Polar numbers for Discus A

Dan, I have the USB to serial working in modern windows, but the Cambridge software only had ports 1 to 4 as an option. The USB to serial wire was assigned a higher number like 8.

Were you able to reassign the wire to a lower number or find later Cambridge software with a larger selection of port numbers?

Bruce, I did give you garbage. When the xcsoar numbers came out as a parabola I knew I screwed up big time. I guess those are the number generated when you choose discus.

The actual numbers from Johnson show the kink some talk about so I don't expect them to fit a parabola.

So I took my school boy ruler to the little graph on page 3 of the Johnson article and come up with the following. I guess I am looking for a quadratic equation near these numbers except 97 knots. Because of the kink 97 knots should be off the most.

max L/d 42.5 @ 53kts min sink 115 ft/min @ 45kts
50kts 121 ft/min or 1.195kts or .615 m/s
60kts 160 ft/min or 1.58kts or .813m/s
65kts 195 ft/min or 1.925kts or .99m/s
76kts 270 ft/min or 2.666kts or 1.372m/s
80kts 308ft/min or 3.05kts or 1.569m/s
97kts 650ft/min or 6.42kts or 3.3m/s

You gave me enough I should be able to learn some calculus. I was not able to get there this morning, but I will try again.

Is the A,B,C of see you x y and z of a quadratic?