CNC Spun Aluminum Nose Fairing for Long-Endurance UAV

1. Industry Background

The aerospace UAV (Unmanned Aerial Vehicle) industry demands exceptional performance in:

• Lightweight structural design
• Aerodynamic optimization
• Structural integrity
• Impact resistance
• Environmental durability

Our client, a leading UAV manufacturer, developed a long-endurance reconnaissance drone designed to operate under extreme conditions:

• High altitude: above 5,000 meters
• Strong wind conditions: ≥ 15 m/s
• Wide temperature range

The nose fairing, positioned at the UAV’s forward fuselage, is a critical aerodynamic and structural component. It must:

• Minimize aerodynamic drag
• Maintain structural rigidity
• Withstand impact loads
• Resist thermal cycling

The previous solution used a segmented welded fabrication process, which resulted in:

• Visible seams
• Higher drag coefficient (Cd = 0.32)
• Excess weight (1.1 kg)
• Structural detachment risk at high altitude

To meet performance requirements, the client required a seamless, one-piece CNC metal spinning solution.

2. Product Specifications

Custom CNC Spun 6063 Aluminum UAV Nose Fairing

• Maximum Diameter: Ø450 mm
• Height: 320 mm
• Aerodynamic streamlined geometry

Wall Thickness:

• Main body: 1.2 ± 0.1 mm
• Root flange (mounting section): 3.0 mm reinforced

Material:

• Aluminum Alloy 6063 (ASTM B209 compliant)
• Tensile strength: ≥ 215 MPa
• Yield strength: ≥ 170 MPa
• Excellent corrosion resistance and weldability

Surface Treatment:

• Clear anodizing
• Oxide thickness: 10–12 μm
• Surface hardness: ≥ 300 HV
  

3. Core Manufacturing Process

3.1 Material Inspection and Blank Preparation

• 6063 aluminum sheet certified to ASTM B209
• Ultrasonic testing (UT) to ensure no internal defects
• CNC laser cutting with ±0.05 mm tolerance
• Stress-relief annealing at 350°C for 1 hour

This process eliminates internal stress prior to spinning.

3.2 CNC Cold Metal Spinning

Manufactured using a horizontal 3-roller CNC spinning machine.

Process parameters:

• Feed rate: 5 mm/s
• Spinning force: 80 kN
• Multi-pass progressive cold spinning (4 passes)

Forming sequence:

• Pass 1: 25% reduction — primary contour shaping
• Pass 2–4: Progressive contour refinement

Result:

• Seamless, monolithic structure
• No weld lines
• No stress concentration zones
  

3.3 Precision Surface Refinement

• Custom fixturing system
• CNC surface grinding
• Surface roughness: Ra ≤ 0.8 μm
• Aerodynamic curvature tolerance: ≤ 0.1 mm

Ensures aerodynamic geometry accuracy.

3.4 Mounting Flange Machining

• CNC turning of root flange
• 6 × M8 threaded holes
• Thread tolerance class: 6H

Ensures secure fuselage integration.

3.5 Surface Treatment

Pre-treatment:

• Degreasing
• Acid pickling
• Alkaline cleaning

Followed by anodizing:

• Uniform oxide layer formation
• Hardness ≥ 300 HV
• Enhanced corrosion and wear resistance
  

3.6 Finished Product Inspection

• 3D laser scanning for full profile verification
• Wind tunnel testing for drag coefficient validation
• Drop impact testing (1 kg steel ball from 1 m height)
• Thermal cycling test: -40°C to 60°C

Results:

• No deformation
• No cracking
• No coating delamination
  

4. Our Core Advantages

4.1 Aerodynamic Precision Engineering

Through design optimization and iterative wind tunnel validation, we achieved:

Drag coefficient (Cd): 0.25

Improvement over previous solution: -21.9%

Exceeding client target (Cd ≤ 0.30).

4.2 Lightweight Structural Optimization

Weight reduction:

1.1 kg → 0.8 kg

Reduction: 25%

Cold spinning ensures:

• Optimized grain flow orientation
• Increased impact strength (+40%)
• Superior fatigue resistance
  

4.3 Seamless One-Piece Forming

Compared to welded construction:

• Eliminates joint failure risk
• Eliminates stress concentration
• Improves structural integrity
• Product yield rate: 99.8%
• Service life extended to 8 years
  

4.4 Rapid Customization Capability

• In-house engineering & programming team
• 3D CAD-to-spinning path conversion
• Prototype delivery within 7 days
• Flexible transition from low-volume to mass production
  

5. Product Validation and Performance Testing

Aerodynamic Performance

Wind tunnel verified:

Cd = 0.25

21.9% drag reduction

UAV endurance increased by 15%.

Structural Strength Testing

• 1 kg impact test: no visible damage
• Mounting tensile strength ≥ 3000 N
• 50-cycle thermal test (-40°C to 60°C): no structural degradation

Material & Surface Verification

• Spectrographic alloy confirmation (6063)
• 360-hour salt spray test: no corrosion
• Surface hardness ≥ 300 HV

Certification & Compliance

• AS9100 Aerospace Quality Management System
• Compliant with GB/T 38940-2020 Civil UAV Safety Standard

6. Customer Value Delivered

Aerodynamic & Endurance Improvement

• 21.9% drag reduction
• 15% endurance increase

Weight Reduction & Flight Safety

• 25% weight reduction
• Improved stability in strong wind (+30%)
• Eliminated joint detachment risk

Dimensional Accuracy & Assembly Efficiency

• Full-profile 3D laser validation
• Geometry deviation ≤ 0.1 mm
• Assembly efficiency improved by 50%

Scalable Production

• Monthly capacity: 3,000 units
• Prototype lead time: 7 days
• Supports rapid UAV model iteration