X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 04 Apr 2011 15:42:58 -0400 Message-ID: X-Original-Return-Path: Received: from web36906.mail.mud.yahoo.com ([209.191.85.74] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with SMTP id 4932190 for lml@lancaironline.net; Mon, 04 Apr 2011 12:16:45 -0400 Received-SPF: none receiver=logan.com; client-ip=209.191.85.74; envelope-from=chris_zavatson@yahoo.com Received: (qmail 43155 invoked by uid 60001); 4 Apr 2011 16:16:10 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=zmZaV+hnkxdB+7uifuqPdbiqSfRgC+CW8+Hcolesrzw10CYwg/zFC4tdS4+IOLGgXbPCGaP3ppUoo/QneXuzGyIOL8DlreV060lhPHBllF9zNEZ/wLdhUUA0PiFxOngrXR+NVMXUKVAjjdjY+U77PWwNeKjufAkZ4c4vK2r54oM=; X-Original-Message-ID: <538691.32291.qm@web36906.mail.mud.yahoo.com> X-YMail-OSG: Np.S.ToVM1nEVOm1BjO1U5g1D441zcw7O24NXyPDTi_4Ow9 O7BzzNkKVJNW7LiVX3f7XDHa3uwdPRilY4E7E_RNLDhxtRip_9eeHmSiyS9G osq7Ftu3qPdDXAMmzsse0QOTe.6I915WHbydKE9q4lkuuF70qLyUmJagYtL0 yxvdYB5Jae1Grg9bUh7UBXBqahBe2VJHan3GDb.urzpUCWqFu2pa9pGXqH1g 01YHTDtadZPJ1TFr9Ekwbb0u5CJg99MiZxKdxhLW9jUxduZ4UCk.bIVfFbFV UZH2wAQRuuRrbVKzTKy09jgV.7w.uQ064LFkxJwLgdySAQEIMC3oxXcwg2PZ RxYMNt7iyFGQ40vlPebk7h9xxoR.ceniKR.OE3aqKqbhInTq7GPZeEWpzHzZ VFjuoCNq9WhAHFA-- Received: from [12.130.164.194] by web36906.mail.mud.yahoo.com via HTTP; Mon, 04 Apr 2011 09:16:10 PDT X-Mailer: YahooMailRC/559 YahooMailWebService/0.8.109.295617 References: X-Original-Date: Mon, 4 Apr 2011 09:16:10 -0700 (PDT) From: Chris Zavatson Subject: Re: [LML] Re: LNC2 Gear Hydraulics X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1261999384-1301933770=:32291" --0-1261999384-1301933770=:32291 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Randy,=0AI don't doubt your observations.=C2=A0 I am just really curious wh= at is different in =0Ayour pump.=C2=A0 The only way I can see this happenin= g is if the spool doesn't stay =0Aput after the pump shuts down (slide 21 f= rom my previous post).=C2=A0If the spool =0Agoes back to center both high a= nd low circuits become isolated.=C2=A0 Once that =0Ahappens, temperature ri= se or and internal leak can lock out the pump.=0AI've=C2=A0had my low side = pressure go off the scale of the pressure gauge (1,200+ =0Apsi)=C2=A0while = he plane got baked in my old hangar.=C2=A0 The high side remained at =0Azer= o.=C2=A0 Similarly when descending into hot desert air from 18k, the high s= ide has =0Ahit 2,000 psi. The=C2=A0low side remained at zero.=C2=A0 When th= e spool remains in place, =0Athis makes perfect sense.=C2=A0 The non-operat= ing side has a low resistance escape =0Apath and cannot retain pressure.=C2= =A0 I would love=C2=A0throw=C2=A0your pump=C2=A0on the=C2=A0test =0Abench.= =C2=A0=C2=A0 Let me know if you are interested=0AI just did a more comprehe= nsive video of thermal cycling for the hydraulic =0Asystem, retracted, exte= nded, under heating and cooling.=C2=A0=C2=A0Time is sped up=C2=A02x to =0Ak= eep the total length reasonable.=C2=A0 Worth noting is that the non-active = side =0Aalways remains at zero.=C2=A0 =0A=0Ahttp://www.youtube.com/watch?v= =3DZF3g_uPCzLk=0AChris=0A=0AChris Zavatson=0AN91CZ=0A360std=0Awww.N91CZ.net= =0A=0A=0A=0A________________________________=0AFrom: randy snarr =0ATo: lml@lancaironline.net=0ASent: Sun, April 3, 2011 11:40:= 56 PM=0ASubject: [LML] Re: LNC2 Gear Hydraulics=0A=0A=0AChris,=0ABoth sides= of my system rise and fall with temp...=0AThis is why I installed a dump v= alve with an extra line that dumps to zero =0Apounds on both sides when ope= ned rather than just equalize and still be under =0Apressure. I too used a = wrench a few times to release the pressure. I believe =0Athis condition is = a little worse in my plane as I replace the large factory =0Asupplied hose = with small tight stainless braid lines that most likely resist =0Aexpansion= more than the big factory rubber hoses...