On Wednesday, January 22, 2014 11:36:38 AM UTC-5, Dave Nadler wrote:
On Tuesday, January 21, 2014 7:14:33 PM UTC-5, son_of_flubber wrote:

Get a high tow into still air...

The likelihood of measuring meaningful data yourself is ZERO.

If I cannot empirically measure an accurate polar by for my body in my glider (wearing my shoes), then how is it possible to use a published polar to accurately predict the performance of my glider (with me in it)?

I can see that measuring my own polar and then using it to calculate my ideal glide slope doubles the source of error.

Factoring out weather, I'm thinking that the biggest source of real world deviation from the idealized polar would be the total weight and the CG, and measuring my glider's polar with me in it factors out that error.

Do glider manufacturers have special inventories of still air for empirically derive polars?