X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 04 Apr 2011 09:08:59 -0400 Message-ID: X-Original-Return-Path: Received: from [69.146.254.20] (HELO crmtest.arilabs.net) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTP id 4931931 for lml@lancaironline.net; Mon, 04 Apr 2011 08:32:03 -0400 Received-SPF: none receiver=logan.com; client-ip=69.146.254.20; envelope-from=kevin@arilabs.net Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CBF2C4.378EE143" Subject: RE: [LML] LNC2 Gear Hydraulics X-MimeOLE: Produced By Microsoft Exchange V6.5.6944.0 X-Original-Date: Mon, 4 Apr 2011 06:31:55 -0600 X-Original-Message-ID: <3E1C96B95693C640B0AC2F59D2500F3B0FE2CF@crmtest.arilabs.net> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] LNC2 Gear Hydraulics Thread-Index: AcvyvWKuioozBqCLSjGU7ciO0KF0aQABsCTg From: "Kevin Stallard" X-Original-To: "Lancair Mailing List" This is a multi-part message in MIME format. ------_=_NextPart_001_01CBF2C4.378EE143 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Tom, =20 This is great, thank you for taking the time to publish your notes. =20 Kevin =20 =20 ________________________________ From: TOM GARDINER To: lml@lancaironline.net Sent: Sat, April 2, 2011 8:52:18 PM Subject: Fw: LNC2 Gear Hydraulics Folks, =20 I have had various requests from people to post the attachments that I thought had already made it to the forum from my original post. But as the moderator kindly informed me, my attachments were way too large. So hopefully this slideshow will make it. Nice tool - thanks Marvin. =20 =20 =20 http://www.berkut13.com/108%20Startup%20Instructions.pdf http://www.swagelok.com/downloads/WebCatalogs/EN/ms-02-331.pdf http://oemys-performance.com/media/autopark%20pump%20108a.pdf http://www.berkut13.com/108%20RV%20adjusting%20and%20cleaning.pdf =20 =20 A few items I failed to mention in my earlier post that came to mind after reading Chris Zavaston's excellent post. The article listed the failure modes of the hydraulic system as follows: =20 Reversed Spool Valve The reversed spool is a common problem. The standard adapter is always configured this way and needs to be reversed =20 Drifting Spool Valve The drifing spool is mitigated by the centering springs when used with the symmetric spool. =20 =20 Leaks, internal and external The symmetric spool has two O rings instead of one. The O rings are fitted on each end and allows for a better seal and better allignment of the spool while moving inside the adapter barrel. There will also be less wear as a consequence. Transmission fluid may be used in place of hydraulic fluid which has better lubricating qualities =20 Contamination Keep it clean, clean, clean!=20 =20 Regarding the 3 way valve, I decided to go with this since it is the only reliable way to extend the gear without power. As noted in previous posts there are failure modes that will prevent the gear comming down in normal operation even after operating the 2 way dump valve. Using a circuit to momentarily short out the down pressure switch will allow the pump to work but I dont want to find out that the problem has been lurking in my system when the power fails. The valve I used is the same as the one specified for the Legacy. The Legacy uses a vent to the tank =20 =20 =20 ----- Forwarded Message ---- From: TOM GARDINER To: Lancair Mailing List Sent: Sun, March 27, 2011 11:21:12 PM Subject: LNC2 Gear Hydraulics =20 Folks, =20 I thought I would take some time here to outline my recent experience with the parker oildyne pump so that it would save some of you the same time and expense i have had to deal with recently. My pump had been sitting in the aircraft for a number of years through the early construction phase without exercise. Once I began swinging the gear and flying I experienced various issues: =20 1. Gear would not retract - despite operation of the dump valve=20 2. Gear would not lower unless dump valve was actuated 3. Pump would screech and make various noises=20 4. Pump would turn on and off frequently during flight =20 After experiencing all of these issues I decided to make it my mission to learn as much about the system and eliminate all of the failure modes. Lessons learned: =20 1. The pump has many applications in the marine industry for which there is some excellent documentation 2. The two way dump valve supplied with the kit is poor quality and cannot be trusted (can leak internally and externally) 3. It is a very good idea to install pressure gauges in both up and down hydraulic lines 4. The original pump is slow to raise and lower the gear 5. Nobody knows more about the equipment than Parker/Oildyne 6. Heat will cause pressure increases in the lines to the point that the pressure switches will drop out 7. Seals inside the pump will eventually leak through wear and tear especially after sitting for a long period 8. There are numerous failue modes to the system, the goal is to eliminate as many of them as possible =20 Following 2 instances of not being able to raise my gear in flight I had had enough. After studying all of the related posts on this site I then elected to call Oildyne. The people there were kind enough to share with me their engineering drawings and their recommendation of the correct configuration for the pump internals for the LNC2 application. Contrary to some of the posts to LML the preferred spool type is a symmetrical one that is centered using two additional springs. The attached drawings provide a good understanding of how the spool, check valves and relief valves work. Armed with the data I set about modifying my hydraulic system as follows: =20 1. Removed the original pump adapter from the pump motor - Parker p/n781021 2. Removed the relief valves from the pump adapter and installed on a new adapter - Parker p/n 781047 3. Replaced the gear pump module for the high output upgrade - Parker p/n 634218=20 4. Replaced the dump valve with a high quality swagelok 3 way valve that dumps to the tank B-42XHF2=3DBKB 5. Replaced one of the pressure switches for another (was replaced under warranty - had a 500psi hysteresis) 6. Installed a small pressure gauge for diagnostic use 7. Installed a new fluid reservoir. New design does not have the mounting hole in the bottom A 781021 can be converted to a 781047 by performing the following steps =20 1. Remove the asymmetric spool in the pump adapter and replace it with the symmetric one along with the two centering springs 2. Remove center relief valve as shown in drawing - it is unnecessary=20 =20 Net results: =20 1. All gear legs move together and at about the same rate 2. No screeching - sounds smooth with positive cut off - I believe the center relief valve to be responsible for the occasional screeching=20 3. Emergency dump valve dumps pressure on both sides of the pump to zero with return to the tank 4. No internal leaks - Hence no cycling of the pump in flight 5. 100% reliability on gear operations=20 All mods to pump done for $250 =20 =20 =20 Notes: =20 To inspect the check valve poppet as a possible leak down cause, remove the hex plug, on whichever side of the power unit is having the problem. Inside there is the spring and the poppet. Check the rubber face seal of the poppet for any chips which might be embedded. On a rare occasion the face seal itself, which has a 'stepped' design, may delaminate, which can cause a leak. When finished doing all this, retorque the hex plug to 450-600 in-lbs. =20 Parts can be sourced from=20 Western Fluid Power, 2759 South 300 West, Suite H, Salt Lake City, Utah 84115. Talk to Boyd Ottenstein at 801-486-6500 =20 Oildyne Sales contact=20 larry.fern@parker.com =20 Tom Gardiner LNC2 826CT =20 ------_=_NextPart_001_01CBF2C4.378EE143 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Tom,

