SAFE Symposium London March 2010 Stewart Gregory Survitec Group - PowerPoint PPT Presentation

“Meeting the Thermal Burden Needs of Today’s Aircrew in Any Given Scenario” SAFE Symposium London March 2010 Stewart Gregory Survitec Group

Overview  Problem Statement  Approach to the Solution  Design Drivers  Comfort & Mobility  Sizing & Fit  Fully Integrated Design  Integrity  Manufacturability  Performance

The Problem Rectal Temperature (without LCG) Rectal Temperature (without LCG) 38.7 38.5 o C) 38.3 38.1 Rectal Temperature ( 37.9 37.7 37.5 37.3 37.1 36.9 36.7 36.5 0 20 40 60 80 100 120 140 160 180 200 220 240 Time (min) Heart Rate (Without LCG) 130 Heart Rate (Without LCG) 120 110 -1 ) 100 Heart Rate (beats.min 90 80 70 60 50 40 0 20 40 60 Donning & Baseline Exercise & Trial Rest Period Time (min) measurement

The Problem: Thermal Stress – Limiting Performance  Consequences of Thermal Stress: - Fatigue (increased heart rate, oxygen uptake) - Dehydration - Impaired Concentration - Ultimately reduces human performance and endurance  RFDB Solution → circulate cooled liquid around the body to extract heat and mitigate the onset of thermal stress

The Solution - Where do we begin?  Understanding the User’s Needs: - Local Environment - Mission Roles - Ambient Conditions

Design Drivers  Comfort & Mobility  Sizing & Fit  Fully Integrated Design  Integrity  Manufacturability  Performance

Comfort & Mobility  Maximising Endurance & Mission Effectiveness …“ comfortable pilot is an effective pilot!”…

Fully Integrated Design  Summer Land  Winter Land  Winter Sea  Chem Bio

LCV Design Summary FEATURE BENEFIT  Ergonomic Tabard Design - Ease of Donning & Doffing - Adjustment for fit - Reduced wear on garment - Minimal size range  Moisture Transfer System - Comfort - Minimises ‘chill effect’ - Encourages natural body cooling  Manifold & Network Tubing - Maximise heat transfer - Minimise pressure drop - Comfort (thermal sensation)  Materials Selection - Comfort and weight - Durability - Laundering (300 cycles)

Performance  Fast Jet Thermal Burden Human Physiology Trials

Performance – Thermal Burden Human Physiology Trials Specification Requirements  – Maintain body core temperature at or below 38.0 C (100.4F) – Environment conditions: 1% hot day • Ambient = 48.8 C (120 F) • Relative Humidity = 20% • Solar Load = 1120 W.m -2  Withdrawal Criteria – A trial was terminated if: • Rectal temperature exceeded 38.5 C (101.4 F) • Heart rate exceeded 165 beats per minute • The subject wished to be removed from the thermal chamber • The Supervising Medical Officer or the Principal Investigator, or a member of the Study Team thought it advisable to remove him

Performance – Thermal Burden Human Physiology Trials Pre-Test Preparation Ambient: Room Temperature 20 C, Air speed 0.5 m.s -1  1 male subject instrumented  Subject sat for 30 minutes at rest  LCV coolant set-up: Tyfoxit F50, Flow Rate 1.0 l.min -1 , Inlet Temperature 18 C Test Procedure (Worst Case Scenario) Ambient: Dry-bulb Temperature 48.8 C, RH 20%, Air speed 0.5 m.s -1  Subject entered chamber and donned AEA ensemble (Winter/Sea or Summer/Land or Winter/Sea with Chem. Bio & respirator)  Subject walked 50 metres on treadmill (LCV connected), ascended & descended 3 steps of a ladder (simulating aircrew ground operations)  Subject strapped into ejection seat and remained at rest for a period of 15 minutes (LCV disconnected) (simulating cockpit purging)  Subject executed 60 minute exercise regime (LCV connected) by means of a leg ergometer (simulating fast jet cockpit workload ~ 100 W.m -2 )  Subject walked 50 metres on treadmill (LCV connected), ascended & descended 3 steps of a ladder (simulating aircrew ground operations)  Subject doffed clothing ensemble and exited the chamber Nude body weight was recorded before and after each trial to calculate body fluid loss.

Performance – Thermal Burden Human Physiology Trials Change In Rectal Temperature Without LCV With LCV 39.2 39.0 38.8 38.5 C 38.6 Rectal Temperature ( o C) 38.4 38.2 38.0 37.8 37.6 37.4 37.2 37.0 36.8 36.6 36.4 36.2 0 10 20 30 40 50 60 70 80 90 100 110 Time (min) Baseline Donning & Cockpit Workload Measurement  Winter Sea clothing ensemble: • Without LCV: core temperature exceeded 38.5 C after 39 mins of exercise → trial aborted • With LCV: core temperature maintained below 38.5 C for duration of trial (~90 mins) → specification compliance

Performance – Thermal Burden Human Physiology Trials Heart Rate 140 without LCV with LCV 120 Heart rate (beats.min -1 ) 100 80 60 40 20 0 Duration of test Baseline Donning & Cockpit Workload Measurement  Winter Sea clothing ensemble: • Without LCV: heart rate increased to ~ 120 beats.min -1 • With LCV: heart rate maintained at ~ 85 beats.min -1

Performance – Thermal Burden Human Physiology Trials 1.6 1.5 Total Body Fluid Loss 1.4 1.2 Water Loss (litres) 1 0.8 0.6 0.6 0.4 0.2 0 With LCV 1 2 Without LCV  Winter Sea clothing ensemble: • Without LCV: total body water loss of 1.5 litres after 39 minutes of exercise • With LCV: total body water loss of 0.6 litres after full duration of trial

Performance – Thermal Burden Human Physiology Trials  Thermal Burden Comparison of LCV (Non operating) v Standard Cotton T-shirt  Ambient Temperature 35 C (95 C), Relative Humidity 40%, Air speed 0.5 m.s -1  Clothing Schedule: Summer Land  Test Protocol: As previous

Performance – Thermal Burden Human Physiology Trials LCV (Non operating) v Standard Cotton T-shirt Rectal Temperature 37.4 Non operating CG Cotton T-shirt 37.3 37.2 o C) Rectal temperature ( 37.1 37 36.9 36.8 36.7 0 20 40 60 80 100 120 Time (min)

Performance – Thermal Burden Human Physiology Trials LCV (Non operating) v Standard Cotton T-shirt Heart Rate 110.0 Non operating CG Cotton T-shirt 100.0 90.0 Heart rate (bt.min -1 ) 80.0 70.0 60.0 50.0 0 10 20 30 40 50 60 70 80 90 100 110 120 Time (min)

Performance – Thermal Burden Human Physiology Trials LCV (Non operating) v Standard Cotton T-shirt Total Body Water Loss 1.4 1.2 1.2 1 Sweat loss (L) 0.8 0.8 0.6 0.4 0.2 0 Non operating CG Cotton T-shirt

Performance – Thermal Burden Human Physiology Trials Soldier Cooling – Exercise Regime & Cognitive Assessment

Lessons Learned Liquid Cooling Liquid Cooling Air Cooling Full coverage torso 36 port cross-torso manifolds Closed loop system Single inlet outlet port Ergonomic tabard design 1960s 1980s Present

Pilot Cooling Unit and Associated Equipment

The Pilot Cooling Unit

The Pilot Cooling Unit

Handle Carry Scheme