Tempest 2820-970 Performance Test Data
Magnets Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (4S)
14-Pole 12-Turn Delta 970 RPM/Volt Io = 2.30 Amps @ 10v Rm = 0.038 Ohms 50 Amps 740 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 2.146 A 2.296 A 2.344 A 2.561 A 1034 RPM/Volt @ 10v 0.0376 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 9x6-E 3 11.1 17.15 190.3 9,629 54.7 979 34.53 5.14
APC 9x7.5-E 3 11.1 26.27 291.6 8,980 63.8 1046 36.90 3.59
APC 9x8x3-E 3 11.1 26.41 293.2 8,877 67.3 1339 47.23 4.57
APC 9x9-E 3 11.1 29.80 330.7 8,703 74.2 1014 35.77 3.07
APC 10x6-E 3 11.1 23.12 256.7 9,217 52.4 1322 46.63 5.15
APC 10x6-F 3 11.1 19.10 212.0 9,540 54.2 1129 39.82 5.33
APC 10x7-E 3 11.1 27.13 301.2 8,900 59.0 1343 47.37 4.46
APC 10x8-E 3 11.1 29.85 331.3 8,683 65.8 1347 47.51 4.07
APC 10x10-E 3 11.1 37.66 418.1 8,015 75.9 1117 39.40 2.67
APC 11x5.5-E 3 11.1 28.88 320.6 8,756 45.6 1653 58.31 5.16
APC 11x7-E 3 11.1 33.13 367.8 8,425 55.8 1706 60.18 4.64
APC 11x7x3-E 3 11.1 32.58 361.6 8,457 56.1 1815 64.02 5.02
APC 11x8-E 3 11.1 35.33 392.2 8,219 62.3 1649 58.17 4.20
APC 11x8-F 3 11.1 31.01 344.2 8,630 65.4 1616 57.00 4.70
APC 11x8.5-E 3 11.1 37.72 418.7 8,029 64.6 1638 57.78 3.91
APC 11x10-E 3 11.1 42.32 469.8 7,672 72.7 1419 50.05 3.02
APC 12x6-E 3 11.1 36.03 400.0 8,184 46.5 1960 69.14 4.90
APC 12x8-E 3 11.1 42.26 469.1 7,667 58.1 1701 60.00 3.63
APC 12x8.5-F 3 11.1 37.71 418.6 8,077 65.0 1927 67.97 4.60
APC 12x10-E 3 11.1 47.15 523.3 7,169 67.9 1696 59.82 3.24
APC 12x12-E 3 11.1 52.04 577.6 6,704 76.2 1431 50.48 2.48
APC 13x4-E 3 11.1 31.88 353.9 8,516 32.3 1993 70.30 5.63
APC 13x5.5-E 3 11.1 38.11 423.0 8,003 41.7 2147 75.73 5.08
APC 13x6.5-E 3 11.1 45.07 500.3 7,374 45.4 2205 77.78 4.41
APC 13x7-F 3 11.1 41.47 460.3 7,800 51.7 2206 77.81 4.79
APC 13x8-E 3 11.1 47.23 524.2 7,139 54.1 2138 75.41 4.08
APC 13x10-F 3 11.1 50.79 563.8 7,290 69.0 2311 81.52 4.10
APC 14x6-E 3 11.1 43.16 479.0 7,549 42.9 2383 84.06 4.97
BadAss 10x5-W 3 11.1 18.92 210.0 9,531 45.1 1097 38.69 5.22
BadAss 10x6-W 3 11.1 25.18 279.5 9,066 51.5 1093 38.55 3.91
BadAss 10x7-W 3 11.1 27.11 300.9 8,916 59.1 1051 37.07 3.49
BadAss 10x8-W 3 11.1 29.82 331.0 8,679 65.8 1142 40.28 3.45
BadAss 11x5-W 3 11.1 24.50 272.0 9,123 43.2 1393 49.14 5.12
BadAss 11x6-W 3 11.1 28.27 313.8 8,828 50.2 1560 55.03 4.97
BadAss 11x7-W 3 11.1 28.55 316.9 8,790 58.3 1536 54.18 4.85
BadAss 11x8-W 3 11.1 35.51 394.1 8,215 62.2 1313 46.31 3.33
BadAss 12x6-W 3 11.1 33.24 368.9 8,403 47.7 1756 61.94 4.76
BadAss 12x7-W 3 11.1 38.14 423.4 7,993 53.0 1878 66.24 4.44
