21. The more wave drag is created, the more energy a swimmer must put out to make progress through the water. 22. Wave drag is a sudden rise in drag on the aircraft, caused by air building up in front of it.23. However, this would limit the design to slower speeds below about Mach 0.7 ( see wave drag ). 24. It calculates the wave drag on a transonic or supersonic aircraft . It just happens to have been written in the 50s. 25. All propellers lose efficiency at high speed, due to an effect known as wave drag which occurs just below supersonic speeds. 26. Although butterfly is very compatible with diving, the resulting reduction in wave drag does not lead to an overall reduction of drag. 27. Supersonic airflow over the upper surface of the traditional airfoil induced excessive wave drag and a form of stability loss called Mach tuck. 28. This process is far more complicated than it sounds, due to the resistance the advancing wavefront encounters ( similar to wave drag ). 29. Similarly, for a fixed volume, the shape for minimum wave drag is the "'Von Karman Ogive " '. 30. A supercritical airfoil is an airfoil designed, primarily, to delay the onset of wave drag on aircraft in the transonic speed range.
