West Side Triangles

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The increasing popularity of the OLC has led to an increasing element of competition for XC soaring with an ever-increasing world wide participation.  It also has led to a competitive drive to get the most OLC points for a given flight and before 2011, when the points were determined by simple distance (discounted for the 4^th and 5^th legs), this gave rise to the preponderance of “Yo-Yo” flights, i. e. flying back and forth along a line of good lift.  This worked really well for flights in ridge lift and waves but eliminated some of the challenges of deviating from such lift lines.  So since 2011 the OLC gives now bonus points for the largest FAI (Federation Aeronautique Internationale) triangles included in the total flight path, adding 30 percent of the triangle distance points to the total.  In other words, the total points can be 30 percent higher for an FAI triangle than for the same distance in a straight out-and-return mode.

FAI triangles are defined as having legs of at least 28 percent of the total triangle distance.   Triangles can be started at either a turn point or between first and third turn points.  The OLC scoring program has an optimizer that calculates the largest FAI triangle for a given flight path in addition to calculating the longest total distance based on six legs.  This simplifies analysis considerably.

Considering flying on the west side, and Arlington in particular, soaring is quite often limited to a narrow roughly North – South corridor along the foothills based on cloud base and geography.  There are coast lines and some control areas to the west and higher mountains to the east.  This invites Yo-Yo flying in this corridor while making triangles more challenging and so far our best WBC flights have had triangles of rarely more than 50 percent of the total distance.  Nonetheless, for the OLC point collectors the triangles offer quite an incentive to maximize the points for a given day.  It proved to be the deciding factor for the WBC 2011, when Ron Clark was able to beat Noel Wade despite Noel having the longest distance (both still have the longest soaring flights on the west side).

Note that, while Noel still has the longest ever flight on the west side, Ron’s triangle of 259 km (49 percent of the total distance) is still the largest triangles on the west side.

So while triangles are more difficult because they inevitably involve flying in the mountains they are hard to neglect because of the point advantage (if one is trying to maximize points).  So what kind of strategy should one pursue to win the WBC?  Leaching on to Ron is one possibility but has proven to be pretty difficult (or requiring more guts than most have).  It seems to involve getting deep into the mountains and that is not always possible even with a lot of experience and high performance sailplanes.  Comparing a flight consisting only of a triangle with a straightforward Yo-Yo flight, the average Yo-Yo speed would have to be 30 percent higher to give you the same points (for the same flight time).   However, if 40 percent of the triangle distance is flown along the Yo-Yo direction then the average Yo-Yo speed would have to be 50 percent higher.  Thus even smaller triangles are worthwhile and they make even more sense (in the right conditions) when thermals in the mountains last longer than outside.  It is always satisfying to come back from a long way out in the mountains after thermal activity at Arlington has died down.  All this is predicated on being able to fly in the mountains at some penalty in average speed.  And while most of the more experienced XC pilots love to fly in the mountains, that is quite often very limited because of the weather even when flying along the foothills is quite feasible   These are interesting considerations and tradeoffs, and as usual they depend on the particular weather conditions of the day.

Meanwhile, we are still waiting for the first pilot to fly a 300 km FAI triangle on the west side of the mountains, something that is almost standard fare on the east side.  I am convinced that it will happen  - there is now enough talent in Evergreen Soaring, not to mention expertise and ambition.

                                                                                                by Fred Hermanspann