Brodhead Pietenpol Association

Original Posted By: "Jack Phillips"
Subject: Pietenpol-List: considering a conceptHaving picked up my parts and such and thinking about my engine assembly I was also thinking about suction /vacuum sources? Pump, venturi or, here comes the brainstorm idea....... like in automotive, tap the engine vacuum from the intake side.Does anyone have any experience in doing that on a Lycoming engine? I would be curious about anyone's experience in trying that to operate vac instruments.Any ideas on how that may impact engine performance with what will appear to the engine as a vacuum leak on the intake side.Obviously I am just exploring an idea here and have not committed to anything on this but was curious about the concept. Conceivable one could operate all sorts of vacuum controls for airflow, heat, vents similar to a car using the same control block and parts to open and close dampers or other devices. rubber hose is much lighter and flexible than steel cable dampers.Okay, what say you group?ThanksJohn________________________________________________________________________________

Original Posted By: owner-pietenpol-list-server(at)matronics.com
What vacuum device does a Pietenpol need, other than possibly a Turn andBank indicator? I have a T&B on mine, powered by a venturi on the belly.Works great, and has come in handy a couple of times when weatherdeteriorated suddenly (like last Sunday, leaving Sun 'n' Fun).Automobiles used to use vacuum powered windshield wipers. I remember howfrustrating it was when driving in the rain, behind a slow truck. Whenyou'd get a chance to pass, and floored the accelerator the windshieldwipers would nearly stop, because there wasn't enough vacuum at wide openthrottle to power them, so you were passing a truck with all the spray itwas throwing, and you had no wiper action.Since airplanes operate at or close to WOT most of the time, I doubt you'dhave enough vacuum to reliably power much. You need 4" to 6" of vacuum formost instruments.Jack PhillipsNX899JPRaleigh, NC _____

Original Posted By: Tim Willis

Original Posted By: Jim Markle

Original Posted By: Jeff Boatright
Can't speak for anyone else, but I'd say, KISS.David PauleP.S. "Keep It Simple, Stupid," is a well-known engineering rule. Frequently violated at significant cost and schedule impact, and it has been learned that there's usually a performance cost as well. Since you can at best achieve only two of these attributes, Good, Fast and Cheap, or if you wish to be corporate, Performance, Schedule and Cost, try very hard not to fail at them all. ----- Having picked up my parts and such and thinking about my engine assembly I was also thinking about suction /vacuum sources? Pump, venturi or, here comes the brainstorm idea....... like in automotive, tap the engine vacuum from the intake side. Does anyone have any experience in doing that on a Lycoming engine? I would be curious about anyone's experience in trying that to operate vac instruments. Conceivable one could operate all sorts of vacuum controls for airflow, heat, vents similar to a car using the same control block and parts to open and close dampers or other devices. rubber hose is much lighter and flexible than steel cable dampers. Okay, what say you group? Thanks John________________________________________________________________________________Date: Thu, 22 Apr 2010 12:11:26 -0400

Original Posted By: Dan Yocum