X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 06 Mar 2012 14:02:04 -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 5.4.4) with ESMTP id 5430673 for lml@lancaironline.net; Tue, 06 Mar 2012 11:12:36 -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=Xp94yC59 c=1 sm=0 a=MHZY6FYWMEQOp7S43i2QIw==:17 a=3Zlka_XeuxsA:10 a=DTcCN-Bu46AA:10 a=ttCsPuSJ-FAA:10 a=Ia-xEzejAAAA:8 a=5FIZSGrRAAAA:8 a=rTjvlri0AAAA:8 a=qvHWOgoosV-jkQ7WH5EA:9 a=FoxHOE7E3_91wTff4akA:7 a=QEXdDO2ut3YA:10 a=wR8WdYEwGqoA:10 a=EzXvWhQp4_cA:10 a=Dr9Wx-Q63l4A:10 a=CjxXgO3LAAAA:8 a=LaKdgnI-Gh-idkCQxaYA:9 a=K_Rk2RkVRzlno1mw1p4A:7 a=tXsnliwV7b4A:10 a=rC2wZJ5BpNYA:10 a=MHZY6FYWMEQOp7S43i2QIw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.218.201.50 Received: from [74.218.201.50] ([74.218.201.50:1383] helo=lobo) by hrndva-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 01/09-16206-057365F4; Tue, 06 Mar 2012 16:12:00 +0000 X-Original-Message-ID: <008001ccfbb3$d7f57fd0$6701a8c0@lobo> From: "Wolfgang" X-Original-To: References: Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch X-Original-Date: Tue, 6 Mar 2012 11:11:52 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_007D_01CCFB89.EEF95230" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_007D_01CCFB89.EEF95230 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable It's a matter of cost effectiveness. I'm still waiting for positive = evidence of what exactly is causing the failure so your fix can be = validated.=20 Again, I have come up with a fix that WILL fix that problem . . . for = less than what it costs to "fix" the pump, not to mention down time . . = . assuming that springs and vibration is what's causing the problem. But = you have said that vibration can't do that ? ? Your "fix" could be the answer but there is no way to know for sure what = is inside a particular pump without a dissection because part numbers = are not reliable. I'm thinking the springs are the culprit but that needs to be = demonstrated. The springs with the help of vibration are the only thing = that I can think of that can move the spindle off it's end position = against O-ring friction. I'm thinking that no springs and maybe harder = O-rings could be the answer. That scenario makes sense to me. You have the test rig you made up so why don't you simulate the supposed = problem and implement the supposed fix and document for all what the = "correct" answer is ?=20 Let us know if your approach WILL fix the problem. I have already done that with my electric module. Assuming the pump modification is a valid fix, which is more cost effective, remove, dissect, re-assemble, replace the = pump=20 or simply add the electric module using it's push-on connectors ? Wolfgang ----- Original Message -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Monday, March 05, 2012 8:21 AM Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch=20 Wolfgang, If a mechanic were to install a new cylinder on my plane using = incorrect rings that subsequently led to oil consumption of 2 qt/hr, I = could theoretically design a system that refills the sump to assure I = don=E2=80=99t run out of oil during long flights. The more customary = approach would be to remove the cylinder and install the correct rings. The =E2=80=98problem=E2=80=99 here is not that oil needs to be = replenished. The problem is the installation of incorrect parts. The = =E2=80=98fix=E2=80=99 is not to add a system to keep the sump = replenished. The fix is to use the correct rings. Chris Zavatson N91CZ 360std www.N91CZ.net=20 From: Wolfgang To: lml@lancaironline.net=20 Sent: Saturday, March 3, 2012 4:01 PM Subject: [LML] Re: 320/360 Hydraulic Pressure Switch=20 =EF=BB=BF=20 Chris, Life is complicated enough so when I fly, I like to enjoy it. Being a = slave to the system like a cog in a flying machine is not my idea of = "enjoyment". Don't get me wrong, I like getting into technicals up to my = eyebrows, but I prefer to do that at my choosing, not while tending to a = malfunction in flight. That's why I cane up with the gear module.=20 After you detailed the presence of springs in the pump to help center = the spool and popets, I see that my original supposition that the spool = is coming off it's end position is confirmed. It looks like the springs = are in fact, capable of overcoming the friction of the O-rings. You keep = measuring the forces in G's but that does not give us an actual force = measurement that is what the springs are operating against.=20 It remains that some pump installations have the problem of the spool = not maintaining the required position for safe flight operations. You = have come up with many details that go toward esplaining the problem and = a possible fix (take out the springs). I have come up with a module that = WILL fix that problem. Wolfgang ----- Original Message -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Friday, March 02, 2012 7:54 AM Subject: [LML] Re: 320/360 Hydraulic Pressure Switch=20 Wolfgang,=20 It is a sad day when removing a pump from the aircraft is too much = effort to investigate an anomaly.=20 Wolfgang wrote:<> As aircraft owners we are responsible for knowing the configuration = of the aircraft systems. If something is out of the ordinary, = investigate. We know a lot about what the configuration should be and = how it works and behaves. We also know of configurations that do not = work. You may very well be holding the key to a new, as of yet, = unidentified failure mode, but we may never know. Wolfgang wrote: <> If my tire has a flat and I see a nail sticking through the side = wall, I am rather confident in assuming the nail was the source of my = leak. Likewise, if I open up a lock-up prone pump and find return = springs, I will have a high degree of confidence I have found the source = of the problem. Could there be a second cause? Possibly, but as of = yet, none have been documented. Wolfgang wrote:<<=E2=80=A6original suspicion of the spool coming off = it's end point (with the help of springs and airframe vibration) is in = fact what's causing the problem.>> Springs definitely - that is what they were designed to do. Oildyne = started adding springs to center the spool to the Legacy pump in ~2003. = Our system will eventually fail if these springs are installed. = Fortunately the vast majority of our pumps do not have them. If you = have springs installed, simply remove them. Vibration - the evidence says otherwise. Measurements of various = spool and pump combinations required from 13 g's (9 year old 'soft' = o-ring) to 70 g's (new 'stiff' o-ring) to move the spool. Aircraft = vibration at the pump was measured to be +/- 0.1 g (flying) to +/-1.3 g = (engine start). Vibration is not nearly sufficient to have any effect on = the spool.=20 Wolfgang wrote:<> The springs are very strong, 26 lb/in. Wolfgang wrote:<> See MIL-STD-810 for expected vibration levels in aircraft = environments. =20 Wolfgang wrote:<> I would still like to know how push buttons can overload anything. = And why would anyone want to override more than one at a time? Wolfgang wrote:< I have never had a thermal lock up, yet I use pressure gauges and = the momentary push buttons on a regular basis. They were originally = installed to deal with sticking VEP switches, but it is like getting a = new tool. After you have it, you can't imagine how you lived without = out it. I have already discussed the benefits of momentary switches not = related to hydraulic lock-up. Wolfgang wrote:<> One should label the push buttons appropriately. Wolfgang wrote:<> Recall that the Legacy pump configuration =E2=80=9CCZZ=E2=80=9D is = proprietary to Lancair. Companies generally don=E2=80=99t post = proprietary materials on-line. <> Not really. I avoid them by thorough examination, no matter what it = requires. Chris Zavatson N91CZ 360std www.N91CZ.net ------=_NextPart_000_007D_01CCFB89.EEF95230 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
It's a matter of cost effectiveness. = I'm still=20 waiting for positive evidence of what exactly is causing the failure so = your fix=20 can be validated.
Again, I have come up with a fix that = WILL fix that=20 problem . . . for less than what it costs to "fix" the pump, not to = mention down=20 time . . . assuming that springs and vibration is what's causing = the=20 problem. But you have said that vibration can't do that ? ?
 
