On Friday, August 22, 2014 2:08:12 AM UTC-4, Andrew Ouellet wrote:
In many of Johnson's flight test reports, he refers to something like 'the square root of the wing loading' method to unify glide polars taken from different gliders at different wing loadings down to a common wing loading in order to be effectively compared. Can someone explain what this is and how to do this?



I have a strong engineering background so no need to mince words.



Thanks!

It all comes from the lift equation which can be used to determine what airspeed (and sink rate) is needed to achieve the same glide ratio following a weight change. When I wrote this I forgot your original question was about wing loading. So, pretty much what you'd do is figure out what weight each glider needs to be to achieve the same wing loading and correct each of their polars to that weight and plot them together.

Here's the write up explaining how the weight correction can be derived...
https://dl.dropboxusercontent.com/u/...ght_change.pdf