December 6, 2009

Back from Australia and the OLC Equation

My trip to Australia was a big success. I flew with Jim Staniforth in Lake Keepit's beautiful Duo Discus. We flew for 24 total hours over 6 days. Flying a 500km task, a 400km task, 3 300km tasks and one local area flight. It was a great learning experience, flying in very differing weather conditions. Lesson learned - fly dual with another cross country pilot whenever you can. There is no better way I can think of bettering your flying.

On to an equally interesting topic. I was flying for the first time this year from a soaring site in the US where I had a chance to place in the top 50 in the OLC distance competition (rules). It raised an interesting question, what would my average point score have to be to place in the top 50? I found the results interesting and I thought I would share them here.

To my surprise, the average score for the first 200 pilots in the United States is defined, very accurately, by an exponential equation. The equation is:

Average flight points = -132.9*ln(Your standing)+1100.9
Note: ln is the natural log

The equation is found by importing data from the top 200 pilots in the US into excel and applying a simple curve fit to the data. The R^2 value, a measure of how well the equation fits the data (1 being a perfect fit), is .996! Looking at the data, the issue actually comes from the variance in the top 3 pilots, who usually fly predominately in wave or ridge lift. This represents a break from the generally homogeneous population of pilots posting mostly thermal flights with some wave and ridge. If you remove the top 3 pilots the equation holds true to a R^2 value of .999! So what does this mean? I take away that the general population of soaring pilots is fairly homogeneous and that there is a core group of top pilots who combine excellent flying skill with superb weather to achieve great flight scores.

This result actually encouraged me to run the same analysis on data from 2008 and 2007. The results were equally exciting. Each year can be explained by a simple exponential function which has good correlation to the the real data, however the change in the curve from year to year has a clear trend. See figure 1:

Figure 1

What figure 1 shows that the OLC in the US for cross country distance is getting more competitive. If you remove the top 3 pilots from each year ,I call this the Jim Payne factor, the results point ever more to a general trend of increased competition (i.e. moving from #15 in the us to #10 takes more points each year). Also, to be in the top 50 requires the pilot to average ~25 more points per flight. Congratulations US pilots, you are getting better at flying, or more realistically more pilots are posting to the OLC, either way both are good things!

For you international pilots out there if you would like to perform this analysis for your country feel free to contact me and i can send you the excel files to get the results. Also this will not be my last post regarding the OLC, I have does some research developing a tool to locate thermals from multiple flight and map "hot spots" as a function of time of year and time of day. Not a new idea, but plenty of good results non the less!

Keep soaring (and posting to the OLC)

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