Tempest 2820-840 Performance Test Data
Magnets Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (4S)
14-Pole 14-Turn Delta 840 RPM/Volt Io = 1.82 Amps @ 10v Rm = 0.045 Ohms 45 Amps 670 W
 
Stator Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
12-Slot 35.4 mm,  1.394 in. 38.4 mm,  1.512 in. 60.8 mm,  2.394 in. 5.00 mm,  0.197 in. 136 gm,   4.80 oz
 
Test Data From Input 8.0 V 10.0 V 12.0V 14.0V Measured Kv value Measured Rm Value
Sample Motor Io Value 1.721 A 1.820 A 1.951 A 2.047 A 857 RPM/Volt @ 10v 0.0447 Ohms
 
3-cell Li-Po Test Data
Prop Prop Li-Po Input Motor Input Prop Pitch Speed Thrust  Thrust Thrust Eff.
Manf. Size Cells Voltage Amps Watts RPM in MPH Grams Ounces Grams/W
APC 9x8x3-E 3 11.1 19.70 218.7 8,153 61.8 1132 39.93 5.18
APC 10x6-F 3 11.1 13.74 152.5 8,616 49.0 904 31.89 5.93
APC 10x8-E 3 11.1 22.21 246.6 7,971 60.4 1127 39.75 4.57
APC 10x10-E 3 11.1 28.96 321.5 7,489 70.9 966 34.07 3.01
APC 11x5.5-E 3 11.1 20.93 232.3 8,050 41.9 1365 48.15 5.88
APC 11x7-E 3 11.1 24.44 271.3 7,780 51.6 1432 50.51 5.28
APC 11x7x3-E 3 11.1 24.29 269.6 7,843 52.0 1531 54.00 5.68
APC 11x8-E 3 11.1 26.40 293.1 7,658 58.0 1418 50.02 4.84
APC 11x8-F 3 11.1 22.80 253.1 7,920 60.0 1346 47.48 5.32
APC 11x8.5-E 3 11.1 28.33 314.4 7,500 60.4 1412 49.81 4.49
APC 11x10-E 3 11.1 32.11 356.5 7,140 67.6 1216 42.89 3.41
APC 12x6-E 3 11.1 26.95 299.2 7,625 43.3 1670 58.91 5.58
APC 12x8-E 3 11.1 32.06 355.8 7,177 54.4 1486 52.42 4.18
APC 12x8.5-F 3 11.1 28.38 315.0 7,490 60.3 1640 57.85 5.21
APC 12x10-E 3 11.1 36.95 410.1 6,817 64.6 1534 54.11 3.74
APC 12x12-E 3 11.1 41.25 457.8 6,398 72.7 1299 45.82 2.84
APC 13x4-E 3 11.1 23.64 262.4 7,870 29.8 1674 59.05 6.38
APC 13x5.5-E 3 11.1 28.83 320.0 7,455 38.8 1846 65.12 5.77
APC 13x6.5-E 3 11.1 34.53 383.2 6,950 42.8 1935 68.25 5.05
APC 13x7-F 3 11.1 31.09 345.0 7,275 48.2 1885 66.49 5.46
APC 13x8-E 3 11.1 37.06 411.4 6,776 51.3 1926 67.94 4.68
APC 13x10-E 3 11.1 45.63 506.5 6,295 59.6 1655 58.38 3.27
APC 13x10-F 3 11.1 37.99 421.6 6,709 63.5 1946 68.64 4.62
APC 14x6-E 3 11.1 33.16 368.1 7,094 40.3 2088 73.65 5.67
APC 14x7-E 3 11.1 40.41 448.6 6,480 43.0 2147 75.73 4.79
APC 14x8.5-E 3 11.1 41.77 463.7 6,310 50.8 2139 75.45 4.61
APC 14x10-E 3 11.1 41.98 466.0 6,285 59.5 2111 74.46 4.53
APC 14x10-F 3 11.1 44.37 492.5 6,049 57.3 2126 74.99 4.32
APC 14x12-E 3 11.1 54.86 608.9 5,546 63.0 1620 57.14 2.66
APC 15x4-E 3 11.1 34.50 382.9 6,967 26.4 2233 78.75 5.83
APC 15x6-E 3 11.1 41.51 460.7 6,351 36.1 2352 82.96 5.10
APC 15x7-E 3 11.1 41.53 461.0 6,319 41.9 2337 82.43 5.07
APC 15x8-E 3 11.1 45.18 501.5 6,300 47.7 2365 83.42 4.72
BadAss 11x7-W 3 11.1 21.11 234.3 8,040 53.3 1283 45.26 5.48
BadAss 11x8-W 3 11.1 27.04 300.1 7,630 57.8 1138 40.14 3.79
BadAss 12x6-W 3 11.1 25.03 277.8 7,790 44.3 1489 52.52 5.36
BadAss 12x7-W 3 11.1 29.05 322.5 7,468 49.5 1624 57.28 5.04
BadAss 12x8-W 3 11.1 33.70 374.1 7,029 53.3 1310 46.21 3.50
