X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 15 Dec 2005 22:11:04 -0500 Message-ID: X-Original-Return-Path: Received: from imo-d03.mx.aol.com ([205.188.157.35] verified) by logan.com (CommuniGate Pro SMTP 5.0.4) with ESMTP id 884259 for lml@lancaironline.net; Thu, 15 Dec 2005 21:18:56 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.157.35; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d03.mx.aol.com (mail_out_v38_r6.3.) id q.231.3c64092 (4410) for ; Thu, 15 Dec 2005 21:18:10 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <231.3c64092.30d37de2@aol.com> X-Original-Date: Thu, 15 Dec 2005 21:18:10 EST Subject: Re: [LML] LNC2 Nose Gear Door Goofy X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1134699490" X-Mailer: 9.0 Security Edition for Windows sub 5300 X-Spam-Flag: NO -------------------------------1134699490 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 12/15/2005 11:39:38 A.M. Central Standard Time, Lee.Metcalfe@jocogov.org writes: The nose gear door on my 320 has started this strange behavior of gradually moving towards the closed position over a period of days with plane in the hangar. I think the design of the system is per the Lancair build manual. Only the up side of the actuator is plumbed into the hydraulic system. The down side is open to the atmosphere and down-force is supplied by a "coil-over" spring on the actuator. The up side hydraulic line goes through a sequence valve actuated by the gear being fully retracted. The only thing I can think of is the sequence valve is leaking pressure to the actuator, but where would that pressure come from? Isn't the up side of the system depressurized in the gear-down mode? Is down side pressure leaking to the up side somewhere? Moon Dog, Stop flying in the cold weather and then storing the magic carpet in a heated hangar. I think your think is right - the sequence valve is leaking (or the down side is leaking to the upside), the hydraulic system is warming up and expanding and (or) the plane is parked during beautiful weather generated by a local high pressure and then, after hangaring, gloom arrives via a nasty winter low accompanied by ugly overcasts - thus the open "down" side pressure is lessened and - voila! - just like the water level in an unused toilet after pressure changes. Has the ghost of Christmas Past been bothering you lately? Grayhawk -------------------------------1134699490 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 12/15/2005 11:39:38 A.M. Central Standard Time,=20 Lee.Metcalfe@jocogov.org writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>The nose=20 gear door on my 320 has started this strange behavior of
gradually movi= ng=20 towards the closed position over a period of days with
plane in the=20 hangar. I think the design of the system is per the
Lancair build= =20 manual. Only the up side of the actuator is plumbed into
the=20 hydraulic system. The down side is open to the atmosphere=20 and
down-force is supplied by a "coil-over" spring on the actuator.&nbs= p;=20 The up
side hydraulic line goes through a sequence valve actuated by th= e=20 gear
being fully retracted. The only thing I can think of is the=20 sequence
valve is leaking pressure to the actuator, but where would tha= t=20 pressure
come from? Isn't the up side of the system depressurized= in=20 the
gear-down mode? Is down side pressure leaking to the up side=20 somewhere?

Moon Dog,

Stop flying in the cold weather and then storing the magic carpet in a=20 heated hangar. I think your think is right - the sequence valve is lea= king=20 (or the down side is leaking to the upside), the hydraulic system is warming= up=20 and expanding and (or) the plane is parked during beautiful weather generate= d by=20 a local high pressure and then, after hangaring, gloom arrives via a na= sty=20 winter low accompanied by ugly overcasts - thus the open "down" side pressur= e is=20 lessened and - voila! - just like the water level in an unused toilet after=20 pressure changes.

Has the ghost of Christmas Past been bothering you lately?

Grayhawk

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