PPRuNe Forums - View Single Post - Question about descent planning in tailwind.
Old 9th April 2009 | 12:14
  #14 (permalink)  
Checkboard
25 Anniversary
 
Joined: Aug 1998
: ATPL
Posts: 6,623
Likes: 847
From: Ex-pat Aussie in the UK
The kinetic energy changes of your aircraft circling in a wind is the same from either reference (the earth, or the air mass).

From the position of an observer on the earth, the aircraft goes from zero velocity flying upwind (to the right, say) to 400 knots flying to the left.

An observer in the airmass (sitting in a hot air balloon, say) observes the aircraft flying to the right at 200 knots, and transitioning to flying to the left at 200 knots.

Same change in velocity in both cases, same kinetic energy change, same work done by the lift force of the wings in both cases.
Checkboard is offline  
Reply