X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 14 Feb 2013 14:48:56 -0500 Message-ID: X-Original-Return-Path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTP id 6064190 for lml@lancaironline.net; Thu, 14 Feb 2013 12:57:41 -0500 Received-SPF: none receiver=logan.com; client-ip=71.74.56.122; envelope-from=Wolfgang@MiCom.net X-Original-Return-Path: X-Authority-Analysis: v=2.0 cv=adbjbGUt c=1 sm=0 a=MHZY6FYWMEQOp7S43i2QIw==:17 a=3Zlka_XeuxsA:10 a=tVOIxAE17E8A:10 a=ttCsPuSJ-FAA:10 a=rTjvlri0AAAA:8 a=wDVdaLyLW1oA:10 a=Ia-xEzejAAAA:8 a=ndVRne3UAAAA:8 a=CjxXgO3LAAAA:8 a=5FIZSGrRAAAA:8 a=KNfte85PAAAA:8 a=AfjjMVoruyijhITKdVYA:9 a=wPNLvfGTeEIA:10 a=ILeVjEvywfEA:10 a=EzXvWhQp4_cA:10 a=Dr9Wx-Q63l4A:10 a=rC2wZJ5BpNYA:10 a=8m6LRutVOowA:10 a=rsdEobEFAa5EZ9a-:21 a=CUWIS-3i0SYYVlpm:21 a=e41pxzEGBIYIWVsgNsUA:9 a=_W_S_7VecoQA:10 a=tXsnliwV7b4A:10 a=6PxA8PxfQsVVtMR5:21 a=gkrtPzvcDPK8gqWe:21 a=9gQU34zAuVjkjBRp:21 a=MHZY6FYWMEQOp7S43i2QIw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.218.201.50 Received: from [74.218.201.50] ([74.218.201.50:1103] helo=lobo) by hrndva-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id D7/7A-27807-3752D115; Thu, 14 Feb 2013 17:57:07 +0000 X-Original-Message-ID: From: "Wolfgang" X-Original-To: References: Subject: Re: [LML] Fw: [LML] Re: Thermal influence on Hydraulic Pressure X-Original-Date: Thu, 14 Feb 2013 12:57:01 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00C9_01CE0AB2.C81CF340" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5512 This is a multi-part message in MIME format. ------=_NextPart_000_00C9_01CE0AB2.C81CF340 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable What did you measure to come up with that 70 g's ? and . . . the springs trying to center the spool in some models = certainly don't help. So the question still lingers from more than a year ago,=20 How do some spools come off their end position and cause the reported = failures ? That's why I came up with the module I have.=20 It powers the spool back into position whenever needed, regardless of = pump model. Wolfgang ----- Original Message -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Wednesday, February 13, 2013 7:55 AM Subject: Re: [LML] Fw: [LML] Re: Thermal influence on Hydraulic = Pressure Reposted from June 2011 = =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 -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Saturday, June 25, 2011 12:35 PM Subject: Re: [LML] Re: LNC2 Gear Hydraulics Curiosity got the best of me. Here are the peak vibration values = recorded today at the hydraulic pump measured on the axis of the spool = valve. Start up: +/- 1.3 g Take off: +/- 0.3 g Cruise: +/- 0.1 g Descent: +/- 0.1 g Landing: +/- 0.6 g It would appear the O-ring has more design margin than just about any = other component on the plane. Chris Zavatson N91CZ 360std www.N91CZ.com = =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 From: Wolfgang To: lml@lancaironline.net=20 Sent: Monday, February 11, 2013 12:36 PM Subject: [LML] Fw: [LML] Re: Thermal influence on Hydraulic Pressure 70 g's is an impressive number. How was that measured ?=20 Or is that just a measure of the vibration that the part lives under = during flight ? Wolfgang From: Chris Zavatson To: lml@lancaironline.net=20 Sent: Saturday, January 26, 2013 12:24 PM Subject: [LML] Re: Thermal influence on Hydraulic Pressure Randy, Thanks. =20 There are two things I have been doing to pumps to eliminate the = need for 'dump valve rescues'. =20 First is the removal of the return springs that entered the Legacy = pump design in about 2005. They added no useful functionality and = unfortunately introduced a lock-up failure mode. Removing the springs = primarily addresses lock-up on the ground during thermal swings. The second thing I have been doing is to set the low pressure switch = to 800-850 psi. This eliminates the gear extension lock-up mode that = occasionally prevents the gear from fully extending. The original = setting was to low to overcome the pressure spike that propagates = through the system when the gear first come out of the wheel wells. The other thing I have been doing is measuring the spool = resistance on every pump that comes across my desk. I haven't found any = issues there. 70g's is the typical result. I have also been making thermal relief valves adjustable, bringing the = set-point into a usable range (2,000 psi) for our systems. The three-way dump valve references in that write-up were merely = describing the Legacy hydraulic system. The Legacy cannot perform a = gear free-fall extension without a three way valve due to cylinder = orientation. I still use a two-way valve in my 360. Chris Chris Zavatson N91CZ 360std 1,400 hrs http://www.n91cz.net/ From: randy snarr To: lml@lancaironline.net=20 Sent: Friday, January 25, 2013 5:23 AM Subject: [LML] Re: Thermal influence on Hydraulic Pressure Nice Work Chris.. I am happy to hear that I have already done what you suggested which = is to install a 3 way dump valve and run the dump line to the reservoir = in a low pressure line. It has worked very 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. Have you found a solution for this with your research that makes the = original system function without having to ever dump the pressure = manually? Randy Snarr 235/320 N694RS=20 "Flight by machines heavier than air is unpractical and insignificant, = if not utterly impossible" -Simon Newcomb, 1902 From: Chris Zavatson To: lml@lancaironline.net=20 Sent: Tuesday, September 4, 2012 2:18 PM Subject: [LML] Re: Thermal influence on Hydraulic Pressure Danny, No affect on gear movement. I should add however that elevated high-side pressure is one of the = contributing factors to gear extension failures in a standard system set = up. My low pressure setting is higher than the nominal 550 psi. It is = set to 800 psi to avoid the pressure spike that propogates through the = system when gear down is selected. see "Failure to Extend" on page 10 for more detail. http://www.n91cz.com/Hydraulics/Lancair%20Hydraulics.pdf Chris Zavatson N91CZ 360std http://www.n91cz.net/=20 From: Danny To: lml@lancaironline.net=20 Sent: Monday, September 3, 2012 11:54 AM Subject: [LML] Re: Thermal influence on Hydraulic Pressure Chris, What was the impact on the gear movement? Danny LNC2-360 N 38=B0 43' 25.7" W 77=B0 30' 38.6" From: Chris Zavatson [mailto:chris_zavatson@yahoo.com]=20 Sent: Saturday, September 01, 2012 11:32 PM To: lml@lancaironline.net Subject: [LML] Thermal influence on Hydraulic Pressure -took this photo after a descent from 16.5k to 1,500 ft. OAT went from 42 to 94 degrees. High Pressure gauge is pegged at 2,000+ psi -Didn't get a photo, but the opposite happened on the ramp in Spokane. = After sitting for an hour, the low pressure gauge was pegged at 1,200 = psi+. 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 previous leg. Temperature changes have a big impact on system pressure.=20 Chris Zavatson N91CZ 360std http://www.n91cz.net/ =20 ------=_NextPart_000_00C9_01CE0AB2.C81CF340 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
What did you measure to come up with = that 70 g's=20 ?
and . . . the springs trying to center = the spool in=20 some models certainly don't help.
 
