Cobra CM-2820/32 Multirotor Motor, Kv=350
Cobra CM-2820/32 Multirotor Motor, Kv=350
Cobra Brushless Multirotor Motors offer performance and value for Your RC Models. They are built from high quality components, and are designed to give years of top-level performance. All Cobra Motors are shipped in a custom designed package that features protective foam on all sides, with separate compartments to protect the motor and accessory pack.

The Cobra CM-2820 series motors have a 5.0mm motor shaft for extra strength, as well as oversize ball bearings to support the shaft and provide a long life. The stators are made with 0.20mm laminations for maximum efficiency and minimum Eddy Current losses. Since these motors are typically soldered directly to the speed controller for reliability, the 2820 motors come without bullet connectors and feature extended pre-tinned motor leads that are 17 inches (430mm) long. These motors also have 3mm threaded holes in a 25x25mm pattern on the back plate for easy installation on your model.

The CM-2820 series motors include mounting options for both flat carbon fiber props and conventional style props. The top of the motor has a 4mm centering pin and four M3x0.5mm threaded holes on a 12mm mounting circle. Also included is a bolt-on style prop adapter that features an M6x1.0mm thread, along with a prop washer and nylon insert prop nut to provide solid attachment for standard style propellers that will not loosen up and slip during use.

Included with every Cobra CM-2820 Series Motor is a complete accessory package which contains the following items:

● Four M3x5mm Socket Head Screws
● Four M3x6mm Phillips Head Screws
● Two M3x8mm Socket Head Screws
● Machined Aluminum Top Plate for Carbon Fiber Props
● Machined Aluminum Prop Adapter
● Machined Aluminum Prop Washer
● Locking Prop Nut with Nylon Insert

Click here for the Cobra CM-2820/32 Propeller Data Chart

Cobra CM-2820/32 Motor Specifications
 Stator Diameter 28.0 mm (1.102 in)
 Stator Thickness 20.0 mm (0.787 in)
 Number of Stator Slots 12
 Number of Magnet Poles 14
 Motor Wind 32 Turn Delta
 Motor Kv Value 350 RPM per Volt
 No Load Current (Io) 0.33 Amps @ 15 Volts
 Motor Resistance (Rm) per Phase 0.300 Ohms
 Motor Resistance (Rm) Phase to Phase 0.200 Ohms
 Maximum Continuous Current 20 Amps
 Max Continuous Power (5-cell Li-Po) 370 Watts
 Max Continuous Power (6-cell Li-Po) 450 Watts
 Motor Weight 146 grams (5.15 oz.)
 Outside Diameter 35.0 mm (1.378 in.)
 Motor Shaft Diameter 5.00 mm (0.197 in.)
 Prop Shaft Diameter 6.00 mm (0.236 in.)
 Motor Body Length 46.4 mm (1.827 in.)
 Overall Shaft Length 52.6 mm (2.071 in.)
 Motor Timing 5-10 degrees
 PWM Frequency 8 KHz

Motor Performance Graphs

The following downloadable PDF files show the performance data curves of the Cobra CM-2820/32 motor, over its entire throttle range, with a variety of propellers. These graphs can be downloaded and printed to use as a reference for calculating power requirements at specific thrust levels, and enable the user to calculate flight times, current draw and other motor parameters.

5-Cell Li-Po Power

Cobra CM-2820/32 Performance Data with APC 18x5.5-MR prop on 5S Li-Po

Cobra CM-2820/32 Performance Data with RC-Timer 16x5.5-CF prop on 5S Li-Po

6-Cell Li-Po Power

Cobra CM-2820/32 Performance Data with APC 16x5.5-MR prop on 6S Li-Po

Cobra CM-2820/32 Performance Data with GemFan 16x4.5-MRW prop on 6S Li-Po

Cobra CM-2820/32 Performance Data with RC-Timer 14x5.5-CF prop on 6S Li-Po

Performance Graph Instructions

This downloadable PDF file shows the step by step process to use for interpreting the data shown in the Motor Performance Graphs. By following this procedure, you can determine how to select a proper motor for a Multirotor aircraft, as well as calculate required power levels, determine overall prop efficiency and calculate expected flight times based on the battery size that is used. This document can be printed out and saved as a valuable reference tool to keep in your workshop for future use as well.

Motor Performance Graph Instructions