X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 07 Sep 2012 16:46:49 -0400 Message-ID: X-Original-Return-Path: Received: from snt0-omc3-s21.snt0.hotmail.com ([65.55.90.160] verified) by logan.com (CommuniGate Pro SMTP 6.0c1) with ESMTP id 5750006 for lml@lancaironline.net; Fri, 07 Sep 2012 16:02:02 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.55.90.160; envelope-from=gary21sn@hotmail.com Received: from SNT112-DS12 ([65.55.90.137]) by snt0-omc3-s21.snt0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Fri, 7 Sep 2012 13:01:25 -0700 X-Originating-IP: [75.142.5.231] X-EIP: [uhiRUlj/sg8aXhezvxVx4OhaoLy4sOH1] X-Originating-Email: [gary21sn@hotmail.com] X-Original-Message-ID: X-Original-Return-Path: gary21sn@hotmail.com From: "Gary Edwards" X-Original-To: "Lancair Mailing List" References: Subject: Thermal influence on Hydraulic Pressure X-Original-Date: Fri, 7 Sep 2012 13:02:07 -0700 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="----=_NextPart_000_0207_01CD8CF8.FC2629F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V10.20.0091.1100 Seal-Send-Time: Fri, 7 Sep 2012 13:02:07 -0700 X-OriginalArrivalTime: 07 Sep 2012 20:01:25.0559 (UTC) FILETIME=[8F986470:01CD8D33] This is a multi-part message in MIME format. ------=_NextPart_000_0207_01CD8CF8.FC2629F0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable For me, I would send the pump to Chris for examination. Come winter = time, there will be plenty of consecutive non-flying days. Gary LNC2=20 ----- Original Message -----=20 From: Wolfgang=20 To: lml@lancaironline.net=20 Sent: Friday, September 07, 2012 10:38 AM Subject: [LML] Re: Thermal influence on Hydraulic Pressure =EF=BB=BF=20 I have said it before, removing a pump and taking it apart to fix a = supposed design problem, putting the aircraft down for the duration, is = not always the best solution. After it's apart, you're still looking to = verify your supposition. Installing a fix like mine guarantees a = solution in about 30 minutes. Pilot's choice. 30 minutes is a small = price to pay. Wolfgang ----- Original Message -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Thursday, September 06, 2012 8:15 AM Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure Wolfgang, The =E2=80=98failure to retract=E2=80=99 issue, to which you refer, = sounds like a pump configuration issue. =20 For example, the current pump sold by Lancair for the 320/360/Legacy = contains spool return springs. This configuration has the potential = to lock up due to thermal heating. This configuration is simply not = compatible with the design of the Lancair two-seat hydraulic systems. =20 Lock-up = video:http://www.n91cz.com/Hydraulics/NewPumpLockUp_0001.wmv With personnel turn-over at both companies, neither side knows why = the return springs were added. However, both Parker and Lancair agree = that a lock up on the ground is possible with the springs installed. = This lock-up has been experienced by some, including the factory Legacy. = It just has not been reported enough to drive an engineering change at = Lancair. =20 Parker has graciously supplied parts to revert currently sold = =E2=80=9CCZZ=E2=80=9D pumps back to the original 320/360 configuration = with respect to spool operation. I have been forwarding these parts = free of charge to anyone who needs them.=20 See conversion instructions here: = http://www.n91cz.com/Hydraulics/Pump-Unlock.pdf I applaud your ingenuity in devising your circuit. Unfortunately = your energy seems to be a little misplaced. I would prefer to = investigate and fix the root cause of any out of the ordinary = behavior-especially on an airplane! If my engine was burning a quart = of oil per hour, the fix would not to design a gadget that would pump = oil from an onboard supply into the sump and replenish the lost oil. = The solution, albeit painful in the short term, would be to open up the = engine, find and fix the problem and then fly like other engines. I understand that removing a pump, in particular those mounted = behind the baggage bulkhead is no fun. Poor access is a real deterrent = for any maintenance activity. That is simply human nature. In the = grand scheme of things, it is a small price to pay. =20 My offer still stands to examine your (Lorn=E2=80=99s) pump or any = other that is able to lock-up both circuits. I have not yet come across = one that did not have an obvious cause-like the springs mentioned above, = so any such reported behavior of great interest to me and is worth = investigating. =20 Chris Zavatson N91CZ 360std www.N91CZ.net From: Wolfgang To: lml@lancaironline.net=20 Sent: Wednesday, September 5, 2012 9:28 AM Subject: [LML] Re: Thermal influence on Hydraulic Pressure Let's not forget this thermal influence causing non-function can = also happen in reverse. It has been reported that a thermal a soak on = the ground after a cold night can and has caused a failure to retract = after take off. A while back I offered a solution of bumping the pump automatically = whenever both pressure switches, HI and LO, are open due to high = pressure. This would put the system back in normal operation mode = without the need for pilot intervention Wolfgang ------=_NextPart_000_0207_01CD8CF8.FC2629F0 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
For me, I would send the pump to Chris for examination.  Come = winter=20 time, there will be plenty of consecutive non-flying days.
 
