Tempest 2820-1940 Performance Test Data
Magnets Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (4S)
14-Pole 6-Turn Delta 1940 RPM/Volt Io = 5.20 Amps @ 10v Rm = 0.014 Ohms 80 Amps 1185 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. 137 gm,   4.83 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 4.782 A 5.197 A 5.724 A 6.022 A 1937 RPM/Volt @ 10v 0.0138 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 6.5x5.5-P 3 11.1 35.58 394.9 19,341 100.7 990 34.92 2.51
APC 6.5x6.0-P 3 11.1 39.40 437.3 19,053 108.3 978 34.50 2.24
APC 6.5x6.5-P 3 11.1 42.05 466.7 18,833 115.9 937 33.05 2.01
APC 7x4-E 3 11.1 47.00 521.7 18,580 70.4 1564 55.17 3.00
APC 7x4-SP 3 11.1 37.05 411.3 19,356 73.3 1417 49.98 3.45
APC 7x5-E 3 11.1 55.93 620.9 17,889 84.7 1513 53.37 2.44
APC 7x5-SP 3 11.1 42.87 475.8 18,791 89.0 1387 48.92 2.91
APC 7x6-E 3 11.1 57.58 639.2 17,751 100.9 1594 56.23 2.49
APC 7x6-SP 3 11.1 47.59 528.2 18,421 104.7 1458 51.43 2.76
APC 7x7-E 3 11.1 67.98 754.6 16,914 112.1 1522 53.69 2.02
APC 7x9-SP 3 11.1 69.26 768.7 16,810 143.3 1214 42.82 1.58
APC 8x4-E 3 11.1 64.63 717.4 17,151 65.0 1968 69.42 2.74
APC 8x6-E 3 11.1 86.31 958.0 15,708 89.3 2163 76.30 2.26
MAS 6x4x3 3 11.1 28.40 315.2 19,904 75.4 1040 36.68 3.30
MAS 7x4x3 3 11.1 44.40 492.8 18,680 70.8 1513 53.37 3.07
MAS 8x6x3 3 11.1 80.29 891.3 16,099 91.5 2501 88.22 2.81
 
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 6x4-E 4 14.8 44.73 662.0 25,632 97.1 1419 50.05 2.14
APC 6x4.3E 4 14.8 57.72 854.3 24,593 100.1 1987 70.09 2.33
APC 6x4.5-E 4 14.8 53.41 790.5 24,930 106.2 1981 69.88 2.51
APC 6x5.5-E 4 14.8 54.39 805.0 24,845 129.4 1340 47.27 1.66
APC 6x6-E 4 14.8 58.87 871.2 24,484 139.1 1471 51.89 1.69
APC 6.5x5.0-P 4 14.8 55.09 815.3 24,746 117.2 1567 55.27 1.92
APC 6.5x5.5-P 4 14.8 58.47 865.3 24,488 127.5 1571 55.41 1.82
APC 6.5x6.0-P 4 14.8 64.24 950.7 24,033 136.6 1553 54.78 1.63
APC 6.5x6.5-P 4 14.8 67.27 995.5 23,813 146.6 1503 53.02 1.51
APC 7x4-SP 4 14.8 61.46 909.6 24,250 91.9 2159 76.16 2.37
APC 7x5-SP 4 14.8 70.39 1041.8 23,594 111.7 2128 75.06 2.04
APC 7x6-SP 4 14.8 79.24 1172.7 22,861 129.9 2189 77.21 1.87
MAS 6x4x3 4 14.8 44.93 665.0 25,608 97.0 1684 59.40 2.53
MAS 7x4x3 4 14.8 71.91 1064.3 23,516 89.1 2280 80.42 2.14
 
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 6x4-E 5 18.5 65.97 1220.4 30,585 115.9 1965 69.31 1.61
APC 6x4.3E 5 18.5 84.33 1560.0 28,947 117.9 2761 97.39 1.77
APC 6x4.5-E 5 18.5 76.22 1410.1 29,676 126.5 2815 99.30 2.00
APC 6x5.5-E 5 18.5 77.91 1441.4 29,530 153.8 1880 66.31 1.30
APC 6x6-E 5 18.5 84.35 1560.5 28,909 164.3 2009 70.86 1.29
APC 6.5x5.0-P 5 18.5 79.59 1472.3 29,361 139.0 2165 76.37 1.47
APC 6.5x5.5-P 5 18.5 83.98 1553.6 28,867 150.3 2162 76.26 1.39
APC 6.5x6.0-P 5 18.5 91.23 1687.8 28,163 160.0 2023 71.36 1.20
MAS 6x4x3 5 18.5 66.59 1232.0 30,559 115.8 2172 76.61 1.76
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
APC Props with -SP on the part number are from the APC Sport Glow Series.  Example:  APC 7x6-SP
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.