Out-slot
Outrunner Brushless – High-Torque Stator Cores for UAV & Drone Propulsion
Outrunner motor torque limiting your drone's payload? Stator quality inconsistent? Need a reliable UAV motor stator partner in China?Outrunner brushless motors are the dominant propulsion technology for drones and UAVs—delivering exceptional torque density, smooth low-speed operation, and direct-drive efficiency for propeller applications. As an outrunner brushless UAV motor stator supplier in China, Reenives delivers precision stator cores with 0.2mm ultra-thin silicon steel, 12N14P or 24N22P configurations, burr height < 0.03mm, and epoxy coating—maximizing torque density, reducing core loss by up to 30%, and enabling reliable propulsion for FPV racing, UAV logistics, agriculture, and eVTOL applications worldwide.
- •What Is Outrunner Brushless?
- •Classification of Outrunner Brushless Stators
- •Technical Specifications & Verified Data
- •Applications: FPV Racing, UAVs, eVTOL & More
- •6-Step Engineering Selection Guide for Outrunner Stators
- •FAQ: Outrunner Brushless Stator Technical Questions
- •Why Reenives – Outrunner Brushless UAV Motor Stator Supplier in China
- •Dongguan Runlu Motor Technology Co., Ltd.
What Is Outrunner Brushless?
Outrunner brushless refers to a brushless DC motor configuration where the permanent magnet rotor spins on the outside of the stator electromagnets. In this design, the stator is fixed to the motor shaft, while the rotor rotates around it. This external-rotor configuration allows the motor to contain more magnetic poles of greater strength than would be possible if the magnets had to be arranged on a smaller diameter inner space, making outrunner motors ideal for drone direct-drive systems.
Key advantages of outrunner brushless motors:
- High torque density – Large rotor diameter provides mechanical advantage for direct-drive propellers
- Smooth low-speed operation – Excellent for drone hover and precision control
- Direct drive capability – No gearbox needed; propeller mounts directly to the rotor
- High efficiency – Eliminates gearbox losses for maximum energy efficiency
ⓘ Outrunner brushless insight:"Outrunner brushless motors are the preferred choice for drone propulsion because they deliver high torque directly to the propeller without heavy gearboxes—maximizing efficiency and reliability."
Reenives manufactures precision outrunner brushless stator cores using imported 0.2mm silicon steel, progressive stamping dies, and automated epoxy powder coating—enabling maximum torque density for demanding drone, UAV, and eVTOL applications.
Classification of Outrunner Brushless Stators
Reenives supplies outrunner brushless stators across four primary series, tailored to different power classes and applications:
| Series | Power Range | Stator OD (mm) | Slot/Pole Configuration | Lamination Thickness | Best For |
|---|---|---|---|---|---|
| Series A – Micro Outrunner | <500W | 12–22mm | 9N12P | 0.15–0.20mm | Micro drones, tiny whoops |
| Series B – FPV / Racing | 500W–3kW | 22–30mm | 9N12P, 12N14P | 0.15–0.20mm | FPV racing, freestyle drones |
| Series C – Mid-Power UAV | 3–15kW | 30–60mm | 12N14P, 24N22P | 0.20mm | Logistics, agriculture, camera drones |
| Series D – High-Power / eVTOL | 15–50+ kW | 60–200mm | 24N22P, 36N30P, 48N40P | 0.20mm | Heavy-lift, eVTOL, electric aviation |
Outrunner brushless stators are characterized by:
- Large diameter – Up to 200mm to accommodate high torque requirements
- Multi-pole configurations – 9N12P, 12N14P, 24N22P, 36N30P for smooth torque
- Thin laminations – 0.15–0.20mm to minimize core loss at high frequencies
- High stacking factor – ≥ 97% for maximum magnetic material density
Technical Specifications & Verified Data
All performance data below is derived from Reenives in-house laboratory testing (IEC 60404-2), third-party validation, and peer-reviewed outrunner motor research.
| Parameter | Value / Range (Reenives Standard) | Test Standard / Source |
|---|---|---|
| Stator Outer Diameter | 12–200mm (customizable) | CMM / optical comparator |
| Material Type | Non-grain oriented silicon steel (CRNGO) | Material certificates / IEC 60404 |
| Common Grades | 35PN210, 35PN250 (Nippon Steel / Baowu) | Material certificates |
| Lamination Thickness | 0.15mm / 0.20mm / 0.27mm / 0.35mm | Micrometer / IEC 60404-2 |
| Core Loss @ 1.0T, 400Hz (0.20mm) | ≤ 8.5 W/kg — 30% lower than 0.35mm | IEC 60404-2 / Reenives R&D |
| Saturation Flux Density Bs | 1.68 – 1.72 T | Epstein frame test |
| Burr Height (max) | < 0.03mm | Optical measurement |
| Epoxy Coating Thickness | 30–60 µm, dielectric > 2.5 kV | ASTM D149 |
| Stacking Factor | ≥ 97% | Weight method |
| Concentricity Tolerance | ±0.01mm – ±0.015mm | CMM measurement |
| Slot/Pole Configurations | 9N12P, 12N14P, 24N22P, 36N30P, custom | Reenives design standards |
| Winding Factor (12N14P) | 0.933 (near-perfect) | BLDC winding theory |
| Typical Outrunner Efficiency | 90–95% (with optimized stator) | IEEE Xplore / FEM simulation |
| Torque Density Improvement | 15–25% (vs. standard 0.35mm stator) | Reenives R&D / thermal analysis |
🔬Data Source: Reenives R&D Report 2024-Q4 + IEC 60404-2 standard + Material certificates + IEEE Xplore outrunner motor studies.
