I’ve also seen it calculated for speeds and sink rates directly as: factor = sqrt(actual weight / polar weight) or factor = sqrt(wing loading / polar wing loading) - they give the same result
Then multiply BOTH sink rate and speed by factor > On 25 Oct 2016, at 17:29 , Matthew Scutter <[email protected]> wrote: > > const auto loading_factor = sqrt(GetTotalMass() / reference_mass); > const auto inv_bugs = 1. / bugs; > > polar.a = inv_bugs * ideal_polar.a / loading_factor; > polar.b = inv_bugs * ideal_polar.b; > polar.c = inv_bugs * ideal_polar.c * loading_factor; > > Stolen from XCSoar source code. Assumes the usual quadratic 3-number polar as > a, b and c. > > So you square root of difference between the masses to get the loading > factor, divide a by the loading factor, leave b the same, multiple c by the > loading factor. > > Doesn't account for the change in reynolds numbers though (the polar is > probably slightly better than this accounts for) > > On Tue, Oct 25, 2016 at 5:01 PM, Adam Woolley <[email protected] > <mailto:[email protected]>> wrote: > G’day All, > > > > Just wondering whether anyone knows the formula for converting a baseline > empty polar curve (speeds/sink rates) to a ballasted polar curve? I’ve read > it somewhere in the past, but cant find it easily now. > > > > > > Cheers, > > WPP > > > _______________________________________________ > Aus-soaring mailing list > [email protected] <mailto:[email protected]> > http://lists.base64.com.au/listinfo/aus-soaring > <http://lists.base64.com.au/listinfo/aus-soaring> > > > _______________________________________________ > Aus-soaring mailing list > [email protected] > http://lists.base64.com.au/listinfo/aus-soaring
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