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From: Martin S. <Mar...@mg...> - 2008-08-20 12:17:12
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James, I can't tell much about the use cases in the FlightGear code, just from real-life experience. Take this as an aide, if it helps you - if it doesn't help, I dont mind you ignoring it silently :-) James Turner wrote: > One interesting thing I've come across is how the runway _length and > _width fields are used - it turns out they're pretty much always used > to calculate some particular positions on the runway, notably the > threshold and the 'other end' point (sorry, there must be a better > piece of terminology than that), or some offset from those points - eg > five metres in, or several NM 'out' along the extended runway > centreline. Personally I'd simply call this 'other end' the 'opposite threshold' - but I'm not a native English speaker, so there might be a different, 'official' definition for it. When you look at the 'data/Scenery/Airports/K/H/A/KHAF.threshold.xml' file for example, then you'll realize that the notation almost matches the use case you're describing here: Threshold position plus the heading along the centerline. In real-life, the displaced threshold doesn't count for takeoff - you're going to begin your start run wherever you enter the runway, shortly behind the 'reglar' threshold. I guess, this should (logically) also apply for the cases when a certain threshold offset is being calculated in FlightGear for takeoff. The stopway is a different thing. It lies outside the area that's being embraced by the two regular thresholds, you don't use it for takeff, you should not use it for landing - but it might serve as your life insurance if you're too-high-to-fast during aproach .... Cheers, Martin. -- Unix _IS_ user friendly - it's just selective about who its friends are ! -------------------------------------------------------------------------- |