X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 18 Apr 2011 21:56:21 -0400 Message-ID: X-Original-Return-Path: Received: from smtp116-mob.biz.mail.gq1.yahoo.com ([98.136.185.207] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with SMTP id 4949945 for lml@lancaironline.net; Mon, 18 Apr 2011 13:34:03 -0400 Received-SPF: none receiver=logan.com; client-ip=98.136.185.207; envelope-from=chris_zavatson@yahoo.com Received: (qmail 16691 invoked from network); 18 Apr 2011 17:33:29 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:References:In-Reply-To:X-Apple-Yahoo-Original-Message-Folder:Mime-Version:Content-Type:Content-Transfer-Encoding:Message-Id:X-Mailer:From:X-Apple-Yahoo-Replied-Msgid:Subject:Date:To; b=ScqEFIDDqO7tAqZ+UVfkklrQ9JSfr6c5EcIiLjBYjAGBNN0f+WRbOStOE1rngLUddyV+mNr7xBvPXw+4y9F2cz4kJJdZLgstziLjjo6I4Hv2Zn1lSMT94ZQBLT7fJP/QexjZH7EwnvD7WaDXb3kOiP8y6QVlzf5LBesNB5vU8lQ= ; Received: from [10.130.69.24] (chris_zavatson@166.205.138.202 with xymcookie) by smtp116-mob.biz.mail.gq1.yahoo.com with SMTP; 18 Apr 2011 10:33:20 -0700 PDT X-Yahoo-SMTP: 076hgjCswBC.G6e0vm7vgvZ9JJ0zmeBo_Oyw X-YMail-OSG: CCeUUOQVM1lByOwU12jaxSJW5_4H7nuGfSJcCdIZbwkQd2k Ye3SOQ5QU.FCr.QMkH4ZTb6gumqul97AS0eGaVQ.Uby_aoQi9BlxDdQBtv9h mN_LMXNSvL11XHL1MzO8PUGN74J4_RVgBNzY9a887u7c_QSzFSJk37P.z7U3 31hTOt0O0.1Ye5Ihb8zNUOtdUu4ErVvDK7lOJ9899FykHMLJDLpQ4UFq6lMa cKwblhndKBg10UFtf8ViKuZVPIboxwSsFonNSBIVVjrsGQV1s6KLQbqumpYh R_rD4YvIt04Q3M8Yg68M2kvfaGIK8L2niF_ChsXzwWxbKaEHOmpM3pNAJq.. Pc9r3aTJTsfCj1f22uBDJ8o6O0AcuqOtG.ouqCq3SUg-- X-Yahoo-Newman-Property: ymail-3 References: In-Reply-To: X-Apple-Yahoo-Original-Message-Folder: Inbox Mime-Version: 1.0 (iPad Mail 8C148) Content-Type: multipart/alternative; boundary=Apple-Mail-17-570768465 Content-Transfer-Encoding: 7bit X-Original-Message-Id: X-Mailer: iPad Mail (8C148) From: Chris X-Apple-Yahoo-Replied-Msgid: 1_11848044_AEhVv9EAAWpETaxifAha/BKYFog Subject: Re: [LML] Re: Gear operation fix for the LNC2 X-Original-Date: Mon, 18 Apr 2011 10:33:11 -0700 X-Original-To: Lancair Mailing List --Apple-Mail-17-570768465 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Tom, Please be carefull with system changes. I still sounds like you have design= ed in the very condition we seek to avoid. The spool must keep the poppet v= alve open else you seal off the side that needs to remain at zero pressure. = Wolfgang's circuit will undo this undesirable condition once the "zero side= " has been pressurized enough to close the pressure switch. Until then howe= ver, the net working pressure of the system is reduced (net=3Dhigher side pr= essure minus lower side pressure). It also adds wear and tear by requiring a= dditional pump cycles to restore the unlocked condition. Best to keep the s= pool where it was last commanded, the way the pump was designed to do. The s= ymmetric spool avoids installation errors - a good thing (I would really lik= e to examine schematics and drawings to look for any unintended consequences= ). Pressure gauges should be considered a must-have. If your pump now has some new way of keeping the non-working side from becom= ing pressurized, please elaborate. In all seriousness, we just want to make= sure you don't end up in one of those you-tube videos. Chris Zavatson N91CZ 360std www.N91CZ.net Sent from my iPad On Apr 18, 2011, at 9:09 AM, TOM GARDINER wrote: > Folks, > =20 > As I posted some time back, there is a fix for the spool getting stuck in o= ne position or the other. Oildyne offers additional springs and a symmetric= spool (not the original symmetric spool) The alternative spool is ported o= n both sides to allow fluid to move freely to tank when pushing excess blind= end fluid back to tank. (The other side being ported does not really matte= r) The springs which are quite heavy will certainly center the spool and ta= ke it off the poppets and bypass relief valve after the pump is de-energized= . Oildyne actually sent me the spool and spring upgrade free of charge (no g= uarantee that would happen for everybody on the forum!). With the new self c= entering spool and 3 way dump valve I am now 100% confident I will not have a= gear actuation failure - seen too many u-tube videos of various types belly= landing over a stupid hydraulic or electrical failure. > =20 > Tip: add pressure gauges to your system if you have not already done so. = You will learn a tonne about your system > =20 > Tom > 826Ct LNC2 360 >=20 > From: Wolfgang > To: lml@lancaironline.net > Sent: Sun, April 17, 2011 10:13:18 AM > Subject: [LML] Gear operation fix for the LNC2 >=20 > Here are some details on the Gear Fix Module - - - - - > There is a potential for the landing gear to fail to operate in the LNC2. > =20 > The spool in the hydraulic pump can come off it's end position and seal th= e fluid volume in the lines. When the system incurs a large temperature rise= , the trapped fluid expands raising the pressure in the lines, tripping both= pressure switches open and making the hydraulic pump inoperable. > =20 > A module to fix this gear operation failure in the LNC2 using the standard= hydraulic system is now available. It is installed across the pressure swit= ches and monitors their operation. If both switches are tripped open by high= pressure, the pump is made to run in the direction set by the gear switch r= e-seating the spool in it's end position restoring normal pump operation and= relieving pressure in the offending side. This happens automatically withou= t pilot intervention. > =20 > The module is 2.5" x 1.5" x .75", weighs 2.3 oz. and has two pairs of lead= s that connect directly to each pressure switch with 1/4" spade terminals. N= o other wiring is necessary. Price is $250.00 each. Simple installation inst= ructions included. > =20 > Contact Wolfgang Franke at 248-471-2000 