Thursday, November 17, 2011


Thanks to a recommendation from Jaime Menendez de Luarca, I have just bought this industrial fan, the Euritesca DF 20P. The idea is to use it whenever I have to train indoors, either on the treadmill or the turbo trainer. The fan I have currently has only 50 Watts; this beast has 170 Watts. It can churn out 4,080 cubic meters of air per hour. Being a bit of a nerd, I have worked out how this compares to running outside.

Firstly, we need to know what surface area we present to the wind. Using a formula I nicked off the internet - 0.0204*height in meters^0.725*weight in kilos^0.425 - and dividing by two, I came up with a surface area of 1.07 square meters. (Obviously this is a good example of false accuracy - the real number will be less because the skin between your toes has no bearing on the amount of air you displace while running, for example.) So that means that 4,080 cubic meters per hour is equivalent to running in still air at 4,080 / 1.07 / 1,000 = 3.8 kph. Is that all?? There is another model which is much more powerful and generates a "breeze" equivalent to running at about 16 kph but I think this would be going too far. Just imagine it - if you were to turn this thing on, you would go from running upright on the treadmill, to having to lean into the wind as you do when you run outside (see my previous post on this topic). And that is supposing you can set things up in such a way that the air current hits your body uniformly. According to Jack Daniels' formula, running outside is equivalent to running on a treadmill with a gradient of 1% because there is no need to overcome air resistance. In fact I have always set the gradient to 1% on the treadmill for this reason but with my new mega-fan maybe I will have to take air resistance into account!

Here it is installed...

No comments:

Post a Comment