X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 09 Mar 2012 11:06:55 -0500 Message-ID: X-Original-Return-Path: Received: from nm15.bullet.mail.bf1.yahoo.com ([98.139.212.174] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with SMTP id 5434538 for lml@lancaironline.net; Fri, 09 Mar 2012 02:26:43 -0500 Received-SPF: none receiver=logan.com; client-ip=98.139.212.174; envelope-from=chris_zavatson@yahoo.com Received: from [98.139.212.146] by nm15.bullet.mail.bf1.yahoo.com with NNFMP; 09 Mar 2012 07:26:07 -0000 Received: from [98.139.212.225] by tm3.bullet.mail.bf1.yahoo.com with NNFMP; 09 Mar 2012 07:26:07 -0000 Received: from [127.0.0.1] by omp1034.mail.bf1.yahoo.com with NNFMP; 09 Mar 2012 07:26:07 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 261354.68790.bm@omp1034.mail.bf1.yahoo.com Received: (qmail 95081 invoked by uid 60001); 9 Mar 2012 07:26:07 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; 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Thu, 08 Mar 2012 23:26:07 PST X-Mailer: YahooMailWebService/0.8.116.338427 References: X-Original-Message-ID: <1331277967.38843.YahooMailNeo@web160404.mail.bf1.yahoo.com> X-Original-Date: Thu, 8 Mar 2012 23:26:07 -0800 (PST) From: Chris Zavatson Reply-To: Chris Zavatson Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="630850330-762980032-1331277967=:38843" --630850330-762980032-1331277967=:38843 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable This first video shows the stock LB configuration operating normally while = going through multiple extreme thermal cycles both retracted and extended.= =C2=A0 Note that the non-pressurized side remains at zero pressure througho= ut the entire test.=C2=A0 =C2=A0The pump responds, hot or cold, retracted o= r extended.=0Ahttp://www.n91cz.com/Hydraulics/Thermal%20Cycling%20IIII.wmv= =0AThis second video shows the CZZ configuration used on the Legacy which a= dds return springs to the LB spool (actually LD, in this case) and removes = the back pressure feed in the return line. =C2=A0This configuration is not = compatible with the 320/360 hydraulic system. =C2=A0As shown in the video, = this configuration locks up.=C2=A0 Note that the both high and low sides ri= se and fall with temperature.=C2=A0 Once the pressure rises above the press= ure switch set points, the pump cannot be engaged.=C2=A0 =0Ahttp://www.n91c= z.com/Hydraulics/NewPumpLockUp_0001.wmv=0AReverting the CZZ configuration b= ack to the 320/360 configuration took about 10 minutes.=0Ahttp://www.n91cz.= com/Hydraulics/Pump-Unlock.pdf=0AOnce the 320/360 pump configuration incorp= orated the LB back pressure circuit, it became an incredibly reliable and t= rouble free part of the aircraft design.=C2=A0 It has tens, perhaps, hundre= ds of thousands of hours of trouble free service.=C2=A0 I gladly contribute= d 1,350 of those hours.=0AI am not advocating any =E2=80=98fix=E2=80=99 and= certainly not any modification.=C2=A0 Quite the contrary, I have never fou= nd the stock LB configuration to need a fix. =C2=A0I do advocate ensuring t= he proper configuration and proper adjustments are maintained.=C2=A0 =0AOve= r the years, I have helped many Lancair owners resolve hydraulic issues.=C2= =A0=C2=A0 I have=C2=A0found assembly errors (reversed spool valve), bad pop= pet valves, pressure switch issues, both adjustment errors and failures, fa= ulty relays, hydraulic cylinder issues, even leaking dump valves.=C2=A0 Not= once was the problem tied to the pump design.=C2=A0 =0AI think it is a mat= ter of maintenance philosophy.=0AChris Zavatson=0AN91CZ=0A360std=0Awww.N91C= Z.net=0A=0A=0AFrom: Wolfgang =0ATo: lml@lancaironline.n= et =0ASent: Tuesday, March 6, 2012 11:02 AM=0ASubject: [LML] Re: 320/360 Hy= draulic Pressure Switch =0A=0A=0A=EF=BB=BF =0AIt's a matter of cost effecti= veness. I'm still waiting for positive evidence of what exactly is causing = the failure so your fix can be validated. =0AAgain, I have come up with a f= ix that WILL fix that problem . . . for less than what it costs to "fix" th= e pump, not to mention down time=C2=A0. . . assuming that springs and vibra= tion is what's causing the problem. But you have said that vibration can't = do that ? ?