From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Re: hydraulic gauge
To: lml
Date: Thu, 21 Nov 2002 10:27:53 -0500
Message-ID: <web-1883653@logan.com>
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Posted for Bob Pastusek <rpastusek@htii.com>:

Lorn & Joe,

The hydraulic systems are different between the Lancair 300 series and the
IV series. I believe the Legacy is the same as the 300 series aircraft, but
haven't seen one first hand. The 300 series systems operate as you describe,
basically reversing the flow to raise and lower the gear. The IV's have a
system that flows hydraulic fluid in only one direction through the pump,
and uses a series of valves on the gear/flap control quadrant to shuttle the
1000 PSI fluid from the up to the down side of the gear cylinders as needed.
The  fluid coming from the "low pressure" side of these cylinders is shunted
back to the reservoir at essentially zero pressure. The flap circuit has a
clever twist that applies the high pressure fluid to cylinder faces with
different surface areas to reduce the operating force, but it basically
works the same way as the gear circuit. (Anyone want to take on the
technical explanation of how it really works?)

Bob Pastusek