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Old 30th Aug 2012, 23:07
  #190 (permalink)  
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Join Date: Jun 2009
Location: florida
Age: 81
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The one gee command

Spot on, OG, that is exactly what I am saying based upon the documents provided by several here.

So if I am at 30 degrees of pitch, the actual Airbus command would be 0.87 gee. This is different than the Viper control law. Ours commanded "absolute" gee according to how we had the jet trimmed ( - one plus a bit or so, and + 3.5 gees). We had no bias for pitch attitude, so at an extreme pitch attitude, the jet would try to pull up to maintain the trimmed gee, which was mostly 1 gee.

The result of this control law was if you released the side stick the system would keep cranking in elevator to reach the one gee "command" that most of us used. The Airbus doesn't allow a gee command to be manually trimmed, and it looks to me that it always tries to achieve one gee corrected for pitch attitude. This also plays on the apparent speed stability, as the system has zero stick pressure changes to compensate for AoA changes due to speed changes - the basic "feeling" most of us had with the conventional systems and the original systems in the Chipmunk, Cub, Luscombe, et al.

Just some thots from an old FBW veteran.
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