So the question still lingers from more = than a year=20 ago,
How do some spools come off their end = position and=20 cause the reported failures ?
 
That's why I came up with the module I = have.=20
It powers the spool back into position = whenever=20 needed, regardless of pump model.
 
Wolfgang
 
----- Original Message -----
From:=20 Chris=20 Zavatson
Sent: Wednesday, February 13, = 2013 7:55=20 AM
Subject: Re: [LML] Fw: [LML] = Re: Thermal=20 influence on Hydraulic Pressure

Reposted from June 2011
=
=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
-----=20 Original Message ----- From:=20 Chris=20 Zavatson To:=20 lml@lancaironline.net Sent:=20 Saturday, June 25, 2011 12:35 PM Subject:=20 Re: [LML] Re: LNC2 Gear Hydraulics

Curiosity got the best of me. Here are the peak vibration = values=20 recorded today at the hydraulic pump measured on the axis = of the=20 spool valve.
Start up: +/- 1.3 g
Take off: +/- 0.3 g
Cruise: +/- 0.1 g
Descent: +/- 0.1 g
Landing: +/- 0.6 g
It would appear the O-ring has more design margin than just = about=20 any other component on the=20 plane.
Chris Zavatson
N91CZ
360std
= =

=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
From: Wolfgang=20 <Wolfgang@MiCom.net>
To: lml@lancaironline.net =
Sent: Monday, February 11, 2013 = 12:36=20 PM
Subject: [LML] = Fw: [LML]=20 Re: Thermal influence on Hydraulic Pressure

70 g's is an impressive number. How = was that=20 measured ?
Or is that just a measure of the = vibration=20 that the part lives under during flight ?
 
