X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 19 Feb 2013 07:52:01 -0500 Message-ID: X-Original-Return-Path: Received: from nm8-vm2.bullet.mail.ne1.yahoo.com ([98.138.90.156] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTPS id 6070948 for lml@lancaironline.net; Tue, 19 Feb 2013 00:36:07 -0500 Received-SPF: none receiver=logan.com; client-ip=98.138.90.156; envelope-from=chris_zavatson@yahoo.com Received: from [98.138.90.53] by nm8.bullet.mail.ne1.yahoo.com with NNFMP; 19 Feb 2013 05:35:32 -0000 Received: from [98.138.88.234] by tm6.bullet.mail.ne1.yahoo.com with NNFMP; 19 Feb 2013 05:35:32 -0000 Received: from [127.0.0.1] by omp1034.mail.ne1.yahoo.com with NNFMP; 19 Feb 2013 05:35:32 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 614585.65345.bm@omp1034.mail.ne1.yahoo.com Received: (qmail 14808 invoked by uid 60001); 19 Feb 2013 05:35:32 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=xuzbjydIISQTduaZkVSmERru6ym/hafOEnT4LLlWI+oMLGHWOHPf8b0e+zCurgQk6XJngnZHCimMcL0O7Y0msO8hKoEALcC60qqZSvj8kbjUZQJVFOZYZzvuiorQ5ZerQdI7tWO/vAiUrqNVUuMkO0vPvboJEemfLTy+RwZYWF0=; X-YMail-OSG: zCLKrvgVM1kfFJFFLJo7WJpd9lkiPY96Dh4Z5_aJbVknMKU mYzDAEAMuouXwu8vEwmIfQtiQ2IX.bwcOdtShc_8NrnxIB4ztGQbYfyK.599 .JM895XvyTT0ayCwKOokU2DoG6rAvvu44GQdY3zCjeWulkHJpzz6T.VXUd8j V.0hYxGMdflXj0CJlBFqhEEq4zClVtSIEtbQoyXuT7gfFiEMLHGhQSrR_fiK IcgVAtf0sShF_7CMMRgGsmqsrhqXvnvEK1Yc8Z7oY.iWMv3Z0yKXgQ_hkWS0 MQKxb1THC4nWuyiexOxwPffed4CYfXj8o33kdEesB47ayUlROv1FzxxdnqeG LSdYSQ1WQZx2ZZ38GKnXiuibKSUv4fSzLDV0B0Zjhmwph5Evexlvef1A8IqM 6TP55Ui2aEQUCxb9muU57y3SBsmx.c2a3c4WeneN2.79qXVvpXIB_lLHBFDY RjMPciC1O_Qck_llqEBGEhy9gwsF4sXrHEg6.Qq930pj5P_IMcTBH61.Njd6 qfocD3tIXuhrpGfT4oUkvt7visBaVnGPOBA73eQdvGev40smnFUzCfCICa04 s3SO2u24KqFgecpNVWLrUyIt9ElFFtVHFyEZn3k1HSrjjBo6Tbnn4FI0Nr3B gOSjzI.E- Received: from [76.246.32.109] by web121604.mail.ne1.yahoo.com via HTTP; Mon, 18 Feb 2013 21:35:32 PST X-Rocket-MIMEInfo: 001.001,Tm90IGEgcHJvYmxlbS7CoCBJIHdpbGwga2VlcCBteSBvcGluaW9uIHRoYXQgZml4aW5nIHRoZSByb290IGNhdXNlIGlzIGJldHRlciB0aGFuIGEgYmFuZC1haWRlLgrCoApIZXJlIGFyZSB0aGUgaW5zdHJ1Y3Rpb25zIHRvIGN1cmUgdGhlIHByb2JsZW0gZm9yIHRoZSAzMjAvMzYwcyB0aGF0IGhhdmUgdGhlIExlZ2FjeSB0eXBlIHB1bXAgaW5zdGFsbGVkLsKgIGh0dHA6Ly93d3cubjkxY3ouY29tL0h5ZHJhdWxpY3MvUHVtcC1VbmxvY2sucGRmCi1zaG91bGQgdGFrZSBhYm91dCAxNSBtaW51dGVzIG9uIHRoZSABMAEBAQE- X-Mailer: YahooMailWebService/0.8.134.513 References: X-Original-Message-ID: <1361252132.11837.YahooMailNeo@web121604.mail.ne1.yahoo.com> X-Original-Date: Mon, 18 Feb 2013 21:35:32 -0800 (PST) From: Chris Zavatson Reply-To: Chris Zavatson Subject: Re: [LML] Re: Fw: [LML] Re: Thermal influence on Hydraulic Pressure X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-36511695-2139279335-1361252132=:11837" ---36511695-2139279335-1361252132=:11837 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Not a problem.=C2=A0 I will keep my opinion that fixing the root cause is b= etter than a band-aide.=0A=C2=A0=0AHere are the instructions to cure the pr= oblem for the 320/360s that have the Legacy type pump installed.=C2=A0 http= ://www.n91cz.com/Hydraulics/Pump-Unlock.pdf=0A-should take about 15 minutes= on the bench.=C2=A0=0A=C2=A0=0APage 9 of this report adds some more detail= http://www.n91cz.com/Hydraulics/Lancair%20Hydraulics.pdf=0A=C2=A0=0AI woul= d still like to hear an explanation as to how the module can detect the gea= r down failure.=0A=C2=A0=C2=A0=C2=A0=C2=A0-gear locked, partially extended= =0A=C2=A0=C2=A0=C2=A0=C2=A0-low side switch open=0A=C2=A0=C2=A0=C2=A0=C2=A0= -high side switch closed=0A=C2=A0=C2=A0=C2=A0=C2=A0-both sides pressurized = to just above low side pressure switch setting=0A=C2=A0=0AChris Zavatson=0A= N91CZ=0A360std 1,400 hrs (lock-up free)=0Ahttp://www.n91cz.net/=0A =0A=0A__= ______________________________=0A From: Wolfgang =0ATo:= lml@lancaironline.net =0ASent: Saturday, February 16, 2013 7:21 PM=0ASubje= ct: [LML] Re: Fw: [LML] Re: Thermal influence on Hydraulic Pressure=0A =0A= =0A=EF=BB=BF =0AChris, =0A=C2=A0 =0AOk, let's agree to disagree. =0A=C2=A0= =0AYou want to take a plane down for a couple of weeks while =0Ayou tear d= own the pump.