Cobra C-2221-16 Motor Propeller Data
Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (3S)
16 Turn Delta 940 RPM/Volt Io = 0.69 Amps @ 10v Rm = 84 Ohms 25 Amps 280 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 Speed Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM MPH Grams Ounces Grams/W
APC 8x6-E 11.1 10.68 118.5 8,603 48.9 640.4 22.59 5.40
APC 8x6-SF 11.1 13.65 151.5 8,136 46.2 714.5 25.20 4.72
APC 8x8-E 11.1 14.13 156.8 8,080 61.2 597.3 21.07 3.81
APC 9x3.8-SF 11.1 11.33 125.8 8,490 30.6 806.7 28.46 6.42
APC 9x4.5-E 11.1 10.27 114.0 8,674 37.0 738.5 26.05 6.48
APC 9x4.7-SF 11.1 11.42 126.8 8,471 37.7 821.2 28.97 6.48
APC 9x6-E 11.1 11.99 133.0 8,403 47.7 757.3 26.71 5.69
APC 9x6-SF 11.1 18.51 205.4 7,389 42.0 948.4 33.45 4.62
APC 9x7.5-E 11.1 16.62 184.5 7,721 54.8 804.4 28.37 4.36
APC 9x7.5-SF 11.1 16.62 184.5 7,721 54.8 804.4 28.37 4.36
APC 9x9-E 11.1 19.57 217.2 7,250 61.8 746 26.31 3.43
APC 10x3.8-SF 11.1 17.02 188.9 7,601 27.4 1099.2 38.77 5.82
APC 10x4.7-SF 11.1 18.08 200.7 7,461 33.2 1116.8 39.39 5.56
APC 10x5-E 11.1 13.86 153.8 8,120 38.4 943.5 33.28 6.13
APC 10x6-E 11.1 15.54 172.5 7,873 44.7 987.4 34.83 5.72
APC 10x7-E 11.1 17.38 193.0 7,581 50.3 1007.3 35.53 5.22
APC 10x7-SF 11.1 23.07 256.1 6,644 44.0 1134.8 40.03 4.43
APC 10x10-E 11.1 23.56 261.5 6,645 62.9 800.2 28.23 3.06
APC 11x3.8-SF 11.1 18.69 207.4 7,347 26.4 1221.2 43.08 5.89
APC 11x4.7-SF 11.1 21.54 239.1 6,878 30.6 1281.7 45.21 5.36
APC 11x5.5-E 11.1 18.31 203.2 7,457 38.8 1195.8 42.18 5.88
APC 11x7-E 11.1 20.77 230.5 7,048 46.7 1225 43.21 5.31
APC 11x8-E 11.1 21.96 243.7 6,847 51.9 1172.3 41.35 4.81
APC 11x8.5-E 11.1 23.12 256.6 6,644 53.5 1166.7 41.15 4.55
APC 11x10-E 11.1 25.63 284.5 6,214 58.8 981.8 34.63 3.45
APC 12x3.8-SF 11.1 24.41 271.0 6,393 23.0 1424 50.23 5.25
APC 12x6-E 11.1 21.92 243.3 6,834 38.8 1367.4 48.23 5.62
APC 12x8-E 11.1 25.57 283.8 6,202 47.0 1159.5 40.90 4.09
APC 13x4-E 11.1 20.06 222.7 7,152 27.1 1410.4 49.75 6.33
APC 13x6.5-E 11.1 26.42 293.3 6,045 37.2 1483.8 52.34 5.06
GEM 9x4.7 11.1 11.30 125.5 8,487 37.8 809 28.54 6.45
GEM 9x4.7-C 11.1 12.43 137.9 8,336 37.1 857.8 30.26 6.22
GEM 10x4.5 11.1 16.83 186.8 7,642 32.6 1077.6 38.01 5.77
GEM 10x4.5-C 11.1 16.93 187.9 7,644 32.6 1081.1 38.13 5.75
GEM 11x4.7-C 11.1 20.68 229.5 7,072 31.5 1293.4 45.62 5.64