BadAss 12x8-W 3 11.1 43.88 487.0 7,513 56.9 1496 52.77 3.07
BadAss 13x6-W 3 11.1 38.67 429.2 7,955 45.2 2050 72.31 4.78
BadAss 13x8-W 3 11.1 47.14 523.2 7,155 54.2 1943 68.54 3.71
BadAss 13x10-W 3 11.1 59.14 656.5 6,650 63.0 1750 61.73 2.67
BadAss 14x6-W 3 11.1 46.02 510.8 7,254 41.2 2221 78.34 4.35
BadAss 14x8-W 3 11.1 53.58 594.7 6,975 52.8 2420 85.36 4.07
GemFan 10x6-F 3 11.1 21.08 234.0 9,414 53.5 1253 44.20 5.35
GemFan 11x8-F 3 11.1 36.28 402.7 8,192 62.1 1497 52.80 3.72
GemFan 12x8-F 3 11.1 43.46 482.4 7,650 58.0 1777 62.68 3.68
GemFan 13x8-F 3 11.1 43.35 481.2 7,622 57.7 2096 73.93 4.36
MAS 9x7x3 3 11.1 24.05 266.9 9,187 60.9 1279 45.11 4.79
MAS 10x5x3 3 11.1 21.72 241.1 9,360 44.3 1309 46.17 5.43
MAS 10x7x3 3 11.1 30.40 337.5 8,670 57.5 1595 56.26 4.73
MAS 11x7x3 3 11.1 35.37 392.6 8,256 54.7 1806 63.70 4.60
MAS 11x8x3 3 11.1 37.75 419.0 8,056 61.0 1840 64.90 4.39
MAS 12x6x3 3 11.1 38.86 431.4 7,990 45.4 2012 70.97 4.66
MAS 12x8x3 3 11.1 48.38 537.0 7,058 53.5 2214 78.10 4.12
MAS 13x8x3 3 11.1 53.26 591.2 7,027 53.2 2426 85.57 4.10
 
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 7x7-E 4 14.8 18.51 274.0 12,959 85.9 886 31.25 3.23
APC 8x6-E 4 14.8 24.07 356.2 12,504 71.0 1318 46.49 3.70
APC 8x8-E 4 14.8 29.76 440.4 12,050 91.3 1261 44.48 2.86
APC 9x4.5-E 4 14.8 24.44 361.8 12,479 53.2 1614 56.93 4.46
APC 9x5-F 4 14.8 20.28 300.2 12,820 60.7 1316 46.42 4.38
APC 9x6-E 4 14.8 28.30 418.8 12,130 68.9 1578 55.66 3.77
APC 9x7.5-E 4 14.8 42.25 625.3 10,976 78.0 1589 56.05 2.54
APC 9x8x3-E 4 14.8 41.08 608.0 10,981 83.2 2099 74.04 3.45
APC 9x9-E 4 14.8 45.33 670.9 10,686 91.1 1546 54.53 2.30
APC 10x5-E 4 14.8 33.84 500.9 11,719 55.5 1967 69.38 3.93
APC 10x6-E 4 14.8 37.48 554.7 11,404 64.8 2017 71.15 3.64
APC 10x6-F 4 14.8 29.59 437.9 12,054 68.5 1818 64.13 4.15
APC 10x7-E 4 14.8 42.44 628.2 10,951 72.6 2047 72.21 3.26
APC 10x8-E 4 14.8 45.76 677.2 10,609 80.4 1993 70.30 2.94
APC 10x10-E 4 14.8 57.07 844.7 9,903 93.8 1691 59.65 2.00
APC 11x5.5-E 4 14.8 45.28 670.2 10,659 55.5 2557 90.19 3.82
APC 11x7-E 4 14.8 50.80 751.8 10,088 66.9 2547 89.84 3.39
APC 11x7x3-E 4 14.8 49.11 726.8 10,244 67.9 2755 97.18 3.79
APC 11x8-F 4 14.8 46.68 690.8 10,538 79.8 2470 87.13 3.58
APC 13x4-E 4 14.8 48.81 722.4 10,277 38.9 3044 107.37 4.21
BadAss 10x5-W 4 14.8 29.71 439.8 12,037 57.0 1768 62.36 4.02
BadAss 10x6-W 4 14.8 38.75 573.5 11,289 64.1 1690 59.61 2.95
BadAss 10x7-W 4 14.8 41.33 611.7 11,053 73.3 1612 56.84 2.63
BadAss 10x8-W 4 14.8 44.87 664.1 10,693 81.0 1726 60.88 2.60