=C2=A0I don't need a pump sent to me for tear down and =0Amodi= fication. My module is a 20 minute add-on that will mitigate the problem fo= r =0Aboth up and down function . . . without getting particular with the pr= essure =0Asettings. The only down side (as with any other part of the airfr= ame) is if you =0Afailed to build your hydraulic system to spec. =0A=C2=A0 = =0AWolfgang =0A=C2=A0 =0A----- Original Message ----- =0A>From: Chris Zav= atson =0A>To: lml@lancaironline.net =0A>Sent: Friday, February 15, 2013 4= :04 PM =0A>Subject: Re: [LML] Re: Fw: [LML] Re: Thermal influence on Hydr= aulic Pressure =0A>=0A> =0A> =0A>Wolfgng, =0A>=E2=80=9CHow do some spools = come off their endpoints and cause reported failure?=E2=80=9D=C2=A0 =0A>T= hat question was answered long ago. =C2=A0I can show you how to rig a pum= p to lock up and then I can show you how to rig it such that it can=E2=80= =99t lock up.=C2=A0 =0A>Developing a fix for a problem before understandi= ng the root cause is not a smart way to go about things.=C2=A0 You saw an = issue on one airplane. Unfortunately you refused to pull the pump to look = at it, simply telling us that the pump was too difficult to reach. That is= a really poor excuse. =C2=A0Yes, the pump was behind the baggage bulkhead= and it is not easy to get to it.=C2=A0 How can that be a valid reason for = not examining the actual hardware? =0A>Initially it was claimed this mod= ule would solve lock-up in both directions.=C2=A0 Reading through the descr= iption of its theory of operation, it is clear the module cannot catch the= =E2=80=98failure to extend=E2=80=99 lock-up.=C2=A0 A system state was mi= ssed. =0A>There are downsides to having to use the pump to forcibly unlo= ck a thermally locked system.=C2=A0 I am sure you are aware of those. =C2= =A0I am curious what new failure modes have been introduced if any one par= t of the module fails? =0A>I offered to look at Lorn=E2=80=99s pump as I= have done for others.=C2=A0 Your reply was that a week or two of down tim= e was too much of a price to pay.=C2=A0 Really! =0A>I am still in search = of a pump that falls outside the expected behavior when configured properl= y.=C2=A0 I would truly like to find one as it can only serve to further ou= r understanding of our planes.=C2=A0 What a shame and loss to the communi= ty if you (or really Lorn) truly possess such a pump.=C2=A0 I know, I know,= it is too much effort to pull the pump. =0A>Please don=E2=80=99t extrap= olate the behavior of the one pump you saw only from the outside to the re= st of the fleet. =0A>Disclaimer:=C2=A0 I don=E2=80=99t have a financial = interest in this discussion=E2=80=A6=E2=80=A6.well maybe I do.=C2=A0 I am t= rying to keep our insurance rates from going up. =0A>For your entertainm= ent I have attached some photos of my pressure gauges after my plane was e= xposed to thermal soak, both in the air and on the ground.=C2=A0 You will s= ee that only the commanded side is affected by thermal influence. =0A>And= here are some video clips: =0A>The first video shows how a pump with sp= ool return springs can lock up when subjected to rising temperatures.=C2= =A0 The second clip shows a pump without return springs.=C2=A0 Only the cu= rrently active side is affected by temperature changes.=C2=A0 No lock-up = =0A>Hydraulic Lock due to thermal cycling(=E2=80=9CCZZ=E2=80=9D configured = pump with spool return springs installed) =0A>Normal Pump operation when = subjected to thermal cycling.