or Wolfgang@MiCom.net > > > =20 > ----- Original Message ----- > From: Bryan Wullner > To: lml@lancaironline.net > Sent: Saturday, April 16, 2011 8:24 PM > Subject: Re: [LML] Re: LNC2 Gear Hydraulics >=20 > Wolfgang, > What is your gear fix module? > Bryan >=20 > On Fri, Apr 15, 2011 at 10:11 AM, Wolfgang wrote: > =46rom a design point of view, I still have a big concern about relying on= the friction from an O-ring to keep the landing gear functioning properly. V= ibration levels can exceed 70 G's. I would be much happier with a spring loa= ded ball detent or something similar. > =20 > That's why I came up with the gear fix module. > =20 > Wolfgang > =20 > ----- Original Message ----- > From: Chris Zavatson > To: lml@lancaironline.net > Sent: Wednesday, April 13, 2011 8:25 AM > Subject: Re: [LML] Re: LNC2 Gear Hydraulics >=20 > A symmetric back-pressure circuit and spool will eliminate the possibility= of installing the spool backwards as happened with pumps manufactured in ab= out the '96 through '98 time frame. The spool must still remain in place af= ter the pump shuts down to prevent both high and low circuits from locking u= p simultaneously. > Using o-ring 013-70 requires 30 g's to move the spool. > Using o-ring 013-90 requires 70 g's to move the spool. > This includes the return force generated by the poppet springs (410462).=20= > The difference between the two o-rings is durometer. I have been using th= e softer one without any problems. The stiffer o-ring (intended for pumps w= ith back pressure circuits) should leave no doubt. The first thing to do wi= th a pump that has a history of locking up both sides is to measure the retu= rn force for the spool and make sure it has an o-ring installed. > =20 > Chris Zavatson > N91CZ > 360std > www.N91CZ.net >=20 > From: Wolfgang > To: lml@lancaironline.net > Sent: Mon, April 11, 2011 4:56:57 AM > Subject: [LML] Re: LNC2 Gear Hydraulics >=20 > When I first got into this problem with the hydraulic pumps last year, I h= ad a few conversations with the product manager of the Oildyne 108 pump. The= re have been many changes in it's production life and one of them was to mak= e the spool symmetrical and have the relief circuit the same both ways. > =20 > Wolfgang > Wolfgang, > Yes, I have considered this. The spool with O-ring is a very tight fight.= While I have not tried to measure the force to move it, I would estimate s= omething over 50 g's to move it (I'll measure this the next time I have a pu= mp opened up) Could it be that a pump somehow ended up mounted such that it= was subjected to some resonant frequency? Seems like a remote possibilty g= iven all the variables and the mass of the pump. How about wear and tear?= Perhaps sitting dry and idle for ten years would do it. A missing O-ring o= r a spool that doesn't utilize an O-ring would allow the spool to move very e= asily. Parker does make spools that don't even have O-rings. Did these end= up getting installed by chance? >=20 > Based on reports from the LML, the behavior seems to be rather binary. On= the one hand we have planes with over 1000 hours and more than ten years of= service that have never once had the spool move off the poppet. On the oth= er hand, we have planes with circuits that lock up right out of the box (put= into service). > This leads me to believe there is a difference in configuration. The easi= est way to verify this is to simply open up a pump that is known to lock up h= i and low circuits simultaneously. >=20 > While I have opened up several pumps (primarily to flip around spool valve= s), I have not yet worked on one that had this lock up issue. I am optimist= ic the difference will be quite obvious upon inspection. =20 >=20 > Chris Zavatson > N91CZ > 360std > www.N91CZ.net >=20 >=20 > Sent from my iPad >=20 > On Apr 7, 2011, at 11:53 AM, "Wolfgang" wrote: >=20 >> Chris, have you considered what effect airframe vibration has on the posi= tion of the spool in the pump and the problem in general ? >> =20 >> Wolfgang >> From: Chris >> Sender: >> Subject: Re: [LML] Re: LNC2 Gear Hydraulics >> Date: Wed, 06 Apr 2011 07:38:35 -0400 >> To: lml@lancaironline.net >> I would like to extend the offer to the whole group. I think the entire c= ommunity would benefit from understanding why some pumps are allowing the sy= stem to lock up. If anyone has a pump that exhibits this behavior and could= part with it for a week, I am willing to check it out on the test stand and= examine the internal configuration. >>=20 >> Chris Zavatson >> N91CZ >> 360std >> www.N91CZ.net >=20 --Apple-Mail-17-570768465 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
Tom,
Please be carefull with s= ystem changes.  I still sounds like you have designed in the very condi= tion we seek to avoid.  The spool must keep the poppet valve open else y= ou seal off the side that needs to remain at zero pressure.  Wolfgang's= circuit will undo this undesirable condition once the "zero side" has been p= ressurized enough to close the pressure switch.  Until then however, th= e net working pressure of the system is reduced (net=3Dhigher side pressure m= inus lower side pressure).  It also adds wear and tear by requiring add= itional pump cycles to restore the unlocked condition.  Best to keep th= e spool where it was last commanded, the way the pump was designed to do. &n= bsp;The symmetric spool avoids installation errors - a good thing (I would r= eally like to examine schematics and drawings to look for any unintended con= sequences).  Pressure gauges should be considered a must-have.
If yo= ur pump now has some new way of keeping the non-working side from becoming p= ressurized, please elaborate.  In all seriousness, we just want to make= sure you don't end up in one of those you-tube videos.

