I'm trying to use Paul Remde's very handy "Reichmann to Cambridge and SeeYou" spreadsheet to derive some usable SeeYou polar numbers for my Diana-1. But I'm having a heck of a time picking three speed/sink-rate pairs from the data set that result in Max L/D and Best Glide Speed numbers that pass the sniff test.

For example, I can enter 3 pairs of values from early, middle, and late in the data set, and it tells me I have a max L/D of 49 (wouldn't that be nice!) at ... 38 km/h. Uh, that's well below stall speed!

Is there any conventional wisdom on this?

Are there any other tools available that can take a set of sink rates (hopefully more than 3) and produce some decent numbers?

Wishing the flight computers would just start with lookup tables,

tuno/ES