GEM 12x4.5-C 11.1 23.41 259.9 6,639 28.3 1288.9 45.46 4.96
GWS 8x4x3-DD 11.1 7.03 78.0 9,172 34.7 537.7 18.97 6.89
GWS 9x5-DD 11.1 10.06 111.6 8,696 41.2 772.3 27.24 6.92
GWS 9x5x3-DD 11.1 12.61 140.0 8,303 39.3 852.5 30.07 6.09
GWS 10x6-DD 11.1 16.43 182.3 8,181 46.5 933.8 32.94 5.12
GWS 10x6x3-DD 11.1 17.03 189.0 7,634 43.4 1111.5 39.21 5.88
MAS 8x6x3 11.1 11.16 123.9 8,527 48.4 654.3 23.08 5.28
MAS 9x7x3 11.1 16.36 181.6 7,739 51.3 939.8 33.15 5.17
MAS 10x5x3 11.1 14.83 164.7 7,960 37.7 988.1 34.85 6.00
MAS 10x7x3 11.1 19.83 220.1 7,210 47.8 1149.7 40.55 5.22
MAS 11x7x3 11.1 22.62 251.1 6,729 44.6 1280.3 45.16 5.10
MAS 11x8x3 11.1 23.81 264.3 6,532 49.5 1274.3 44.95 4.82
MAS 12x6x3 11.1 24.37 270.5 6,509 37.0 1405 49.56 5.19
 
Prop Prop Input Motor Watts Prop Pitch Speed Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM MPH Grams Ounces Grams/W
APC 7x6-E 14.8 10.79 159.7 11,801 67.1 729.4 25.73 4.57
APC 8x4-E 14.8 11.82 174.9 11,622 44.0 909.6 32.08 5.20
APC 8x6-E 14.8 17.28 255.7 10,702 60.8 1033.6 36.46 4.04
APC 8x8-E 14.8 21.78 322.4 9,930 75.2 902.7 31.84 2.80
APC 9x4.5-E 14.8 16.36 242.2 10,840 46.2 1238.8 43.70 5.12
APC 9x6-E 14.8 18.79 278.1 10,441 59.3 1210.5 42.70 4.35
APC 9x7.5-E 14.8 25.27 373.9 9,363 66.5 1202.6 42.42 3.22
APC 9x9-E 14.8 27.98 414.1 8,770 74.7 1118.2 39.44 2.70
APC 10x5-E 14.8 21.44 317.4 9,996 47.3 1490.4 52.57 4.70
APC 10x6-E 14.8 23.39 346.1 9,652 54.8 1522.7 53.71 4.40
APC 10x7-E 14.8 26.03 385.2 9,107 60.4 1475 52.03 3.83
APC 11x5.5-E 14.8 27.20 402.6 8,886 46.3 1780.8 62.82 4.42
GEM 8x4.5-C 14.8 16.80 248.6 10,775 45.9 1157.5 40.83 4.66
GEM 9x4.7-C 14.8 18.92 280.0 10,404 46.3 1351.6 47.68 4.83
GEM 10x4.5-C 14.8 25.45 376.7 9,277 39.5 1645.5 58.04 4.37
GWS 8x4-DD 14.8 9.28 137.4 12,082 45.8 805.9 28.43 5.87
GWS 8x4x3-DD 14.8 11.37 168.3 11,719 44.4 905.2 31.93 5.38
GWS 9x5-DD 14.8 16.06 237.6 10,917 51.7 1255.5 44.29 5.28
GWS 9x5x3-DD 14.8 19.89 294.3 10,249 48.5 1348.5 47.57 4.58
GWS 10x6-DD 14.8 20.79 307.7 10,087 57.3 1479.5 52.19 4.81
GWS 10x6x3-DD 14.8 25.22 373.3 9,294 52.8 1676.6 59.14 4.49
MAS 8x6x3 14.8 16.94 250.7 10,743 61.0 1130.5 39.88 4.51
MAS 9x7x3 14.8 24.15 357.4 9,494 62.9 1476.1 52.07 4.13
MAS 10x5x3 14.8 22.24 329.2 9,820 46.5 1558.1 54.96 4.73
MAS 10x7x3 14.8 28.41 420.4 8,643 57.3 1683.5 59.38 4.00
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.