X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 22 Mar 2008 21:40:12 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m26.mx.aol.com ([64.12.137.7] verified) by logan.com (CommuniGate Pro SMTP 5.2.1) with ESMTP id 2812495 for lml@lancaironline.net; Fri, 21 Mar 2008 18:51:17 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.7; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m26.mx.aol.com (mail_out_v38_r9.3.) id q.c2a.2091bfa5 (39330) for ; Fri, 21 Mar 2008 18:50:35 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Fri, 21 Mar 2008 18:50:35 EDT Subject: Re: [LML] Gear wouldn't come up, LNC2 X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1206139835" X-Mailer: Unknown sub 34 X-Spam-Flag: NO -------------------------------1206139835 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Byron, While focusing on your last sentence, remember this: In flight and at any request to retract the gear, there are no external forces on the hydraulic system - i.e. every thing is down and LOCKED. In flight and issuing a request to drop the gear, gravity, door springs and the gas nose spring are all imputing forces to the hydraulic system - usually enough to unlock any subpart, especially if the dump valve is opened. This is good when approaching a landing field for any reason requiring contact with earth. Grayhawk In a message dated 3/21/2008 4:59:31 P.M. Central Daylight Time, breskesen@comcast.net writes: As Randy S points out, opening the dump valve merely equalizes the pressure on both sides. But, it's a much lower pressure and therefore allows the up pressure switch to stay open even when the fluid temperature has increased substantially. I shut down the engine, turn off the master, and then open the dump valve which I leave open while parked. Remember that the landing gear has an over center mechanism on each gear leg that locks the gear in the extended position. The gear stays locked until hydraulic pressure is used to unlock the over center mechanism(s) at the beginning of the retract cycle. If you were to open the dump valve with the master switch on, the pump will run continuously but will build no pressure till the valve is closed. For those of us who occassionally have the pump not respond to the down switch while in flight, opening the dump valve momentarilly will reduce the hydraulic pressure that has built up during our flight through changing temperatures, thus allowing the pump to come on and extending the gear. **************Create a Home Theater Like the Pros. Watch the video on AOL Home. (http://home.aol.com/diy/home-improvement-eric-stromer?video=15?ncid=aolhom00030000000001) -------------------------------1206139835 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Byron,
 
While focusing on your last sentence, remember this: In flight=20 and at any request to retract the gear, there are no external= =20 forces on the hydraulic system - i.e. every thing is down and LOCKED. =20= In=20 flight and issuing a request to drop the gear, gravity, door springs and the= gas=20 nose spring are all imputing forces to the hydraulic system - usually enough= to=20 unlock any subpart, especially if the dump valve is opened.  This is go= od=20 when approaching a landing field for any reason requiring contact with=20 earth.
 
Grayhawk
 
In a message dated 3/21/2008 4:59:31 P.M. Central Daylight Time,=20 breskesen@comcast.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
As Randy S points out, opening the dump v= alve=20 merely equalizes the pressure on both sides. But, it's a much lower pressu= re=20 and therefore allows the up pressure switch to stay open even when the flu= id=20 temperature has increased substantially.  I shut down the engine, tur= n=20 off the master, and then open the dump valve which I leave open while=20 parked.  Remember that the landing gear has an over center mechanism=20= on=20 each gear leg that locks the gear in the extended position.  The gear= =20 stays locked until hydraulic pressure is used to unlock the over center=20 mechanism(s) at the beginning of the retract cycle.  If you were to o= pen=20 the dump valve with the master switch on, the pump will run continuously b= ut=20 will build no pressure till the valve is closed.  For those of us who= =20 occassionally have the pump not respond to the down switch while in flight= ,=20 opening the dump valve momentarilly will reduce the hydraulic pressure tha= t=20 has built up during our flight through changing temperatures, thus allowin= g=20 the pump to come on and extending the gear. =20



Create a Home Theater Like the Pros. Watch the video on AOL Home= .
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