Gary
LNC2 
----- Original Message -----
From: Wolfgang
Sent: Friday, September 07, = 2012 10:38=20 AM
Subject: [LML] Re: Thermal = influence on=20 Hydraulic Pressure

=EF=BB=BF=20
I have said it before, removing a = pump and taking=20 it apart to fix a supposed design problem, putting the aircraft down = for the=20 duration, is not always the best solution. After it's apart, you're = still=20 looking to verify your supposition. Installing a fix like mine = guarantees a=20 solution in about 30 minutes. Pilot's choice. 30 minutes is a small = price to=20 pay.
 
Wolfgang
 
----- Original Message -----
From:=20 Chris Zavatson
To: lml@lancaironline.net =
Sent: Thursday, September 06, = 2012 8:15=20 AM
Subject: Re: [LML] Re: = Thermal=20 influence on Hydraulic Pressure

Wolfgang,
The=20 =E2=80=98failure to retract=E2=80=99 issue, to which you refer, = sounds like a pump=20 configuration issue. =20
For example, the current pump = sold by=20 Lancair for the 320/360/Legacy contains spool return springs.    This configuration = has the=20 potential to lock up due to thermal heating.  This configuration is = simply not=20 compatible with the design of the Lancair two-seat hydraulic = systems. 
Lock-up = video:http://ww= w.n91cz.com/Hydraulics/NewPumpLockUp_0001.wmv
With personnel turn-over at = both companies,=20 neither side knows why the return springs were added.  However, both Parker and = Lancair=20 agree that a lock up on the ground is possible with the springs=20 installed.  This = lock-up has=20 been experienced by some, including the factory Legacy.  It just has not been = reported enough=20 to drive an engineering change at Lancair. 
Parker=20 has graciously supplied parts to revert currently sold = =E2=80=9CCZZ=E2=80=9D pumps back to=20 the original 320/360 configuration with respect to spool = operation.  I have been forwarding = these parts=20 free of charge to anyone who needs them.
See conversion instructions = here: http://www.n91cz= .com/Hydraulics/Pump-Unlock.pdf
I applaud your ingenuity in = devising your=20 circuit.  = Unfortunately your=20 energy seems to be a little misplaced.   I would prefer to = investigate=20 and fix the root cause of any out of the ordinary = behavior-especially on an=20 airplane!   If my = engine=20 was burning a quart of oil per hour, the fix would not to = design a=20 gadget that would pump oil from an onboard supply into the sump and=20 replenish the lost oil.  = The=20 solution, albeit painful in the short term, would be to = open up=20 the engine, find and fix the problem and then fly like other=20 engines.
I understand that removing a = pump, in=20 particular those mounted behind the baggage bulkhead is no fun.  Poor access is a real = deterrent for=20 any maintenance activity.  = That=20 is simply human nature.  = In the=20 grand scheme of things, it is a small price to pay. 
My offer still stands to = examine your=20 (Lorn=E2=80=99s) pump or any other that is able to lock-up both = circuits.  I have not = yet come=20 across one that did not have an obvious cause-like the springs = mentioned=20 above, so any such reported behavior of great interest to me and is = worth=20 investigating.
  Chris=20 Zavatson
N91CZ
360std
www.N91CZ.net


From: Wolfgang=20 <Wolfgang@MiCom.net>
To: lml@lancaironline.net =
Sent: Wednesday, September 5, = 2012 9:28=20 AM
Subject: [LML] = Re:=20 Thermal influence on Hydraulic Pressure
Let's not forget this thermal = influence causing=20 non-function can also happen in reverse. It has been reported that a = thermal=20 a soak on the ground after a cold night can and has caused a failure = to=20 retract after take off.
 
A while back I offered a solution = of bumping=20 the pump automatically whenever both pressure switches, HI and LO, = are open=20 due to high pressure. This would put the system back in normal=20 operation mode without the need for pilot intervention
 
Wolfgang
------=_NextPart_000_0207_01CD8CF8.FC2629F0--