=0A=C2=A0=0AYour "fix" could be the answer but there is no way t= o know for sure what is inside a particular pump without a dissection becau= se part numbers are not reliable.=0A=C2=A0=0AI'm thinking the springs are t= he 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.=0A=C2=A0=0AYou 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 w= hat the "correct" answer is ? =0ALet us know if your=C2=A0approach WILL fix= the problem.=0A=C2=A0=0AI have already done that with my electric module.= =0A=C2=A0=0AAssuming the pump modification is a valid fix,=0Awhich is more = cost effective,=C2=A0remove, dissect, re-assemble, replace=C2=A0the pump = =0Aor simply add the electric=C2=A0module using it's push-on connectors ?= =0A=C2=A0=0AWolfgang=0A=C2=A0=0A----- Original Message ----- =0A>From: Chri= s Zavatson =0A>To: lml@lancaironline.net =0A>Sent: Monday, March 05, 2012 8= :21 AM=0A>Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch =0A>=0A>= =0A>Wolfgang,=0A>If a mechanic were to install a new cylinder on my plane u= sing 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.=C2=A0 The more customary app= roach would be to remove the cylinder and install the correct rings.=0A>The= =E2=80=98problem=E2=80=99 here is not that oil needs to be replenished.=C2= =A0 The problem is the installation of incorrect parts.=C2=A0 The =E2=80=98= fix=E2=80=99 is not to add a system to keep the sump replenished.=C2=A0 The= fix is to use the correct rings.=0A>Chris Zavatson=0A>N91CZ=0A>360std=0A>w= ww.N91CZ.net =0A>=C2=A0=0A>=0A>From: Wolfgang =0A>To: l= ml@lancaironline.net =0A>Sent: Saturday, March 3, 2012 4:01 PM=0A>Subject: = [LML] Re: 320/360 Hydraulic Pressure Switch =0A>=0A>=0A>=EF=BB=BF =0A>Chris= ,=0A>=C2=A0=0A>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 m= y 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. =0A>=C2= =A0=0A>After you detailed the presence of springs in the pump to help cente= r the spool and popets, I see that my original supposition that the spool i= s 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 measur= ing the forces in G's but that does not give us an actual force measurement= that is what the springs are operating against. =0A>=C2=A0=0A>It remains t= hat some pump installations have the problem of the spool not maintaining t= he 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.=0A>= =C2=A0=0A>Wolfgang=0A>=C2=A0=0A>----- Original Message ----- =0A>>From: Chr= is Zavatson =0A>>To: lml@lancaironline.net =0A>>Sent: Friday, March 02, 201= 2 7:54 AM=0A>>Subject: [LML] Re: 320/360 Hydraulic Pressure Switch =0A>>=0A= >>=0A>>Wolfgang, =0A>>=C2=A0=0A>>It is a sad day when removing a pump from = the aircraft is too much effort to investigate an anomaly.=0A>>=C2=A0=0A>>W= olfgang wrote:<>=0A>>=C2=A0=0A>>As aircraft = owners we are responsible for knowing the configuration of the aircraft sys= tems.=C2=A0 If something is=C2=A0out of the ordinary, investigate.=C2=A0 We= know a lot about what the configuration should be and how it works and beh= aves.=C2=A0 We also know of configurations that do not work.=C2=A0 You may= =C2=A0very well be holding the key to a=C2=A0new, as of yet, unidentified f= ailure mode, but we=C2=A0may never know.=0A>>=C2=A0=0A>>Wolfgang wrote:<>=0A>>=C2=A0=0A>>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.=C2=A0 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 o= f the problem.=C2=A0 Could there be a second cause?=C2=A0 Possibly, but as = of yet, none have been documented.=0A>>=C2=A0=0A>>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.>= >=0A>>=C2=A0=0A>>Springs definitely - that is what they were designed to do= . =C2=A0Oildyne started adding springs to center the spool to the Legacy pu= mp in ~2003.=C2=A0 Our system will eventually fail if these springs are ins= talled. Fortunately the vast majority of our pumps=C2=A0do not have them.