Originally Posted by

**70sflyer**
I am not sure of my battery choice and would like some feed back.I am building a 60 hanger 9 Corsair.Im thinking close to 9 lbs when completed.Motor is AXI 4130/20,305 KV.controller is Phoenix 80 ESC.Prop is 15/8.For battery I am thinking a 5000MAH,6S,30C.Is that in the ball park?Any help would be appreciated.Thanks Dean

Check out

www.motocalc.com, free for 30 days, then $39. This will get you into the ballpark.

Question, do you all ready have the motor? AXI motor specs show that their motors winding resistance is 0.099 ohms, rather high for the power expected out of the motor. At 40 Amps, that's 150 watts lost directly in the motor windings itself.

Other options, check out the various Hacker A50 series motors. I've got both their A50-12S and A50-16S motors, for three years now. The A50-16S motor is very close in weight and KV to the AXI motor, but will far outperform it, per motocalc. The winding resistance of the A50-16S motor is 0.026 ohms, 1/4 that of the AXI. This motor is actually a fraction of an ounce lighter than the AXI.

My A50-16S motor is in a Showtime 50 with 6S2P A123 cells (about the same as a 5S1P 4000 Mah Lipo) with a 16X12 APC-E prop. The motor turns this prop at about 5900 RPM, and pulls the 8 pound Showtime with authority.

Also got two A50-12S motors with same 6S2P A123 cells with a 14X10 APC-E prop. This motor turns the prop at 7950 RPM, and pulls two other 8 pound models with authority. This motor is pulling about 60 Amps on the ground.

Hope that helps.