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Phoenix Rooivalk Mechanical Design - Architecture Decision Records

Executive Summary​

This document consolidates all Architecture Decision Records (ADRs) for the Phoenix Rooivalk mechanical design, covering critical design decisions for the RKV-M tilt-quad system. The ADRs document the rationale behind key mechanical design choices, trade-offs, and implementation strategies.

Design Philosophy: Modular, mission-adaptable mechanical architecture with emphasis on survivability, performance, and operational flexibility.

ADR-0001: Ducted vs Open Props for Tilt Pods (RKV-M-TQ)​

Status: Accepted • Date: 2025-09-25 • Owner: J

Context​

Tilt-quad pods must supply high static thrust, survive debris/strikes, control acoustic signature, and tolerate frequent tilt transitions. Outer duct = 0.60 m; tip clearance target ≥ 10 mm; pod centers x = 0.50/1.20 m, ±y = 0.795 m.

Options Considered​

  1. Ducted + Single rotor
  2. Ducted + Coax (3+3)
  3. Open + Single rotor
  4. Open + Coax

Decision​

Adopt Ducted + Single as the baseline tilt pod. Keep Ducted + Coax as a mission kit (TQ-XR) for hot/high or heavy payload cases. Open props are reserved for the QP tail pusher variant only.

Rationale​

  • Survivability & Safety: Duct protects tips and bystanders; best debris tolerance
  • Static Thrust & Control: Ducted single has higher FoM at hover; smoother transitions than coax; simpler mixer/faults
  • Acoustics: Duct enables lower tip speed for equal thrust; reduced tones vs open/coax
  • Mass/Complexity: Ducted single is lowest for protected pods
  • Mission Flexibility: Coax kit available for extreme conditions

Implementation​

  • Baseline Configuration: 4x ducted single-rotor tilt pods
  • Mission Kit: TQ-XR with ducted coax for high-altitude/heavy payload missions
  • Duct Design: 0.60m outer diameter with 10mm+ tip clearance
  • Pod Positioning: x = 0.50/1.20 m, ±y = 0.795 m

ADR-0002: Single vs Coaxial Rotor for Tilt Pods​

Status: Accepted • Date: 2025-09-26 • Owner: J

Context​

Decision between single and coaxial rotor configurations for the RKV-M tilt-quad system, considering performance, complexity, and mission requirements.

Options Considered​

  1. Single Rotor: One rotor per pod
  2. Coaxial Rotor: Two counter-rotating rotors per pod

Decision​

Single rotor for baseline configuration, with coaxial option available as mission kit for extreme conditions.

Rationale​

  • Performance: Single rotor provides higher figure of merit (FoM) at hover
  • Complexity: Single rotor reduces mechanical complexity and failure modes
  • Control: Simpler control mixing and fault handling
  • Mass: Lower mass for standard missions
  • Flexibility: Coaxial available for high-altitude/heavy payload missions

Implementation​

  • Baseline: Single rotor per tilt pod
  • Mission Kit: Coaxial configuration (TQ-XR) for extreme conditions
  • Control System: Simplified mixing for single rotor, advanced mixing for coaxial

ADR-0003: Blade Count Selection​

Status: Accepted • Date: 2025-09-27 • Owner: J

Context​

Selection of optimal blade count for the RKV-M tilt-quad system, balancing performance, acoustics, and manufacturing considerations.

Options Considered​

  1. 2-Blade: Simple, lightweight
  2. 3-Blade: Balanced performance and complexity
  3. 4-Blade: High performance, increased complexity
  4. 5+ Blade: Maximum performance, high complexity

Decision​

3-blade configuration for baseline, with 4-blade option for high-performance missions.

Rationale​

  • Performance: 3-blade provides optimal balance of thrust and efficiency
  • Acoustics: Reduced blade passing frequency compared to 2-blade
  • Manufacturing: Standard 3-blade manufacturing processes
  • Flexibility: 4-blade option for high-performance missions
  • Maintenance: Reasonable complexity for field maintenance

Implementation​

  • Baseline: 3-blade rotors for all tilt pods
  • High-Performance: 4-blade option for TQ-XR mission kit
  • Manufacturing: Standard 3-blade tooling and processes

ADR-0004: Powerplant Classes​

Status: Accepted • Date: 2025-09-28 • Owner: J

Context​

Selection of powerplant classes for the RKV-M system, considering power requirements, efficiency, and mission flexibility.

Options Considered​

  1. Electric: Battery-powered electric motors
  2. Hybrid: Electric with range-extending generator
  3. Turbine: Small gas turbine engines
  4. Multi-Fuel: Flexible fuel options

Decision​

Electric for baseline with Hybrid option for extended missions.