(=E2=80=9CLB=E2=80=9D) configured pump withou= t return springs =0A>320/360 Hydraulics Tutorial =0A>Chris Zavatson = =0A>N91CZ =0A>L360std 1,400 hrs (lock-up free) =0A>http://www.n91cz.net/= =0A>=0A> =0A>=0A>________________________________=0A>From: Wolfgang =0A>To: lml@lancaironline.net =0A>Sent: Thursday, February = 14, 2013 11:48 AM=0A>Subject: [LML] Re: Fw: [LML] Re: Thermal influence o= n Hydraulic Pressure=0A>=0A>=0A>What did you measure to come up with that 7= 0 g's ? =0A>and . . . the springs trying to center the spool in some mode= ls certainly don't help. =0A>=C2=A0 =0A>So the question still lingers from = more than a year ago, =0A>How do some spools come off their end position = and cause the reported failures ? =0A>=C2=A0 =0A>That's why I came up with= the module I have. =0A>It powers the spool back into position whenever n= eeded, regardless of pump model. =0A>=C2=A0 =0A>Wolfgang =0A>=C2=A0 =0A>---= -- Original Message ----- =0A>>From: Chris Zavatson =0A>>To: lml@lancai= ronline.net =0A>>Sent: Wednesday, February 13, 2013 7:55 AM =0A>>Subject: = Re: [LML] Fw: [LML] Re: Thermal influence on Hydraulic Pressure =0A>>=0A>> = =0A>>Reposted from June 2011 =0A>>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D----- = Original Message ----- =0A>>From: Chris Zavatson =0A>>To: lml@lancaironl= ine.net =0A>>Sent: Saturday, June 25, 2011 12:35 PM =0A>>Subject: Re: [LML= ] Re: LNC2 Gear Hydraulics =0A>>=0A>> =0A>>Curiosity got the best of me. He= re are the peak vibration values recorded today at the hydraulic pump meas= ured on the axis of the spool valve. =0A>>Start up: +/- 1.3 g =0A>>Take of= f: +/- 0.3 g =0A>>Cruise: +/- 0.1 g =0A>>Descent: +/- 0.1 g =0A>>Landing: += /- 0.6 g =0A>>It would appear the O-ring has more design margin than just a= bout any other component on the plane. =0A>>Chris Zavatson =0A>>N91CZ = =0A>>360std =0A>>www.N91CZ.com =0A>>=0A>>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D =0A>>=0A>>________________________________=0A>>From: Wolfgang =0A>>To: lml@lancaironline.net =0A>>Sent: Monday, February 11, = 2013 12:36 PM=0A>>Subject: [LML] Fw: [LML] Re: Thermal influence on Hydra= ulic Pressure=0A>>=0A>>=0A>>70 g's is an impressive number. How was that m= easured ? =0A>>Or is that just a=C2=A0measure of the vibration that the p= art lives under during flight ? =0A>>=C2=A0 =0A>>Wolfgang =0A>>=C2=A0 =0A>>= =C2=A0 =0A>>From: Chris Zavatson =0A>>To: lml@la= ncaironline.net =0A>>Sent: Saturday, January 26, 2013 12:24 PM=0A>>Subject= : [LML] Re: Thermal influence on Hydraulic Pressure=0A>>=0A>>=0A>>Randy, = =0A>>Thanks.=C2=A0 =0A>>=C2=A0=C2=A0=C2=A0=C2=A0There are two things I ha= ve been doing to pumps to eliminate the need for 'dump valve rescues'.=C2= =A0 =0A>>First is the removal of the return springs that entered the Lega= cy pump design in about 2005.=C2=A0 They=C2=A0added no useful=C2=A0functio= nality and=C2=A0unfortunately introduced a lock-up failure mode.=C2=A0 Rem= oving the springs primarily addresses lock-up on the ground during thermal= swings. =0A>>The second thing I have been doing is to set the low pressure= switch to 800-850 psi.=C2=A0 This eliminates the gear extension lock-up m= ode that occasionally prevents the gear from fully extending.=C2=A0 The or= iginal setting was to low to overcome the pressure spike that=C2=A0propaga= tes through the system when the gear first come out of the wheel wells. = =0A>>=C2=A0=C2=A0=C2=A0=C2=A0The other thing I=C2=A0have been doing is mea= suring the spool resistance on every pump that comes across my desk.=C2=A0= I haven't found any issues there.