Applications: FPV Racing, UAVs, eVTOL & More
Outrunner brushless stator cores power a wide range of drone and UAV applications:
| Application | Power Range | Stator Requirements | Performance Priorities |
|---|---|---|---|
| FPV Racing Drones | 500W–3kW | 9N12P/12N14P, 0.15–0.20mm | High RPM, rapid acceleration, responsiveness |
| Logistics & Delivery Drones | 3–15kW | 24N22P, 0.20mm, high efficiency | Long flight time, payload capacity, reliability |
| Agriculture Spraying UAVs | 3–15kW | 24N22P, corrosion-resistant coating | Heavy payload, dust/chemical resistance, durability |
| eVTOL / Air Taxis | 15–50+ kW | 36N30P, 48N40P, 0.20mm | Safety, redundancy, high continuous power |
| Heavy-Lift Cargo Drones | 5–20kW | 24N22P, 36N30P | Maximum thrust, reliability, sustained power |
"Outrunner brushless motors with precision stator cores deliver exceptional torque density—enabling direct-drive propulsion without the complexity and losses of gearboxes."
6-Step Engineering Selection Guide for Outrunner Stators
For motor designers and procurement engineers, selecting the optimal outrunner brushless stator requires systematic evaluation. Here is a practical 6-step framework:
- Define Power & Torque Requirements – Identify your motor's performance targets:
- Continuous power: 500W, 5kW, 15kW, 50+ kW?
- Peak torque: How much overload capacity is needed?
- Operating RPM range: Low-speed high-torque or high-speed?
- Select Stator Outer Diameter – Match motor size to power class:
- 12–22mm: Micro outrunners (<500W)
- 22–30mm: FPV/racing (500W–3kW)
- 30–60mm: Mid-power UAV (3–15kW)
- 60–200mm: High-power/eVTOL (15–50+ kW)
- Choose Slot/Pole Configuration – Critical for torque and efficiency:
- 9N12P: Most common for FPV—excellent torque and smoothness
- 12N14P: Near-perfect winding factor (0.933)—most popular for UAVs
- 24N22P: High torque, low cogging, heavy-lift applications
- 36N30P: Maximum torque density for eVTOL
- 48N40P: Ultra-smooth, extreme power applications
- Specify Lamination Thickness – Thinner laminations reduce core loss at high frequencies:
- 0.15mm: Ultimate high-RPM performance, racing outrunners
- 0.20mm: Optimal balance—most outrunner applications
- 0.35mm: Not recommended for high-performance outrunner motors
ⓘ"0.20mm laminations reduce core loss by approximately 30% compared to 0.35mm—enabling 15–25% higher torque density."
- Verify Thermal & Structural Requirements – Outrunner motors demand:
- High stacking factor (≥ 97%) for maximum magnetic material
- Epoxy coating (30–60µm, Class H 180°C) for thermal durability
- Strong interlock or welding for structural integrity
- Precision concentricity (≤ ±0.01mm) for consistent air gap
- Choose a Specialist Outrunner Stator Supplier – Evaluate expertise:
- Experience with outrunner stator designs (9N12P, 12N14P, 24N22P, etc.)
- Ultra-thin lamination capability (0.15–0.20mm)
- Large diameter capability (up to 200mm)
- Precision stamping: burr < 0.03mm, concentricity ±0.01mm
- Epoxy coating for outrunner thermal environments
- Material certificates and third-party test reports
- Proven global track record with outrunner motor manufacturers
- Engineering support for outrunner motor optimization
FAQ: Outrunner Brushless Stator Technical Questions
Outrunner brushless refers to a brushless DC motor configuration where the permanent magnet rotor spins on the outside of the stator electromagnets. This external-rotor design allows the motor to contain more magnetic poles of greater strength than would be possible if the magnets had to be arranged on a smaller diameter inner space. Outrunner brushless motors are preferred for UAV applications because: (1) high torque density allows direct propeller drive without gearboxes—reducing weight and complexity, (2) large rotor diameter provides mechanical advantage for low-speed high-torque operation, (3) multi-pole designs deliver smooth torque with minimal cogging, and (4) elimination of gearbox losses improves overall efficiency.
For outrunner brushless UAV motors, the optimal stator core features: 0.20mm (or 0.15mm for racing) silicon steel, slot/pole configurations such as 9N12P, 12N14P, or 24N22P, burr height < 0.03mm, epoxy coating (30–60µm, Class H 180°C), and stacking factor ≥ 97%. The 12N14P configuration delivers a near-perfect winding factor of 0.933 and low cogging torque. Reenives specializes in these outrunner motor stator cores.