BadAss 11x5-W 4 14.8 38.20 565.4 11,348 53.7 2179 76.86 3.85
BadAss 11x6-W 4 14.8 43.03 636.8 10,884 61.8 2393 84.41 3.76
BadAss 11x7-W 4 14.8 43.59 645.2 10,820 71.7 2373 83.70 3.68
BadAss 11x8-W 4 14.8 53.68 794.5 10,123 76.7 1974 69.63 2.48
BadAss 12x6-W 4 14.8 49.61 734.2 10,185 57.9 2589 91.32 3.53
GemFan 9x5-F 4 14.8 22.73 336.3 12,616 59.7 1502 52.98 4.47
GemFan 10x6-F 4 14.8 32.60 482.5 11,865 67.4 2001 70.58 4.15
GemFan 11x8-F 4 14.8 55.88 827.0 10,088 76.4 2285 80.60 2.76
MAS 8x6x3 4 14.8 24.20 358.2 12,503 71.0 1462 51.57 4.08
MAS 9x7x3 4 14.8 36.96 547.0 11,517 76.3 2051 72.35 3.75
MAS 10x5x3 4 14.8 33.99 503.0 11,787 55.8 2130 75.13 4.23
MAS 10x7x3 4 14.8 45.29 670.2 10,692 70.9 2439 86.03 3.64
MAS 11x7x3 4 14.8 53.54 792.4 10,258 68.0 2776 97.92 3.50
 
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 7x6-E 5 18.5 22.34 413.3 16,050 91.2 1305 46.03 3.16
APC 7x7-E 5 18.5 28.22 522.1 15,641 103.7 1289 45.47 2.47
APC 8x4-E 5 18.5 26.25 485.6 15,769 59.7 1673 59.01 3.45
APC 8x6-E 5 18.5 36.57 676.5 14,863 84.4 1895 66.84 2.80
APC 8x8-E 5 18.5 43.68 808.1 14,197 107.6 1777 62.68 2.20
APC 9x4.5-E 5 18.5 36.87 682.1 14,836 63.2 2421 85.40 3.55
APC 9x6-E 5 18.5 42.20 780.6 14,303 81.3 2234 78.80 2.86
APC 10x5-E 5 18.5 48.91 904.9 13,536 64.1 2657 93.72 2.94
APC 10x6-E 5 18.5 52.55 972.1 13,189 74.9 2660 93.83 2.74
BadAss 10x5-W 5 18.5 42.67 789.3 14,230 67.4 2466 86.98 3.12
BadAss 10x6-W 5 18.5 54.02 999.4 13,373 76.0 2338 82.47 2.34
BadAss 11x5-W 5 18.5 52.84 977.5 13,102 62.0 2941 103.74 3.01
GemFan 8x5-F 5 18.5 23.59 436.5 15,998 75.7 1571 55.41 3.60
GemFan 9x5-F 5 18.5 32.67 604.4 15,204 72.0 2171 76.58 3.59
MAS 7x4x3 5 18.5 17.45 322.7 16,470 62.4 1160 40.92 3.59
MAS 8x6x3 5 18.5 34.94 646.4 14,989 85.2 2129 75.10 3.29
MAS 9x7x3 5 18.5 51.39 950.7 13,667 90.6 2918 102.93 3.07
MAS 10x5x3 5 18.5 46.93 868.2 13,814 65.4 2992 105.54 3.45
 
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 7x4-E 6 22.2 24.99 554.8 19,225 72.8 1659 58.52 2.99
APC 7x5-E 6 22.2 30.84 684.7 18,677 88.4 1654 58.34 2.42
APC 7x6-E 6 22.2 31.88 707.7 18,580 105.6 1752 61.80 2.48
APC 7x7-E 6 22.2 38.28 849.8 17,957 119.0 1701 60.00 2.00
APC 8x4-E 6 22.2 36.73 815.5 18,119 68.6 2207 77.85 2.71
APC 8x6-E 6 22.2 50.37 1118.2 16,719 95.0 2429 85.68 2.17
APC 9x4.5-E 6 22.2 50.35 1117.7 16,762 71.4 3156 111.32 2.82
APC 9x6-E 6 22.2 58.30 1294.3 16,300 92.6 2869 101.20 2.22
MAS 7x4x3 6 22.2 23.60 523.9 19,360 73.3 1601 56.47 3.06
MAS 8x6x3 6 22.2 45.57 1011.6 17,216 97.8 2841 100.21 2.81
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.