Vacuum pressure on the 170
My point is you DID use the correct term. Aircraft engine manifold "vacuum" is expressed in pressure, whether under vacuum, or supercharged under pressure
At least some of these measure "absolute" manifold pressure, meaning, when the engine is stopped, and the manifold is at atmospheric pressure, the guage will read barometric pressure instead of zero like an automotive vacuum gauge does.
Pressure is pressure. It can be "negative" that is lower than absolute atmospheric, or "positive" like in a tire, higher than atmospheric
My point is you DID use the correct term. Aircraft engine manifold "vacuum" is expressed in pressure, whether under vacuum, or supercharged under pressure
At least some of these measure "absolute" manifold pressure, meaning, when the engine is stopped, and the manifold is at atmospheric pressure, the guage will read barometric pressure instead of zero like an automotive vacuum gauge does.
Pressure is pressure. It can be "negative" that is lower than absolute atmospheric, or "positive" like in a tire, higher than atmospheric
