X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 26 Apr 2014 13:28:26 -0400 Message-ID: X-Original-Return-Path: Received: from nm36-vm6.bullet.mail.bf1.yahoo.com ([72.30.238.142] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 6847510 for lml@lancaironline.net; Fri, 25 Apr 2014 21:47:39 -0400 Received-SPF: pass receiver=logan.com; client-ip=72.30.238.142; envelope-from=chris_zavatson@yahoo.com Received: from [98.139.212.153] by nm36.bullet.mail.bf1.yahoo.com with NNFMP; 26 Apr 2014 01:47:05 -0000 Received: from [98.139.212.233] by tm10.bullet.mail.bf1.yahoo.com with NNFMP; 26 Apr 2014 01:47:05 -0000 Received: from [127.0.0.1] by omp1042.mail.bf1.yahoo.com with NNFMP; 26 Apr 2014 01:47:05 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 231691.84551.bm@omp1042.mail.bf1.yahoo.com Received: (qmail 85118 invoked by uid 60001); 26 Apr 2014 01:47:05 -0000 X-YMail-OSG: UqdJbQEVM1meNXtyWp83Y6dLbuKVXlIAWuE62FHd9BMaQnb aCLUocMyP73UZ13pxRYPBohcRM_.uigVX1O55Q3ZDqfGv6N.tbldLbUE6XtA aIlz272gs1CnBXaXcuq6VGTYcC7HTAGoHSO1Fkenyly2pfb8ABwf5iwswO7Q XTL02C5jFkxvalaU.DpilX7YKktaWDyl.b7OBl3UypNd8n8KfMyZf.M3Yl.I xg6a8oPypI2LzGlozPzqPvAcv1a5J.xTKBnowtNbgX2aJWVYLyJ2BKRZ8lGD 9wkM4EIcFWt59jTKQ1Eg14IFEiLPq8ztYiyqaMyCkb3gL3PSssL6ajg_qA8j Z4EU4grt2mJYd_gBXbPipnISy_zFALpZE3z7kbdnKueejlcffxgctmMmj8iH lpXvUPs7zJ.OvOtL.iWM3QdyVmq7cULiP5sD39Ty_j1ffoKv7GS5Yk.afv6h GI3YZoSMSw0KvrU6CCYN.C4Rw7V.qfsKCv40if05HwaAEf9pUQ1fPTqG73Br EAlyr.EtiQdfffcr_g4OeTvikUTx7D3DZYC5DYhofOM5tzSGWAos4YQc0j_C TCerzGRyD6FsOs_sQPjCHi0Lx4JfqNLBq7oSitct9mx106PSfEA-- Received: from [172.14.16.72] by web161203.mail.bf1.yahoo.com via HTTP; Fri, 25 Apr 2014 18:47:04 PDT X-Rocket-MIMEInfo: 002.001,V29sZmdhbmcsCjw84oCcSSBiZWxpZXZlIGluIHJlZHVuZGFuY3kgYW5kIGl0IGxvb2tzIGxpa2UgeW91CmRvbid04oCmLuKAnT4.CkkgYW0gYSBiaWcgcHJvcG9uZW50IG9mIHJlZHVuZGFuY3kuwqAgVGhhdCBpcyByZWR1bmRhbmN5IGRlZmluZWQgYXMgYSB0cnVlIGJhY2stdXAKdG8gYW4gb3RoZXJ3aXNlIHRyb3VibGUtZnJlZSBzeXN0ZW0uCkZpcnN0LCBJIGhhdmUgcmVkdW5kYW50IHN3aXRjaGVzIHRvIHBvd2VyIHRoZSBwdW1wCnNvbGVub2lkcy7CoCBUaGlzIGFsbG93cyBtZSB0byByYWlzZSBhbmQKbG8BMAEBAQE- X-Mailer: YahooMailWebService/0.8.185.657 X-Original-Message-ID: <1398476824.57457.YahooMailNeo@web161203.mail.bf1.yahoo.com> X-Original-Date: Fri, 25 Apr 2014 18:47:04 -0700 (PDT) From: Chris Zavatson Reply-To: Chris Zavatson Subject: Gear Down...INOP X-Original-To: LML posts , Kevin Stallard , Doug Baleshta MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-852950040-1284969777-1398476824=:57457" ---852950040-1284969777-1398476824=:57457 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Wolfgang,=0A<<=E2=80=9CI believe in redundancy and it looks like you=0Adon'= t=E2=80=A6.=E2=80=9D>>=0AI am a big proponent of redundancy.=C2=A0 That is = redundancy defined as a true back-up=0Ato an otherwise trouble-free system.= =0AFirst, I have redundant switches to power the pump=0Asolenoids.=C2=A0 Th= is allows me to raise and=0Alower the gear in case of the failure of either= of the pressure switches.=C2=A0 It doesn=E2=80=99t happen very often, but = it does=0Ahappen - twice in 17 years of flying my 360.=C2=A0 =0AI also have= redundant gear down indications.=C2=A0 Two completely separate systems, se= parate switches,=0Aseparate wires and separate indicators.=C2=A0 The second= set of switches is mounted directly on the over-center links. =0AI even ca= rry two iPads and a iPhone - just in case=0A<<=E2=80=9CThe pressure pulse y= ou're talking about will=0Asubside (glad you agree) and as it does, because= the cylinder is only partially=0Aextended,=C2=A0the cylinder will continue= s to extend, the low switch will close=0Aagain, and enable the pump to cont= inue . .=E2=80=9D>>=0AThe part you seem to be missing here is that the mome= ntary=0Apulse is not directly turning off the pump.