PPRuNe Forums - View Single Post - ADF dip
Thread: ADF dip
View Single Post
Old 12th Jan 2002, 01:33
  #18 (permalink)  
Dan Winterland
 
Join Date: Jun 2001
Location: Blighty
Posts: 4,789
Received 7 Likes on 3 Posts
Lightbulb

A better way of describing dip is to imagine an aircraft with wings level with a beacon on a relative bearing of 045 degrees on an intercept heading, the needle will of course 045 degrees off the nose. Now bank the aircraft, i.e turn onto the inbound track. You now have a horizontal and vertical component of the bearing. The vertical component increases, the horizontal reduces. If you have problems imagining this, consider if the aircraft was to use 90 degrees angle of bank. The horizontal component will be zero as the needle attempts to point directly at the beacon indicating a relative bearing of zero. This is the dip, and it only occurs with bank causing the relative bearing to reduce.

To counter it, anticipate by lagging your roll out a bit . I'm sure someone more clever than I could work out how much lag would be necessary depending on the cosine of the angle of bank, but I was taught to use th TLAR method. (That Looks About Right). It is a function of the angle of bank, regardless of aircraft type.
Dan Winterland is offline