X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 26 Jan 2013 14:24:43 -0500 Message-ID: X-Original-Return-Path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTP id 6030820 for lml@lancaironline.net; Sat, 26 Jan 2013 12:33:50 -0500 Received-SPF: none receiver=logan.com; client-ip=71.74.56.122; envelope-from=Wolfgang@MiCom.net X-Original-Return-Path: X-Authority-Analysis: v=2.0 cv=W/m6pGqk c=1 sm=0 a=MHZY6FYWMEQOp7S43i2QIw==:17 a=3Zlka_XeuxsA:10 a=f_ZkDAzIiSUA:10 a=ttCsPuSJ-FAA:10 a=rTjvlri0AAAA:8 a=f5qw7zG_ri8A:10 a=Ia-xEzejAAAA:8 a=5npX_Cm-W69DWLUU3zYA:9 a=wPNLvfGTeEIA:10 a=EzXvWhQp4_cA:10 a=Cvx5BxySACNcjF7g:21 a=vYbh6oJydSR6Lf4H:21 a=o1OHuDzbAAAA:8 a=Ec33akswEw0sikdeSOEA:9 a=_W_S_7VecoQA:10 a=ILCZio5HsAgA:10 a=QSGxmdIGXPU8qGXQ:21 a=MHZY6FYWMEQOp7S43i2QIw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.218.201.50 Received: from [74.218.201.50] ([74.218.201.50:1112] helo=lobo) by hrndva-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id FF/6C-08009-A5314015; Sat, 26 Jan 2013 17:33:14 +0000 X-Original-Message-ID: From: "Wolfgang" X-Original-To: References: Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure X-Original-Date: Sat, 26 Jan 2013 12:33:06 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0057_01CDFBC1.4ACC5F20" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5512 This is a multi-part message in MIME format. ------=_NextPart_000_0057_01CDFBC1.4ACC5F20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable This has been covered at great length before. Some take the position = that "real pilots" don't need anything but the dump valve. I have proposed two answers, 1) replace the dump valve that only opens a port between the HI and LO = sides with a dump valve that dumps back to the pump reservoir. 2) install a small electric module I make across the pressure switches = that runs the pump to relieve the over pressure in the "wrong" line = automatically. Wolfgang ----- Original Message -----=20 From: Charles Brown=20 To: lml@lancaironline.net=20 Sent: Saturday, January 26, 2013 2:07 AM Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure This has happened to me even at the beginning of a flight, if the = temps in the hangar have gone from cold on a previous day, to warm on = flight day. I guess cold temps shrink the fluid and suck more from the = reservoir into the lines, and when it warms, the pressure builds on both = sides of the system, so that the "up" and "down" pressure switches are = both open and the gear won't move until I pop the bleed valve. Nasty when the gear won't retract just after blasting off into a low = overcast. Charley Brown Legacy #299 200 hr On Jan 25, 2013, at 7:23 AM, randy snarr wrote: . I dont like having to open the dump valve but it is necessary once = in a while especially when it is cold. The pressures on both sides of = the system climb due to the engine heat and the gear sometimes will not = move without dumping the pressure. ------=_NextPart_000_0057_01CDFBC1.4ACC5F20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
This has been covered at great length = before. Some=20 take the position that "real pilots" don't need anything but the = dump=20 valve.
I have proposed two = answers,
1) replace the dump valve that only = opens a port=20 between the HI and LO sides with a = dump valve=20 that dumps back to the pump reservoir.
2) install a small electric module I = make across=20 the pressure switches that runs the pump to relieve the over = pressure=20 in the "wrong" line automatically.
 
Wolfgang
----- Original Message -----
From:=20 Charles=20 Brown
Sent: Saturday, January 26, = 2013 2:07=20 AM
Subject: Re: [LML] Re: Thermal = influence=20 on Hydraulic Pressure

This has happened to me even at the beginning of a flight, if the = temps=20 in the hangar have gone from cold on a previous day, to warm on flight = day.=20  I guess cold temps shrink the fluid and suck more from the = reservoir=20 into the lines, and when it warms, the pressure builds on both sides = of the=20 system, so that the "up" and "down" pressure switches are both open = and the=20 gear won't move until I pop the bleed valve.

Nasty when the gear won't retract just after blasting off into a = low=20 overcast.

Charley Brown
Legacy #299  200 hr

On Jan 25, 2013, at 7:23 AM, randy snarr wrote:

.=20 I dont like having to open the dump valve but it is necessary once in = a while=20 especially when it is cold. The pressures on both sides of the system = climb=20 due to the engine heat and the gear sometimes will not move without = dumping=20 the pressure.

= ------=_NextPart_000_0057_01CDFBC1.4ACC5F20--