BadAss 13x6-W 3 11.1 29.48 327.2 7,405 42.1 1764 62.22 5.39
BadAss 13x8-W 3 11.1 37.02 410.9 6,764 51.2 1752 61.80 4.26
BadAss 13x10-W 3 11.1 43.94 487.7 6,060 57.4 1484 52.35 3.04
BadAss 14x6-W 3 11.1 35.84 397.8 6,843 38.9 1964 69.28 4.94
BadAss 14x8-W 3 11.1 40.42 448.7 6,428 48.7 2079 73.33 4.63
BadAss 14x10-W 3 11.1 51.63 573.1 5,891 55.8 1995 70.37 3.48
BadAss 15x6-W 3 11.1 41.68 462.6 6,307 35.8 2232 78.73 4.82
BadAss 15x7-W 3 11.1 42.85 475.6 6,174 40.9 2285 80.60 4.80
BadAss 15x8-W 3 11.1 46.55 516.7 6,100 46.2 2367 83.49 4.58
GemFan 10x6-F 3 11.1 15.19 168.7 8,502 48.3 1012 35.70 6.00
GemFan 11x8-F 3 11.1 27.42 304.4 7,580 57.4 1275 44.97 4.19
GemFan 12x8-F 3 11.1 32.73 363.3 7,151 54.2 1541 54.36 4.24
GemFan 13x8-F 3 11.1 33.39 370.6 7,086 53.7 1821 64.23 4.91
MAS 9x7x3 3 11.1 17.48 194.1 8,315 55.1 1019 35.94 5.25
MAS 10x5x3 3 11.1 15.72 174.5 8,460 40.1 1054 37.18 6.04
MAS 10x7x3 3 11.1 22.56 250.4 7,954 52.7 1323 46.67 5.28
MAS 11x7x3 3 11.1 26.81 297.6 7,629 50.6 1546 54.53 5.19
MAS 11x8x3 3 11.1 28.76 319.3 7,463 56.5 1580 55.73 4.95
MAS 12x6x3 3 11.1 29.48 327.2 7,396 42.0 1721 60.71 5.26
MAS 12x8x3 3 11.1 38.22 424.2 6,668 50.5 1967 69.38 4.64
MAS 13x8x3 3 11.1 40.22 446.5 6,458 48.9 2059 72.63 4.61
MAS 14x7x3 3 11.1 46.48 516.0 6,183 41.0 2351 82.93 4.56
 
4-cell Li-Po Test Data
Prop Prop Li-Po Input Motor Input Prop Pitch Speed Thrust  Thrust Thrust Eff.
Manf. Size Cells Voltage Amps Watts RPM in MPH Grams Ounces Grams/W
APC 9x6-E 4 14.8 20.71 306.5 11,083 63.0 1331 46.95 4.34
APC 9x7.5-E 4 14.8 31.18 461.5 10,175 72.3 1374 48.47 2.98
APC 9x8x3-E 4 14.8 31.16 461.2 10,225 77.5 1829 64.51 3.97
APC 9x9-E 4 14.8 34.38 508.8 9,918 84.5 1351 47.65 2.66
APC 10x5-E 4 14.8 24.39 361.0 10,768 51.0 1667 58.80 4.62
APC 10x6-E 4 14.8 27.11 401.3 10,548 59.9 1737 61.27 4.33
APC 10x6-F 4 14.8 21.82 322.9 10,992 62.5 1507 53.16 4.67
APC 10x7-E 4 14.8 31.79 470.5 10,146 67.3 1769 62.40 3.76
APC 10x8-E 4 14.8 34.73 514.0 9,883 74.9 1742 61.45 3.39
APC 10x10-E 4 14.8 43.55 644.6 9,151 86.7 1474 51.99 2.29
APC 11x5.5-E 4 14.8 33.84 500.8 9,965 51.9 2206 77.81 4.40
APC 11x7-E 4 14.8 38.49 569.7 9,521 63.1 2225 78.48 3.91
APC 11x7x3-E 4 14.8 37.37 553.0 9,661 64.0 2385 84.13 4.31
APC 11x8-E 4 14.8 41.28 611.0 9,283 70.3 2119 74.74 3.47
APC 11x8-F 4 14.8 35.28 522.1 9,808 74.3 2117 74.67 4.05
APC 11x8.5-E 4 14.8 43.80 648.2 9,049 72.8 2065 72.84 3.19
APC 11x10-E 4 14.8 49.65 734.8 8,763 83.0 1871 66.00 2.55
APC 12x6-E 4 14.8 42.24 625.1 9,219 52.4 2569 90.62 4.11
APC 12x8-E 4 14.8 50.80 751.9 8,792 66.6 2295 80.95 3.05
APC 12x8.5-F 4 14.8 42.68 631.7 9,143 73.6 2491 87.87 3.94
APC 13x4-E 4 14.8 36.91 546.3 9,657 36.6 2642 93.19 4.84
APC 13x5.5-E 4 14.8 43.81 648.4 9,018 47.0 2811 99.15 4.34
BadAss 10x5-W 4 14.8 21.83 323.1 10,987 52.0 1475 52.03 4.57
BadAss 10x6-W 4 14.8 28.77 425.8 10,391 59.0 1451 51.18 3.41
BadAss 10x7-W 4 14.8 30.97 458.4 10,205 67.6 1383 48.78 3.02
BadAss 10x8-W 4 14.8 34.21 506.3 9,930 75.2 1508 53.19 2.98