Your "fix" could be the answer but = there is no way=20 to know for sure what is inside a particular pump without a dissection = because=20 part numbers are not reliable.
 
I'm thinking the springs are the = culprit but that=20 needs to be demonstrated. The springs with the help of vibration are the = only=20 thing that I can think of that can move the spindle off it's end = position=20 against O-ring friction. I'm thinking that no springs and maybe harder = O-rings=20 could be the answer. That scenario makes sense to me.
 
You have the test rig you made up so = why don't you=20 simulate the supposed problem and implement the supposed fix and = document for=20 all what the "correct" answer is ?
Let us know if your approach WILL = fix the=20 problem.
 
I have already done that with my = electric=20 module.
 
Assuming the pump modification is a = valid=20 fix,
which is more cost=20 effective, remove, dissect, re-assemble, replace the pump=20
or simply add the electric module = using it's=20 push-on connectors ?
 
Wolfgang
 
----- Original Message -----
From:=20 Chris=20 Zavatson
Sent: Monday, March 05, 2012 = 8:21=20 AM
Subject: Re: [LML] Re: 320/360 = Hydraulic=20 Pressure Switch

Wolfgang,
If a mechanic were to install a = new cylinder=20 on my plane using incorrect rings that subsequently led to oil = consumption of=20 2 qt/hr, I could theoretically design a system that refills the sump = to assure=20 I don=E2=80=99t run out of oil during long flights.  The more = customary=20 approach would be to remove the cylinder and install the correct=20 rings.
The =E2=80=98problem=E2=80=99 = here is not that oil needs to=20 be replenished.  The = problem is=20 the installation of incorrect parts. =20 The =E2=80=98fix=E2=80=99 is not to add a system to keep the = sump replenished.  The fix is to use the = correct=20 rings.
Chris Zavatson
N91CZ
360std
www.N91CZ.net
 
 
From: Wolfgang=20 <Wolfgang@MiCom.net>
To: lml@lancaironline.net =
Sent: Saturday, March 3, 2012 = 4:01=20 PM
Subject: [LML] = Re: 320/360=20 Hydraulic Pressure Switch

=EF=BB=BF=20
Chris,
 
Life is = complicated enough so=20 when I fly, I like to enjoy it. Being a slave to the system like a cog = in a=20 flying machine is not my idea of "enjoyment". Don't get me wrong, I = like=20 getting into technicals up to my eyebrows, but I prefer to do that at = my=20 choosing, not while tending to a malfunction in flight. That's why I = cane up=20 with the gear module.
 