=C2=A0 70g's is the typical result. =0A>= >I have also been making thermal relief valves adjustable, bringing the se= t-point into a usable range (2,000 psi) for our systems. =0A>>=C2=A0 =0A>>= =C2=A0=C2=A0=C2=A0=C2=A0The three-way dump valve references in that write-= up were=C2=A0merely describing=C2=A0the Legacy hydraulic system.=C2=A0=C2= =A0The Legacy cannot perform a gear free-fall extension without=C2=A0a thr= ee way valve=C2=A0due to cylinder orientation.=C2=A0 I still use=C2=A0a tw= o-way valve in my 360. =0A>>Chris =0A>>=C2=A0 =0A>>Chris Zavatson =0A>>N91= CZ =0A>>360std 1,400 hrs =0A>>http://www.n91cz.net/ =0A>>=C2=A0 =0A>>=0A>> = =0A>>=0A>>________________________________=0A>>From: randy snarr =0A>>To: lml@lancaironline.net =0A>>Sent: Friday, January 25, = 2013 5:23 AM=0A>>Subject: [LML] Re: Thermal influence on Hydraulic Pressu= re=0A>>=0A>>=0A>>Nice Work Chris.. =0A>>I am happy to hear that I have alr= eady done what you suggested which is to install a 3 way dump valve and ru= n the dump line to the reservoir in a low pressure line. It has worked ver= y well. 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. =0A>>Have you found a solution for this with= your research that makes the original system function without having to e= ver dump the pressure manually? =0A>>=0A>> =0A>>Randy Snarr =0A>>235/320 = =0A>>N694RS=C2=A0 =0A>>=0A>>"Flight by machines heavier than air is unpra= ctical and insignificant, if not utterly impossible"=0A>>-Simon Newcomb, 1= 902=0A>> =0A>>=0A>>________________________________=0A>>From: Chris Zavatso= n =0A>>To: lml@lancaironline.net =0A>>Sent: Tues= day, September 4, 2012 2:18 PM=0A>>Subject: [LML] Re: Thermal influence o= n Hydraulic Pressure=0A>>=0A>>=0A>>Danny, =0A>>No affect on gear movement.= =0A>>I should add however that elevated high-side pressure is one of the = contributing factors to gear extension failures in a standard system set u= p.=C2=A0 My low pressure setting=C2=A0is higher than the nominal 550 psi.= =C2=A0=C2=A0It is set to 800 psi to avoid the pressure spike that propogat= es through the system when gear down is selected. =0A>>see "Failure to Ext= end" on page 10 for more detail. =0A>>http://www.n91cz.com/Hydraulics/Lanc= air%20Hydraulics.pdf =0A>>=C2=A0 =0A>>Chris Zavatson =0A>>N91CZ =0A>>360st= d =0A>>http://www.n91cz.net/=C2=A0 =0A>>=C2=A0 =0A>>=0A>> =0A>>=0A>>_______= _________________________=0A>>From: Danny =0A>>To: lml@l= ancaironline.net =0A>>Sent: Monday, September 3, 2012 11:54 AM=0A>>Subject= : [LML] Re: Thermal influence on Hydraulic Pressure=0A>>=0A>>=0A>> =0A>>Ch= ris, =0A>>What was the impact on the gear movement? =0A>>=C2=A0 =0A>>Danny= =0A>>LNC2-360 =0A>>N 38=C2=B0 43' 25.7" =0A>>W 77=C2=B0 30' 38.6" =0A>>= =C2=A0 =0A>>From:Chris Zavatson [mailto:chris_zavatson@yahoo.com] =0A>>Sen= t: Saturday, September 01, 2012 11:32 PM=0A>>To: lml@lancaironline.net=0A>= >Subject: [LML] Thermal influence on Hydraulic Pressure =0A>>=C2=A0 =0A>>-= took this photo after=C2=A0a descent from 16.5k to 1,500 ft. =0A>>OAT=C2= =A0went from 42 to 94 degrees. =0A>>High Pressure gauge is pegged at 2,00= 0+ psi =0A>>-Didn't get a photo, but the opposite happened on the ramp in = Spokane.=C2=A0After sitting for an hour, the low pressure gauge was pegged= at 1,200 psi+.=C2=A0 Spokane might not be the warmest spot in the country= , but at 85 deg F, it was 55 degrees warmer than the cold soak on the prev= ious leg. =0A>>Temperature changes have a big impact on system =0Apressur= e.=C2=A0 =0A>>=C2=A0 =0A>>Chris Zavatson =0A>>N91CZ =0A>>360std =0A>>http:= //www.n91cz.net/=0A>>=0A>>=0A>>=0A>>=0A>>=0A>>=C2=A0 =0A>>=0A>>=0A>>=0A>>= =0A>=0A> ---36511695-2139279335-1361252132=:11837 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Not a problem.  = I will keep my opinion that fix= ing the root cause is better than a band-aide.
 
