Cobra CM-2204-2850 Motor Propeller Data
Magnets Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (4S)
14-Pole 22-Turn Delta 2850 RPM/Volt Io = 0.993 Amps @ 10v Rm = 0.052 Ohms 24 Amps 355 W
 
Stator Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
12-Slot 27.0 mm,  1.063 in. 14.2 mm,  0.559 in. 32.5 mm,  1.146 in. 3.00 mm,  0.118 in. 24.6 gm,   0.87 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 0.759 A 0.873 A 0.993 A 1.104 A 2898 RPM/Volt @ 10v 0.052 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
HQ 3x3 3 11.1 6.34 70.4 29,457 83.7 214.8 7.58 3.05
HQ 4x4 3 11.1 14.27 158.4 26,244 99.4 493.3 17.40 3.11
HQ 4x4x3 3 11.1 18.05 200.3 24,927 94.4 588.4 20.75 2.94
HQ 4x4.5 3 11.1 10.03 111.3 27,900 118.9 360.3 12.71 3.24
HQ 4x4.5-BN 3 11.1 19.19 213.0 24,470 104.3 573.3 20.22 2.69
HQ 5x3 3 11.1 13.20 146.5 26,673 75.8 583.7 20.59 3.98
HQ 5x4 3 11.1 18.53 205.7 24,772 93.8 715.2 25.23 3.48
HQ 5x4x3 3 11.1 24.43 271.2 22,717 86.0 835.6 29.47 3.08
HQ 5x4.5 3 11.1 19.79 219.6 24,341 103.7 716.5 25.27 3.26
HQ 6x3 3 11.1 19.03 211.3 24,591 69.9 802.0 28.29 3.80
 
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
HQ 3x3 4 14.8 9.79 144.8 37,647 107.0 354.6 12.51 2.45
HQ 4x4 4 14.8 20.48 303.2 33,242 125.9 764.0 26.95 2.52
HQ 4x4x3 4 14.8 25.79 381.7 31,211 118.2 887.5 31.31 2.33
HQ 4x4.5 4 14.8 15.51 229.5 35,178 149.9 575.4 20.30 2.51
HQ 4x4.5-BN 4 14.8 28.41 420.5 30,381 129.5 871.3 30.73 2.07
HQ 5x3 4 14.8 19.88 294.2 33,494 95.2 911.1 32.14 3.10
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.