Final glide

On Wednesday, September 25, 2019 at 3:45:29 PM UTC-4, Eric Greenwell wrote:
moshe... wrote on 9/25/2019 11:31 AM:
On Wednesday, September 25, 2019 at 2:14:48 PM UTC-4, Eric Greenwell wrote:
unclhank... wrote on 9/25/2019 5:41 AM:
On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.

The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.

You don't really do that, do you? I'll bet you fly the final glide rather slowly
if your final thermal is weak, and rather fast if that thermal is strong, and
don't pay any attention to how fast the flight was before the final thermal.

That depends on the task. The MacCready theory for final glide speed that depends only on the climb rate in the last thermal applies to assigned tasks. AATs (TATs) are different, *if* your decision (last thermal) happens before the last turn, so that you can then choose, e.g., to fly farther into the last turn area but do the whole final glide (from the last thermal to the turn to the finish) slower. In that case, the optimal speed is the MC STF that corresponds to the average climb rate over the whole task. Yeah I know it sounds weird. Reference: the Brigliadoris' book.

That does sound weird, but I stopped flying contests before the turn areas offered
a large range of choices. Does going farther in that situation add more points,
compared to going faster?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Assuming you won't finish under-time either way, going farther (up to a point) gives you more points since it increases the overall task speed (total distance divided by total time). The conditions (average climb rate) determine the best XC speed you can get, along with the STF between climbs, and since the distance is flexible you can maintain that speed for the best score.

What is not clear to me is how do you then decide when to leave that last thermal? Perhaps when the climb rate falls below that average climb rate? Assuming you have enough altitude to reach into the last turn area by that point.