Manifold vacuum can be used to drive accessories on automobiles. The best-known application is the vacuum servo, used to provide power assistance for the brakes. Obsolete applications include vacuum-driven windscreen wipers and Autovac fuel pumps. Some aircraft instruments (Attitude Indicator (AI) and the Heading Indicator (HI)) are typically vacuum-powered, as protection against loss of all (electrically powered) instruments, since early aircraft often did not have electrical systems, and since there are two readily available sources of vacuum on a moving aircraft—the engine and an external venturi. Vacuum induction melting uses electromagnetic induction within a vacuum. COUNT 5
QSN1 What provides power assistance for auto brakes? ANS1 vacuum servo QSN2 What are two available sources of vacuum on a moving airplane? ANS2 engine and an external venturi QSN3 Why are the Attitude indicator and heading indicator vacuum-powered? ANS3 protection against loss of all (electrically powered) instruments, QSN4 What does a manifold vacuum do on a car? ANS4 drive accessories QSN5 What no longer used accessories were powered by vacuum? ANS5 vacuum-driven windscreen wipers and Autovac fuel pumps