X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 31 Jan 2013 12:02:37 -0500 Message-ID: X-Original-Return-Path: Received: from imr-ma06.mx.aol.com ([64.12.78.142] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTP id 6038877 for lml@lancaironline.net; Thu, 31 Jan 2013 11:59:38 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.78.142; envelope-from=ROGG@aol.com Received: from mtaomg-db03.r1000.mx.aol.com (mtaomg-db03.r1000.mx.aol.com [172.29.51.201]) by imr-ma06.mx.aol.com (Outbound Mail Relay) with ESMTP id 144F91C000452 for ; Thu, 31 Jan 2013 11:59:04 -0500 (EST) Received: from core-doc002c.r1000.mail.aol.com (core-doc002.r1000.mail.aol.com [172.29.160.197]) by mtaomg-db03.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 79E10E000082 for ; Thu, 31 Jan 2013 11:59:03 -0500 (EST) From: ROGG@aol.com Full-name: ROGG X-Original-Message-ID: <5087.76634cc.3e3bfcd7@aol.com> X-Original-Date: Thu, 31 Jan 2013 11:59:03 -0500 (EST) Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_5087.76634cc.3e3bfcd7_boundary" X-Mailer: AOL 9.7 sub 55 X-Originating-IP: [69.106.49.33] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:481933216:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d33c9510aa2d73898 --part1_5087.76634cc.3e3bfcd7_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en the TCW asw-1 is an airspeed switch =20 =20 In a message dated 1/30/2013 10:45:44 P.M. Pacific Standard Time, =20 browncc1@verizon.net writes: Just went through that problem on my Legacy; VEP switch prevented =20 retraction; checked out perfectly on the ground, regularly malfunctioned if= flight.=20 I polled the LML and got several great inputs; selected the TCW ASW-1,=20 available for $45 from Aircraft Spruce (vs $380 quote from Lancair for the= =20 VEP). It's much smaller, lighter, easy to calibrate, and so far, is worki= ng=20 perfectly. On Jan 30, 2013, at 11:30 AM, Gary Edwards wrote: =20 Rob, =20 Most likely the original VEP switches will be internally corroided and not= =20 usuable if they have never been put into service. I went thru that=20 situation years ago (1990's) during the extended build time. It cost a fo= rtune=20 to have the VEP company even just test them them, more than a new set from= =20 Lancair would cost for the new style. And the new style is install and fl= y,=20 whereas the VEP's require adjustments during new flight hours, a big=20 inconvenience. =20 Gary Edwards LNC2=20 =20 From: _Chris Zavatson_ (mailto:chris_zavatson@yahoo.com) =20 To: _lml@lancaironline.net_ (mailto:lml@lancaironline.net) =20 Sent: Wednesday, January 30, 2013 5:28 AM Subject: [LML] Re: Thermal influence on Hydraulic Pressure Rob, Lancair carries a new type that is much more reliable. I forget the brand= =20 name. =20 Chris Zavatson N91CZ 360std 1,400 hrs _http://www.n91cz.net/_ (http://www.n91cz.net/)=20 =20 =20 From: Stevens Family <_stevens5@swiftdsl.com.au_=20 (mailto:stevens5@swiftdsl.com.au) > To: _lml@lancaironline.net_ (mailto:lml@lancaironline.net) =20 Sent: Tuesday, January 29, 2013 6:40 PM Subject: [LML] Re: Thermal influence on Hydraulic Pressure =20 =20 =20 Chris, =20 I am interested in your comment about the =E2=80=9COld VEP pressure switch= es=E2=80=9D.=20 The 360 kit I am building comes with those pressure switches. What do you= =20 recommend we should use in place of them? =20 Thanks again. =20 Rob Stevens Perth, Western Australia. =20 =20 =20 =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of =20 Chris Zavatson Sent: Tuesday, 29 January 2013 11:56 PM To: _lml@lancaironline.net_ (mailto:lml@lancaironline.net)=20 Subject: [LML] Re: Thermal influence on Hydraulic Pressure =20 =20 =20 Scott, =20 Yep, the failure modes are completely unrelated to each other. =20 There is a second failure-to-retract mode. In fact, it is the only one I= =20 experienced in my plane. It was with the old VEP pressure switches. They= =20 would stick open on occassion. Then the problem is not too much pressure,= =20 it is not having any.=20 =20 Failure to retract can be a bit more serious if in IMC or taking off at=20 high density altitude. =20 =20 The failure to extend can be fixed by simply raising the operating=20 pressure of the low side circuit. =20 I have looked at pumps spanning the 95 to 2011 manufacturing time frame. = =20 The only one that would lock up on the ground had spool return springs. = =20 Since the 70g rattle-your-spool controversy appeared, I have also been=20 measuring the spool resistance in every pump I get my hands on. -haven't = found =20 an outliers yet, but I will keep looking. =20 =20 Chris Zavatson =20 N91CZ =20 360std 1,400hrs =20 _http://www.n91cz.net/_ (http://www.n91cz.net/)=20 =20 =20 =20 =20 From: "_Sky2high@aol.com_ (mailto:Sky2high@aol.com) " <_Sky2high@aol.com_= =20 (mailto:Sky2high@aol.com) > To: _lml@lancaironline.net_ (mailto:lml@lancaironline.net) =20 Sent: Tuesday, January 29, 2013 5:27 AM Subject: [LML] Re: Thermal influence on Hydraulic Pressure =20 =20 =20 =20 Chris, =20 =20 While waiting