X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 07 Mar 2012 07:58:53 -0500 Message-ID: X-Original-Return-Path: Received: from nm30-vm1.bullet.mail.ne1.yahoo.com ([98.138.90.46] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with SMTP id 5431772 for lml@lancaironline.net; Wed, 07 Mar 2012 07:02:09 -0500 Received-SPF: none receiver=logan.com; client-ip=98.138.90.46; envelope-from=n20087@yahoo.com Received: from [98.138.90.54] by nm30.bullet.mail.ne1.yahoo.com with NNFMP; 07 Mar 2012 12:01:32 -0000 Received: from [98.138.89.194] by tm7.bullet.mail.ne1.yahoo.com with NNFMP; 07 Mar 2012 12:01:32 -0000 Received: from [127.0.0.1] by omp1052.mail.ne1.yahoo.com with NNFMP; 07 Mar 2012 12:01:32 -0000 X-Yahoo-Newman-Id: 950579.4321.bm@omp1052.mail.ne1.yahoo.com Received: (qmail 62674 invoked from network); 7 Mar 2012 12:01:32 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=DKIM-Signature:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Subject:References:From:Content-Type:X-Mailer:In-Reply-To:Message-Id:Date:To:Content-Transfer-Encoding:Mime-Version; b=Ry0cHu073ty5SneVSu1LLY0wINkF3JZzvCoqJLdrFF6zacfYo54h7mc2uCIGts+EL/HiGyJIdqk8rGcvWK9o3gjzwbyeTgrk7j3g1IYKSxU+7m5zhsDbRzB37b2vIt6xN2LzVHNeuy+se2ePlsaUKhPy3V0M+vLmv934/9T9KsY= ; X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: TAM4I9gVM1mZcw.VmK9ESfMhmLIcIwORj2g0h6owPUtYzMV Y0q0TGV0TIQiCFOCPNZf9FfDK1dXZ8Ckom0TDTdBoJVpsWHfaJ2_.JOwxzFV Qr6gH.3DvBLmfSxRsFMAx1Qna9P6Vmp.5nvktJA_gdbV53dYmAI4QNbkm..W 5f0y2svZ3jZktsT8tjAlZXCCbmuV4vHeRXhmV01jnBZ5USnHKaFsDMQigrKw MUzU2woDpKw0oSNsCIdnlN9bf.ygdklVfBdOcmsOoYcOERlHw6VUpCHUqC40 KB9FJ8m2uc12tXKzDkzgvzN4rKk87kmhCSDnaADZN985VVKmZbqvY8Loh_Gw 9s2OnJfHgb9RW7OYajE7ap7rAV2MSvj1l0BO0AwG3Cb6i9okL7ublldaX3K3 YuxHvSaEskXwK7IXHf1EdxfG0azh8SyFwnP78N31879bc5qPh7USX0XcQFC0 ajPSGSrckzbzcnGudMNs- X-Yahoo-SMTP: NQQt3c2swBAKSrExoA1eZuT7_w-- Received: from [10.174.64.183] (n20087@198.228.207.72 with xymcookie) by smtp110-mob.biz.mail.ne1.yahoo.com with SMTP; 07 Mar 2012 04:01:31 -0800 PST Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch References: From: N20087 Content-Type: multipart/alternative; boundary=Apple-Mail-EA6D6328-F054-4A63-B638-6AC234F315B9 X-Mailer: iPad Mail (9A334) In-Reply-To: X-Original-Message-Id: <8DD02EFA-E529-4875-ADC9-901585E96C40@yahoo.com> X-Original-Date: Wed, 7 Mar 2012 07:01:27 -0500 X-Original-To: Lancair Mailing List Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-EA6D6328-F054-4A63-B638-6AC234F315B9 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 This is a very important topic for all of us. A gear failure is certainly a= n expensive and likely dangerous situation in any Lancair. While building t= his was an area I paid a great deal of attention to since I had witnessed ha= ng ups while swinging the gear (140 times!) I guess I was fortunate in a way that I did see these hang ups and set about= eliminating as many of the failure modes that I could nail down. I think w= hat flushed out many of my problems were due to the fact that i had the asym= metric spool installed the wrong way and the pump had sat for at least 3 yea= rs in oil without any cycling which led to what I think we're weak O rings I swapped the spool orientation and I was still able to demonstrate hangups a= lbeit a good deal less. So, my next step was to read all of the related posts (shout out Chris for t= he great drawings and description of how the pump is supposed to work) on LM= L and gather all of the drawings for the pump mechanism and then get on the h= orn with the manufacturer. My experience was that there is very little deta= iled institutional knowledge remaining in Parker about the Lancair applicati= on. So after describing the system in detail to a seasoned tech I took their= advice and installed a new pump body with a symmetrical spool. I could have= used the original pump but I wanted to upgrade to 2x speed which works grea= t by the way. The spool I chose has 2 heavy rings instead of one. =20 Since replacing all this equipment I have not had a single issue. But since= i had witnessed earlier hang ups that could not be cleared using the origin= al dump valve I decided to install a three way dump that allows pressure to b= e relieved across both pump ports to tank. This is a scenario that can happ= en due to heating and leakage (See other posts) The three way dump was impl= emented in the legacy by the way. In addition, I wanted the extra piece of m= y mind that if the flow of electrons into the pump motor could not be energi= zed for any reason (total electrical failure, control circuit failure, break= er failure, solenoid failure, motor failure, porting issue inside the pump) t= hat I would be guarantied the