Cobra C3515/18 Motor Propeller Data
Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (4S)
18-Turn Delta 740 RPM/Volt Io = 1.01 Amps @ 14v Rm = 0.043 Ohms 36 Amps 530 W 
 
Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
43.0 mm,  1.69 in. 41.0 mm,  1.61 in. 63.0 mm,  2.48 in. 5.00 mm,  0.197 in. 178 gm,   6.28 oz
 
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 11.1 17.75 197.0 6,609 62.6 767 27.05 3.89
APC 11x4.7-SF 11.1 15.93 176.8 6,754 30.1 1202 42.40 6.80
APC 11x7-SF 11.1 22.14 245.8 6,308 41.8 1389 49.00 5.65
APC 11x8.5-E 11.1 17.34 192.5 6,639 53.4 1101 38.84 5.72
APC 11x10-E 11.1 20.63 229.0 6,409 60.7 990 34.92 4.32
APC 12x3.8-SF 11.1 19.68 218.5 6,481 23.3 1444 50.94 6.61
APC 12x6-E 11.1 16.32 181.1 6,733 38.3 1275 44.97 7.04
APC 12x6-SF 11.1 25.89 287.4 6,027 34.2 1654 58.34 5.76
APC 12x8-E 11.1 20.53 227.8 6,411 48.6 1172 41.34 5.14
APC 12x8-SF 11.1 30.67 340.4 5,764 43.7 1692 59.68 4.97
APC 12x10-E 11.1 23.68 262.9 6,219 58.9 1275 44.97 4.85
APC 13x4.7-SF 11.1 25.26 280.3 6,104 27.2 1752 61.80 6.25
APC 13x6.5-E 11.1 21.91 243.2 6,330 39.0 1570 55.38 6.45
APC 13x8-E 11.1 23.62 262.2 6,176 46.8 1581 55.77 6.03
APC 13x10-E 11.1 28.27 313.8 5,904 55.9 1529 53.93 4.87
APC 14x7-E 11.1 26.28 291.7 5,996 39.7 1820 64.20 6.24
APC 14x8.5-E 11.1 28.72 318.7 5,888 47.4 1861 65.64 5.84
APC 14x10-E 11.1 28.49 316.2 5,902 55.9 1829 64.52 5.78
APC 14x12-E 11.1 37.43 415.5 5,328 60.5 1594 56.23 3.84
APC 15x4-E 11.1 22.06 244.8 6,326 24.0 1809 63.81 7.39
APC 15x6-E 11.1 27.94 310.1 5,933 33.7 2037 71.85 6.57
APC 15x8-E 11.1 30.55 339.1 5,761 43.6 2089 73.69 6.16
APC 15x10-E 11.1 38.20 424.0 5,263 49.8 2056 72.52 4.85
APC 16x8-E 11.1 39.84 442.3 5,182 39.3 2368 83.53 5.35
MAS 11x7x3 11.1 16.82 186.6 6,679 44.3 1179 41.59 6.32
MAS 11x8x3 11.1 18.61 206.6 6,578 49.8 1263 44.55 6.11
MAS 12x6x3 11.1 18.80 208.6 6,575 37.4 1353 47.73 6.48
MAS 12x8x3 11.1 25.38 281.8 6,068 46.0 1643 57.95 5.83
MAS 13x8x3 11.1 28.14 312.4 5,935 45.0 1823 64.30 5.84
MAS 14x7x3 11.1 32.14 356.7 5,706 37.8 2057 72.56 5.77
MAS 14x9x3 11.1 37.03 411.1 5,416 46.2 2206 77.81 5.37
MAS 15x7x3 11.1 38.03 422.2 5,320 35.3 2303 81.24 5.46
 
