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Old 08-05-2015 | 09:01 AM
  #89  
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Timbo
Runs with scissors
 
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From: Going to hell in a bucket, but enjoying the ride .
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Originally Posted by Carl Spackler
Sigh. I'm going to break my own rule and talk to the guy on the park bench. Clamp's physics teacher is right and yours was wrong. Two aircraft of the exact same weight will use much more brake energy for a rejected takeoff than an overweight landing. The overweight landing is decelerating into the flare, touchdown and brake application. The takeoff aircraft is accelerating, therefore a huge amount of brake energy is used in the initial brake application where go from an accelerating state, to a state of just beginning to decelerate. From THAT point, the two energy dissipation rates are the same for equally weighted aircraft.

It is that extra requirement to stop the acceleration that makes an RTO braking energy event greater than an equal weight landing event.

Carl
And then there's the added aerodynamic drag from the 'landing flaps' where the 'takeoff flaps' are usually quite a bit less (5 degrees flaps for takeoff, and 30 degrees for landing on the 777).
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