On Monday, January 20, 2014 1:39:11 PM UTC-8, wrote:

RC gets two constant demands. One, as in the original post, is to add carefully constructed point carpentry around the finish, with 10 points for this and 20 points for that. The other is to simplify the rules, and especially to make sure pilots don't need to do lots of strategizing and in-air calculations. As you come up with alternatives, make sure they satisfy simplicity and clarity too!

John Cochrane

This particular issue has received scores of hours of thought, debate and analysis, including just about every conceivable scenario from the beginning of a final glide (below, at, and above optimal Mc final glide OR best L/D glide to the finish) and every major decision scenario as glides go bad (or don't get better - including able to make the cylinder but not the airport, vice-versa and under different penalty structures) ALSO various lift scenarios (none, less than current Mc, and climb rates all they way down to climbs so slow you are losing speed points faster than you lose penalty points). Zoomies at the edge, terrain in the last 10, 5 and 1 miles to the airport, proximity to a ridge, number of runways, configuration of the approach versus the finish, trees at the end of the runway and number of competitors trying to land at once with how much energy. It ALL gets assessed and debated, including the bizarre potential choices pilots might make (although pilots can be very creative in coming up with bizarre things - the analysis did include low circling to get up to finish height even right up to the edge of the cylinder). Then what gets discussed is which are likely versus unlikely scenarios and which ones are pilot decision issues versus places where the rules beg the pilot to take a chance in order to score more points. LASTLY it all gets put into the filter of don't change anything and make it simple (against the tide of requests for specific exceptions to handle odd cases).

In this case the higher order issues boiled down to: 1) The rules should not be set up to award points to pilots who cross the finish cylinder at an altitude from which it is unlikely that (s)he can safely reach the airport (including scenarios with the runway not lined up, into the wind and with trees), 2) Assess a modest penalty for most common glide gone wrong errors, such that a pilot would not ignore a reasonable-looking climb along the way on a marginal glide to MFH.

If you do the math what you find is if you allow (as we do) different finish heights and different sized finish circles you can end up with not much room between the bottom of the mild penalty and "can't get to the airport" height. A penalty structure that varies the steepness of the penalty depending on the cylinder radius and MFH is possible, but complex and was set aside as was restricting the finish height to 1000' or above as some sites with ridges like the flexibility to finish right off the ridge.

It's mostly documented in the RC notes. I'd be happy to take anyone through the "all the scenarios" analysis offline - there's a lot to think about before you boil it down to a set of simple rules and it's easy to fix one thing while braking something else.

9B