for Wolfgang's answer, some 200/300 series pilots are=20 becoming concerned that they can't get the gear down when needed. First, = Lorn's =20 secondary problem is that he didn't look for the "gear down and locked" =20 lights before landing. While the gear down pressure switch saw enough=20 pressure to not allow the pump to start, the failure to recognize that the= gear=20 was not down contributed to the belly in landing. =20 =20 To allow people to be more comfortable about the hydro-electric system=20 they should be reminded of this =20 =20 1. The failure to RETRACT the gear because of high pressure on both sides = =20 is a problem because of the safe design. Opening the dump valve doesn't= =20 resolve the problem because the system is in a static state with the gear= =20 down and locked. There are no physical forces able to change the system= =20 condition - no G-maneuvers, no slips or skids, nada. =20 =20 2. The failure to EXTEND the gear because of high pressure on both sides= =20 is different. Opening the dump valve (allowing down side fluid to flow to= =20 the upside) will allow the gear to "emergency" extend because of gravity on= =20 the mains and the nose gear gas spring. OK, maybe the nose gear might not= =20 extend all the way at 120 KIAS (max gear extension speed), but the =20 pressure lock has been broken and the pump will start if the switch is down= and=20 the pump breaker is closed. Close the dump valve to complete the process.= =20 As a matter of fact, assuming everything is normal and the gear down switc= h=20 is selected but nothing happens, it may merely require momentarily crackin= g=20 the dump valve to relieve the hydraulic constipation. =20 =20 Failing to retract is a nuisance. Failing to extend is, uh, more serious,= =20 but resolvable.=20 =20 =20 Scott Krueger AKA Grayhawk =20 =20 =20 In a message dated 1/29/2013 6:54:27 A.M. Central Standard Time,=20 _chris_zavatson@yahoo.com_ (mailto:chris_zavatson@yahoo.com) writes: =20 =20 =20 =20 =20 Wolfgang, =20 I seem to recall you dismissed the idea of a three-way valve previously.= =20 =20 <> =20 =20 <<..........Automatic action by my module can prevent these problems for= =20 both up and down gear operation. =20 Wolfgang>> =20 =20 Could you please explain how your module will prevent the gear extension= =20 lock-up failures. Recall Lorn's photo after his extension failure and gea= r =20 up landing. Both pressure gauges showed around 500 psi. The system is=20 hydraulically locked with one switch open and one closed. =20 =20 Chris Zavatson =20 N91CZ =20 360std, 1,400 hrs =20 _http://www.n91cz.net/_ (http://www.n91cz.net/)=20 =20 =20 =20 =20 From: Wolfgang <_Wolfgang@MiCom.net_ (mailto:Wolfgang@MiCom.net) > To: _lml@lancaironline.net_ (mailto:lml@lancaironline.net) =20 Sent: Saturday, January 26, 2013 11:24 AM Subject: [LML] Re: Thermal influence on Hydraulic Pressure =20 =20 =20 =20 This has been covered at great length before. Some take the position that= =20 "real pilots" don't need anything but the dump valve. =20 I have proposed two answers, =20 1) replace the dump valve that only opens a port between the HI and LO=20 sides with a dump valve that dumps back to the pump reservoir. =20 2) install a small electric module I make across the pressure switches =20 that runs the pump to relieve the over pressure in the "wrong" line=20 automatically. =20 =20 Wolfgang =20 ----- Original Message -----=20 =20 From: _Charles Brown_ (mailto:browncc1@verizon.net) =20 =20 To: _lml@lancaironline.net_ (mailto:lml@lancaironline.net) =20 =20 Sent: Saturday, January 26, 2013 2:07 AM =20 Subject: Re: [LML] Re: Thermal influence on Hydraulic Pressure =20 =20 This has happened to me even at the beginning of a flight, if the temps in= =20 the hangar have gone from cold on a previous day, to warm on flight day. = =20 I guess cold temps shrink the fluid and suck more from the reservoir into= =20 the lines, and when it warms, the pressure builds on both sides of the=20 system, so that the "up" and "down" pressure switches are both open and th= e gear=20 won't move until I pop the bleed valve. =20 =20 Nasty when the gear won't retract just after blasting off into a low=20 overcast. =20 =20 Charley Brown =20 Legacy #299 200 hr =20 =20 =20 On Jan 25, 2013, at 7:23 AM, randy snarr wrote: =20 =20 =20 =20 . I dont like having to open the dump valve but it is necessary once in a= =20 while especially when it is cold. The pressures on both sides of the syste= m=20 climb due to the engine heat and the gear sometimes will not move without= =20 dumping the pressure. =20 =20 -- For archives and unsub=20 _http://mail.lancaironline.net:81/lists/lml/List.html_ (http://mail.lancair= online.net:81/lists/lml/List.html)=20 =20 =20 -- For archives and unsub=20 _http://mail.lancaironline.net:81/lists/lml/List.html_ (http://mail.lancair= online.net:81/lists/lml/List.html)=20 =3D --part1_5087.76634cc.3e3bfcd7_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
the TCW asw-1 is an airspeed switch
 
