The EMAX ECO II 4320 is a large-format brushless outrunner for 13- to 15-inch FPV, long-range and heavy-lift multirotors. Four windings—350KV, 380KV, 420KV and 500KV—cover 6S through 12S systems around a 12N14P architecture, M6 propeller shaft and four-hole 30 × 30mm airframe mount.
Four KV options. One 4320 platform.350KV / 380KV: 8S–12S420KV: 8S500KV: 6SPublished propeller range: 13–15 inches
Motor weight298gIncluding 400mm leads
Motor sizeØ50.6mm68.7mm overall length
Mount30 × 30mmExactly four M4 holes
Framework12N14PLarge outrunner architecture
Large-prop power across four windings. Official EMAX bench sheets recorded up to 9.281kg of thrust, while the 350KV through 500KV range supports 6S–12S aircraft configurations.
01 / KV Selection
Match winding, voltage and propeller load.
Electrical limits and bench highlights come from the official ECO II 4320 specification and load-test sheets.
350KV
8S–12S / 13–15-inch props
Idle current1.5A @ 10V
Resistance47mΩ
Published peak82.1A / 3847W
Bench: 9.281kg at 47.04V, HQ1308 three-blade.
380KV
8S–12S / 13–15-inch props
Idle current1.7A @ 10V
Resistance44mΩ
Published peak69.3A / 3274W
Bench: 8.507kg at 47.24V, GF1308 three-blade.
420KV
8S / 13–15-inch props
Idle current1.9A @ 10V
Resistance39mΩ
Published peak82.5A / 2556W
Bench: 8.243kg at 30.96V, HQ1507 three-blade.
500KV
6S / 15-inch props
Idle current2.8A @ 10V
Resistance30mΩ
Published peak74.7A / 1797W
Bench: 6.490kg at 24.05V, HQ1507 three-blade.
02 / Performance Envelope
Maximum recorded thrust by winding.
350KV
9.281kg
380KV
8.507kg
420KV
8.243kg
500KV
6.490kg
Configuration-dependent maximum-throttle bench results from official EMAX load-test sheets.
03 / Construction
Large-outrunner hardware with precision support.
01 / SHAFT
Steel M6 Shaft
A CW-threaded M6 propeller interface and 6mm bearing section support the rotating assembly.
02 / ROTOR
Anodized Rotor Bell
The rigid outer bell surrounds a full-height 14-pole permanent-magnet ring.
03 / STATOR
12-Slot Wound Stator
Dense multi-strand copper windings form the fixed 12-slot stator.
04 / BEARING
Precision Bearing
Concentric bearing support promotes smooth rotation under sustained load.
05 / MOUNT
Four-Hole Mount
The 30 × 30mm base has exactly four M4 airframe mounting holes.
06 / LEADS
400mm 16 AWG Leads
Long silicone motor leads provide routing flexibility in large aircraft.
04 / Mechanical Data
4320 geometry and installation details.
Motor model
EMAX ECO II 4320
Framework
12N14P
Motor diameter
Ø50.6mm
Overall length
68.7mm
Weight
298g with wire
Bearing shaft
Ø6mm
Propeller shaft
M6 CW thread
Mounting pattern
30 × 30mm, four M4 holes
Motor leads
400mm 16 AWG silicone wire
Propeller range
13–15 inches, KV-dependent
One platform, four power profiles.
The shared 4320 mechanical package lets builders choose voltage and winding without changing the four-hole airframe interface.
The official drawing specifies 50.6mm diameter, 68.7mm overall length and a 30 × 30mm four-M4 mounting pattern.
Installation note: Confirm frame clearance, screw engagement, propeller retention, ESC headroom and cooling before operation.