BadAss 11x5-W 4 14.8 28.19 417.2 10,446 49.5 1848 65.19 4.43
BadAss 11x6-W 4 14.8 32.45 480.2 10,081 57.3 2059 72.63 4.29
BadAss 11x7-W 4 14.8 32.75 484.6 10,053 66.6 2022 71.32 4.17
BadAss 11x8-W 4 14.8 40.89 605.2 9,385 71.1 1710 60.32 2.83
BadAss 12x6-W 4 14.8 38.16 564.8 9,595 54.5 2289 80.74 4.05
BadAss 12x7-W 4 14.8 43.94 650.3 9,030 59.9 2277 80.32 3.50
BadAss 12x8-W 4 14.8 51.36 760.1 8,725 66.1 1991 70.23 2.62
BadAss 13x6-W 4 14.8 43.97 650.8 9,048 51.4 2672 94.25 4.11
BadAss 13x8-W 4 14.8 56.11 830.5 8,372 63.4 2609 92.03 3.14
GemFan 9x5-F 4 14.8 16.66 246.5 11,425 54.1 1223 43.14 4.96
GemFan 10x6-F 4 14.8 24.04 355.8 10,800 61.4 1653 58.31 4.65
GemFan 11x8-F 4 14.8 41.83 619.1 9,252 70.1 1931 68.11 3.12
GemFan 12x8-F 4 14.8 51.29 759.1 8,713 66.0 2337 82.43 3.08
MAS 8x6x3 4 14.8 17.74 262.5 11,340 64.4 1185 41.80 4.51
MAS 9x7x3 4 14.8 27.21 402.7 10,539 69.9 1693 59.72 4.20
MAS 10x5x3 4 14.8 24.82 367.3 10,734 50.8 1746 61.59 4.75
MAS 10x7x3 4 14.8 34.40 509.1 9,906 65.7 2095 73.90 4.12
MAS 11x7x3 4 14.8 40.21 595.1 9,407 62.4 2365 83.42 3.97
MAS 11x8x3 4 14.8 42.83 633.9 9,245 70.0 2400 84.66 3.79
MAS 12x6x3 4 14.8 45.19 668.9 9,211 52.3 2691 94.92 4.02
 
5-cell Li-Po Test Data
Prop Prop Li-Po Input Motor Input Prop Pitch Speed Thrust  Thrust Thrust Eff.
Manf. Size Cells Voltage Amps Watts RPM in MPH Grams Ounces Grams/W
APC 7x7-E 5 18.5 19.93 368.7 14,139 93.7 1064 37.53 2.89
APC 8x4-E 5 18.5 18.23 337.3 14,293 54.1 1364 48.11 4.04
APC 8x6-E 5 18.5 26.04 481.8 13,585 77.2 1579 55.70 3.28
APC 8x8-E 5 18.5 31.75 587.4 13,064 99.0 1499 52.88 2.55
APC 9x4.5-E 5 18.5 26.22 485.1 13,561 57.8 1971 69.52 4.06
APC 9x6-E 5 18.5 30.49 564.0 13,195 75.0 1890 66.67 3.35
APC 9x7.5-E 5 18.5 45.09 834.2 11,851 84.2 1874 66.10 2.25
APC 9x8x3-E 5 18.5 43.50 804.8 12,012 91.0 2531 89.28 3.15
APC 9x9-E 5 18.5 49.33 912.5 11,775 100.4 1898 66.95 2.08
APC 10x5-E 5 18.5 36.08 667.4 12,675 60.0 2315 81.66 3.47
APC 10x6-E 5 18.5 39.55 731.6 12,341 70.1 2348 82.82 3.21
APC 10x7-E 5 18.5 46.09 852.6 12,080 80.1 2486 87.69 2.92
APC 10x8-E 5 18.5 51.20 947.1 11,725 88.8 2428 85.64 2.56
APC 11x5.5-E 5 18.5 49.83 921.9 11,711 61.0 3119 110.02 3.38
BadAss 10x5-W 5 18.5 31.15 576.2 13,130 62.2 2111 74.46 3.66
BadAss 10x6-W 5 18.5 40.03 740.5 12,290 69.8 2003 70.65 2.71
BadAss 10x7-W 5 18.5 42.87 793.0 12,034 79.8 1895 66.84 2.39
BadAss 10x8-W 5 18.5 46.90 867.7 11,634 88.1 2036 71.82 2.35
BadAss 11x5-W 5 18.5 39.93 738.6 12,281 58.1 2584 91.15 3.50
BadAss 11x6-W 5 18.5 46.08 852.6 12,025 68.3 2889 101.90 3.39
GemFan 9x5-F 5 18.5 23.64 437.4 13,809 65.4 1797 63.39 4.11
GemFan 10x6-F 5 18.5 33.99 628.8 12,864 73.1 2367 83.49 3.76
MAS 7x4x3 5 18.5 12.66 234.2 14,137 53.5 919 32.42 3.92
MAS 8x6x3 5 18.5 25.29 467.9 13,665 77.6 1746 61.59 3.73
MAS 9x7x3 5 18.5 37.91 701.4 12,498 82.8 2419 85.33 3.45
MAS 10x5x3 5 18.5 35.10 649.4 12,757 60.4 2536 89.45 3.90
