<<  Most gyros need vacuum, not pressure.

 > I thought they just needed a 4 inch pressure differential, be it either a
 > vacuum on the exhaust side, or a pressure on the intake side.
 >
 > Bob Darrah >>

The instrument can't tell the difference. (is there a difference), they use a
vacuum because it was free. Just a venturi outside to run everything. There
were no electrical systems to worry about. You can't use intake vacuum
because at full tilt there isn't enough. You can't use exhaust because the
acid and water will destroy the instruments. So it's vacuum pump or venturi
or both.
Lynn E. Hanover

 
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