=C2=A0 Thus when the pul= se subsides, the pump doesn=E2=80=99t just spring back to=0Alife.=C2=A0 The= pulse pushes the spool in the=0Awrong direction -against the pump flow.=C2= =A0 This locks the poppet that the pump just opened up a fraction of a=0Ase= cond earlier.=C2=A0 When this happens, the=0Ahigh side begins to pressurize= along with the low side.=C2=A0 As soon as both sides reach the low side=0A= pressure setting, the pump is turned off.=C2=A0 This is why you see both hi= gh and low circuits pressurized to the same=0Avalue in Lorn=E2=80=99s photo= .=0ATo prevent this, the low side pressure settings should be=0Araised.=C2= =A0 800 psi has proven=0Asufficient.=C2=A0 The high volume gear pump=0Awill= reduce the size of the pulse since the higher volume pump is able to=0Aabs= orb incoming fluid at a higher rate.=0AI highly recommend pressure gauges f= or both high and low=0Acircuit be installed in a location visible to the pi= lot.=C2=A0 The state of the system can always be=0Averified.=C2=A0 One can = immediately diagnose any=0Ain-flight problem.=C2=A0 Leaks can be caught=0Ae= arly.=C2=A0 And adjusting pressure settings=0Ais no longer guess work.=0ACh= ris Zavatson=0AN91CZ=0A360std=0Awww.N91CZ.net ---852950040-1284969777-1398476824=:57457 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Wolfgang,
=0A=0A
<<= ;=E2=80=9CI believe in redundancy and it looks like you=0Adon't=E2=80=A6.= =E2=80=9D>>
=0A=0A<= br>
I am a big proponent of redundancy.  That is redundancy defined a= s a true back-up=0Ato an otherwise trouble-free system.
=
=0A=0A
First, I have redundant switches to power the pump=0Asolenoids.  This allows me to raise and=0Al= ower the gear in case of the failure of either of the pressure switches.  It doesn=E2=80=99t happen ver= y often, but it does=0Ahappen - twice in 17 years of flying my 360. =0A
= =0A=0A
I al= so have redundant gear down indications.=   Two completely separate systems, separate switches,=0Aseparat= e wires and separate indicators. = =0AThe second set of switches is mounted directly on the over-center= links.=0A
=0A=0A
I ev= en carry two iPads and a iPhone - just in case
=0A=0A
= <<=E2=80=9CThe pressure pulse you're talking about will=0Asubs= ide (glad you agree) and as it does, because the cylinder is only partially= =0Aextended, the cylinder will continues to extend, the low switch wil= l close=0Aagain, and enable the pump to continue . .=E2=80=9D>>
=0A=0A
=
The part you seem to be missing here is that the mome= ntary=0Apulse is not directly turning off the pump. =0AThus when the pulse subsides, the pump doesn=E2= =80=99t just spring back to=0Alife. = ; The pulse pushes the spool in the=0Awrong direction -against the p= ump flow. =0AThis locks the = poppet that the pump just opened up a fraction of a=0Asecond earlier.  When this happens, the=0Ahigh si= de begins to pressurize along with the low side.  As soon as both sides reach the low side=0Apressure s= etting, the pump is turned off. =0A= This is why you see both high and low circuits pressurized to the sa= me=0Avalue in Lorn=E2=80=99s photo.
=0A=0A
To prevent this, th= e low side pressure settings should be=0Araised.  800 psi has proven=0Asufficient.  The high volume gear pump=0Awill reduce the siz= e of the pulse since the higher volume pump is able to=0Aabsorb incoming fl= uid at a higher rate.
=0A= =0A
I highly recommend pressure gauge= s for both high and low=0Acircuit be installed in a location visible to the= pilot.  The state of the sy= stem can always be=0Averified.  One can immediately diagnose any=0Ain-flight problem.  Leaks can be caught=0Aearly.  And adjusting pressure settings=0Ais no lo= nger guess work.
=0A=0ACh= ris Zavatson
N91CZ=
360std
www.N91CZ.net
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