= =C2=A0=C2=A0If you have springs installed, simply remove them.=0A>>=C2=A0= =0A>>Vibration - the evidence says otherwise.=C2=A0 Measurements of various= spool and pump combinations=C2=A0required from 13 g's=C2=A0(9 year old 'so= ft' o-ring) to 70 g's (new 'stiff' o-ring)=C2=A0to move the spool.=C2=A0 Ai= rcraft vibration at the pump was measured to be +/- 0.1 g (flying) to +/-1.= 3 g (engine start). Vibration=C2=A0is not nearly=C2=A0sufficient to have an= y effect on the spool.=C2=A0=0A>>=C2=A0=0A>>Wolfgang wrote:<>=0A>>The springs= are very strong, 26 lb/in.=0A>>=C2=A0=0A>>Wolfgang wrote:<>=0A>>See MIL-STD-810 for expected vibration levels in = aircraft environments.=0A>>=C2=A0=C2=A0=0A>>Wolfgang wrote:<>=0A>>I would still like to know how push butt= ons can overload anything.=C2=A0=C2=A0And why would anyone want to override= more than one at a time?=0A>>=C2=A0=0A>>Wolfgang wrote:<=0A>>I have never had a thermal lock up,= yet I use pressure gauges and the momentary push buttons on a regular basi= s.=C2=A0 They were originally installed to deal with sticking VEP switches,= but it is like getting a new tool.=C2=A0 After you have it, you can't imag= ine how you lived without out it.=C2=A0 I have already discussed the benefi= ts of momentary switches not related to hydraulic lock-up.=0A>>=C2=A0=0A>>W= olfgang wrote:<>=0A>>One should label=C2=A0the push buttons appropriately.= =0A>>=C2=A0=0A>>Wolfgang wrote:<>Springs = that are not documented in the Oildyne spec sheet ?>>=0A>>Recall that the L= egacy pump configuration =E2=80=9CCZZ=E2=80=9D is proprietary to Lancair.= =C2=A0 Companies generally don=E2=80=99t post proprietary materials on-line= .=0A>>=C2=A0=0A>><>=0A>>Not really.=C2=A0 I avoid them by thorough examination, no matt= er what it requires.=0A>>=C2=A0=0A>>Chris Zavatson=0A>>N91CZ=0A>>360std=0A>= >www.N91CZ.net=0A>>=C2=A0=0A>>=C2=A0=0A>=0A> --630850330-762980032-1331277967=:38843 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
This first video sh= ows the stock LB configuration operating normally while going through multi= ple extreme thermal cycles both retracted and extended.  Note that the non-pressurized side remains at z= ero pressure throughout the entire test.&= nbsp;  Th= e pump responds, hot or cold, retracted or extended.
http://www.n91cz.com/Hydraulics/Thermal%20Cycling%20IIII.wmv
This second video s= hows the CZZ configuration used on the Legacy which adds return springs to = the LB spool (actually LD, in this case) and removes the back pressure feed= in the return line.  This co= nfiguration is not compatible with the 320/360 hydraulic system.  As shown in the video, this configurat= ion locks up.  Note that the = both high and low sides rise and fall with temperature.  Once the pressure rises above the pressure swit= ch set points, the pump cannot be engaged. 
http://www.n91cz.com/Hydrau= lics/NewPumpLockUp_0001.wmv
= Reverting the CZZ configuration back to the 320/360 co= nfiguration took about 10 minutes.
http://www.n91cz.com/Hydraulics/Pu= mp-Unlock.pdf
Once the 320/360 pu= mp configuration incorporated the LB back pressure circuit, it became an in= credibly reliable and trouble free part of the aircraft design.  It has tens, perhaps, hundreds of thou= sands of hours of trouble free service.  I gladly contributed 1,350 of those hours.
I am not advocating= any =E2=80=98fix=E2=80=99 and certainly not any modification.  Quite the contrary, I hav= e never found the stock LB configuration to need a fix.  I do advocate ensuring the proper = configuration and proper adjustments are maintained. 
Over the years, I h= ave helped many Lancair owners resolve hydraulic issues.   I have found assembly = errors (reversed spool valve), bad poppet valves, pressure switch issues, b= oth adjustment errors and failures, faulty relays, hydraulic cylinder issue= s, even leaking dump valves.=   Not once was the problem tied to the pump design. 
I think it is a mat= ter of maintenance philosophy.
<= FONT face=3DCalibri>Chris Zavatson
<= FONT face=3DCalibri>N91CZ
<= FONT face=3DCalibri>360std
www.N91CZ.net

