On Sunday, June 16, 2019 at 2:05:01 PM UTC-5, danlj wrote:
I'm curious.

After two successive near-midairs about 5 years ago, I installed PowerFlarm and a transponder that wouldn't deplete my battery during flight.

This required, due lack of panel space, that I give up my beloved ILEC S-10 flight computer (and its remote control). An Oudie IGC and and S-80 were recommended to replace it. The change has led to some conclusions about what flight computers should do in the cockpit.

1: Speed to fly
Flight computers all seem to calculate wind, and to be able to use the glider's polar. Not all use wind to revise STF.
It seems to me that we could use two rather different STF indications:
A: expected arrival altitude at next waypoint given polar, altitude, wind, and and optionally achieved mean L/D
B: best immediate speed for optimal L/D given polar, wind, and lift/sink over the last X seconds (user selectable)

(does any current flight computer offer these sorts of enhancements?)

2: Waypoint modification
Requiring the pilot to make an alphabetic search during flight to make a waypoint change is beyond stupid (it's a dangerous distraction).
- There are too many options for naming waypoints - recalling which name it was given is sometimes impossible.
- seldom are ICAO designations used, which aren't in any case easier to recall.
It seems to me that the best UI would have the ability to quickly limit the waypoint choices and swiftly move through the limited choices by spinning a knob or touch-pressing a knob-equivalent.
One is faced with either
- the need to modify one or more waypoints of a task
- the need to create a new task, the simplest of which is direct-to
Logical ways to create a limited set of waypoint choices include:
- distance (I think everybody offers this)
- direction (bearing, heading, or azimuth)
- distance & direction
- waypoints near current leg
- waypoints near current task

Do any current flight computers offer waypoint selection direction as well as distance?

Danl J

Comments below force a response.
1: the most efficient calibrated airspeed for progress over the ground DOES vary with the wind. A published rule of thumb is with a headwind, add 1/3 the headwind component to best glide; with a tailwind, fly at minimum sink.
Jean Marie Clement has created a beautiful graph showing that the most efficient CAS against headwind is a curve -- it looks like it's an hyperbola. It's reproduced on page 51 of Brigliadoris' Competing in Gliders.

2: The Oudie IGC manual is quite clear that ONLY polar and pre-set MacCready are used in calculating speed to fly and arrival altitude. Wind is specifically not used in their calculation, and you can of course set your MacCready to the mean climb in the last thermal if you like.

The S8x manual does not indicate whether current lift/sink is used to modify the instant STF arrows indication, nor whether wind is taken into account.. The STF *is* based on the next waypoint, polar, and (I think) MacCready. I haven't used this, and will reconfigure my S80 now that I've updated the firmware and watch its behavior.

3: Does anyone on this forum actually ever do the research before replying? Just curious. The B/S ratio applies to more than thermals...