Vacuum Systems

[@aviationone7896]

Good explanation

[@tonyp3282]

How can you tell if it's a suction or pressure system?

[@adrenalinefoodiem9034]

Its just facts, basically how the instruments were designed ... the altimeter, airspeed, and vertical speed indicator are pressure systems because they use Pitot( total pressure ) and static pressure ( actual outside pressure ) to work out the correct speed and altitude and rate of climb/descent unlike those instruments disuccussed here they are gyroscopic instruments so they solely rely on the right operation of the gyros inside each instrument that's why they need that vacuum pressure for them to work and they don't need any pressure inputs . Hope that makes sense

[@janeromnicki6598]

I heard very good opinions about the Woodglut plans.