From:= Wolfgang <Wolfgang@MiCom.net>
To: lml@lancaironline.net
Sent: Tuesday, March 6, 2012 11:02 AM
Subject: [LML] Re: 320/360 Hydraul= ic Pressure Switch

=EF=BB=BF=20
It's a matter of cost effectiveness. I'm s= till waiting for positive evidence of what exactly is causing the failure s= o your fix can be validated.
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 ? ?<= /FONT>
 
Your "fix" could be the answer but there i= s no way to know for sure what is inside a particular pump without a dissec= tion because part numbers are not reliable.
 
I'm thinking the springs are the culprit b= ut that needs to be demonstrated. The springs with the help of vibration ar= e 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 h= arder O-rings could be the answer. That scenario makes sense to me.<= /DIV>
 
You have the test rig you made up so why d= on't you simulate the supposed problem and implement the supposed fix and d= ocument for all what the "correct" answer is ?
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 i= s more cost effective, remove, dissect, re-assemble, replace the = pump
or simply add the electric module usi= ng it's push-on connectors ?
 
Wolfgang
 
----- Original Message -----
Sent: Monday, March 05, 2012 8:21 AM=
Subject: Re: [LML] Re: 320/360 Hydra= ulic Pressure Switch

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 coul= d theoretically design a system that refills the sump to assure I don=E2=80= =99t run out of oil during long flights.  The more custom= ary 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 incorrec= t parts.  The =E2=80=98fix=E2=80=99 is not to add a syste= m to keep the sump replenished.  The fix is to use the co= rrect rings.
Chris Zavatson
N91CZ
360std
www.N91CZ.net
 
 
From: Wolfgang <Wolfgan= g@MiCom.net>
To: lml@= lancaironline.net
Sent:= Saturday, March 3, 2012 4:01 PM
Su= bject: [LML] Re: 320/360 Hydraulic Pressure Switch

=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 mach= ine 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 w= hile tending to a malfunction in flight. That's why I cane up with the gear= module.
 
After you detailed the presence of springs= in the pump to help center the spool and popets, I see that my original su= pposition that the spool is coming off it's end position is confirmed. It l= ooks like the springs are in fact, capable of overcoming the friction of th= e O-rings. You keep measuring the forces in G's but that does not give us a= n actual force measurement that is what the springs are operating against. =
 
It remains that some pump installations ha= ve the problem of the spool not maintaining the required position for safe = flight operations. You have come up with many details that go toward esplai= ning 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 -----
Sent: Friday, March 02, 2012 7:54 AM=
Subject: [LML] Re: 320/360 Hydraulic= Pressure Switch

Wolfgang,
 
It is a sad day when removing a pump from the a= ircraft is too much effort to investigate an anomaly.
 
Wolfgang wrote:<<We would all like to get at the root= cause of the problem but, as yet, that hasn't happened. Likely because it'= s too much work to track down the actual cause and fix it. =E2=80=A6>>= ;
 
As aircraft owners we are responsible for knowi= ng the configuration of the aircraft systems.  If something is ou= t of the ordinary, investigate.  We know a lot about what the configur= ation should be and how it works and behaves.  We also kn= ow of configurations that do not work.  You may very= well be holding the key to a new, as of yet, unidentified failure mod= e, but we may never know.
 
Wolfgang wrote: <<So far we only have a good plausible theo= ry missing only demonstratable proof.>>
 
If my tire has a flat and I see a nail sticking through the s= ide wall, I am rather confident in assuming the nail was the source of my l= eak.  Likewise, if I open up a lock-up prone pump and fin= d 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 susp= icion 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 des= igned to do.  Oildyne started adding springs to center th= e spool to the Legacy pump in ~2003.  Our system will eve= ntually fail if these springs are installed. Fortunately the vast majority = of our pumps do not have them.  If you have springs installe= d, 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 m= ove 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&nbs= p;sufficient to have any effect on the spool. 
 
Wolfgang wrote:<<If it takes that much = force to move the spindle against the O-rings then those springs must be pr= etty darn strong. I find that dificult to accept.>>
The springs are very strong, 26 lb/in.
 
Wolfgang wrote:<<Vibration l= evels can exceed 70 G's>>
See MIL-STD-810 for expected vibration levels i= n aircraft environments.
  
Wolfgang wrote:<<Yes, that would be eas= y . . . except . . . you can only override one pressure switch at a time or= overload the system>>
I would still like to know how push buttons can= overload anything.  And why would anyone want to override more t= han one at a time?
 
Wolfgang wrote:<<The items you cited ar= e more a one-of condition ...>
I have never had a thermal lock up, yet I use p= ressure gauges and the momentary push buttons on a regular basis.  The= y were originally installed to deal with sticking VEP switches, but it is l= ike 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 moment= ary switches not related to hydraulic lock-up.
 
Wolfgang wrote:<<In the event of a prob= lem you have to make sure you push the right switch.>>
One should label the push buttons appropri= ately.
 
Wolfgang wrote:<<Are you saying that Oi= ldyne is putting springs in the spool to center it when the pump is not run= ning ?
Springs that are not documented in the Oildyn= e spec sheet ?>>
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.
 
<<You seem to want to be "involved" in= the anomalies of flight.>>
Not really.  I avoid them by = thorough examination, no matter what it requires.
 
Chris Zavatson
N91CZ
360std
 
 




<= /DIV>
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