Because airplanes are designed to cruise with the fuselage in the least draggy attitude, it follows that there may be some extra fuselage drag when the airplane is, say, five degrees nose-up for climb. Therefore, some flap deflection, by lowering the nose, may not only reduce wing drag, but may reduce fuselage drag as well. But the effect will be minimal; the incremental drag due to tilting a streamlined body a few degrees is small. For a sailplane, the speed called Vy, the best rate of climb speed for a powered airplane is, instead, the minimum sink speed. Many high-performance sailplanes rely on variable camber, usually achieved by means of sealed plain flaps, to adjust the location of the "drag bucket"-the range of speeds within which laminar flow occurs. The effect of variable camber is quite real, but it is significant only in airplanes with large, very smooth and well-contoured wings able to sustain large areas of laminar flow, and with flaps whose deflection does not create gaps and discontinuities that add drag. Few powered airplanes meet these criteria.