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Old 22nd Dec 2005, 10:41
  #279 (permalink)  
Dagger Dirk
 
Join Date: Sep 1999
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What they call Immutable Logic Methinks

RatherbeFlying said
the basic physics:

Once you are on the ground, back stick produces a couple about the main gear and downforce on the tailplane which adds to the weight on the main gear.

Of course backstick produces a subtraction of downforce at the nosewheel, but that is more than countered by the couple and downforce produced by braking at the main gear. Reverse from engines below the wing will also produce another couple about the main gear that adds downforce to the nose gear.

So back stick, once reverse and braking are applied, has to work against considerable forces that are not present in the air before the nosewheel could come up. Until the nosewheel starts coming up, the AOA must remain constant.

The physics behind Belgique's suggestion of backstick during braking looks perfectly sound to me.
Looks perfectly sound to me too.

The next step is for the manufacturer(s) and FAA to validate it, measure it and advocate it. Then maybe we will see fewer airplanes going off the end.

However it might need to sit on the NTSB's "list of desired fixes" for a few qualifying years first.
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