Here are the instructions to cure the problem for = the 320/360s that have the Legacy type pump installed.  http://www.n91cz.com/Hydrauli= cs/Pump-Unlock.pdf
-should take about 15 minutes= on the bench. 
 
P= age 9 of this report adds some more detail http://www.n91cz.com/Hydraulics/Lancai= r%20Hydraulics.pdf
 
I would still like to hear an explanation as to how the module can detect the gear down failure.
 &n= bsp;  -gear locked, partially extended
    -low si= de switch open
    -high side swi= tch closed
=   &nb= sp; -both sides pressurized to just above low side pressure switch set= ting
=  
Chris Zavatson
N91CZ
360std 1,400 hrs (lock-up free)
<= div>http://www.n91cz.net/<= /span>

From: Wolfg= ang <Wolfgang@MiCom.net>
To= : lml@lancaironline.net
Sent: Saturday, Febr= uary 16, 2013 7:21 PM
Subject: [LML] Re: Fw: [LML] Re: Thermal influence on Hydraulic Pressure

=0A
=EF=BB=BF=0A=0A =0A =0A=0A
Chris,
=0A
 
=0A
Ok, let's agree to disa= gree.
=0A
 
=0A
= You want to take a plane down for a couple of weeks wh= ile =0Ayou tear down the pump. I don't need a pump sent to me for tear= down and =0Amodification. My module is a 20 minute add-on that will mitiga= te the problem for =0Aboth up and down function . . . without getting parti= cular with the pressure =0Asettings. The only down side (as with any other = part of the airframe) is if you =0Afailed to build your hydraulic system to= spec.
=0A
 
=0A
= Wolfgang
=0A
 
=0A
=0A =0A To: lml@lancaironline.net
=0A
Sent:<= /b> Friday, February 15, 2013 4:04 =0A PM
=0A
Subject:= Re: [LML] Re: Fw: [LML] Re: =0A Thermal influence on Hydraulic Pressu= re
=0A