 

This is great, thank you for taking = the time to publish your notes.

 

Kevin

 

 

From: TOM GARDINER <n20087@yahoo.com>
To: = lml@lancaironline.net
Sent: Sat, April 2, 2011 = 8:52:18 PM
Subject: Fw: LNC2 Gear = Hydraulics

Folks,

 

I have had various requests from people to post the attachments that I thought had already made it to the forum from my = original post.  But as the moderator kindly informed me, my attachments = were way too large.  So hopefully this slideshow will make = it.  Nice tool - thanks Marvin. 

 

 

http://www.berkut13.com/108%20Startup%20Instructions.p= df

http://www.swagelok.com/downloads/WebCatalogs/EN/ms-02= -331.pdf

http://oemys-performance.com/media/autopark%20pump%201= 08a.pdf
http://www.berkut13.com/108%20RV%20adjusting%20and%20cleaning.pdf

 

 

A few items I failed to mention in my earlier post = that came to mind after reading Chris Zavaston's excellent post.  The article = listed the failure modes of the hydraulic system as = follows:

 

Reversed Spool = Valve

The reversed spool is a common problem.  The standard adapter is always configured this way and = needs to be reversed

 

Drifting Spool = Valve

The drifing spool is mitigated by the centering springs when used with the symmetric spool. 

 

Leaks, internal and = external

The symmetric spool has two O rings instead of one.   The O rings = are fitted on each end and allows for a better seal and better allignment of = the spool while moving inside the adapter barrel.  There will also be = less wear as a consequence.  Transmission fluid may be used in place of = hydraulic fluid which has better lubricating qualities

 

Contamination

Keep it clean, clean, clean! 

