Cobra C2808/16 Motor Propeller Data
Motor Wind Motor Kv No-Load Current Motor Resistance I Max P Max (3S)
16-Turn Delta 1780 RPM/Volt Io = 1.35 Amps @ 10v Rm = 0.037 Ohms 30 Amps 330 W 
Outside Diameter Body Length Total Shaft Length Shaft Diameter Motor Weight
35.0 mm,  1.38 in. 28.1 mm,  1.11 in. 48.0 mm,  1.89 in. 5.00 mm,  0.197 in. 80.5 gm,   2.85 oz
Prop Prop Input Motor Watts Prop Pitch Thrust  Thrust Thrust Eff.
Manf. Size Voltage Amps Input RPM Speed Grams Ounces Grams/W
APC 6x4-E 11.1 15.10 167.6 17,312 65.6 661 23.32 3.94
APC 6x5.5-E 11.1 18.87 209.5 16,716 87.1 676 23.84 3.23
APC 7x4-E 11.1 24.92 276.6 15,818 59.9 1077 37.99 3.89
APC 7x5-E 11.1 30.67 340.4 14,952 70.8 1040 36.68 3.05
APC 7x6-E 11.1 31.47 349.3 14,811 84.2 1103 38.91 3.16
APC 8x4-E 11.1 34.92 387.6 14,273 54.1 1352 47.69 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)
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.