gear would fall and lock. (make sure you test t= he emergency dump system once a month or so, friction is a nasty thing that c= an suddenly appear for one reason or another) By the way on a lighter but related note. Last week I flew a trip of about a= n hour or so with my foot on the rudder because I could not keep the ball ca= ged. I thought I lost my rudder tab. On inspection I noticed the set screw= for the inner gear door valve was missing. Emm well that explains that, pr= oblem solved plane now flys straight! Tom Sent from my iPad On Mar 6, 2012, at 2:02 PM, "Wolfgang" wrote: > It's a matter of cost effectiveness. I'm still waiting for positive eviden= ce of what exactly is causing the failure so 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 . . . assumi= ng that springs and vibration is what's causing the problem. But you have sa= id that vibration can't do that ? ? > =20 > Your "fix" could be the answer but there is no way to know for sure what i= s inside a particular pump without a dissection because part numbers are not= reliable. > =20 > 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. T= hat scenario makes sense to me. > =20 > You have the test rig you made up so why don't you simulate the supposed p= roblem and implement the supposed fix and document for all what the "correct= " answer is ? > Let us know if your approach WILL fix the problem. > =20 > I have already done that with my electric module. > =20 > Assuming the pump modification is a valid fix, > which is more cost effective, remove, dissect, re-assemble, replace the pu= mp > or simply add the electric module using it's push-on connectors ? > =20 > Wolfgang > =20 > ----- Original Message ----- > From: Chris Zavatson > To: lml@lancaironline.net > 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 r= ings that subsequently led to oil consumption of 2 qt/hr, I could theoretica= lly design a system that refills the sump to assure I don=E2=80=99t run out o= f oil during long flights. The more customary approach would be to remove t= he 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 t= he correct rings. > Chris Zavatson > N91CZ > 360std > www.N91CZ.net > =20 > =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 >=20 > =EF=BB=BF > Chris, > =20 > Life is complicated enough so when I fly, I like to enjoy it. Being a slav= e 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 fli= ght. 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 s= pool 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, c= apable of overcoming the friction of the O-rings. You keep measuring the for= ces in G's but that does not give us an actual force measurement that is wha= t the springs are operating against. > =20 > It remains that some pump installations have the problem of the spool not m= aintaining the required position for safe flight operations. You have come u= p 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 pro= blem. > =20 > Wolfgang > =20 > ----- Original Message ----- > From: Chris Zavatson > To: lml@lancaironline.net > 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 t= o investigate an anomaly. > =20 > Wolfgang wrote:<> > =20 > As aircraft owners we are responsible for knowing the configuration of the= aircraft systems. If something is out of the ordinary, investigate. We kn= ow 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 ho= lding the key to a new, as of yet, unidentified failure mode, but we may nev= er know. > =20 > Wolfgang wrote: <> > =20 > If my tire has a flat and I see a nail sticking through the side wall, I a= m 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 h= igh degree of confidence I have found the source of the problem. Could ther= e be a second cause? Possibly, but as of yet, none have been documented. > =20 > Wolfgang wrote:<<=E2=80=A6original suspicion of the spool coming off it's e= nd point (with the help of springs and airframe vibration) is in fact what's= causing the problem.>> > =20 > Springs definitely - that is what they were designed to do. Oildyne start= ed adding springs to center the spool to the Legacy pump in ~2003. Our syst= em will eventually fail if these springs are installed. Fortunately the vast= majority of our pumps do not have them. If you have springs installed, sim= ply remove them. --Apple-Mail-EA6D6328-F054-4A63-B638-6AC234F315B9 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
This is a very important t= opic for all of us.  A gear failure is certainly an expensive and likel= y dangerous situation in any Lancair.  While building this was an area I= paid a great deal of attention to since I had witnessed hang ups while swin= ging the gear (140 times!)