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 14.8 18.12 268.2 8,992 63.9 1030 36.33 3.84
APC 9x9-E 14.8 21.14 312.9 8,734 74.4 1038 36.61 3.32
APC 10x6-E 14.8 16.04 237.4 9,160 52.0 1326 46.77 5.59
APC 10x7-E 14.8 18.48 273.4 8,963 59.4 1401 49.42 5.12
APC 10x10-E 14.8 26.44 391.4 8,332 78.9 1254 44.23 3.20
APC 11x5.5-E 14.8 20.14 298.0 8,816 45.9 1667 58.80 5.59
APC 11x7-E 14.8 23.84 352.8 8,528 56.5 1763 62.19 5.00
APC 11x8-E 14.8 25.49 377.2 8,409 63.7 1740 61.38 4.61
APC 11x8.5-E 14.8 27.36 405.0 8,225 66.2 1714 60.46 4.23
APC 11x10-E 14.8 31.89 472.0 7,953 75.3 1557 54.92 3.30
APC 12x6-E 14.8 26.03 385.2 8,372 47.6 2045 72.13 5.31
APC 12x8-E 14.8 31.85 471.4 7,906 59.9 1830 64.55 3.88
APC 12x10-E 14.8 37.22 550.8 7,567 71.7 1940 68.43 3.52
APC 13x4-E 14.8 20.67 305.9 8,772 33.2 1932 68.15 6.32
APC 13x6.5-E 14.8 34.41 509.2 7,710 47.5 2446 86.28 4.80
APC 13x8-E 14.8 37.35 552.8 7,547 57.2 2387 84.20 4.32
APC 15x4-E 14.8 34.65 512.9 7,749 29.4 2865 101.06 5.59
MAS 9x7x3 14.8 16.76 248.0 9,064 60.1 1272 44.87 5.13
MAS 10x5x3 14.8 15.03 222.5 9,259 43.8 1294 45.64 5.82
MAS 10x7x3 14.8 21.48 318.0 8,712 57.8 1617 57.04 5.09
MAS 11x7x3 14.8 25.51 377.5 8,373 55.5 1886 66.53 5.00
MAS 11x8x3 14.8 28.02 414.7 8,199 62.1 1968 69.42 4.75
MAS 12x6x3 14.8 28.08 415.6 8,172 46.4 2123 74.89 5.11
MAS 12x8x3 14.8 38.04 563.0 7,485 56.7 2512 88.61 4.46
 
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 18.5 21.51 398.0 11,036 83.6 1072 37.81 2.69
APC 9x6-E 18.5 17.27 319.6 11,410 64.8 1389 49.00 4.35
APC 9x7.5-E 18.5 26.48 489.9 10,608 75.3 1456 51.36 2.97
APC 9x9-E 18.5 29.52 546.1 10,355 88.3 1471 51.89 2.69
APC 10x5-E 18.5 21.33 394.6 11,042 52.3 1785 62.96 4.52
APC 10x6-E 18.5 22.64 418.8 10,933 62.1 1898 66.95 4.53
APC 10x7-E 18.5 26.32 487.0 10,623 70.4 2019 71.22 4.15
APC 10x10-E 18.5 36.86 681.9 9,732 92.2 1730 61.02 2.54
APC 11x5.5-E 18.5 29.00 536.5 10,407 54.2 2399 84.62 4.47
APC 11x7-E 18.5 34.13 631.5 10,015 66.4 2499 88.15 3.96
APC 11x8-E 18.5 36.83 681.3 9,796 74.2 2304 81.27 3.38
APC 12x6-E 18.5 37.65 696.5 9,735 55.3 2903 102.40 4.17
APC 13x4-E 18.5 28.67 530.3 10,440 39.5 2950 104.06 5.56
MAS 8x6x3 18.5 14.98 277.0 11,606 65.9 1251 44.13 4.52
MAS 9x7x3 18.5 23.49 434.5 10,868 72.0 1859 65.57 4.28
MAS 10x5x3 18.5 21.01 388.6 11,077 52.4 1884 66.46 4.85
MAS 10x7x3 18.5 29.63 548.1 10,348 68.6 2294 80.92 4.19
MAS 11x7x3 18.5 35.49 656.6 9,894 65.6 2679 94.50 4.08
MAS 11x8x3 18.5 38.87 719.0 9,664 73.2 2789 98.38 3.88
MAS 12x6x3 18.5 39.12 723.6 9,602 54.6 2999 105.79 4.14
 
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 22.2 14.43 320.3 14,085 53.4 1323 46.67 4.13
APC 8x6-E 22.2 22.81 506.4 13,196 75.0 1535 54.14 3.03
APC 8x8-E 22.2 29.02 644.2 12,655 95.9 1401 49.42 2.17
APC 9x4.5-E 22.2 20.45 454.0 13,446 57.3 1947 68.68 4.29
APC 9x6-E 22.2 23.49 521.4 13,127 74.6 1865 65.79 3.58
APC 9x7.5-E 22.2 36.11 801.6 12,059 85.6 1906 67.23 2.38
APC 10x5-E 22.2 29.23 649.0 12,632 59.8 2325 82.01 3.58
APC 10x6-E 22.2 30.25 671.6 12,483 70.9 2450 86.42 3.65
APC 10x7-E 22.2 36.00 799.2 12,070 80.0 2604 91.85 3.26
APC 11x5.5-E 22.2 39.69 881.2 11,759 61.2 3170 111.82 3.60
MAS 8x6x3 22.2 20.08 445.7 13,480 76.6 1740 61.38 3.90
MAS 9x7x3 22.2 30.60 679.3 12,488 82.8 2464 86.91 3.63
MAS 10x5x3 22.2 27.69 614.7 12,760 60.4 2536 89.45 4.13
MAS 10x7x3 22.2 39.05 866.9 11,785 78.1 3027 106.77 3.49
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.