Mailing List lml@lancaironline.net Message #67393
From: Todd Long <toddlong1@gmail.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Removing vacuum pump? (LIVP)
Date: Mon, 14 Oct 2013 13:16:25 -0400
To: <lml@lancaironline.net>
This dukes is electrically controlled. It does not work like what you find in a king air. 

Typing and grammar errors courtesy of Siri and the iPhone.

On Oct 14, 2013, at 7:14, Paul Miller <pjdmiller@gmail.com> wrote:

If the pressure controller on the panel has rate of climb and cabin altitude settings (like a Garrett), it likely uses the vacuum line to modulate the outflow valves (pull them open).  That modulation is what provides the signal to allow the cabin to climb or descend.   I don't know what controller is in place but the vacuum is for cabin differential control.  The squat switch is for ground use or emergency and simple opens the outflow to a maximum.  In a typical situation, the outflow closes with wheels up then the vacuum signal starts to open the valves to provide the differential required to either climb or hold the cabin as set by the controller.

If the vacuum is disconnected, I suspect you simply are running with a fully closed outflow valve and the cabin pressure is an open loop with whatever pressure is supplied from the firewall.  Does that sound about right?

What I am missing is if there is no vacuum line then why install the controller?  How does it control anything?  Those controllers can't be cheap.


On 12 October 2013 17:00, jeffrey liegner <liegner@ptd.net> wrote:
  The device might function better (although I can't prove that), but it is not necessary.  I recall that it is to help the valve move initially (and has no value after that first movement) and effect a seal early 
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