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The EMAX ECO II 4215 is a high-output brushless motor platform for 13-inch multirotor propellers. Four winding options—350KV, 420KV, 520KV and 660KV—cover 6S through 12S power systems, while the 12N14P architecture, 49.1mm diameter, 65.35mm length, M6 threaded propeller shaft and 30 × 30mm mounting pattern provide a practical foundation for large multirotor propulsion.
High-voltage 13-inch propulsion. The 350KV configuration supports up to 12S, and the supplied 48V bench test recorded as much as 8.13kg of thrust with an HQ 1309 three-blade propeller.
Published electrical limits come from the supplied EMAX specification workbook. Tested thrust values are the highest recorded values in the matching load-test workbooks.
Choose from the complete aircraft backward. Match motor KV to battery voltage, propeller load, ESC rating, aircraft mass, airflow and required thrust. Published ranges are selection guidance; validate the final power system under realistic thermal conditions.
Each bar shows the highest thrust recorded in the supplied test workbook for that winding. All bars share an 8.13kg scale.
Maximum values above were recorded with an HQ 1309 three-blade propeller. Bench results are configuration-dependent and are not guaranteed aircraft-level performance.
Steel shaft construction supports the long M6 threaded propeller interface used by the 4215 platform.
Anodized metal surfaces provide a durable finish for regular installation and service.
A four-hole 30 × 30mm mounting pattern provides a defined mechanical interface for the airframe.
Multi-strand winding is specified for the high-current operating range of this large outrunner.
Precision bearing hardware supports smooth rotation under sustained propeller load.
Long silicone motor leads provide routing flexibility during large-airframe power-system installation.
| Motor model | EMAX ECO II 4215 |
|---|---|
| Framework | 12N14P |
| Motor diameter | Ø49.1mm |
| Motor length | 65.35mm |
| Weight | 209g; 660KV listed at 210g, without silicone wire |
| Bearing shaft | Ø6mm |
| Propeller shaft | M6 threaded |
| Shaft direction | CW thread |
| Mounting pattern | 30 × 30mm, four-hole |
| Motor leads | 300mm 16 AWG silicone wire |
| Propeller specification | 13 inches |
| KV options | 350KV / 420KV / 520KV / 660KV |
The shared mechanical package makes it possible to select a winding around the intended voltage without changing the motor's basic airframe interface.
The published 6S–12S envelope belongs to the complete product family. Each individual KV option has its own cell-count limit shown in the electrical table below.
Installation note: Confirm frame clearance, screw engagement, propeller retention, ESC headroom and cooling before operation.
Performance without unnecessary complexity. The ECO II 4215 combines a consistent mechanical platform with four winding choices for large multirotor builders who need to match voltage, current and thrust targets.
Use only the voltage range published for the selected winding. The 520KV and 660KV cell references below are reconciled with the supplied 32V and 25V test files and the published maximum-power values.
| KV | Cells | Propeller | Idle Current | Resistance | Peak Current | Max Power |
|---|---|---|---|---|---|---|
| 350KV | 6S–12S | 13" | 1.0A @ 10V | 62mΩ | 71A @ 12S | 3408W @ 12S |
| 420KV | 6S–10S | 13" | 1.2A @ 10V | 49mΩ | 81A @ 10S | 3240W @ 10S |
| 520KV | 6S–8S | 13" | 1.9A @ 10V | 38mΩ | 75A @ 8S | 2400W @ 8S |
| 660KV | 6S | 13" | 2.3A @ 10V | 26mΩ | 90A @ 6S | 2250W @ 6S |
The expandable tables show the final, highest-load row from each propeller set in the supplied workbooks.
| Voltage | Propeller | Current | Thrust | Power | Efficiency |
|---|---|---|---|---|---|
| 48V | Gemfan 1310, 3-blade | 62.2A | 7500g | 2985.6W | 2.51g/W |
| 48V | HQ 1309, 3-blade | 70.7A | 8130g | 3393.6W | 2.40g/W |
| 48V | 13 × 4 carbon-fiber, 2-blade | 36.2A | 6080g | 1737.6W | 3.50g/W |
Final recorded row from each 350KV propeller series. RPM was marked "Max" rather than numerically reported at these endpoints.
| Voltage | Propeller | Current | Thrust | Power | Efficiency |
|---|---|---|---|---|---|
| 40V | Gemfan 1310, 3-blade | 71.3A | 7250g | 2852W | 2.54g/W |
| 40V | HQ 1309, 3-blade | 80.6A | 7840g | 3224W | 2.43g/W |
| 40V | 13 × 4 carbon-fiber, 2-blade | 42.0A | 5780g | 1680W | 3.44g/W |
Final recorded row from each 420KV propeller series. RPM was marked "Max" rather than numerically reported at these endpoints.
| Voltage | Propeller | Current | Thrust | Power | Efficiency |
|---|---|---|---|---|---|
| 32V | HQ 1309, 3-blade | 73.9A | 6350g | 2364.8W | 2.69g/W |
Final recorded row from the supplied 520KV load-test series.
| Voltage | Propeller | Current | Thrust | Power | Efficiency |
|---|---|---|---|---|---|
| 25V | HQ 1309, 3-blade | 85.3A | 5980g | 2132.5W | 2.80g/W |
Final recorded row from the supplied 660KV load-test series.
Package contents: one EMAX ECO II 4215 brushless motor, four M4 × 12mm screws, one steel M6 nylock nut and one propeller washer.
