X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 26 Feb 2012 16:42:35 -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 5414211 for lml@lancaironline.net; Fri, 24 Feb 2012 18:39:33 -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=Z7xu7QtA 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=o1OHuDzbAAAA:8 a=R8KLJHR1gzFlE-RsgYEA:9 a=JzZxbYjo1eAOljm5MXgA:7 a=QEXdDO2ut3YA:10 a=CVU0O5Kb7MsA:10 a=wR8WdYEwGqoA:10 a=EzXvWhQp4_cA:10 a=Dr9Wx-Q63l4A:10 a=ILCZio5HsAgA:10 a=sh6PArqQtYdngLzxv5aEQJAsMbE=:19 a=CjxXgO3LAAAA:8 a=US1ht0A_Lv_IjUjbB-gA:9 a=t7IAIeAyOnUiEVXDJeQA:7 a=tXsnliwV7b4A:10 a=jgaHk8FzMKAA:10 a=CiY9YAmrM3UA:10 a=rC2wZJ5BpNYA:10 a=MHZY6FYWMEQOp7S43i2QIw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.218.201.50 Received: from [74.218.201.50] ([74.218.201.50:1074] helo=lobo) by hrndva-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id D1/5F-04292-09F184F4; Fri, 24 Feb 2012 23:38:57 +0000 X-Original-Message-ID: <002e01ccf34d$77e94770$6701a8c0@lobo> From: "Wolfgang" X-Original-To: References: Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch X-Original-Date: Fri, 24 Feb 2012 18:38:53 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002B_01CCF323.8EDEE900" 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_002B_01CCF323.8EDEE900 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Chris, I don't believe I missed anything, just focusing on the more likely = problem. The items you cited are more a one-of condition but the thermal = soaking causing gear failure is more frequent.=20 With that in mind, I would be inclined to come up with a simple test = scenario to validate one's pump without having to remove it from the = aircraft. It does sound from your comments on the springs that my = original 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. The module I came up with powers up the pump when necessary and = forces the spool back into position in spite of the springs. Wolfgang ----- Original Message -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Friday, February 24, 2012 4:36 PM Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch Wolfgang, I think you missed the point of my last post. I was describing the = benefits of having momentary switches Angier suggested to jumper across = the pressure switches. The three examples cited are not in any way = related to hydraulic lock-up nor are they addressed by your module. = Designing another circuit to detect, identify and properly respond to = component failures is a tad complex. The pressure switch failure I = described is a perfect example. In those situations, having more = information along with more options available to the pilot is a good = thing? Regarding the pumps Lancair currently sells, both Oildyne and Lancair = have already acknowledged that the pump currently sold can lock up when = used in a stock 320/360. The reason for not offering the proper pump = configuration for the 320/360 is purely financial - very low volume. = Lancair did suggest that they could include a warning regarding the lock = up potential each time they ship a pump as a replacement for a 320/360. = This leaves the aircraft owner in an awkward position. The ironic thing = is that a properly configured pump can be obtained directly from a = Parker distributor for much less. My concern with misconfigured pumps trickling out into the fleet is = that it will eventually catch pilots unaware of the technical issues = off-guard. Chris Zavatson N91CZ 360std www.N91CZ.net From: Wolfgang To: lml@lancaironline.net=20 Sent: Wednesday, February 22, 2012 9:36 AM Subject: [LML] Re: 320/360 Hydraulic Pressure Switch We can keep this up for the next year but I believe talking it to = death will not fix the problem. My preference is to have a system that = takes care of itself. You seem to want to be "involved" in the anomalies = of flight. If most people wanted