=
Chris Zavatson
N91CZ
360std

Sent from my iPad
<= div>
On Apr 18, 2011, at 9:09 AM, TOM GARDINER <n20087@yahoo.com> wrote:

Folks,

 

As I posted some time back, there&= nbsp;is a fix for the spool getting stuck in one position or the other. = ; Oildyne offers additional springs and a symmetric spool (not the original s= ymmetric spool)  The alternative spool is ported on both sides to allow= fluid to move freely to tank when pushing excess blind end fluid back to ta= nk.  (The other side being ported does not really matter)  The spr= ings which are quite heavy will certainly center the spool and take it off t= he poppets and bypass relief valve after the pump is de-energized.  Oil= dyne actually sent me the spool and spring upgrade free of charge (no guaran= tee that would happen for everybody on the forum!).  With the new self c= entering spool and 3 way dump valve I am now 100% confident I will not have a= gear actuation failure - seen too many u-tube videos of various types belly landing over a stupid hydraulic or electrical failure.<= o:p>

 

Tip:  add pressure gauges to y= our system if you have not already done so.  You will learn a tonne abo= ut your system

 

Tom

826Ct LNC2 360

From: Wolfgang <Wolfgang@MiCom.net>
To: <= a href=3D"mailto:lml@lancaironline.net">lml@lancaironline.net
= Sent: Sun, April 17, 2011 10:13= :18 AM
Subject: [LML] Gea= r operation fix for the LNC2

Here are some details on the Gear Fix M= odule - - - - -
There is a potential for the landing ge= ar to fail to operate in the LNC2.
 
The spool in the hydraulic pump can com= e off it's end position and seal the fluid volume in the lines. When the sys= tem incurs a large temperature rise, the trapped fluid expands raising the p= ressure in the lines, tripping both pressure switches open and making t= he hydraulic pump inoperable.
 
A module to fix this gear operation fai= lure in the LNC2 using the standard hydraulic system is now available. I= t is installed across the pressure switches and monitors their operation. If= both switches are tripped open by high pressure, the pump is made to r= un in the direction set by the gear switch re-seating the spool in it's end p= osition restoring normal pump operation and relieving pressure in the o= ffending side. This happens automatically without pilot intervention.=
 
The module is 2.5" x 1.5" x .75", w= eighs 2.3 oz. and has two pairs of leads that connect directly to each p= ressure switch with 1/4" spade terminals. No other wiring is necessary. Pric= e is $250.00 each. Simple installation instructions included.
 
