NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Allowing for current
From: Paul Hirose
Date: 2009 Oct 02, 13:17 -0700
From: Paul Hirose
Date: 2009 Oct 02, 13:17 -0700
George Huxtable wrote: > Estimate the > passage time, sum up the overall tidal displacement that would occur during > that period (now non-zero), make the appropriate offset from the course to > destination by a simple vector diagram, and then steer that course, without > bothering about any "cross-track error" that may arise. That's known in air navigation as the "single drift correction" method: "The individual drift corrections, normally applied to a straight course to compensate for the cross-wind component, vary considerably during a long flight due to local variations in the wind-flow pattern; whereas, the net drift over the entire course may be small. If the aircraft were to compensate only for the net drift, so that the speed of the aircraft would not be reduced by excessive crabbing, the actual time in flight could be reduced." (U.S. Air Force Manual 51-40, "Air Navigation", 1955) The single drift correction would be applied to each heading of the no-wind flight plan. (It might have several heading changes to approximate a great circle course.) -- --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---