MAS 10x7x3 5 18.5 48.81 903.0 11,794 78.2 2991 105.50 3.31
 
6-cell Li-Po Test Data
Prop Prop Li-Po Input Motor Input Prop Pitch Speed Thrust  Thrust Thrust Eff.
Manf. Size Cells Voltage Amps Watts RPM in MPH Grams Ounces Grams/W
APC 7x6-E 6 22.2 22.25 494.0 16,816 95.5 1435 50.62 2.90
APC 7x7-E 6 22.2 27.53 611.2 16,346 108.4 1431 50.48 2.34
APC 8x4-E 6 22.2 25.74 571.4 16,515 62.6 1836 64.76 3.21
APC 8x6-E 6 22.2 36.68 814.3 15,597 88.6 2100 74.07 2.58
APC 8x8-E 6 22.2 43.64 968.8 14,863 112.6 1964 69.28 2.03
APC 9x4.5-E 6 22.2 36.87 818.4 15,599 66.5 2717 95.84 3.32
APC 9x6-E 6 22.2 42.48 943.1 15,020 85.3 2483 87.58 2.63
APC 10x5-E 6 22.2 50.23 1115.2 14,497 68.6 3010 106.17 2.70
BadAss 10x5-W 6 22.2 42.58 945.2 14,995 71.0 2707 95.49 2.86
BadAss 10x6-W 6 22.2 53.69 1191.9 14,186 80.6 2645 93.30 2.22
MAS 7x4x3 6 22.2 16.80 372.9 17,343 65.7 1278 45.08 3.43
MAS 8x6x3 6 22.2 33.79 750.2 15,832 90.0 2381 83.99 3.17
MAS 9x7x3 6 22.2 50.65 1124.4 14,480 96.0 3299 116.37 2.93
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)
Notes about Propellers used in the Motor Tests
APC Props with -E on the part number are from the APC Thin Electric Series.  Example:  APC 10x6-E
APC Props with -F on the part number are from the APC Folding Electric Series.  Example:  APC 11x8-F
APC Props with -SF on the part number are from the APC Slow-Fly Electric Series.  Example:  APC 10x4.7-SF
APC Props with -P on the part number are from the APC Pylon Racing Series.  Example:  APC 6.5x5.5-P
BadAss Props with -W on the part number are from the BadAss Electric Wood Series.  Example:  BadAss 11x6-W
GemFan Props with -F on the part number are from the GemFan Folding Electric Series.  Example:  GemFan 10x6-F
MAS Props are Master Airscrew 3-Blade Propellers.  Example:  MAS 10x5x3
PLEASE NOTE:
The Data contained in this Prop Chart is based on actual measurements, taken in a controlled test environment, at an altitude of
584 feet above sea level.  The test voltages used are based on the standard output of a Li-Po battery under load, which is 3.70 volts
per cell.  If you are using a battery that is larger in capacity than normal, or has a very high C-rating, then your actual voltages will
be higher than those shown in the chart, and this will result in a higher current and power value for every prop used.  You should
always test your actual power system with a watt meter before flying your model to make sure that you are not exceeding the 
recommended current and power ratings of the motor being used.  The prop recommendations in this chart assume that the motor
receives adequate cooling throughout its operation.  If your motor is being used inside a cowl or fuselage, you must ensure that
the motor receives sufficient airflow, and does not get too hot during operation.  It is always best to use a prop size that pulls no
more than 80% of the motors maximum recommended current value to ensure safe operation under all conditions.