Issued Footwear Analysis

Braden Eagar Robert McClain25 Mar 09

ME EN 340 - 2

Overview

• Introduction• Functional Specifications• Measured Data• Results/Conclusions

Introduction

• To fly, fight and win, airmen need footwear that is comfortable and functional in a variety of environments.

• U.S. Air Force issues socks, but airmen are authorized to purchase socks at their own expense

• Objective:Determine if proprietary (Gold Toe) sock material cools better than 100% cotton or wool issued socks in a hot environment

Functional Specifications

Ellsworth AFB, S.D.90 deg F in June

Ellsworth AFB, S.D.15 deg F in June

Issued Boots designed for:•Varied Temp Range•Varied Environments•Hot/Cold•Wet/Dry

•Break-In Easy•Rigid, Ankle Support

Socks•Can be changed depending on the environment•Issued socks: 100% wool•Other varieties: 100% cotton, proprietary cotton-poly blend

Measured Data

• We measured the amount of time the issue boots require to cool from a high temperature

• Black boot temperatures were used to calculate the thermal conductivity (k) of the sock.

Results

• Calculations– Air

• RaD = 1029.38• NuD = 3.13• hair = 0.926 W/m2 K∙

– Sock• k = 0.014 W/m K∙

• Noise:– Uncertain contact resistance– Uniform heating in oven to control temperature and reduce

moisture

Sock Leather Quiescent Air

L = 0.003175 m L = 0.00158 m

Ti Tsur T∞

Conclusions

• Thermal conductivities compared– Wool: k = 0.07 W/m K∙– Cotton: k = 0.03 W/m K∙– Proprietary (Gold Toe): k = 0.014 W/m K∙

• Proprietary sock– Insulates better– Longer time to heat up– Longer time to dissipate heat

Questions?