Cobra C2814/20 Motor Propeller Data
Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (3S)
20-Turn Delta 850 RPM/Volt Io = 0.70 Amps @ 10v Rm = 0.066 Ohms 25 Amps 280 W 
 
Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
35.0 mm,  1.38 in. 34.1 mm,  1.34 in. 54.0 mm,  2.13 in. 5.00 mm,  0.197 in. 109 gm,   3.84 oz
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 9x7.5-E 11.1 13.23 146.9 7,459 53.0 713 25.15 4.85
APC 9x9-E 11.1 16.44 182.4 7,131 60.8 685 24.16 3.75
APC 10x5-E 11.1 11.00 122.1 7,685 36.4 826 29.14 6.76
APC 10x6-E 11.1 12.20 135.5 7,563 43.0 889 31.36 6.56
APC 10x7-E 11.1 13.92 154.5 7,382 48.9 936 33.02 6.06
APC 10x10-E 11.1 20.59 228.5 6,703 63.5 811 28.61 3.55
APC 11x5.5-E 11.1 14.94 165.9 7,285 37.9 1100 38.80 6.63
APC 11x7-E 11.1 17.57 195.0 7,021 46.5 1170 41.27 6.00
APC 11x8-E 11.1 18.72 207.8 6,903 52.3 1139 40.18 5.48
APC 11x8.5-E 11.1 20.15 223.6 6,752 54.3 1146 40.42 5.13
APC 11x10-E 11.1 23.70 263.0 6,374 60.4 996 35.13 3.79
APC 12x6-E 11.1 18.88 209.5 6,889 39.1 1323 46.67 6.31
APC 12x8-E 11.1 23.19 257.4 6,439 48.8 1204 42.47 4.68
APC 13x4-E 11.1 16.79 186.3 7,095 26.9 1334 47.05 7.16
APC 13x6.5-E 11.1 24.41 270.9 6,304 38.8 1554 54.82 5.74
APC 13x8-E 11.1 26.06 289.2 6,109 46.3 1542 54.39 5.33
GWS 9x5x3-DD 11.1 9.62 106.8 7,825 37.1 729 25.71 6.83
GWS 10x6-DD 11.1 10.35 114.9 7,757 44.1 810 28.57 7.05
GWS 10x6x3-DD 11.1 13.72 152.3 7,409 42.1 1006 35.49 6.61
GWS 10x8-HD 11.1 17.03 189.0 7,066 53.5 886 31.25 4.69
GWS 11x7-DD 11.1 15.80 175.4 7,201 47.7 1143 40.32 6.52
GWS 12x6-HD 11.1 17.29 191.9 7,046 40.0 1271 44.83 6.62
GWS 12x8-DD 11.1 22.08 245.0 6,534 49.5 1371 48.36 5.60
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 8x4-E 14.8 8.77 129.8 10,730 40.6 743 26.21 5.73
APC 8x6-E 14.8 13.42 198.6 10,195 57.9 905 31.92 4.56
APC 8x8-E 14.8 17.87 264.4 9,696 73.5 836 29.49 3.16
APC 9x4.5-E 14.8 12.70 187.9 10,278 43.8 1079 38.06 5.74
APC 9x6-E 14.8 14.79 218.9 10,043 57.1 1096 38.66 5.01
APC 9x7.5-E 14.8 21.40 316.7 9,309 66.1 1131 39.89 3.57
APC 9x9-E 14.8 24.63 364.5 8,928 76.1 1097 38.70 3.01
APC 10x5-E 14.8 17.75 262.7 9,708 46.0 1353 47.73 5.15
APC 10x6-E 14.8 19.32 286.0 9,559 54.3 1450 51.15 5.07
APC 10x7-E 14.8 21.84 323.2 9,250 61.3 1496 52.77 4.63
APC 11x5.5-E 14.8 23.77 351.7 9,024 47.0 1760 62.08 5.00
APC 11x7-E 14.8 27.28 403.7 8,604 57.0 1808 63.77 4.48
APC 13x4-E 14.8 26.29 389.0 8,717 33.0 2119 74.74 5.45
 
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 18.5 8.42 155.7 13,579 51.4 768 27.09 4.93
APC 7x5-E 18.5 11.02 203.9 13,241 62.7 814 28.71 3.99
APC 7x6-E 18.5 11.52 213.1 13,177 74.9 879 31.01 4.13
APC 8x4-E 18.5 13.03 241.1 12,994 49.2 1119 39.47 4.64
APC 8x6-E 18.5 20.29 375.4 12,113 68.8 1300 45.86 3.46
APC 8x8-E 18.5 25.97 480.5 11,426 86.6 1173 41.38 2.44
APC 9x4.5-E 18.5 18.46 341.6 12,325 52.5 1580 55.73 4.63
APC 9x6-E 18.5 21.34 394.8 11,953 67.9 1556 54.89 3.94
APC 10x5-E 18.5 25.88 478.7 11,428 54.1 1901 67.06 3.97
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.