to be "involved", we wouldn't have = things like FADEC's and auto pilots. The module I provide can help keep = flight a bit more self sufficient and safer. If you could convince = Oildyne and Lancair that they have a problem with the pumps as used in = Lancairs, and fix the problem, then more power to you and the Lancair = owners. But in the mean time. I still like my gear module. Wolfgang ----- Original Message -----=20 From: Chris Zavatson=20 To: lml@lancaironline.net=20 Sent: Tuesday, February 21, 2012 9:01 AM Subject: Re: [LML] Re: 320/360 Hydraulic Pressure Switch " . . . you can only override one pressure switch at a time or = overload the system. You need one switch each for the up and down. In the event of a = problem you have to make sure you push the right switch"... Overload what exactly? The gear selector determines which pressure = switch is powered. If you jumper across an unpowered switch, nothing = happens. =20 While I do not advocate putting in switches to mask a pump problem = that should really be investigated and fixed at the source, momentary = switches have other benefits. =20 1. Checking the relief valve settings in the pump. By holding down = the switch, one can see the relief valve setting of the pump. 2. Back-up for a failed pressure switch. This was more common with = the VEP switches, but current version is not immune.=20 3. Recharging the system on demand - The hysteresis loop on the = pressure switches is quite large. The gear can start to sag before the = pressure switch recharges the system. This is more of an issue for the = Outback Gear due to the higher aerodynamic loads pulling on the gear.=20 With automation and complexity come new failure modes. Give the = pilot enough information about the state of the aircraft systems to = figure out what happened and enough controls to solve the problem. Last summer when the high pressure switch went out, the pump shut = off before the gear was all the way up. Higher than normal air noise = was the first clue. A quick look at the pressure gauges revealed the = high side at only 800 psi. The momentary switch pulled the gear the = rest of the way up. Examination of the pressure switch uncovered = intermittent electrical contact within the switch when pressurized.=20 Chris Zavatson N91CZ 360std www.N91CZ.net From: Wolfgang To: lml@lancaironline.net=20 Sent: Monday, February 20, 2012 4:58 AM Subject: [LML] Re: 320/360 Hydraulic Pressure Switch Yes, that would be easy . . . except . . . you can only override one = pressure switch at a time or overload the system.You need one switch = each for the up and down. In the event of a problem you have to make = sure you push the right switch.If you come up with some more complicated = wiring, you could make it work with only one switch for both up and down = but you still have to push the button if something isn't working as = required.. . . or . . . you could put in a completely automatic system . = . .Wolfgang----- Original Message ----- From: "Greenbacks, UnLtd." = To: Sent: Friday, February 17, = 2012 1:07 PMSubject: Re:320/360 Hydraulic Pressure SwitchSeems to me the = simplest and least expensive option would be to install a momentary on = switch in the cockpit to override and close the open pressure = switches.Just my 2 cents.Angier AmesN3ZQ --For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html TODAY(Beta) =E2=80=A2 Powered by Yahoo!=20 Obama re-election swag is big business The 2012 campaign is boosting its coffers with an online store = filled with Joe mugs and first lady pins. Privacy Policy=20 ------=_NextPart_000_002B_01CCF323.8EDEE900 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Chris,
I don't believe I missed anything, just = focusing on=20 the more likely problem. The items you cited are more a one-of condition = but the=20 thermal soaking causing gear failure is more frequent.
 
