Cobra CM-2213/36 Motor Propeller Data
Magnets Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (4S)
14-Pole 36-Turn Delta 700 RPM/Volt Io = 0.28 Amps @ 12v Rm = 0.259 Ohms 11 Amps 160 W
 
Stator Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
12-Slot 27.7 mm,  1.091 in. 28.0 mm,  1.102 in. 30.1 mm,  1.185 in. 3.17 mm,  0.125 in. 68.6 gm,   2.42 oz
 
Test Data From Input 10.0 V 12.0 V 14.0V 16.0V Measured Kv value Measured Rm Value
Sample Motor Io Value 0.26 A 0.28 A 0.30 A 0.33 A 670 RPM/Volt @ 10v 0.259 Ohms
 
Prop Prop Li-Po Input Motor Input Prop Pitch Speed Thrust  Thrust Thrust Eff.
Manf. Size Cells Voltage Amps Watts RPM in MPH Grams Ounces Grams/W
APC 10x4.5 MR 3 11.1 5.40 59.9 5,913 25.2 521 18.38 8.69
APC 11x4.5 MR 3 11.1 6.49 72.0 5,603 23.9 614 21.66 8.52
APC 12x4.5 MR 3 11.1 7.84 87.0 5,194 22.1 713 25.15 8.19
APC 14x5.5 MR 3 11.1 10.74 119.2 4,320 22.5 877 30.93 7.36
GemFan 10x4.5 MR 3 11.1 6.40 71.0 5,620 23.9 559 19.72 7.87
GemFan 11x4.7 MR 3 11.1 7.68 85.2 5,253 23.4 671 23.67 7.87
GemFan 12x4.5 MR 3 11.1 9.06 100.6 4,843 20.6 693 24.44 6.89
GemFan 11x4 MR-W 3 11.1 6.08 67.5 5,709 21.6 573 20.21 8.49
GemFan 12x4 MR-W 3 11.1 7.63 84.7 5,275 20.0 666 23.49 7.86
GemFan 13x4.5 MR-W 3 11.1 8.98 99.7 4,911 20.9 773 27.27 7.75
GemFan 14x4.5 MR-W 3 11.1 10.02 111.2 4,594 19.6 844 29.77 7.59
RC-Timer 10x5.5-CF 3 11.1 4.75 52.7 6,087 31.7 450 15.87 8.53
RC-Timer 11x5.5-CF 3 11.1 6.57 72.9 5,574 29.0 570 20.11 7.82
RC-Timer 12x5.5-CF 3 11.1 9.00 99.9 4,884 25.4 705 24.87 7.06
RC-Timer 13x5.5-CF 3 11.1 10.53 116.9 4,435 23.1 777 27.41 6.65
RC-Timer 14x5.5-CF 3 11.1 12.19 135.3 3,807 19.8 793 27.97 5.86
 
Prop Prop Li-Po Input Motor Input Prop Pitch Speed Thrust  Thrust Thrust Eff.
Manf. Size Cells Voltage Amps Watts RPM in MPH Grams Ounces Grams/W
APC 10x4.5 MR 4 14.8 8.28 122.5 7,303 31.1 831 29.31 6.78
APC 11x4.5 MR 4 14.8 9.68 143.3 6,849 29.2 942 33.23 6.58
APC 12x4.5 MR 4 14.8 11.42 169.0 6,221 26.5 1055 37.21 6.24
GemFan 8x4.5 MR 4 14.8 6.10 90.3 7,967 34.0 587 20.71 6.50
GemFan 9x4.7 MR 4 14.8 6.98 103.3 7,706 34.3 702 24.76 6.80
GemFan 10x4.5 MR 4 14.8 9.51 140.7 6,906 29.4 858 30.26 6.10
GemFan 11x4.7 MR 4 14.8 11.30 167.2 6,325 28.2 1013 35.73 6.06
GemFan 12x4.5 MR 4 14.8 12.83 189.9 5,790 24.7 993 35.03 5.23
GemFan 10x4 MR-W 4 14.8 8.50 125.8 7,236 27.4 810 28.57 6.44
GemFan 11x4 MR-W 4 14.8 9.01 133.3 7,049 26.7 891 31.43 6.68
GemFan 12x4 MR-W 4 14.8 11.00 162.8 6,368 24.1 1017 35.87 6.25
RC-Timer 10x5.5-CF 4 14.8 7.35 108.8 7,571 39.4 733 25.86 6.74
RC-Timer 11x5.5-CF 4 14.8 9.89 146.4 6,793 35.4 879 31.01 6.01
RC-Timer 12x5.5-CF 4 14.8 12.63 186.9 5,725 29.8 984 34.71 5.26
Propeller Chart Color Code Explanation
   The prop is to small to get good performance from the motor. (Less than 50% power)
   The prop is sized right to get good power from the motor. (50 to 80% power)
   The prop can be used, but full throttle should be kept to short bursts. (80 to 100% power)
   The prop is too big for the motor and should not be used. (Over 100% power)
PLEASE NOTE:
The Data contained in this Prop Chart is based on actual measurements, taken in a controlled test environment, at an altitude of
512 feet above sea level.  The test voltages used are based on the standard output of a Li-Po battery under load, which is 3.70 volts
per cell.  If you are using a battery that is larger in capacity than normal, or has a very high C-rating, then your actual voltages will
be higher than those shown in the chart, and this will result in a higher current and power value for every prop used.  You should
always test your actual power system with a watt meter before flying your model to make sure that you are not exceeding the 
recommended current and power ratings of the motor being used.  The prop recommendations in this chart assume that the motor
receives adequate cooling throughout its operation.  If your motor is being used inside a cowl or fuselage, you must ensure that
the motor receives sufficient airflow, and does not get too hot during operation.  It is always best to use a prop size that pulls no
more than 80% of the motors maximum recommended current value to ensure safe operation under all conditions.