The valve helps smooth out pressurization changes with power changes. It allows the outflow valves to do their job better. But yes it would provide a small margin of pressurization after the engine failure. That would change the event from a rapid decompression to leak down. If it was a rapid decompression it will fog or ice up your window at altitude. One more thing to deal with. I was just wondering if anybody knew I wasn't in the system. Because all the engineers of all the certified pressurized aircraft have them.
Typing and grammar errors courtesy of Siri and the iPhone. What would be the advantage? seconds more pressurized time in case of engine failure? On Oct 11, 2013, at 7:52 AM, Todd Long wrote: Does anyone know why there is no check valve on the pressurization? Cessna P210 and Malibu both have them.
Typing and grammar errors courtesy of Siri and the iPhone. 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. 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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