=0A
=0A
=0A
Wolfgng,
=0A
= =E2=80=9CHow do =0A some spools come off their endpoints and cause reporte= d failure?=E2=80=9D 
=0A
=0A
That =0A question was= answered long ago.  I =0A can show you how to rig a pum= p to lock up and then I can show you how to rig =0A it such that it can=E2= =80=99t lock up.  =0A
=0A
=0A
Developing a fix fo= r a problem before understanding the root =0A cause is not a smart way to = go about things.  You saw an issue on one airplane. =0A = Unfortunately you refused to pull the pump to look at it, simply telling us= =0A that the pump was too difficult to reach. That is a really poor excus= e.  Yes, the pump was behind the baggage =0A bulkhead an= d it is not easy to get to it.  How can that be a valid r= eason for not =0A examining the actual hardware?
=0A
=0A
Initially = =0A it was claimed this module would solve lock-up in both directions.  Reading through the description of its =0A theory of opera= tion, it is clear the module cannot catch the =E2=80=98failure to =0A exte= nd=E2=80=99 lock-up.  A system state =0A was missed.
=0A
=0A
There are =0A downsides to having to use the pump to forcibly= unlock a thermally locked =0A system.  I am sure you ar= e aware =0A of those.  I am curious what new =0A failur= e modes have been introduced if any one part of the module =0A fails?
=0A
=0A
I offered =0A to look at Lorn=E2=80=99s pump as I have done for o= thers.  Your reply was that a week or two of =0A down ti= me was too much of a price to pay.  Really!
= =0A
=0A
I am =0A still in search of a pump that falls outside the expected behavi= or when =0A configured properly.  I would =0A truly lik= e to find one as it can only serve to further our understanding of =0A our= planes.  What a shame and loss =0A to the community if = you (or really Lorn) truly possess such a pump.  I know, = I know, it is too much effort =0A to pull the pump.
=0A
=
=0A
Please = =0A don=E2=80=99t extrapolate the behavior of the one pump you saw only fr= om the outside =0A to the rest of the fleet.
=0A
=0A
Disclaimer:  I don=E2=80=99t =0A have a financial interest in this disc= ussion=E2=80=A6=E2=80=A6.well maybe I do.  I am trying to= keep our insurance =0A rates from going up.
=0A
=0A
For your =0A en= tertainment I have attached some photos of my pressure gauges after my plan= e =0A was exposed to thermal soak, both in the air and on the ground.  You will see that only the commanded =0A side is affected b= y thermal influence.
=0A
<= /font>
=0A
And here =0A are some video clips:
=0A
=0A
The first =0A video shows how a pump with spool return springs can= lock up when subjected to =0A rising temperatures.  The= second =0A clip shows a pump without return springs.  O= nly the currently active side is =0A affected by temperature changes.  =0A No lock-up
=0A
=0A
Hydr= aulic Lock due to thermal cycling (=E2=80= =9CCZZ=E2=80=9D configured pump with spool return springs =0A installed)
=0A
=0A
Normal Pump operation when sub= jected to thermal =0A cycling.(=E2=80=9C= LB=E2=80=9D) configured pump without return =0A springs
=0A <= div>
=0A
320/360 Hydraulics Tutorial
=0A
=0A
Chris = =0A Zavatson
=0A
<= /div>=0A
N91CZ
=0A
=0A
L360std =0A 1,400 hrs (lock-up= free)
=0A
= =0A
ht= tp://www.n91cz.net/
=0A
=0A
=0A
=0A
From: Wolfgang =0A <Wolfgang@MiCom.net>
<= b>To: lml@lancaironline.net <= br>Sent: Thursday, Februar= y 14, 2013 11:48 =0A AM
Subject:<= /span> [LML] Re: Fw: =0A [LML] Re: Thermal influence on Hydraulic Pres= sure

=0A
=0A
=0A
= What did you measure to come up with that 7= 0 g's =0A ?
=0A
and . . = . the springs trying to center the spool =0A in some models certainly don'= t help.
=0A
 =
=0A
So the question still linge= rs from more than a =0A year ago,
=0A
How do some spools come off their end position =0A and caus= e the reported failures ?
=0A
 
=0A
That's wh= y I came up with the module I have. =0A
=0A
It powers the spool back into position whenever =0A = needed, regardless of pump model.
=0A
 