Rationale​

  • Efficiency: Electric provides highest efficiency for short missions
  • Reliability: Fewer moving parts, higher reliability
  • Maintenance: Simplified maintenance requirements
  • Flexibility: Hybrid option for extended range missions
  • Environmental: Zero emissions for electric operation

Implementation​

  • Baseline: High-performance electric motors with lithium-ion batteries
  • Extended Range: Hybrid system with range-extending generator
  • Power Management: Advanced power management and distribution

ADR-0005: Variant Strategy​

Status: Accepted • Date: 2025-09-29 • Owner: J

Context​

Development of variant strategy for the RKV-M system to address different mission requirements and operational environments.

Options Considered​

  1. Single Variant: One configuration for all missions
  2. Mission Kits: Modular kits for different missions
  3. Multiple Variants: Separate configurations for different missions
  4. Hybrid Approach: Base system with mission-specific kits

Decision​

Hybrid Approach: Base RKV-M system with mission-specific kits and variants.

Rationale​

  • Flexibility: Mission-specific optimization while maintaining commonality
  • Cost: Shared base system reduces development and production costs
  • Logistics: Common maintenance and training across variants
  • Performance: Optimized performance for specific mission requirements
  • Scalability: Easy to add new mission kits and variants

Implementation​

  • Base System: RKV-M with standard configuration
  • Mission Kits: TQ-XR (high-performance), TQ-LR (long-range), TQ-HP (heavy payload)
  • Variants: RKV-M (mothership), RKV-I (interceptor), RKV-G (ground control)

Design Specifications​

Tilt Pod Specifications​

  • Outer Duct Diameter: 0.60 m
  • Tip Clearance: ≥ 10 mm
  • Pod Centers: x = 0.50/1.20 m, ±y = 0.795 m
  • Rotor Configuration: 3-blade single rotor (baseline)
  • Powerplant: Electric motor with lithium-ion battery

Mission Kit Specifications​

  • TQ-XR (High-Performance): 4-blade coaxial rotors, hybrid powerplant
  • TQ-LR (Long-Range): Extended battery capacity, optimized aerodynamics
  • TQ-HP (Heavy Payload): Increased thrust capacity, reinforced structure

Performance Targets​

  • Hover Efficiency: Figure of Merit (FoM) > 0.7
  • Acoustic Signature: < 85 dB at 10m distance
  • Survivability: Debris tolerance, tip protection
  • Control Authority: Smooth tilt transitions, fault tolerance

Manufacturing Considerations​

Production Strategy​

  • Modular Design: Standardized components across variants
  • Mission Kits: Add-on components for mission-specific requirements
  • Commonality: Shared tooling and processes where possible
  • Flexibility: Easy reconfiguration for different missions

Quality Control​

  • Precision Manufacturing: Tight tolerances for aerodynamic performance
  • Testing: Comprehensive testing of all components and systems
  • Certification: Compliance with aviation and military standards
  • Documentation: Complete manufacturing and maintenance documentation

Supply Chain​

  • Standard Components: Use of commercial off-the-shelf (COTS) components where possible
  • Custom Components: Specialized components for unique requirements
  • Vendor Management: Multiple suppliers for critical components
  • Quality Assurance: Supplier qualification and ongoing monitoring

Maintenance and Support​

Field Maintenance​

  • Modular Replacement: Easy replacement of mission kits and components
  • Tool Requirements: Standard aviation tools and procedures
  • Training: Comprehensive maintenance training programs
  • Documentation: Detailed maintenance procedures and troubleshooting guides

Depot Maintenance​

  • Overhaul Procedures: Major overhaul and refurbishment procedures
  • Component Testing: Comprehensive testing of all components
  • Upgrade Paths: Clear upgrade paths for new mission requirements
  • Lifecycle Management: Component lifecycle tracking and replacement

Support Infrastructure​

  • Spare Parts: Comprehensive spare parts inventory and management
  • Technical Support: 24/7 technical support and troubleshooting
  • Training Programs: Ongoing training for operators and maintainers
  • Documentation: Complete technical and operational documentation

Future Enhancements​

Technology Roadmap​

  • Advanced Materials: Composite materials for weight reduction
  • Improved Aerodynamics: Advanced duct and rotor designs
  • Power Systems: Next-generation battery and hybrid systems
  • Control Systems: Advanced flight control and autonomy

Mission Expansion​

  • New Mission Kits: Additional mission-specific configurations
  • Performance Improvements: Enhanced performance capabilities
  • Operational Flexibility: Increased operational envelope
  • Integration: Enhanced integration with other systems

Conclusion​

The Phoenix Rooivalk mechanical design ADRs establish a comprehensive foundation for the RKV-M tilt-quad system. The modular, mission-adaptable architecture provides the flexibility to meet diverse operational requirements while maintaining commonality and cost-effectiveness.

The design decisions documented in these ADRs ensure optimal performance, reliability, and maintainability while providing the flexibility to adapt to changing mission requirements and operational environments.

This document contains confidential mechanical design specifications. Distribution is restricted to authorized personnel only. © 2025 Phoenix Rooivalk. All rights reserved.

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