The Lancair wiring diagram shows an interconnect switch between the landing gear and the pressurization system.  IMHO, this is a complete waste of complexity.  Because there is no backflow valve on the pressure inlet from the intercoolers, once you pull the power below 20 MAP the cabin will completely depressurize.

 

Pete

 

From: William A. Hogarty [mailto:billhogarty@gmail.com]
Sent: Wednesday, October 09, 2013 5:14 PM
To: Lancair Mailing List
Subject: Re: [LML] Removing vacuum pump?

 

I understood that the outflow valve was grounded whenever the gear switch was down.

 

Is this wrong?

 

Bill Hogarty

 

On Wed, Oct 9, 2013 at 9:13 AM, Craig Berland <cberland@systems3.net> wrote:

I have an all-electric airplane as well and chose to not have any vacuum supplied to the Dukes valve.  The only difference is the rate in which pressurization starts building in the cabin on takeoff roll.  Once airborne, vacuum has no effect on the pressurization system.   I choose to apply power a little more slowly than some pilots.  This prevents any pressurization discomfort and typically I don't need any right brake to hold centerline.  Takeoff distance is not an issue.  If I can land there, I can easily takeoff there.  I know one pilot who has developed an electronic circuit to control a small electric vacuum pump based on the landing gear position.  So there are several options.  In my opinion, keeping the engine driven pump is the least desirable.

Craig Berland
N7VG


Hello Dico,
You will need a vacuum port to the Dukes pressure valve for the pressurization to work correctly, I do not have any gyro instruments either but I needed to install an electric vacuum pump near the Dukes valve
Kamal T
N1104T




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