=0A
W= olfgang
=0A
 =
=0A
=0A
---= -- =0A Original Message -----
=0A = =0A =0A <= div style=3D"font: 10pt/normal arial; font-size-adjust: none; font-stretch:= normal;">Sent: =0A Wednesday, February 13, 2013 7:55 AM
=0A=
Subject: =0A Re: [LML] Fw: [LML] Re: Thermal influ= ence on Hydraulic Pressure
=0A

=0A
=0A
Reposted fro= m June 2011
=0A
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=0A
----- =0A Original Message ----- =0A
From: =0A <= a title=3D"chris_zavatson@yahoo.com" href=3D"mailto:chris_zavatson@yahoo.co= m" rel=3D"nofollow" target=3D"_blank" ymailto=3D"mailto:chris_zavatson@yaho= o.com">Chris Zavatson
=0A = =0A
Sent: =0A Saturday, June= 25, 2011 12:35 PM
=0A
Subject: =0A Re: [LML] Re: LNC2 Gear Hydraulics
=0A

=0A
=0A
Cur= iosity got the best of me. Here are the peak vibration values =0A record= ed today at the hydraulic pump measured on the axis of the =0A spool valve.
=0A
Start up: +/- 1.3 g
=0A
Take off: +/- 0.3 g=0A
Cruise: +/- 0.1 g
=0A
Desce= nt: +/- 0.1 g
=0A
Landing: +/- 0.6 g
= =0A
It would appear the O-ring has more design margin than ju= st about =0A any other component o= n the =0A plane.
=0A
=0A =
Chris Zavatson
=0A
N91CZ
= =0A
360std
=0A
=0A

=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=0A
=0A
=0A =0A
From: Wolfgang =0A <Wolfgang@MiCo= m.net>
To: lml@lanca= ironline.net
Sent: Mon= day, February 11, 2013 12:36 =0A PM
Subject: [LML] Fw: [LML] =0A Re: Thermal influence on Hy= draulic Pressure

=0A
=0A =
=0A
70 g's is an impressive n= umber. How was that =0A measured ?
=0A
Or is that just a measure of the vibration =0A = that the part lives under during flight ?
=0A
 
=0A
Wolfgang
=0A
 
=0A
&n= bsp;
=0A
=0A
=0A
=0A
From: Chris Zavatson =0A <chris_zavatson@yahoo.com>
To: lml@lancaironline.net
<= span style=3D"font-weight: bold;">Sent: Saturday, January 26, 20= 13 12:24 =0A PM
Subject:= [LML] Re: =0A Thermal influence on Hydraulic Pressure

=0A
=0A
=0A
=0A
Randy,=0A
Thanks. 
=0A
    There =0A are two= things I have been doing to pumps to eliminate the need for 'dump =0A v= alve rescues'. 
=0A
First is the removal of= the return springs that entered the =0A Legacy pump design in about 200= 5.  They added no =0A useful functionality and unfor= tunately introduced a lock-up =0A failure mode.  Removing the sprin= gs primarily addresses lock-up on the =0A ground during thermal swings.<= /span>
=0A
The second thing I have been doing is to set = the low pressure =0A switch to 800-850 psi.  This eliminates the ge= ar extension lock-up mode =0A that <= span>occasionally =0A prevents the gear from fully extendi= ng.  The original setting was to =0A low to overcome the pressure s= pike that propagates<= /span> through the system =0A when the gear first come out of the wheel = wells.
=0A
 =    The =0A other thing I have been doing is m= easuring the spool resistance on =0A every pump that comes across my des= k.  I haven't found any issues =0A there.  70g's is the typical res= ult.
=0A
I have also been making thermal relief v= alves adjustable, =0A bringing the set-point into a usable range (2,000 = psi) for our =0A systems.
=0A
 =0A
   &nbs= p;The =0A three-way dump valve references in that write-up were&n= bsp;merely =0A describing the Legacy hydraulic system.  T= he Legacy cannot =0A perform a gear free-fall extension without a t= hree way valve due =0A to cylinder orientation.  I still use&n= bsp;a two-way valve in my =0A 360.
=0A
Chris
=0A
 
=0A
Chris Zav= atson
=0A
N91CZ
=0A
360= std 1,400 hrs
=0A
http://www.n91cz.net/=0A
 
