X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 24 Apr 2014 08:18:10 -0400 Message-ID: X-Original-Return-Path: Received: from nm39.bullet.mail.bf1.yahoo.com ([72.30.239.69] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 6844687 for lml@lancaironline.net; Wed, 23 Apr 2014 23:02:45 -0400 Received-SPF: pass receiver=logan.com; client-ip=72.30.239.69; envelope-from=chris_zavatson@yahoo.com Received: from [66.196.81.172] by nm39.bullet.mail.bf1.yahoo.com with NNFMP; 24 Apr 2014 03:02:11 -0000 Received: from [98.139.212.197] by tm18.bullet.mail.bf1.yahoo.com with NNFMP; 24 Apr 2014 03:02:11 -0000 Received: from [127.0.0.1] by omp1006.mail.bf1.yahoo.com with NNFMP; 24 Apr 2014 03:02:11 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 130385.41670.bm@omp1006.mail.bf1.yahoo.com Received: (qmail 18357 invoked by uid 60001); 24 Apr 2014 03:02:11 -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=J2x82kw9C8eTauT2j2KB/DbpnJulE2IALZTGnwrQ9l9jPzVjUcBLSHTk+6nYbXd4RJFpq8txwIfN9nlKH+O0Gfl4+uS84kK15iDN4vvSVSQBnK7A2JmGpNmQ4DEoq8DoQhMeFQ9t+q39ameZJ8UaaqZ8+pePPur0EYJzqYCthLs=; X-YMail-OSG: ocxddQcVM1ndcPhLnuyMIz_8GHad80MrCn83Wr_1wHq24z_ 3_xNDtxe931Kgl6sNzRWHY26h7KvVC1FVFkj4sHiQbpiHaWq69kYaax2So6z 6VbN5bobyCgO6_19Xi.YPW2OtXDxkQl1892qdhRC3qsRuEhYo74DJtXoWw2i uv4F5J91TC1vXIUUA5ebveYFOIOqRzZHdzMmPo.20XAlSmIm5UkosDWHvA.m drfSR3reXugnHs6KuYCxlGkRvibPL2ZpiYLkTr7OOm1z4hGaYzG8SYFu0pgc czGO_WHqADQEy0ZSVur6qLUS0EmIVg9VhYHDAsbNMBC9rZvRYZpf6Xt.jvfK HqfZswxAODG0..AkypTitL5GFjDrlmsNSKgaCa6lfCZbMsz964AhjKTiGJNa qCJFlGDk2DxLdy6uy3rzGBW0y4IdwpmiiYfisQaAQJJAO_Pjq4ufo4EkzOBD BUKveFal3fBsvhcqtfeumY.i.fDj_cUJU9PXdjNXuOyinw_uPwoiEcdpYfKe 2pXXMfNCMXQAelQYd0G_NVnnfiBPzEK4qsK1Hz6XhBqscajZxmd5ORilbySR e1Stm..IjvvQ3eDK0QZPh5MUAi2BP3xVyGOUnt7K.LjxZLSxYPLahEMsU2C6 JEr79G0rq9oUUzc8mVY4yDqpZCyuQE4Pk.rZf4MfyQYOggaixI3KICV7Dka0 CYmbH1kY- Received: from [172.14.16.72] by web161202.mail.bf1.yahoo.com via HTTP; Wed, 23 Apr 2014 20:02:10 PDT X-Rocket-MIMEInfo: 002.001,V29sZmdhbmcsCkJhc2VkIG9uIHlvdXIgc3RhdGVtZW50LCBJIGRvbuKAmXQgdGhpbmsgeW91IHVuZGVyc3RhbmQgdGhpcwpmYWlsdXJlIG1vZGUuCuKAnC4gLiBidXQgb25jZSB0aGUgcHVsc2Ugc3Vic2lkZXMgKG1pbGlzZWNvbmRzKSB0aGF0IGV2ZW50CmlzIG92ZXIgYmVjYXVzZSB0aGUgdW4tZXh0ZW5kZWQgZ2VhciBkb3duIGN5bGluZGVyIHZvbHVtZSB3aWxsIGFic29yYiB0aGF0CnB1bHNlLuKAnQpZZXMsIHRoZSBwdWxzZSBldmVudCBpcyBvdmVyLCBidXQgdGhlIGRhbWFnZSBpcwpkb25lLsKgIFRoZSABMAEBAQE- X-Mailer: YahooMailWebService/0.8.185.657 References: X-Original-Message-ID: <1398308530.38674.YahooMailNeo@web161202.mail.bf1.yahoo.com> X-Original-Date: Wed, 23 Apr 2014 20:02:10 -0700 (PDT) From: Chris Zavatson Reply-To: Chris Zavatson Subject: Re: [LML] Fw: Gear Down...INOP X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="356309654-1680482054-1398308530=:38674" --356309654-1680482054-1398308530=:38674 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Wolfgang,=0ABased on your statement, I don=E2=80=99t think you understand t= his=0Afailure mode.=0A=E2=80=9C. . but once the pulse subsides (miliseconds= ) that event=0Ais over because the un-extended gear down cylinder volume wi= ll absorb that=0Apulse.=E2=80=9D=0AYes, the pulse event is over, but the da= mage is=0Adone.=C2=A0 The gear is stuck partially extended=0Awith one press= ure switch open and one closed.