Ambient pressure concept of pressure becomes irrelevant, and it is undefined at a gravitational singularity. The SI unit of pressure is the pascal (Pa), which is a very small unit relative to atmospheric pressure on Earth, so kilopascals (kPa) are more commonly used in this context. The ambient atmospheric pressure at sea level is not constant: it varies with the weather, but averages around 100 kPa. In fields such as meteorology and underwater diving, it is common to see ambient pressure expressed in bar or millibar. One bar is 100 kPa or approximately ambient pressure at sea level. Ambient pressure may in
Piper PA-24 Comanche tail, laminar flow airfoil, and all-flying stabilator. The standard fuel capacity of the PA-24-180 was . The flaps were manually actuated, controlled by the same Johnson bar actuator as the Piper Cherokee. The aircraft specifications were for cruise speeds of and fuel burns between 7.5 and 10.5 gph at 55-percent and 75-percent power settings. Full-fuel payload with standard fuel was 715 pounds, with a gross weight of and range with 45-minute reserve of 700 nautical miles. When new, standard, average-equipped Comanche 180s sold between $17,850 (1958) and $21,580 (1964). A total of 1,143 were built. In 1958 Piper introduced a