Scott Krueger wrote: OK performance fans -
recently I became interested in aircraft/engine performance related to air
density. Most specifically, related to the dew point. I was lucky
enough to find an instrument (about $80) that displays the air temperature,
%humidity and dew point temperature. The dew point is important to
understand the air density difference from the ISA standard
predicted only by air temperature at some altitude.
Scott, you are correct. When
correcting for power one must reduce the observed Intake Pressure by the Vapor
Pressure. In dry air the Vapor Pressure is "zero" and can increase to over
1.0 In Hg in hot moist air. When the dry bulb is 100 deg F and the wet
bulb is 100 deg F, the Vapor Pressure is 1.92 In Hg. (You know, a nice day in
Florida)
Craig
Berland