=C2=A0 Your module WILL NOT clear this probl= em.=0AWe have very different approaches to aircraft operation=0Aand mainten= ance.=C2=A0 I don=E2=80=99t install gadgets=0Ato undo a problem after it oc= curs.=C2=A0 I=0Aprevent the problem from occurring in the first place.=0A= =E2=80=9CThis solution does not rely on the pump behaving as it=0Ashould = =E2=80=9C=C2=A0 =C2=A0You should not be flying if your pump or any=0Aother = part of the aircraft is not behaving as it should.=C2=A0 Too many have died= doing this.=C2=A0 =0AChris Zavatson=0AN91CZ=0A360std=0Awww.N91CZ.net=0AOn = Wednesday, April 23, 2014 3:04 PM, Wolfgang wrote:=0A = =0AThe dump valves in the 360/320 did not "dump" to =0Athe reservoir, it on= ly cross connected the high and low sides of the hydraulic =0Apump. But you= know that.=0AChanging it out for a valve the that=C2=A0does =0A"dump" to t= he reservoir was one of my suggestions quite a while back since the =0Apump= body already has ports to accommodate that.=0A=C2=A0=0AAgain, forced runni= ng of the pump in the =0Aappropriate direction (determined by the gear swit= ch position) when both hi and =0Alo pressure switches have been tripped ren= dering the pump inoperable, WILL clear =0Athe problem. That's what a pressu= re switch monitoring module does, =0Aautomatically. This solution works for= the 320, 360 and Legacy.=0A=C2=A0=0AThis solution does not rely on the pum= p behaving as =0Ait should for the service life of the pump. I like more th= an one way of =0Apreventing=C2=A0potential hull damage.=0A=C2=A0=0AThis sol= ution can also be implemented by a manual =0Apush button switch on the pane= l but requires pilot intervention.=0A=C2=A0=0A"if condition are just right,= shut the pump down" =0A. . . but once the pulse subsides (miliseconds) =0A= that event is over because the un-extended gear down cylinder volume will a= bsorb =0Athat pulse.=0A. . . unless there is a blockage in the lines . . . = =0Athen you have other problems.=0AThere is no need to theorize the problem= into =0Aobscurity. KISS principal rules.=0A=C2=A0=0AWolfgang=0A=C2=A0=0A--= --- Original Message ----- =0AFrom: Chris =0AZavatson=0ATo: lml@lancaironli= ne.net=0ASent: Tuesday, April 22, 2014 7:59 AM=0ASubject: Gear Down...INOP= =0A=0AHitting the dump valve may =0Aor may not help the problem.=0AIt depen= ds on how much of a temperature increase =0Ayou incurred.=0AWolfgang=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=0AWolfgang,=0AI = =0Asuggest=C2=A0a review of=C2=A0the Legacy hydraulic system schematic in t= he =0Afollowing document (Legacy Addendum).=0Ahttp://www.n91cz.net/Hydrauli= cs/Lancair%20Hydraulics.pdf=0AYou will see that the Legacy has a =0Athree-w= ay dump valve that connects both high and low sides to the =0Areservoir.=C2= =A0 It will always dump pressure regardless of temperature =0Arise.=0A=0AEx= tension failures were more =0Acommon in the 320/360 and=C2=A0can be resolve= d by simply adjusting the low side =0Apressure switch higher (and if needed= , the relief valve also) -see page =0A10.=C2=A0 The higher volume gear pump= in the Legacies reduces the exposure to =0Athe failure when using stock pr= essure settings.