Contact Wolfgang Franke at 248-471-2000= or Wolfgang@MiCom.net

<GearFix2s.jpg>

<GearSw1s.jpg>

 
----- Original Message -----
Sent: Saturday, April 16, 2011 8:24 P= M
Subject: Re: [LML] Re: LNC2 Gear Hydr= aulics

Wolfgang,=20
What is your gear fix module?
Bryan

On Fri, Apr 15, 2011 at 10:11 AM, Wolfgang <Wolfgang@micom.net> wrote:
=46rom a design point of view, I still h= ave a big concern about relying on the friction from an O-ring to keep the l= anding gear functioning properly. Vibration levels can exceed 70 G's. I woul= d be much happier with a spring loaded ball detent or something similar.
 
That's why I came up with the gear fix&= nbsp;module.
 
Wolfgang
 
----- Original Message -----
Sent: Wednesday, April 13, 2011 8:25 A= M
Subject: Re: [LML] Re: LNC2 Gear Hydr= aulics

A symmetric back-pressure circuit and spool will eliminate the possibil= ity of installing the spool backwards as happened with pumps manufactured in= about the '96 through '98 time frame.  The spool must still remain in p= lace after the pump shuts down to prevent both high and low circuits from lo= cking up simultaneously.
Using o-ring 013-70 requires 30 g's to move the spool.
Using o-ring 013-90 requires 70 g's to move the spool.
This inc= ludes the return force generated by the poppet springs (410462). 
The difference between the two o-rings is durometer.  I have been u= sing the softer one without any problems.  The stiffer o-ring (intended= for pumps with back pressure circuits) should leave no doubt.  The fir= st thing to do with a pump that has a history of locking up both sides is to= measure the return force for the spool and make sure it has an o-ring insta= lled.
 
Chris Zavatson
N91CZ
360std
From: Wolfgang <Wolfgang@MiCom.net>
To: <= a href=3D"mailto:lml@lancaironline.net">lml@lancaironline.net
= Sent: Mon, April 11, 2011 4:56:= 57 AM
Subject: [LML] Re: L= NC2 Gear Hydraulics

When I first got into this problem with= the hydraulic pumps last year, I had a few conversations with the product m= anager of the Oildyne 108 pump. There have been many changes in it's product= ion life and one of them was to make the spool symmetrical and have the reli= ef circuit the same both ways.
 
Wolfgang
Wolfgang,
Yes, I have considered this.  The spool with O-ring is a very tigh= t fight.  While I have not tried to measure the force to move it, I wou= ld estimate something over 50 g's to move it (I'll measure this the next tim= e I have a pump opened up)  Could it be that a pump somehow ended up mo= unted such that it was subjected to some resonant frequency?  Seems lik= e a remote possibilty given all the variables and the mass of the pump. &nbs= p;  How about wear and tear?  Perhaps sitt= ing dry and idle for ten years would do it.  A missing O-ring or a spoo= l that doesn't utilize an O-ring would allow the spool to move very easily. &= nbsp;Parker does make spools that don't even have O-rings.  Did these e= nd up getting installed by chance?

Based on reports from the LML, the behavior seems to be rather bi= nary.  On the one hand we have planes with over 1000 hours and more tha= n ten years of service that have never once had the spool move off the poppe= t.  On the other hand, we have planes with circuits that lock up right o= ut of the box (put into service).
This leads me to believe there is a difference in configuration. &= nbsp;The easiest way to verify this is to simply open up a pump that is know= n to lock up hi and low circuits simultaneously.

While I have opened up several pumps (primarily to flip around spool va= lves), I have not yet worked on one that had this lock up issue.  I am o= ptimistic the difference will be quite obvious upon inspection.  
=

Chris Zavatson
N91CZ
360std


Sent from my iPad

On Apr 7, 2011, at 11:53 AM, "Wolfgang" <Wolfgang@MiCom.net= > wrote:

Chris, have you considered what effect a= irframe vibration has on the position of the spool in the pump and the probl= em in general ?
 
Wolfgang
=
From: Chris <chris_zavatson@yahoo.co= m>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: LNC2 Gear Hydraulics
Date: Wed, 06 Apr 2011 07:38:35 -0400
To: lml@lancaironline.net
I would like to extend the offer to the whole group.  I think the e= ntire community would benefit from understanding why some pumps are allowing= the system to lock up.  If anyone has a pump that exhibits this behavi= or and could part with it for a week, I am willing to check it out on the te= st stand and examine the internal configuration.

Chris Zavatson
N91CZ
360std
<= a href=3D"http://www.n91cz.net/" target=3D"_blank" rel=3D"nofollow">www.N91CZ.net
<= /div>
<= /blockquote>= --Apple-Mail-17-570768465--