At 19:03 07 December 2014, Dave Nadler wrote:
On Sunday, December 7, 2014 1:56:25 PM UTC-5, wrote:
Looking at my decade old code for a transducer based variometer,
I see that I went to a bit of trouble to convert pressure to ISA
altitude before differentiating to get rate of climb.

Good, but its much easier just to correct by one_over_sigma ;-)

For even more amusement, consider the relationships between
"altitude corrected" rate of climb, IAS, TAS, calculated total
energy compensation, and speed to fly...

Right, proper instruments consider MC as a 'true' input as
well as correcting vario, IAS-TAS, and of course polar.

Discuss amongst yourselves ;-)

Seems to me that this discussion is about a complete non problem. When we
"read" a vario we are not really interested in the arbitrary figure it
displays but more in the fact of whether the value is higher or lower than
the previous value.
In other words if 4kts is really 2kts at 10,000 ft it does not matter a jot
to us. What does matter is that 4kts will always be greater than 2kts. We
search for better lift not some arbitrary figure.