 

Regarding the 3 way valve, I decided to go with this since it is the only reliable = way to extend the gear without power.  As noted in previous posts there = are failure modes that will prevent the gear comming down in normal = operation even after operating the 2 way dump valve.  Using a circuit to = momentarily short out the down pressure switch will allow the pump to work but I = dont want to find out that the problem has been lurking in my system = when the power fails.  The valve I used is the same as the one specified for = the Legacy.  The Legacy uses a vent to the tank<= /p>

 

 


 

----- Forwarded Message = ----
From: TOM GARDINER <n20087@yahoo.com>
To: Lancair Mailing List <lml@lancaironline.net>
Sent: Sun, March 27, 2011 = 11:21:12 PM
Subject: LNC2 Gear = Hydraulics

 

Folks,

 

I thought I would take some time here to outline my recent experience with the = parker oildyne pump so that it would save some of you the same time and expense = i have had to deal with recently.  My pump had been sitting in the = aircraft for a number of years through the early construction phase without = exercise.  Once I began swinging the gear and flying I experienced various = issues:

 

  1. Gear would not retract - despite operation = of the dump valve 
  1. Gear would not lower unless dump valve was actuated
  1. Pump would screech and make various noises =
  1. Pump would turn on and off frequently = during flight

 

After experiencing all of these issues I decided to make it my mission to = learn as much about the system and eliminate all of the failure = modes.   Lessons learned:

 

  1. The pump has many applications in the = marine industry for which there is some excellent = documentation
  1. The two way dump valve supplied with the = kit is poor quality and cannot be trusted (can leak internally and = externally)
  1. It is a very good idea to install pressure = gauges in both up and down hydraulic lines
  1. The original pump is slow to raise and = lower the gear
  1. Nobody knows more about the equipment than Parker/Oildyne
  1. Heat will cause pressure increases in the = lines to the point that the pressure switches will drop = out
  1. Seals inside the pump will eventually leak through wear and tear especially after sitting for a long = period
  1. There are numerous failue modes to the = system, the goal is to eliminate as many of them as = possible

 

Following 2 instances of not being able to raise my gear in flight I had had = enough.  After studying all of the related posts on this site I then elected to = call Oildyne.  The people there were kind enough to share with me their engineering drawings and their recommendation of the correct = configuration for the pump internals for the LNC2 application.  Contrary to some of = the posts to LML the preferred spool type is a symmetrical one that is = centered using two additional springs.  The attached drawings provide a good understanding of how the spool, check valves and relief valves = work.  Armed with the data  I set about modifying my hydraulic system as follows:

 

  1. Removed the original pump adapter from the = pump motor - Parker p/n781021
  1. Removed the relief valves from the pump = adapter and installed on a new adapter - Parker p/n = 781047
  1. Replaced the gear pump module for the high = output upgrade - Parker p/n 634218 
  1. Replaced the dump valve with a high = quality swagelok 3 way valve that dumps to the tank = B-42XHF2=3DBKB
  1. Replaced one of the pressure switches for = another (was replaced under warranty - had a 500psi = hysteresis)
  1. Installed a small pressure gauge for = diagnostic use
  1. Installed a new fluid reservoir. New = design does not have the mounting hole in the = bottom

A 781021 can be converted to a 781047 by performing the following = steps

 

  1. Remove the asymmetric spool in the = pump adapter and replace it with the symmetric one along with the two = centering springs
  1. Remove center relief valve as shown in = drawing - it is unnecessary

 

Net = results:

 

  1. All gear legs move together and at about = the same rate
  1. No screeching - sounds smooth with = positive cut off - I believe the center relief valve to be responsible for the occasional screeching
  1. Emergency dump valve dumps pressure on = both sides of the pump to zero with return to the = tank
  1. No internal leaks -  Hence no = cycling of the pump in flight
  1. 100% reliability on gear operations =

All mods to pump done for $250

 

 

 

Notes:

 

To inspect the check = valve poppet as a possible leak down cause, remove the hex plug, on whichever = side of the power unit is having the problem. Inside there is the spring and the poppet.  Check the rubber face seal of the poppet for any chips = which might be embedded. On a rare occasion the face seal itself, which has a 'stepped' design, may delaminate, which can cause a leak.  When = finished doing all this, retorque the hex plug to 450-600 = in-lbs.

 

Parts can be sourced from

Western Fluid Power, 2759 South 300 West, Suite H, Salt Lake City, Utah 84115. Talk to Boyd = Ottenstein at 801-486-6500

 

Oildyne Sales contact

larry.fern@parker.com=

 

Tom Gardiner

LNC2 826CT

 

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