On Wednesday, May 4, 2016 at 12:58:11 PM UTC-4, wrote:

I teach that dive brakes/spoilers control the rate of descent(at constant air speed) and control rate of deceleration in and after the round out. The change in drag resulting from the lift to arrest the rate of descent is pretty much meaningless compared to the power of the air brakes.
UH

Let's say the glide ratio of a steep descent is 1:7 and IAS is 70 knots when entering the flare. So the vertical component of the airspeed before flare is 10 knots. The horizontal component of the airspeed before the flare is 60 knots. (Are these assumptions correct?) After the flare the vertical component of the airspeed goes to +/- zero. What is the horizontal airspeed at the end of the flare? 60 knots?