Details

Introduction
The Practice Head is a detachable front module designed for integration with a Practice Torpedo to enable safe, non-explosive exercise firings. Fitted forward with a Homing Head and aft with an oxygen flask, it replaces the live warhead, providing positive buoyancy at
run-end so the torpedo resurfaces for recovery and post-launch analysis.

Key Features
- Advanced Buoyancy Control: A 140 L ballast compartment uses an air-releasing mechanism that opens when flask pressure falls below a set threshold. This forces water out through discharge valves, ensuring reliable positive buoyancy for surface recovery.
- Dynamic Depth Regulation: Integrated depth sensors and roll recorders work in tandem with automatic air-flask adjustments to maintain preset depths throughout the run, replicating warhead hydrodynamics without risking live explosives.
- Trim & Stability Assurance: Four internal AlMg5 reinforcement ribs and a concave separation plate ensure uniform stress distribution and prevent unintended pitch or roll under high-speed conditions.
- Modular Sensor Suite: Standardized front and rear collars (OD 500 mm & OD 532.4 mm, PCD 468 mm & PCD 516 mm with tapped holes) accommodate depth/roll recorders, signal flares, bellow-reducing valves, and noise makers in plug-and-play fashion.
- Hydrodynamic Efficiency: The tapered AlMg5 shell (OD 532.4 → 503.05 mm) minimizes drag, ensuring fidelity to live-warhead runs while reducing energy loss and turbulence.

Technical Specification

  

    

      
Property
      
Specification
    
  
  

    

      
Shell Material
      
Aluminum-Magnesium Alloy AlMg5; thickness 6–8 mm
    
    

      
Overall Length
      
1,204.20 mm (including collars)
    
    

      
Outer Diameter
      
532.4 mm tapering to 503.05 mm
    
    

      
Empty Mass / Assembled Mass
      
58.5 kg / 270 kg
    
    

      
Ballast Capacity
      
140 L
    
    

      
Test Pressures
      
External: 12 kgf/cm²; Ballast: 2 kgf/cm²; Instrument: 1 kgf/cm²
    
    

      
CG Location
      
~64 mm from rear end
    
    

      
Surface Defect Tolerances
      
Scratches ≤ 1/32″ deep & ≤ 3/4″ long; nicks/gouges ≤ 1/32″ deep & ≤ 1/8″ wide
    
  


Applications
- Surface & Subsurface Exercise Drills: Train submarine crews in torpedo deployment and handling against screened or unscreened targets, following NATO’s CASEX A-5 protocols for realistic counter-attack scenarios.
- Anti-Submarine Warfare (ASW) Training: Surface vessels and aircraft can practice detection and evasion tactics against exercise torpedoes equipped with acoustic beacons and homing heads.
- Harbor & Sea Trials: Validate torpedo handling in varied salinity and temperature profiles; recovery capability ensures minimal environmental impact and reusable instrumentation.
- Data Collection & Analysis: Retrieve detailed run-data—including depth profiles, roll angles, and light-signal events—for post-exercise forensic evaluation and system performance tuning.

Manufacturing & Quality Assurance
- Design Documentation: Complete CAD/T-DAP-A1828 series drawings for shell, collars, ribs, and separation plates, with FEA reports identifying stress concentrations under combined pressure and hydrodynamic loads.
- Material Testing: AlMg5 billets undergo tensile, hardness, and corrosion-resistance tests; anodizing per MIL-A-8625 for seawater durability. Test coupons accompany each batch for traceability.
- Welding & Assembly: Weld procedures qualified per ASTM B-594/82 & MIL-STD-2154 Class AA. In-process NDT (radiography, ultrasonic) verifies weld integrity. Custom jigs and fixtures ensure repeatable alignment of ribs and collars.
- Inspection Plan: First-article inspections cover dimensional checks, CG verification, pressure testing, and surface-finish assessments. Production units sampled per ANSI/ASQ Z1.4 lot-sampling for acceptance.

Test & Qualification Procedures
1. Fitment & Alignment: Assembly on torpedo body; verify CG within ±5 mm, conduct radiographic/NDT weld inspections.
2. Vibration: Sine-sweep 10–30 Hz @ 1.3 mm p-p, 31–60 Hz @ 2.3 g p-p for 60 min; leak checks pre- and post-test.
3. Shock: Half-sine shocks: 15 g ± 10% (10 ms) along X; 30 g ± 10% along Y/Z axes.
4. Bump: 1,000 bumps @ 4 Hz, 25 ± 3 mm drop, 400 ± 40 m/s2 peak (JSG 0102 Test 15U).
5. Pressure Cycling: External 12 kgf/cm2 × 20 min × 15 cycles; internal ballast 2 kgf/cm2 × 20 min.
6. Salt-Water Immersion: 18 h immersion + 6 h air dry; post-test visual & coating integrity check.
7. Buckling: Axial compression until yield to confirm design margin.
8. Harbor & Sea Trials: Dry-dock fit and harbor run with empty head; live-fire at sea with recovery.

Compartments & Functional Components
- Ballast Compartment (140 L):
  • Light device & depth/roll recorder
  • Signal flare ejector with pyrotechnic cartridges
  • Discharge & stop-cock valves, bellow-reducing and bypass valves
  • Automated air-release float mechanism and sinking plug

- Instrument Compartment (Dry):
  • Safety & recovery unit with sealed battery pack
  • Homing head electronics & influence exploder emulator
  • Acoustic noise maker and safety valve assembly

- Structural Ribs & Plates: Four AlMg5 frame ribs (Ø 516.4 mm, 15 mm thick) and one tapered-shell rib (Ø 520 → 518 mm) welded to maintain integrity under hydrodynamic
loading.

- External Mounts: Precision-machined collars and recesses for quick-release of recorders, flares, valves, and floats. Stainless-steel fastening inserts ensure corrosion resistance.

Conclusion
By marrying stringent naval standards with modular design, the Practice Head delivers safe, repeatable, and data-rich training for modern ASW and torpedo crews. Its robust AlMg5 construction, advanced buoyancy systems, and exhaustive qualification regimen ensure that
exercise torpedoes perform reliably under real-world conditions, yet remain fully recoverable for cost-effective reuse.