Lamination thickness directly impacts core loss in outrunner brushless motors. 0.20mm laminations achieve core loss ≤ 8.5 W/kg at 400Hz—approximately 30% lower than 0.35mm material. For outrunner motors, this reduction in core loss translates to: (1) higher torque density (15–25% improvement), (2) cooler operation, (3) higher efficiency (90–95%), and (4) reduced cooling requirements. 0.15mm laminations provide ultimate performance for racing and extreme applications.
For outrunner brushless drone motors, the optimal slot/pole configuration depends on the application: (1) 9N12P is most common for FPV and racing outrunners—excellent torque and smoothness, (2) 12N14P offers near-perfect winding factor (0.933) and is most popular for UAV applications, (3) 24N22P provides high torque with low cogging for heavy-lift and logistics drones, (4) 36N30P delivers maximum torque density for eVTOL applications. Reenives supports all these configurations with custom tooling.
Epoxy powder coating provides three critical functions for outrunner brushless stator cores: (1) electrical insulation between laminations to minimize eddy currents and prevent interlaminar shorts—critical for high-current operation, (2) thermal durability up to 180°C (Class H) to withstand the heat generated during sustained high-torque operation, and (3) corrosion resistance for outdoor UAV and marine applications. The coating thickness (30–60µm) is optimized with dielectric strength exceeding 2.5 kV.
Burr height is the raised edge left on stamped metal after the punching process. In outrunner stator cores, burr height must be maintained below 0.03mm because excessive burrs can: (1) damage enamel insulation on copper windings during assembly—causing short circuits, (2) create localized magnetic saturation points that reduce torque output, (3) increase core loss through eddy current concentration, and (4) reduce motor reliability—critical for UAV applications where motor failure means crashing. Reenives maintains burr height < 0.03mm through precision progressive stamping dies.
Yes. Reenives supports full customization of outrunner brushless stator cores including: stator outer diameter (12–200mm), lamination thickness (0.15–0.20mm), slot/pole configurations (9N12P, 12N14P, 24N22P, 36N30P, 48N40P, custom), stacking height, material grade, and epoxy coating specifications. Private mould development is available for high-volume OEM projects with exclusive design rights—from micro racing outrunners to large eVTOL propulsion systems.
Why Reenives – Outrunner Brushless UAV Motor Stator Supplier in China
Reenives has earned its reputation as a specialist outrunner brushless UAV motor stator supplier in China by combining advanced manufacturing technology with deep expertise in outrunner motor design and a reliable global supply chain.
Our Advantages — Outrunner Brushless Stator Specialists
- ✅Ultra-Thin Silicon Steel: 0.15–0.20mm laminations reduce core loss by up to 30%—enabling 15–25% higher torque density
- ✅Large Diameter Capability: Stator OD up to 200mm for high-power outrunner motors
- ✅Multi-Pole Expertise: 9N12P, 12N14P, 24N22P, 36N30P, 48N40P, and custom configurations
- ✅Precision Stamping: Burr height < 0.03mm, concentricity ±0.01mm, stacking factor ≥ 97%
- ✅Epoxy Coating: 30–60µm, Class H 180°C, dielectric > 2.5 kV
- ✅Full Customization: Private mould development for exclusive outrunner designs
- ✅Trusted Quality Control: IEC 60404-2 testing, third-party verification, material certificates
- ✅Global Export: Complete export qualifications with worldwide shipping from China
- ✅Proven Track Record: 4 years experience, 1,000+ enterprise clients, 100+ R&D patents
🇨🇳Our China supplier promise: Outrunner brushless stator cores that maximize torque density and thermal limits. Consistent quality that eliminates rework. Engineering support that optimizes your outrunner motor design. Reliable global supply chain from China that delivers on time. That's why Reenives is the trusted outrunner brushless UAV motor stator supplier in China.
⚡ Ready to maximize your outrunner brushless motor's torque density with precision stator cores?
Contact Reenives today for engineering consultation, OEM samples, and competitive global pricing from China.
📱 WhatsApp: +86-13377741885
Dongguan Runlu Motor Technology Co., Ltd.
Reenives — Professional Drone Stator Core Manufacturer
Founded in 2022, Reenives has rapidly grown into a trusted outrunner brushless UAV motor stator supplier in China for the worldwide drone, FPV, and eVTOL markets.
Independent R&D Technology · Imported stamping & epoxy powder coating production lines · Dust-free workshops · 4 years of manufacturing experience · Solved outrunner stator challenges for 1,000+ enterprises worldwide—including leading drone and UAV manufacturers.
From production to sales, we support bulk purchasing,private mould development, and sample making. We provide tailor-made solutions for your specific outrunner motor production scenarios—with competitive global pricing, consistent quality, and reliable on-time delivery.
🌐www.reenives-bldcmotor.com | 📧 linda_reenives@163.com | 📱 +86-13377741885
✈️ Global outrunner motor manufacturers welcome — consult, visit the factory, or request free samplestoday!
Reenives — Outrunner Brushless UAV Motor Stator Supplier in China
© 2026 Dongguan Runlu Motor Technology Co., Ltd. All rights reserved.
Comprehensive score