View Single Post
  #1  
Old August 6th 15, 03:19 AM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 172
Default OLC FAI triangle geometry different than FAI

Last Saturday, I had a pretty decent flight:
http://www.onlinecontest.org/olc-2.0...l?dsId=4611408

At the end of the day, I was trying to maximize OLC points by making the triangle portion as large as possible. I used the ClearNav "OLC" feature to see how I was doing and to determine which way to go for the biggest triangle. When I turned for home, the optimizer was telling me about what I ended up seeing in SeeYou - 539 km.

After uploading my flight, I saw that OLC awarded me 600 km for the triangle, so I thought to myself that the ClearNav must have under calculated the triangle. I then uploaded my flight to cross-country.aero and found that it only calculated 425km. That was odd, so I fired up SeeYou and again optimized my flight and found that it produces two FAI triangle distances:

One for OLC FAI triangle of 600 km

And one for FAI - gliders triangle of 539 km

So I then visited the OLC website and actually *read* the rules! :-)

4.3.2 FAI OLC Course (based on the FAI)
If possible, three turn points are chosen on the recorded, closed flight path such
that they define an FAI triangle with the greatest possible circumference, whereby
- the shortest leg must be at least 28% of the FAI distance
- if the FAI distance is 500 km or more, the shortest leg must be at least 25% and
the longest leg at most 45% of the FAI distance.

So just "based" on FAI, but not exactly. Looks like the Naviter folks have also read the rules.

I've also reported the cross-country.aero issue and Alexander has promised to tune the algorithm to improve its performance.

No complaints about anything here, just posting information that others might find helpful.

5Z