I guess I was fortunate i= n a way that I did see these hang ups and set about eliminating as many of t= he failure modes that I could nail down.  I think what flushed out many= of my problems were due to the fact that i had the asymmetric spool in= stalled the wrong way and the pump had sat for at least 3 years in oil withou= t any cycling which led to what I think we're weak O rings
= <= br>
I swapped the spool orientation and I was still able to d= emonstrate hangups albeit a good deal less.

So, my next step was to read all of the related posts (shout out Chris f= or the great drawings and description of how the pump is supposed to work) o= n LML and gather all of the drawings for the pump mechanism and then get on t= he horn with the manufacturer.  My experience was that there is very li= ttle detailed institutional knowledge remaining in Parker about the Lancair a= pplication. So after describing the system in detail to a seasoned tech I to= ok their advice and installed a new pump body with a symmetrical spool. I co= uld have used the original pump but I wanted to upgrade to 2x speed which wo= rks great by the way.  The spool I chose has 2 heavy rings instead of o= ne.  

Since replacing all this equ= ipment I have not had a single issue.  But since i had witnessed earlie= r hang ups that could not be cleared using the original dump valve I decided= to install a three way dump that allows pressure to be relieved across both= pump ports to tank.  This is a scenario that can happen due to heating= and leakage (See other posts)  The three way dump was implemented in t= he legacy by the way.  In addition, I wanted the extra piece of my mind= that if the flow of electrons into the pump motor could not be energized fo= r any reason (total electrical failure, control circuit failure, breaker fai= lure, solenoid failure, motor failure, porting issue inside the pump) that I= would be guarantied the gear would fall and lock. (make sure you test the e= mergency dump system once a month or so, friction is a nasty thing that can s= uddenly appear for one reason or another)

<= div>
Tom




Sent from my iPad

On Mar 6, 2012, at 2= :02 PM, "Wolfgang" <Wolfgang@MiCom.= net> wrote:

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 W= ILL fix that=20 problem . . . for less than what it costs to "fix" the pump, not to mention d= own=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 ther= e is no way=20 to know for sure what is inside a particular pump without a dissection becau= se=20 part numbers are not reliable.
 
I'm thinking the springs are the culpri= t but that=20 needs to be demonstrated. The springs with the help of vibration are the onl= y=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-rin= gs=20 could be the answer. That scenario makes sense to me.
 
You have the test rig you made up so wh= y don't you=20 simulate the supposed problem and implement the supposed fix and document fo= r=20 all what the "correct" answer is ?
Let us know if your approach WILL f= ix the=20 problem.
 
I have already done that with my electr= ic=20 module.
 
Assuming the pump modification is a val= id=20 fix,
which is more cost=20 effective, remove, dissect, re-assemble, replace the pump=20
or simply add the electric module u= sing it's=20 push-on connectors ?
 
Wolfgang
 
----- Original Message -----
Sent: Monday, March 05, 2012 8:21=20= AM
Subject: Re: [LML] Re: 320/360 Hydr= aulic=20 Pressure Switch

Wolfgang,
If a mechanic were to install a new c= ylinder=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 as= sure=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 i= s not that oil needs to=20 be replenished.  The problem= is=20 the installation of incorrect parts.&nbs= p;=20 The =E2=80=98fix=E2=80=99 is not to add a system to keep the sump r= eplenished.  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: 3= 20/360=20 Hydraulic Pressure Switch

=EF=BB=BF=20
Chris,
 
Life is complic= ated 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 u= p=20 with the gear module.
 
After you detai= led 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 positio= n is=20 confirmed. It looks like the springs are in fact, capable of overcoming th= e=20 friction of the O-rings. You keep measuring the forces in G's but that doe= s=20 not give us an actual force measurement that is what the springs are opera= ting=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 th= at=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: [L= ML] 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 investi= gate=20 an anomaly.
 
Wolfgang wrote:<&= lt;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 act= ual=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.&nb= sp;=20 We know a lot about what the configuration should be and how it works an= d=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 hi= gh=20 degree of confidence I have found the source of the problem. = =20 Could there be a second cause?  Possibly, but a= s of=20 yet, none have been=20 documented.
 
Wolfga= ng=20 wrote:<<=E2=80=A6original suspicion of the spool coming off it's e= nd point=20 (with the help of springs and airframe vibration) is in fact what's caus= ing=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.
= --Apple-Mail-EA6D6328-F054-4A63-B638-6AC234F315B9--