In a message dated 1/30/2013 10:45:44 P.M. Pacific Standard Time,=20 browncc1@verizon.net writes:
=
Just went through that problem on my Legacy; VEP switch prevented=20 retraction; checked out perfectly on the ground, regularly malfunctioned = if=20 flight.  I polled the LML and got several great inputs; selected the= TCW=20 ASW-1, available for $45 from Aircraft Spruce (vs $380 quote from Lancair= for=20 the VEP).  It's much smaller, lighter, easy to calibrate, and so far= , is=20 working perfectly.


On Jan 30, 2013, at 11:30 AM, Gary Edwards wrote:
Rob,
 
Most likely the original VEP switches will be internally corroided a= nd=20 not usuable if they have never been put into service.  I went t= hru=20 that situation years ago (1990's) during the extended build time.  I= t=20 cost a fortune to have the VEP company even just test them them, more tha= n a=20 new set from Lancair would cost for the new style.  And the new styl= e is=20 install and fly, whereas the VEP's require adjustments during new flight= =20 hours, a big inconvenience.
 
Gary Edwards
LNC2 
 
From: Chris Zavatson
To: lml@lancaironline.net
Sent: Wednesday, January 30, 201= 3 5:28=20 AM
Subject: [LML] Re: Thermal influ= ence on=20 Hydraulic Pressure

Rob,
Lancair carries a new type that is much more reliable.&= nbsp;=20 I forget the brand name.
 