=0A

=0A
=0A =
=0A
=0A =
From: randy snarr =0A= <randylsnarr@yahoo.com>
= To: lml@lancaironline.net
Sent: Friday, January 25, 2013 5:23 =0A AM
Subject: [LML] Re: =0A Thermal inf= luence on Hydraulic Pressure

=0A
=0A
=0A
=0A
Nice Work Chris..
=0A =
I =0A am happy to hear that I have already done what you sug= gested which is to =0A install a 3 way dump valve and run the dump line = to the reservoir in a low =0A pressure line. It has worked very well. I = dont = like having to open the dump valve but it =0A is necessary once in a whi= le especially when it is cold. The pressures on =0A both sides of the sy= stem climb due to the engine heat and the gear sometimes =0A will not mo= ve without dumping the pressure.
=0A
Have you =0A found a solution for th= is with your research that makes the original system =0A function withou= t having to ever dump the pressure manually?
=0A

=0A
Randy =0A Snarr
=0A
235/320
= =0A
N694RS 
=0A
=0A
 =0A
"Flight by machines hea= vier than air =0A is unpractical and insignificant, if not utterly =0A = impossible"
-Simon Newcomb, 1902
=0A
=0A =
=0A
= =0A
From: Chr= is Zavatson =0A <chris_zavatson@yahoo.com>
To: lml@lancaironline.net
Sent: Tuesday, September 4, 2012 2:18 = =0A PM
Subject: [LML= ] Re: =0A Thermal influence on Hydraulic Pressure

= =0A
=0A
=0A
=0A
=0A <= div>=0A
=0A =
Danny,
=0A
No affect on gear =0A movement.
=0A
I should add however that =0A elevated high-side press= ure is one of the contributing factors to gear =0A extension failures in= a standard system set up. = ; My low pressure setting is =0A higher than the nominal 550 psi.&n= bsp; It is set to 800 psi to avoid =0A the pressure spike that prop= ogates through the system when gear down is =0A selected.
= =0A
see "Failure to Extend" on =0A page 1= 0 for more detail.
=0A
http://ww= w.n91cz.com/Hydraulics/Lancair%20Hydraulics.pdf
=0A
 
=0A
Chris =0A Zavatson
=0A
N91CZ
= =0A
360std
=0A =0A
 
=0A

=0A
= =0A
=0A
=0A
From: Danny =0A <danny@n107sd.com&= gt;
To: lml@lancaironli= ne.net
Sent: Monday, S= eptember 3, 2012 11:54 =0A AM
S= ubject: [LML] Re: =0A Thermal influence on Hydraulic Pressure=

=0A
=0A =0A=0A
=0A
= =0A
Chris,
=0A
What was the impact on th= e =0A gear movement?
=0A
 =
=0A
=0A
Danny
=0A
LNC2-= 360
=0A
N 38=C2=B0 43' =0A 25.7"
=0A
W 77=C2=B0 30' =0A 38.6"
=0A=
 
=0A
=0A
=0A From: Chris Zavatson =0A = [mailto:chris_zavatson@yahoo.com]
Sent: Saturday, September 01, 2012 =0A 11:32 PM
To: =0A lml@lancaironline.netSubject: [LML] Thermal in= fluence on =0A Hydraulic Pressure
=0A =
 
=0A
= =0A
=0A
-took =0A = this photo after a descent from 16.5k to 1,500 =0A ft.
=0A
=0A
= OAT went =0A from 42 to 94 degrees.
=0A =
=0A
High =0A Pressur= e gauge is pegged at 2,000+ psi
=0A
=0A =
-Didn't =0A get a photo, but= the opposite happened on the ramp in Spokane. After =0A sitting fo= r an hour, the low pressure gauge was pegged at 1,200 psi+.  =0A Sp= okane might not be the warmest spot in the country, but at 85 deg F, it =0A= was 55 degrees warmer than the cold soak on the previous =0A leg.
=0A
=0A
Temperature =0A changes have a big impact on system =0Apressur= e. 
=0A
=0A
 
=0A
=0A Chris =0A Zavatson
=0A
=0A
= N91CZ
=0A
=0A
360std
=0A
=0A
http://www.n91cz.net/






&nb= sp; =0A




=


=0A


 
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