Cobra CM-2208/34 Motor Propeller Data
Magnets Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (4S)
14-Pole 34-Turn Delta 1200 RPM/Volt Io = 0.36 Amps @ 10v Rm = 0.177 Ohms 12 Amps 180 W
 
Stator Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
12-Slot 27.7 mm,  1.091 in. 24.0 mm,  0.945 in. 45.2 mm,  1.780 in. 3.00 mm,  0.118 in. 44.2 gm,   1.56 oz
 
Test Data From Input 6.0 V 8.0 V 10.0V 12.0V Measured Kv value Measured Rm Value
Sample Motor Io Value 0.30 A 0.33 A 0.36 A 0.39 A 1163 RPM/Volt @ 10v 0.177 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 6x4-E 3 11.1 4.10 45.5 11,342 43.0 263 9.28 5.78
APC 7x4-SF 3 11.1 6.23 69.2 10,508 39.8 424 14.96 6.13
APC 7x5-SF 3 11.1 7.65 84.9 9,936 47.0 445 15.70 5.24
APC 7x5-E 3 11.1 7.66 85.0 9,914 46.9 430 15.17 5.06
APC 8x3.8-SF 3 11.1 9.81 108.9 9,100 32.7 615 21.69 5.65
APC 8x4.5-MR 3 11.1 9.81 108.9 9,131 38.9 606 21.38 5.57
APC 9x3.8-SF 3 11.1 11.97 132.9 8,211 29.5 719 25.36 5.41
APC 9x4.5-MR 3 11.1 12.07 134.0 8,179 34.9 725 25.57 5.41
FC 6x4.5 3 11.1 4.35 48.3 11,236 47.9 318 11.22 6.59
FC 7x4.5x3 3 11.1 9.43 104.7 9,247 39.4 563 19.86 5.38
GemFan 8x4.5-MR 3 11.1 11.53 128.0 8,398 35.8 659 23.25 5.15
GemFan 9x4.7-MR 3 11.1 12.52 139.0 7,945 35.4 732 25.82 5.27
 
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 6x4-E 4 14.8 6.27 92.8 14,380 54.5 444 15.66 4.78
APC 7x4-SF 4 14.8 9.86 145.9 12,825 48.6 673 23.74 4.61
APC 7x5-SF 4 14.8 11.67 172.7 12,047 57.0 676 23.84 3.91
APC 7x5-E 4 14.8 11.69 173.0 12,006 56.8 653 23.03 3.77
APC 8x4.5-MR 4 14.8 14.14 209.3 10,836 46.2 867 30.58 4.14
FC 6x4.5 4 14.8 6.60 97.7 14,238 60.7 512 18.06 5.24
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.