=0AThe initial extension sends a =0Apressure pulse through = the system and can, if condition are just right, shut the =0Apump down.=C2= =A0 The hydraulic system will think the gear is down and =0Apressurized.=C2= =A0 This type of failure is what caught Lorn off-guard and =0Aresulted in a= gear-up landing. See attached, the photo of Lorn=EF=BF=BDs pressure gauges= =0Aafter he slid to a stop.=C2=A0 Both gauges are 500 psi +/-.=0AThe gear = selector is down, the low =0Aside pressure switch is open and=C2=A0the high= side pressure switch is =0Aclosed.=C2=A0 The very same condition as when t= he gear is fully down and =0Alocked.=C2=A0 Based on prior descriptions of y= our module, it will not detect =0Athis condition as a failure and will do n= othing to fix it.=0AMost Legacy pumps have spool =0Areturn springs which ca= n cause pressure rise in both sides due to a temperature =0Aincrease.=C2=A0= This is more=C2=A0often an issue sitting on the ground on a hot =0Aparking= ramp=C2=A0where the potential temperature swing is much greater.=C2=A0 I = =0Arecommend removing these springs per instructions in this link:=0Ahttp:/= /www.n91cz.com/Hydraulics/Pump-Unlock.pdf=0A=0AChris Zavatson=0AN91CZ=0A360= std=0Awww.N91CZ.net=0A=0A=0A--=0AFor archives and unsub http://mail.lancair= online.net:81/lists/lml/List.html --356309654-1680482054-1398308530=:38674 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
=0A=0A
Wolfgang,
= =0A=0A
Based on your statement, I don=E2=80=99t th= ink you understand this=0Afailure mode.
=0A=0A
=E2=80=9C. . but once the pulse subsides (miliseconds) that event=0Ais over = because the un-extended gear down cylinder volume will absorb that=0Apulse.= =E2=80=9D
= =0A=0A
Yes, the pulse event is over, but = the damage is=0Adone.  The g= ear is stuck partially extended=0Awith one pressure switch open and one clo= sed. =0AYour module WILL NOT= clear this problem.
=0A= =0A
We have very different approaches to = aircraft operation=0Aand maintenance.&nb= sp; I don=E2=80=99t install gadgets=0Ato undo a problem after it occ= urs.  I=0Aprevent the proble= m from occurring in the first place.
=0A=0A
=E2=80=9CT= his solution does not rely on the pump behaving as it=0Ashould =E2=80=9C   You should not be flying if your pump or any=0Aother par= t of the aircraft is not behaving as it should.  Too many have died doing this. 
Chris Zavatson
N91CZ
360std=
www.N91CZ.net=
=0A=0A
= On Wednesday, April 23, 2014 3:04 PM, Wolfgang <Wo= lfgang@MiCom.net> wrote:
=0A=0A =0A =0A=0A=0A
=0A=
The dump valves in the 360/320 did not= "dump" to =0Athe reservoir, it only cross connected the high and low sides= of the hydraulic =0Apump. But you know that.
= =0A
Changing it out for a valve = the that does =0A"dump" to the reservoir was one of my suggestions qui= te a while back since the =0Apump body already has ports to accommodate tha= t.
=0A
=  
=0A
Again, forced running of the pump in the =0Aapprop= riate direction (determined by the gear switch position) when both hi and = =0Alo pressure switches have been tripped rendering the pump inoperable, WI= LL clear =0Athe problem. That's what a pressure switch monitoring module do= es, =0Aautomatically. This solution works for the 320, 360 and Legacy.
=0A
 
