Endurance Innovation

Which one Blows Harder?

Episode Summary

Andrew and Michael nerd all the way out on indoor cycling fans and the aero costs of flappy run kit.

Episode Notes

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• 3:30 Cycling Tips review of fans
  • Fan specs: volumetric flow rate, airflow velocity, power
  • Measured skin temp, core temp, heat flux
  • Used an array of Core body temp sensors 
  • Compared no fan, small desktop fan, low velocity air mover, wahoo headwind, scroll fan
  • Heat transfer equation: Q=k*A*ΔT, where Q is the heat transfer, k is  the heat transfer coefficient, A is the surface area, and ΔT is the difference between skin temperature and the air around the skin
  • Maximize all three variable to maximize heat transfer
  • Perception of thermal comfort vs core temperature
• 39:30 how much does a flappy run top cost in terms of run power?
  • Tight clothing improves wicking and cooling
  • Based on a CdA of 1.0, at 4:00/km, aero drag is 40W
  • Flappy kit may increase CdA by 20% or 8W
  • Michael’s 4:00/km Stryd power is 340W, plus 40W for air resistance
  • So floppy kit hit of 8W is an increase of ~2%
  • @ a 5:00/km pace, the aero drag is too small to worry about.

Check out our episodes on heat transfer: 112, 115, 32, and the Core Body Temp Sensor page for their webinars and blog posts.