With that in mind, I would be inclined = to come up=20 with a simple test scenario to validate one's pump without having to = remove it=20 from the aircraft. It does sound from your comments on the springs that = my=20 original suspicion of the spool coming off it's end point (with the help = of=20 springs and airframe vibration) is in fact what's causing the problem. = The=20 module I came up with powers up the pump when necessary and forces the = spool=20 back into position in spite of the springs.
 
Wolfgang
 
----- Original Message -----
From:=20 Chris=20 Zavatson
Sent: Friday, February 24, 2012 = 4:36=20 PM
Subject: Re: [LML] Re: 320/360 = Hydraulic=20 Pressure Switch

Wolfgang,
I = think you=20 missed the point of my last post.  I was describing the benefits = of=20 having momentary switches Angier = suggested to=20 jumper across the pressure switches.  The three examples cited = are not in=20 any way related to hydraulic lock-up nor are they addressed by your=20 module.  Designing another circuit to detect, identify and=20 properly respond to component failures is a tad complex. =  The=20 pressure switch failure I described is a perfect example.  In = those=20 situations, having more information along with more options available = to the=20 pilot is a good thing?
 
Regarding the pumps = Lancair=20 currently sells, both Oildyne and Lancair have already acknowledged = that the=20 pump currently sold can lock up when used in a stock 320/360.  = The reason=20 for not offering the proper pump configuration for the 320/360 is purely = financial=20 - very low volume.  Lancair did suggest that they could = include a=20 warning regarding the lock up potential each time they ship a pump as = a=20 replacement for a 320/360.  This leaves the aircraft owner in an = awkward=20 position.  The ironic thing is that a = properly=20 configured pump can be obtained directly from a Parker distributor for = much=20 less.
My concern with = misconfigured=20 pumps trickling out into the fleet is that it will eventually catch = pilots=20 unaware of the technical issues off-guard.
Chris Zavatson
N91CZ
360std

From: Wolfgang <Wolfgang@MiCom.net>
To: lml@lancaironline.net =
Sent: Wednesday, February 22, = 2012 9:36=20 AM
Subject: [LML] = Re: 320/360=20 Hydraulic Pressure Switch
We can keep this up for the next year = but I=20 believe talking it to death will not fix the problem. My preference is = to have=20 a system that takes care of itself. You seem to want to be "involved" = in the=20 anomalies of flight. If most people wanted to be "involved", we = wouldn't have=20 things like FADEC's and auto pilots. The module I provide can help = keep flight=20 a bit more self sufficient and safer. If you could convince Oildyne = and=20 Lancair that they have a problem with the pumps as used in Lancairs, = and fix=20 the problem, then more power to you and the Lancair owners. But in the = mean=20 time. I still like my gear module.
 
Wolfgang
 
----- Original Message -----
Sent: Tuesday, February 21, = 2012 9:01=20 AM
Subject: Re: [LML] Re: = 320/360=20 Hydraulic Pressure Switch

" . . . you can only override one pressure switch at a = time or=20 overload the system.
You need one switch each for the up and = down. In the=20 event of a problem you have to make sure you push the right=20 switch"...
 
Overload what exactly?  The gear selector determines = which=20 pressure switch is powered.  If you jumper across an unpowered switch, nothing = happens. =20
While I do not advocate putting in switches to mask = a pump=20 problem that should really be investigated and fixed at the = source,=20 momentary switches have other benefits. 
 
1.  Checking the relief valve settings in the = pump.  By=20 holding down the switch, one can see the relief valve setting of the = pump.
2.  Back-up for a failed pressure switch.  = This was=20 more common with the VEP switches, but current version is not immune. 
3.  Recharging the system on demand - The hysteresis = loop on=20 the pressure switches is quite large.  The gear can start to = sag before=20 the pressure = switch=20 recharges the system.  This is more of an issue for = the=20 Outback Gear due to the higher aerodynamic loads pulling on the=20 gear. 
 
With automation and complexity come new failure=20 modes.  Give the pilot enough information about the state = of the=20 aircraft systems to figure out what happened and enough controls to = solve=20 the problem.
Last summer when the high pressure switch went out, = the pump=20 shut off before the gear was all the way up.  Higher than = normal air=20 noise was the first clue.  A quick look at the pressure gauges = revealed=20 the high side at only 800 psi.   The momentary switch = pulled the=20 gear the rest of the way up.   Examination of = the=20 pressure switch uncovered intermittent electrical contact = within the=20 switch when pressurized. 
 
Chris Zavatson
N91CZ
360std
 
 
From: Wolfgang <Wolfgang@MiCom.net>
To: lml@lancaironline.net=20
Sent: Monday, = February 20,=20 2012 4:58 AM
Subject: [LML]=20 Re: 320/360 Hydraulic Pressure Switch
Yes, that = would=20 be easy . . . except . . . you can only override one pressure switch = at a=20 time or overload the system.You need one switch each for the up = and=20 down. In the event of a problem you have to make sure you push the = right=20 switch.If you come up with some more complicated wiring, you = could make=20 it work with only one switch for both up and down but you still have = to push=20 the button if something isn't working as required.. . . or . . = . you=20 could put in a completely automatic system . .=20 .Wolfgang----- Original Message ----- From: = "Greenbacks,=20 UnLtd." <N4ZQ@VERIZON.NET>To: = <lml@lancaironline.net>= ;Sent:=20 Friday, February 17, 2012 1:07 PMSubject: Re:320/360 Hydraulic = Pressure=20 SwitchSeems to me the simplest and least expensive = option=20 would be to install a momentary on switch in the cockpit to override = and=20 close the open pressure switches.Just my 2 = cents.Angier=20 AmesN3ZQ --For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html<= /A>