Wolfgang
 
 
From: Chris Zavatson=20 <chris_zavatson@yahoo.com>
To: lml@lancaironline.net =
Sent: Saturday, January 26, = 2013 12:24=20 PM
Subject: [LML] = Re: Thermal=20 influence on Hydraulic Pressure

Randy,
Thanks. 
    There=20 are two things I have been doing to pumps to eliminate the need for = 'dump=20 valve rescues'. 
First is the removal of the return springs that entered the = Legacy=20 pump design in about 2005.  They added no = useful functionality=20 and unfortunately introduced a lock-up failure mode.  = Removing the=20 springs primarily addresses lock-up on the ground during thermal=20 swings.
The second thing I have been doing is to set the low = pressure=20 switch to 800-850 psi.  This eliminates the gear extension = lock-up mode=20 that occasionally prevents=20 the gear from fully extending.  The original setting was to low = to=20 overcome the pressure spike that propagates through the = system=20 when the gear first come out of the wheel wells.
    The=20 other thing I have been doing is measuring the spool resistance = on every=20 pump that comes across my desk.  I haven't found any issues = there. =20 70g's is the=20 typical result.
I have also been making thermal relief valves adjustable, = bringing=20 the set-point into a usable range (2,000 psi) for our = systems.
 
    The=20 three-way dump valve references in that write-up were merely=20 describing the Legacy hydraulic system.  The Legacy = cannot=20 perform a gear free-fall extension without a three way = valve due to=20 cylinder orientation.  I still use a two-way valve in my=20 360.
Chris
 
Chris Zavatson
N91CZ
360std 1,400 hrs
http://www.n91cz.net/
 

From:=20 randy snarr=20 <randylsnarr@yahoo.com>
To: lml@lancaironline.net =
Sent: Friday, January 25, 2013 = 5:23=20 AM
Subject: [LML] = Re: Thermal=20 influence on Hydraulic Pressure

Nice Work Chris..
I=20 am happy to hear that I have already done what you suggested which is = to=20 install a 3 way dump valve and run the dump line to the reservoir in a = low=20 pressure line. It has worked very well. I dont like having to open the dump = valve but it=20 is necessary once in a while especially when it is cold. The pressures = on both=20 sides of the system climb due to the engine heat and the gear = sometimes will=20 not move without dumping the pressure.
Have = you found=20 a solution for this with your research that makes the original system = function=20 without having to ever dump the pressure manually?

Randy=20 Snarr
235/320
N694RS 
 
"Flight by machines heavier = than air is=20 unpractical and insignificant, if not utterly = impossible"
-Simon=20 Newcomb,=20 1902
From:=20 Chris Zavatson <chris_zavatson@yahoo.com>
To: lml@lancaironline.net =
Sent: Tuesday, September 4, = 2012 2:18=20 PM
Subject: [LML] = Re: Thermal=20 influence on Hydraulic Pressure

Danny,
No affect on gear=20 movement.
I should add however = that=20 elevated high-side pressure is one of the contributing factors to gear = extension failures in a standard system set up.  My low pressure = setting is=20 higher than the nominal 550 psi.  It is set to 800 psi to = avoid the=20 pressure spike that propogates through the system when gear down is=20 selected.
see "Failure to = Extend" on page=20 10 for more detail.
http://www.n91cz.com/Hydr= aulics/Lancair%20Hydraulics.pdf
  Chris=20 Zavatson N91CZ 360std http://www.n91cz.net/   

From: Danny=20 <danny@n107sd.com>
To:=20 lml@lancaironline.net
Sent:=20 Monday, September 3, 2012 11:54 AM
Subject: [LML] Re: Thermal = influence on=20 Hydraulic Pressure

Chris,
What was the impact = on the gear=20 movement?
 
Danny
LNC2-360
N=20 38=B0 43' 25.7"
W=20 77=B0 30' 38.6"
 
From: Chris = Zavatson=20 [mailto:chris_zavatson@yahoo.com]
Sent: Saturday, September 01, = 2012 11:32=20 PM
To:=20 lml@lancaironline.net
Subject: [LML] Thermal = influence on=20 Hydraulic Pressure
 
-took=20 this photo after a descent from 16.5k to 1,500=20 ft.
OAT went=20 from 42 to 94 degrees.
High=20 Pressure gauge is pegged at 2,000+ psi
-Didn't=20 get a photo, but the opposite happened on the ramp in = Spokane. After=20 sitting for an hour, the low pressure gauge was pegged at 1,200 = psi+. =20 Spokane might not be the warmest spot in the country, but at 85 deg F, = it was=20 55 degrees warmer than the cold soak on the previous=20 leg.
Temperature=20 changes have a big impact on system = pressure. 
 
Chris=20 Zavatson
N91CZ
360std
http://www.n91cz.net/






 =20 =



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