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Ticket #1343 (new enhancement)
Need better start gate control
| Reported by: | tangoeight@… | Owned by: | |
|---|---|---|---|
| Priority: | normal | Milestone: | XCSoar Wishlist |
| Component: | Other | Version: | 6.0 |
| Keywords: | Cc: |
Description
I would like to be able to inhibit the auto restart function for a short period of time. The best way to do this would be by adding a button on the first Nav screen which would inhibit auto restart for a (configurable) period of time as shown on the time-below-start-height timer. Typically I would set this to 2 minutes.
background: US contest rules guidance encourages setting start gate height below clouds and below top of lift. A common start tactic is to thermal up through the top of the cylinder well behind the edge for "start out the top".
In some cases, one doesn't get very much higher than the top, so that we glide back below the top before reaching the edge. In almost all cases, the most advantageous start (which is what we score) is the start out the top. XCS at present logs a new start for each exit of the start cylinder, resulting in small errors in task time and statistics.
Some information from the SSA Competition Guide to understand how US starting procedures work. I think it would be worth a discussion on how to best support these rules.
The start cylinder is centered on a designated point and usually has a fairly large radius (often 5 miles). The CD will have set a maximum start height (MSH). To make a start, you must be inside the start cylinder; your start time is the time you leave it – either out the side or out the top.
Sometimes the MSH will be higher than the lift, and so is not a factor. But if you are able to climb above this, you must take care to get below it for at least two minutes prior to your start (plan on a bit more, to be sure). A common misconception says that you must be in the start cylinder during these two minutes, but this is wrong: you must be below the MSH, but it doesn't matter whether you're inside or outside the cylinder. (You must, of course, be inside the start cylinder, at least briefly, some time after the two minutes are up, in order to make your start.)
Because you can start by climbing out the top of the cylinder, and because your scored distance will be taken from the point where you exit the cylinder (provided it's no further from the first turnpoint than the center of the start cylinder), when lift permits this is usually a good tactic. The idea is to find a good strong thermal, climb as high as the good lift will take you, then set out on course.