Cobra C3520/18 Motor Propeller Data
Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (6S)
18-Turn Delta 550 RPM/Volt Io = 0.93 Amps @ 20v Rm = 0.050 Ohms 36 Amps 800 W 
 
Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
43.0 mm,  1.69 in. 46.0 mm,  1.81 in. 68.0 mm,  2.68 in. 5.00 mm,  0.197 in. 216 gm,   7.62 oz
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 11x10-E 14.8 17.42 257.8 6,706 63.5 1085 38.27 4.21
APC 12x8-E 14.8 17.33 256.4 6,707 50.8 1288 45.43 5.02
APC 12x10-E 14.8 20.19 298.9 6,508 61.6 1418 50.02 4.74
APC 12x12-E 14.8 24.15 357.5 6,257 71.1 1259 44.41 3.52
APC 13x6.5-E 14.8 18.81 278.3 6,612 40.7 1755 61.91 6.31
APC 13x8-E 14.8 20.11 297.7 6,471 49.0 1753 61.83 5.89
APC 13x10-E 14.8 26.56 393.1 6,119 57.9 1596 56.30 4.06
APC 14x7-E 14.8 22.57 334.1 6,310 41.8 2035 71.78 6.09
APC 14x8.5-E 14.8 24.48 362.3 6,231 50.2 2122 74.85 5.86
APC 14x10-E 14.8 24.48 362.3 6,252 59.2 2075 73.19 5.73
APC 14x12-E 14.8 34.63 512.5 5,628 64.0 1677 59.15 3.27
APC 15x4-E 14.8 18.42 272.6 6,592 25.0 1986 70.05 7.29
APC 15x6-E 14.8 24.11 356.8 6,270 35.6 2322 81.91 6.51
APC 15x8-E 14.8 25.76 381.2 6,153 46.6 2301 81.16 6.04
APC 15x10-E 14.8 34.32 508.0 5,666 53.7 2445 86.24 4.81
APC 16x8-E 14.8 35.88 531.0 5,575 42.2 2810 99.12 5.29
APC 16x10-E 14.8 38.40 568.3 5,370 50.9 2731 96.33 4.81
MAS 12x6x3 14.8 15.54 229.9 6,837 38.8 1476 52.06 6.42
MAS 12x8x3 14.8 21.35 316.0 6,395 48.4 1829 64.52 5.79
MAS 13x8x3 14.8 23.61 349.4 6,300 47.7 2017 71.15 5.77
MAS 14x7x3 14.8 27.20 402.6 6,091 40.4 2348 82.82 5.83
MAS 14x9x3 14.8 32.12 475.4 5,804 49.5 2599 91.68 5.47
MAS 15x7x3 14.8 33.06 489.3 5,740 38.0 2734 96.44 5.59
MAS 16x8x3 14.8 36.90 546.0 5,475 41.5 2965 104.59 5.43
 
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 10x10-E 18.5 21.00 388.5 8,223 77.9 1161 40.95 2.99
APC 11x7-E 18.5 17.98 332.5 8,447 56.0 1729 60.99 5.20
APC 11x8-E 18.5 19.45 359.8 8,339 63.2 1676 59.12 4.66
APC 11x8.5-E 18.5 21.21 392.3 8,198 66.0 1712 60.39 4.36
APC 11x10-E 18.5 24.57 454.5 7,969 75.5 1544 54.46 3.40
APC 12x6-E 18.5 20.01 370.2 8,299 47.2 2049 72.28 5.53
APC 12x8-E 18.5 24.65 455.9 7,963 60.3 1847 65.15 4.05
APC 12x10-E 18.5 29.10 538.4 7,654 72.5 1970 69.49 3.66
APC 12x12-E 18.5 33.03 611.0 7,401 84.1 1786 63.00 2.92
APC 13x4-E 18.5 17.11 316.6 8,517 32.3 2023 71.36 6.39
APC 13x6.5-E 18.5 26.78 495.4 7,765 47.8 2477 87.37 5.00
APC 13x8-E 18.5 28.93 535.3 7,624 57.8 2457 86.67 4.59
APC 13x10-E 18.5 37.78 698.8 7,105 67.3 2209 77.92 3.16
APC 14x7-E 18.5 33.05 611.4 7,411 49.1 2909 102.61 4.76
APC 14x8.5-E 18.5 34.24 633.5 7,319 58.9 2962 104.48 4.68
APC 14x10-E 18.5 34.38 636.0 7,334 69.5 2895 102.12 4.55
APC 15x4-E 18.5 26.87 497.1 7,823 29.6 2929 103.32 5.89
APC 15x6-E 18.5 34.30 634.5 7,324 41.6 3258 114.92 5.13
APC 15x8-E 18.5 36.07 667.4 7,208 54.6 3209 113.19 4.81
MAS 10x7x3 18.5 16.01 296.2 8,590 56.9 1562 55.10 5.27
MAS 11x7x3 18.5 19.46 360.0 8,337 55.3 1879 66.28 5.22
MAS 11x8x3 18.5 20.94 387.3 8,172 61.9 1938 68.36 5.00
MAS 12x6x3 18.5 21.52 398.1 8,135 46.2 2117 74.67 5.32
MAS 12x8x3 18.5 29.60 547.7 7,611 57.7 2619 92.38 4.78
MAS 13x8x3 18.5 32.45 600.3 7,435 56.3 2863 100.99 4.77
MAS 14x7x3 18.5 37.12 686.7 7,116 47.2 3257 114.89 4.74
 
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 22.2 18.44 409.4 10,123 71.9 1319 46.53 3.22
APC 9x9-E 22.2 21.02 466.7 9,969 85.0 1357 47.87 2.91
APC 10x6-E 22.2 16.05 356.2 10,335 58.7 1643 57.95 4.61
APC 10x7-E 22.2 18.99 421.7 10,129 67.1 1716 60.53 4.07
APC 10x10-E 22.2 27.86 618.4 9,439 89.4 1568 55.31 2.54
APC 11x5.5-E 22.2 20.70 459.5 9,998 52.1 2227 78.55 4.85
APC 11x7-E 22.2 24.42 542.2 9,703 64.3 2343 82.65 4.32
APC 11x8-E 22.2 26.51 588.6 9,497 71.9 2175 76.72 3.70
APC 11x8.5-E 22.2 28.51 632.9 9,347 75.2 2223 78.41 3.51
APC 11x10-E 22.2 32.83 728.8 9,101 86.2 2032 71.68 2.79
APC 12x6-E 22.2 27.07 601.0 9,451 53.7 2758 97.28 4.59
APC 12x8-E 22.2 32.94 731.3 9,097 68.9 2444 86.21 3.34
APC 12x10-E 22.2 39.43 875.3 8,633 81.8 2522 88.96 2.88
APC 13x4-E 22.2 23.12 513.4 9,806 37.1 2753 97.11 5.36
APC 13x6.5-E 22.2 36.80 817.0 8,819 54.3 3272 115.42 4.01
MAS 10x5x3 22.2 14.64 325.1 10,505 49.7 1691 59.65 5.20
MAS 10x7x3 22.2 21.13 469.1 9,956 66.0 2135 75.31 4.55
MAS 11x7x3 22.2 25.20 559.5 9,595 63.6 2494 87.97 4.46
MAS 11x8x3 22.2 27.59 612.5 9,473 71.8 2594 91.50 4.23
MAS 12x6x3 22.2 28.43 631.2 9,405 53.4 2889 101.91 4.58
MAS 12x8x3 22.2 38.54 855.6 8,701 65.9 3435 121.16 4.01
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.