PPRuNe Forums - View Single Post - Why does an aircraft descend quicker when it is lighter?

18th Apr 2010, 12:35

#33 (permalink)

jimmygill

Join Date: May 2009

Location: Birthplace of Aviation

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I apologise Pitt Bull, your formula is correct

Code:

Rate Of Descent = Power Deficit / Weight.
                       = (Drag*TAS) / Weight
                       =   TAS * (Drag/Lift)       Lift = Weight (approx)

In airplane A and B TAS is same for both,

hence Rate of descent is determined by the Ratio of Drag to the Lift in the case.

Just putting the weight in the denominator is robbing us of accuracy amd lending credence to inappropriate analogies such as a car rolling down the hill.

Last edited by jimmygill; 18th Apr 2010 at 12:45.

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