PPRuNe Forums - View Single Post - How does reducing speed in turbulence improve the ride?
Old 14th Jan 2014, 14:57
  #46 (permalink)  
Mad (Flt) Scientist
 
Join Date: Sep 2002
Location: La Belle Province
Posts: 2,179
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by misd-agin
Bravo Shrike!

Skip the theory and tell us the practical considerations. How much does a reduction from .84 or .83 to .82 decrease the turbulence impact in a 777-200 @FL370 @ 500,000 lbs? 3%? 25%? 67%? CliveL??
As mentioned already, to a first approximation the decrease in the 'g' bumps is of the order of the %change in speed. (There are secondary effects due to things like the CL-alpha curve changing with changing Mach, but they ARE secondary). So slowing from 0.84 to 0.82 would reduce the bumps by a factor of 82/84 i.e. about 2.5%

However, that would likely "feel" a lot more, because there's a threshold below which we are physiologically insensitive to bumps - after all, there are ALWAYS some low level of disturbance, even in what we might think of as calm conditions. Since we're now talking of the subjective human reaction, different people are going to evaluate the same objective response differently.

So maybe you are both right!
Mad (Flt) Scientist is offline