=0A=0ARS=0A=0A"Flight by machines= heavier than air is unpractical and insignificant, if not =0Autterly impos= sible"=0A-Simon Newcomb, 1902=0A=0A--- On Fri, 4/1/11, Chris Zavatson wrote:=0A=0A=0A>From: Chris Zavatson =0A>Subject: [LML] Re: LNC2 Gear Hydraulics=0A>To: lml@lancaironl= ine.net=0A>Date: Friday, April 1, 2011, 8:34 AM=0A>=0A>=0A>Keith,=0A>You sh= ould never have to resort to wrenches to get the wheels up =E2=80=93and tha= t is =0A>not just speaking from a safety perspective.=C2=A0 =0A>=0A>The fol= lowing is an extract and renumbered set of slides from a LOBO maintenance = =0A>seminar on the 320/360 hydraulic system.=C2=A0 Slide 21 shows one possi= ble =0A>explanation for your system=E2=80=99s failure to retract.=0A>=C2=A0= =0A>http://www.n91cz.com/misc/LancairHydraulics-LML.pdf=0A>=C2=A0=0A>Temper= ature changes will cause pressure to go up and down, but should only =0A>af= fect the currently operating side of the system.=C2=A0 The non-operating si= de =0A>should be zero and remain zero unless there is some other failure or= =0A>configuration issue. =C2=A0=C2=A0If both operating and non-operating s= ides are affected by =0A>temperature =E2=80=93 investigate.=C2=A0 =0A>=0A>= =C2=A0Note that earlier vintage pumps (~235 era) were internally different.= =0A>You may also find some of the following of interest:=0A>=C2=A0=0A>http= ://www.n91cz.com/Hydraulics/Lancair_Hydraulics.htm=0A>=C2=A0=0A>Chris Zavat= son=0A>N91CZ=0A>360std=0A>www.N91CZ.net=0A>=0A>=0A>=0A>=0A_________________= _______________=0AFrom: Keith Smith =0A>To: lml@lanc= aironline.net=0A>Sent: Thu, March 31, 2011 12:24:59 PM=0A>Subject: [LML] Re= : LNC2 Gear Hydraulics=0A>=0A>Quite possibly one of the best posts I've eve= r read.=C2=A0 Thanks, Tom, for taking =0A>the time so share those experienc= es!=0A>=0A>I recently experienced the inability to raise the gear. A quick = call to Rick =0A>Argente (Lancair owner/builder in NJ) provided the solutio= n...bleed the line. He =0A>said it's a common issue when flying from cold l= ocations (NJ) to warmer =0A>destinations (Georgia).=0A>=0A>I also get hear = the pump activate in flight for a fraction of a second every =0A>20-30 minu= tes or so, which I suspect points to a leak of some sort.=0A>=0A>Keith Smit= h=0A>N360JH=0A> --0-1261999384-1301933770=:32291 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Randy,
=0A
I don't doubt your observations.  I am j= ust really curious what is different in your pump.  The only way I can= see this happening is if the spool doesn't stay put after the pump shuts d= own (slide 21 from my previous post). If the spool goes back to center= both high and low circuits become isolated.  Once that happens, tempe= rature rise or and internal leak can lock out the pump.
=0A
I've&n= bsp;had my low side pressure go off the scale of the pressure gauge (1,200+= psi) while he plane got baked in my old hangar.  The high side r= emained at zero.  Similarly when descending into hot desert air from 1= 8k, the high side has hit 2,000 psi. The low side remained at zero.&nb= sp; When the spool remains in place, this makes perfect sense.  The no= n-operating side has a low resistance escape path and cannot retain pressur= e.  I would love throw your pump on the test bench= .   Let me know if you are interested
=0A
I just did a m= ore comprehensive video of thermal cycling for the hydraulic system, retrac= ted, extended, under heating and cooling.  Time is sped up 2= x to keep the total length reasonable.  Worth noting is that the non-a= ctive side always remains at zero. 
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