=0A
This solution does not rely on the pump behaving as =0Ait= should for the service life of the pump. I like more than one way of =0Apr= eventing potential hull damage.
=0A
 
=0A
This solution ca= n also be implemented by a manual =0Apush button switch on the panel but re= quires pilot intervention.
=0A
 
=0A
"if condition are just rig= ht, shut the pump down" =0A
=0A
. . . but once the pulse subsides (miliseconds= ) =0Athat event is over because the un-extended gear down cylinder volume w= ill absorb =0Athat pulse.
=0A
. . . unless there is a blockage in the lines . = . . =0Athen you have other problems.
=0A
There is no need to theorize the prob= lem into =0Aobscurity. KISS principal rules.
= =0A
 =0A
Wolfgan= g
=0A
<= font size=3D"4"> 
=0A
----- Original Message ----- =0A
From: = Chris =0AZavatson =0A=0A
Sent: Tuesday, April 2= 2, 2014 7:59 AM
=0A
Subject: Gear Down...INOP
=0A

=0A
=0A
=0A
=0A
=0A
Hitting = the dump valve may =0Aor may not help the problem.
It depends on how muc= h of a temperature increase =0Ayou incurred.
= =0A
Wolfgang
=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
=0A
Wolfgang,
I =0Asuggest a review of the Legac= y hydraulic system schematic in the =0Afollowing document (Legacy Addendum)= .
http://www.n91cz.net/Hydraulics/Lancair%= 20Hydraulics.pdf
You will see that the Legacy has a =0Athree-way dump= valve that connects both high and low sides to the =0Areservoir.  It = will always dump pressure regardless of temperature =0Arise.
=0A

Extension failures were more =0Acommon in the 320/360 and = can be resolved by simply adjusting the low side =0Apressure switch higher = (and if needed, the relief valve also) -see page =0A10.  The higher vo= lume gear pump in the Legacies reduces the exposure to =0Athe failure when = using stock pressure settings.
The initial extension sends a =0Apressure pulse through the system= and can, if condition are just right, shut the =0Apump down.  The hyd= raulic system will think the gear is down and =0Apressurized.  This ty= pe of failure is what caught Lorn off-guard and =0Aresulted in a gear-up la= nding. See attached, the photo of Lorn=EF=BF=BDs pressure gauges =0Aafter h= e slid to a stop.  Both gauges are 500 psi +/-.
The gear selector is down, the low =0Aside p= ressure switch is open and the high side pressure switch is =0Aclosed.=   The very same condition as when the gear is fully down and =0Alocked= .  Based on prior descriptions of your module, it will not detect =0At= his condition as a failure and will do nothing to fix it.
=0A
Most Legacy pumps have spool =0Areturn springs which can cause press= ure rise in both sides due to a temperature =0Aincrease.  This is more=  often an issue sitting on the ground on a hot =0Aparking ramp wh= ere the potential temperature swing is much greater.  I =0Arecommend r= emoving these springs per instructions in this link:
=0A=0A

=0A
Chris Zavatson
= =0A
N91CZ
=0A
360std
= =0A
www.N91= CZ.net


--
For archive= s and unsub http://mail.lancaironline.net:8= 1/lists/lml/List.html


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