After you = detailed the=20 presence of springs in the pump to help center the spool and popets, I = see=20 that my original supposition that the spool is coming off it's end = position is=20 confirmed. It looks like the springs are in fact, capable of = overcoming the=20 friction of the O-rings. You keep measuring the forces in G's but that = does=20 not give us an actual force measurement that is what the springs are = operating=20 against.
 
It remains that = some pump=20 installations have the problem of the spool not maintaining the = required=20 position for safe flight operations. You have come up with many = details that=20 go toward esplaining the problem and a possible fix (take out the = springs). I=20 have come up with a module that WILL fix that problem.
 
Wolfgang
 
----- Original Message -----
Sent: Friday, March 02, 2012 = 7:54=20 AM
Subject: [LML] Re:=20 320/360 Hydraulic Pressure Switch

Wolfgang,=20
 
It is a sad=20 day when removing a pump from the aircraft is too much effort to = investigate=20 an anomaly. =
  Wolfgang = wrote:<<We=20 would all like to get at the root cause of the problem but, as yet, = that=20 hasn't happened. Likely because it's too much work to track down the = actual=20 cause and fix it. =E2=80=A6>>   As aircraft=20 owners we are responsible for knowing the configuration of the = aircraft=20 systems.  If something is out of the ordinary, = investigate. =20 We know a lot about what the configuration should be and how it = works and=20 behaves.  We also know of configurations that do = not=20 work.  You may very well be holding the key = to=20 a new, as of yet, unidentified failure mode, but we may = never=20 know.   Wolfgang=20 wrote:=20 <<So far we only have a good plausible theory missing only=20 demonstratable proof.>>   If my tire has = a flat and=20 I see a nail sticking through the side wall, I am rather confident = in=20 assuming the nail was the source of my leak.  = Likewise, if=20 I open up a lock-up prone pump and find return springs, I will have = a high=20 degree of confidence I have found the source of the = problem. =20 Could there be a second cause?  Possibly, = but as of=20 yet, none have been=20 documented.   Wolfgang=20 wrote:<<=E2=80=A6original suspicion of the spool coming off = it's end point=20 (with the help of springs and airframe vibration) is in fact what's = causing=20 the problem.>>   Springs=20 definitely - that is what they were designed to do.=20  Oildyne started adding springs to center the = spool to the=20 Legacy pump in ~2003.  Our system will eventually = fail if=20 these springs are installed. Fortunately the vast majority of our=20 pumps do not have them.  If you have springs = installed,=20 simply remove them.   Vibration -=20 the evidence says otherwise.  Measurements of various spool and = pump=20 combinations required from 13 g's (9 year old 'soft' = o-ring) to 70=20 g's (new 'stiff' o-ring) to move the spool.  Aircraft = vibration at=20 the pump was measured to be +/- 0.1 g (flying) to +/-1.3 g (engine = start).=20 Vibration is not nearly sufficient to have any effect on = the=20 spool.    Wolfgang=20 wrote:<<If it takes that much force to move the spindle = against the=20 O-rings then those springs must be pretty darn strong. I find that = dificult=20 to accept.>> The springs=20 are very strong, 26 lb/in.   Wolfgang=20 wrote:<<Vibration=20 levels can exceed 70 G's>> See=20 MIL-STD-810 for expected vibration levels in aircraft=20 environments.    Wolfgang=20 wrote:<<Yes, that would be easy . . . except . . . you can = only=20 override one pressure switch at a time or overload the=20 system>> I = would=20 still like to know how push buttons can overload = anything.  And=20 why would anyone want to override more than one at a = time?   Wolfgang=20 wrote:<<The items you cited are more a one-of condition=20 ...>
I = have=20 never had a thermal lock up, yet I use pressure gauges and the = momentary=20 push buttons on a regular basis.  They were originally = installed to=20 deal with sticking VEP switches, but it is like getting a new = tool. =20 After you have it, you can't imagine how you lived without out = it.  I=20 have already discussed the benefits of momentary switches not = related to=20 hydraulic lock-up.
 
Wolfgang=20 wrote:<<In the event of a problem you have to make sure you = push the=20 right switch.>>
One should=20 label the push buttons appropriately.
 
Wolfgang=20 wrote:<<Are you saying that Oildyne is putting springs in the = spool to=20 center it when the pump is not running ?
Springs that=20 are not documented in the Oildyne spec sheet = ?>>
Recall that=20 the Legacy pump configuration =E2=80=9CCZZ=E2=80=9D is proprietary = to Lancair. =20 Companies generally don=E2=80=99t post proprietary materials=20 on-line.
 
<<You=20 seem to want to be "involved" in the anomalies of=20 flight.>>
Not=20 really.  I avoid them by thorough examination, no = matter=20 what it requires.
 
Chris=20 Zavatson
N91CZ
360std
www.N91CZ.net
 
 


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