Cobra C2820/14 Motor Propeller Data
Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (3S)
14-Turn Delta 840 RPM/Volt Io = 1.00 Amps @ 10v Rm = 0.047 Ohms 36 Amps 400 W 
 
Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
35.0 mm,  1.38 in. 40.0 mm,  1.57 in. 60.0 mm,  2.36 in. 5.00 mm,  0.197 in. 140 gm,   4.94 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 14.86 164.9 7,784 55.3 777 27.41 4.71
APC 9x9-E 11.1 18.47 205.0 7,528 64.2 778 27.44 3.80
APC 10x7-E 11.1 15.69 174.1 7,736 51.3 1035 36.51 5.94
APC 10x10-E 11.1 23.29 258.6 7,191 68.1 928 32.73 3.59
APC 11x5.5-E 11.1 16.93 187.9 7,637 39.8 1221 43.07 6.50
APC 11x7-E 11.1 20.06 222.6 7,411 49.1 1301 45.89 5.84
APC 11x8-E 11.1 21.88 242.9 7,281 55.2 1255 44.27 5.17
APC 11x8.5-E 11.1 23.25 258.0 7,147 57.5 1298 45.79 5.03
APC 11x10-E 11.1 27.78 308.4 6,874 65.1 1162 40.99 3.77
APC 12x6-E 11.1 21.72 241.1 7,292 41.4 1491 52.59 6.18
APC 12x8-E 11.1 27.40 304.1 6,908 52.3 1379 48.64 4.53
APC 12x10-E 11.1 30.74 341.2 6,617 62.7 1486 52.42 4.35
APC 13x4-E 11.1 17.62 195.6 7,584 28.7 1391 49.07 7.11
APC 13x6.5-E 11.1 28.98 321.6 6,777 41.7 1805 63.67 5.61
APC 13x8-E 11.1 31.05 344.7 6,607 50.1 1802 63.56 5.23
APC 13x10-E 11.1 35.86 398.0 6,192 58.6 1704 60.11 4.28
APC 14x7-E 11.1 34.00 377.4 6,370 42.2 2032 71.68 5.38
APC 14x8.5-E 11.1 36.21 401.9 6,184 49.8 2051 72.35 5.10
APC 14x10-E 11.1 36.19 401.7 6,204 58.8 2037 71.85 5.07
APC 15x4-E 11.1 29.11 323.1 6,790 25.7 2093 73.83 6.48
APC 15x6-E 11.1 35.82 397.6 6,243 35.5 2264 79.86 5.69
APC 15x8-E 11.1 38.13 423.3 6,052 45.8 2259 79.68 5.34
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 8x8-E 14.8 20.46 302.8 10,166 77.0 921 32.49 3.04
APC 9x6-E 14.8 16.36 242.1 10,442 59.3 1164 41.06 4.81
APC 9x7.5-E 14.8 25.09 371.3 9,794 69.6 1257 44.34 3.39
APC 9x9-E 14.8 28.43 420.8 9,510 81.1 1249 44.06 2.97
APC 10x5-E 14.8 20.29 300.2 10,171 48.2 1497 52.80 4.99
APC 10x6-E 14.8 21.85 323.3 10,048 57.1 1594 56.23 4.93
APC 10x7-E 14.8 25.37 375.4 9,767 64.7 1706 60.18 4.54
APC 10x10-E 14.8 35.47 525.0 8,939 84.6 1476 52.06 2.81
APC 11x5.5-E 14.8 27.57 408.0 9,583 49.9 1984 69.98 4.86
APC 11x7-E 14.8 32.00 473.7 9,207 61.0 2061 72.70 4.35
APC 11x8-E 14.8 34.53 511.0 9,010 68.3 1980 69.84 3.87
APC 11x8.5-E 14.8 36.74 543.8 8,829 71.1 1974 69.63 3.63
APC 11x10-E 14.8 41.20 609.7 8,361 79.2 1728 60.95 2.83
APC 12x6-E 14.8 35.11 519.6 8,960 50.9 2407 84.90 4.63
APC 12x8-E 14.8 41.58 615.4 8,405 63.7 2060 72.66 3.35
APC 13x4-E 14.8 27.58 408.2 9,582 36.3 2269 80.04 5.56
 
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 18.5 14.62 270.5 13,441 50.9 1206 42.54 4.46
APC 8x6-E 18.5 23.35 432.0 12,600 71.6 1413 49.84 3.27
APC 8x8-E 18.5 30.03 555.5 12,082 91.5 1305 46.03 2.35
APC 9x4.5-E 18.5 21.30 394.0 12,845 54.7 1755 61.91 4.45
APC 9x6-E 18.5 24.57 454.6 12,545 71.3 1701 60.00 3.74
APC 9x7.5-E 18.5 36.74 679.7 11,472 81.5 1752 61.80 2.58
APC 10x5-E 18.5 30.16 557.9 12,055 57.1 2098 74.00 3.76
APC 10x6-E 18.5 31.90 590.1 11,910 67.7 2255 79.54 3.82
APC 10x7-E 18.5 36.43 674.0 11,497 76.2 2373 83.70 3.52
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 7x5-E 22.2 17.38 385.9 16,079 76.1 1218 42.96 3.16
APC 7x6-E 22.2 18.09 401.5 15,948 90.6 1311 46.24 3.27
APC 8x4-E 22.2 21.05 467.3 15,707 59.5 1666 58.77 3.57
APC 8x6-E 22.2 33.91 752.8 14,471 82.2 1870 65.96 2.48
APC 8x8-E 22.2 41.75 926.7 13,706 103.8 1686 59.47 1.82
APC 9x4.5-E 22.2 29.79 661.3 14,855 63.3 2437 85.96 3.69
APC 9x6-E 22.2 34.42 764.1 14,417 81.9 2255 79.54 2.95
APC 10x5-E 22.2 41.23 915.3 13,642 64.6 2710 95.59 2.96
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.