motor is good for 112A/1600W... then yes, MotoCalc says that a 15x7 would be too much.


Motor: Hacker A40 10S; 880rpm/V; 3.8A no-load; 0.007 Ohms.
Battery: Thunder Power TP5200 (G4 ProRace 50C) (50C); 4 cells; 5200mAh @ 3.7V; 0.001 Ohms/cell.
Speed Control: Castle Creations Phoenix 60; 0.0012 Ohms; High rate.
Drive System: Direct; 15x7 (Pconst=1.17; Tconst=1) direct drive.
Airframe: Anything you want.
Conditions: 700ft above Sea Level, 29.92inHg, 68F
Motor Amps = 112.7
Motor Volts = 14.2
Input (W) = 1602.1
Prop RPM = 8965
Thrust (oz) = 187.6
PSpd (mph) = 59.4

Since the original Hacker A40-010S is rated for 900W/40A max, and even the new V2 is rated for only 1000W/50A max... it will be toast with a 15x7! On 4s 10x7 seems to be about it as far as amp draw goes... if you want to approach 1000W and yet keep amp draw between 40A-50A... you need about 6s and an even smaller prop.
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Last edited by Dr Kiwi; Apr 26, 2012 at 06:31 PM.
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