On Monday, August 12, 2013 8:41:57 AM UTC-7, Dan Marotta wrote:
Your analysis doesn't account for speed and the altitude gained by pulling
up after finishing.

Hi Dan,

Quite right, I didn't include any kinetic-to-potential energy exchange. The number of feet involved can vary quite dramatically. In the end, because IGC rules encourage longer tasking that use up the available day and because the scoring for speed versus distance points yield a greater amount of gaggling and start-gate roulette, I thought it was fair to assume that a significant proportion of finishers would be at low McCready settings where the altitude gained in a pullup would be on the same order as the height of obstacles to be surmounted at the airport boundary. A 2-knot McCready starting speed yields less than 100 feet in a pullup to best L/D speed.

There's no single precise answer to what McCready setting to use for such a single-point analysis, but that's also beside the point. The real question was, why is it preferable to set up the finish by rule in such a way that a significant portion of pilots end up making low, slow, straight-in approaches to the airport? Is it a superior way to set up the finish, and if so, why?

9B