Vacuum Relief Valve Adjustment

How to keep the Cessna 170 flying and airworthy.

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ghostflyer
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Joined: Mon Apr 21, 2008 3:06 am

Re: Vacuum Relief Valve Adjustment

Post by ghostflyer »

My vacuum system has the same figures that Bruce got but my Bat and ball instrument only runs on [needs] 1.5 ins of vacuum. So it has its own small 4 inch Venturi. I haven't put in a relief valve yet as everything works well. Venturi,s do not wear out or shalf,s shear , and are also not affected if the prop is turned backwards etc. we removed the venturies off a early cessna 172 recently and fitted a Garmin G5. The difference in speed per RPM and fuel flow ,"NONE".
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