Cobra C-2221-10 Motor Propeller Data
Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (3S)
10 Turn Delta 1500 RPM/Volt Io = 1.37 Amps @ 10v Rm = 37 Ohms 38 Amps 420 W
 
Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
27.65 mm, 1.089 in. 37.00 mm, 1.457 in. 54.00 mm,  2.126 in. 4.00 mm,  0.157 in. 88 gm,   3.10 oz
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 7x4-E 11.1 16.39 181.9 14,134 53.5 845 29.81 4.64
APC 7x4-SF 11.1 17.20 190.9 14,019 53.1 833.4 29.40 4.37
APC 7x5-E 11.1 20.44 226.9 13,559 64.2 841.7 29.69 3.71
APC 7x5-SF 11.1 21.11 234.3 13,472 63.8 877.8 30.96 3.75
APC 7x6-E 11.1 21.73 241.2 13,399 76.1 927.8 32.73 3.85
APC 7x6-SF 11.1 24.86 276.0 12,948 73.6 834.3 29.43 3.02
APC 8x3.8-SF 11.1 27.76 308.1 12,565 45.2 1268.9 44.76 4.12
APC 8x4-E 11.1 23.86 264.8 13,097 49.6 1139.9 40.21 4.30
APC 8x6-E 11.1 34.16 379.1 11,654 66.2 1214.3 42.83 3.20
APC 8x6-SF 11.1 41.31 458.5 10,624 60.4 1225.9 43.24 2.67
APC 8x8-E 11.1 40.89 453.9 10,673 80.9 1023.3 36.10 2.25
APC 9x3.8-SF 11.1 35.06 389.2 11,543 41.5 1559.4 55.01 4.01
APC 9x4.5-E 11.1 31.82 353.2 11,972 51.0 1512.4 53.35 4.28
APC 9x4.7-SF 11.1 31.68 351.6 12,011 53.5 1537.5 54.23 4.37
APC 9x6-E 11.1 36.06 400.3 11,378 64.6 1412.1 49.81 3.53
APC 10x5-E 11.1 40.09 445.0 10,785 51.1 1694.8 59.78 3.81
GEM 8x4.5 11.1 31.83 353.3 11,973 51.0 1395.5 49.22 3.95
GEM 9x4.7 11.1 34.38 381.7 11,607 51.7 1587.4 55.99 4.16
GEM 10x4.5 11.1 45.69 507.2 9,781 41.7 1831.8 64.61 3.61
MAS 7x4x3 11.1 17.99 199.7 13,921 52.7 835.4 29.47 4.18
MAS 8x6x3 11.1 31.92 354.3 11,978 68.1 1367.5 48.24 3.86
MAS 9x7x3 11.1 43.33 481.0 10,284 68.2 1659.7 58.54 3.45
MAS 10x5x3 11.1 40.33 447.7 10,657 50.5 1778 62.72 3.97
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 6x4-E 14.8 16.51 244.3 19,345 73.3 830.7 29.30 3.40
APC 6x5.5-E 14.8 21.46 317.6 18,546 96.6 776.1 27.38 2.44
APC 7x4-E 14.8 27.88 412.6 17,516 66.3 1360.7 48.00 3.30
APC 7x5-E 14.8 32.60 482.5 16,379 77.6 1303.1 45.97 2.70
APC 7x6-E 14.8 33.84 500.8 16,226 92.2 1412.2 49.81 2.82
APC 8x4-E 14.8 38.81 574.4 15,827 60.0 1693.7 59.74 2.95
MAS 7x4x3 14.8 27.80 411.4 17,536 66.4 1347.8 47.54 3.28
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.  The test voltages used are based on a properly sized Li-Po battery for the current
draw of the motor being tested.  If you are using a larger than normal capacity battery, or a very
high C-Rated battery, your actual voltages will be higher than those shown in this chart, and this
will result in higer current draw for each prop used.  You should always test your power system
with a watt meter whenever a prop is used to ensure that you are not exceeding the recommended
rating of the motor being used.  The prop recommendations in this chart are based on the motor
receiving adequate cooling throughout its operation.  If your motor is being used inside a cowl, you
must provide adequate cooling to the motor and make sure that the motor is not getting too hot
during operation.