Chris Zavatson
N91CZ
360std 1,400 hrs

 
From: Stevens Family <stevens5@swiftdsl.com.au&g= t;
To: lml@lancaironline.net
= Sent: Tuesday, January 29, 2013 = 6:40=20 PM
Subject: [LML] Re= :=20 Thermal influence on Hydraulic Pressure

Chris,
 
I=20 am interested in your comment about the =E2=80=9COld VEP pressure switc= hes=E2=80=9D. The 360=20 kit I am building comes with those pressure switches. What do you recom= mend=20 we should use in place of them?
 
Thanks=20 again.
 
Rob=20 Stevens
Perth,
Western=20 Australia.
 
 
From:=20 Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of=20 Chris Zavatson
Sent: Tuesday, 29 January 2013 11:56=20 PM
To: lml@lancaironline.net
S= ubject:=20 [LML] Re: Thermal influence on Hydraulic Pressure
 
Scott,
Yep, the fai= lure=20 modes are completely unrelated to each other.
There is a s= econd=20 failure-to-retract mode.  In fact, it is the only one I experience= d in=20 my plane.  It was with the old VEP pressure switches.  They w= ould=20 stick open on occassion.  Then the problem is not too much pressur= e, it=20 is not having any. 
Failure to r= etract=20 can be a bit more serious if in IMC or taking off at high density=20 altitude.
 = ;
The failure = to=20 extend can be fixed by simply raising the operating pressure of the low= side=20 circuit.
I have looke= d at=20 pumps spanning the 95 to 2011 manufacturing time frame.  The only = one=20 that would lock up on the ground had spool return springs.  Since = the=20 70g rattle-your-spool controversy appeared, I have also been measuring = the=20 spool resistance in every pump I get my hands on.  -haven't f= ound=20 an outliers yet, but I will keep looking.
 = ;
Chris=20 Zavatson
N91CZ=
360std=20 1,400hrs
http://www.n91cz.net/
 = ;
From:=20 "Sky2high@aol.com" <Sky2high@aol.com>
To:<= /B> lml@lancaironline.net=20
Sent: Tuesday, January 29, 2013 5:27 AM
Subject: [= LML]=20 Re: Thermal influence on Hydraulic Pressure
 
Chris,
 
While=20 waiting for Wolfgang's answer, some 200/300 series pilots are becoming= =20 concerned that they can't get the gear down when needed.  First, L= orn's=20 secondary problem is that he didn't look for the "gear down and locked"= =20 lights before landing.  While the gear down pressure switch s= aw=20 enough pressure to not allow the pump to start, the failure to=20 recognize that the gear was not down contributed to the belly in=20 landing.
 
To=20 allow people to be more comfortable about the hydro-electric system the= y=20 should be reminded of this
 
1.=20 The failure to RETRACT the gear because of high pressure on both s= ides=20 is a problem because of the safe design.  Opening the dump va= lve=20 doesn't resolve the problem because the system is in a static stat= e=20 with the gear down and locked.  There are no physical forces = able=20 to change the system condition - no G-maneuvers, no slips or skids,=20 nada.
 
2.=20 The failure to EXTEND the gear because of high pressure on both sides i= s=20 different.  Opening the dump valve (allowing down side fluid to fl= ow to=20 the upside) will allow the gear to "emergency" extend because of gravit= y on=20 the mains and the nose gear gas spring.  OK, maybe the nose g= ear=20 might not extend all the way at 120 KIAS (max gear extension speed), bu= t the=20 pressure lock has been broken and the pump will start if the switch is = down=20 and the pump breaker is closed.  Close the dump valve to complete = the=20 process.  As a matter of fact, assuming everything is normal and t= he=20 gear down switch is selected but nothing happens, it may merely require= =20 momentarily cracking the dump valve to relieve the hydraulic=20 constipation.
 
Failing=20 to retract is a nuisance.  Failing to extend is, uh, more serious,= but=20 resolvable.
 
Scott=20 Krueger AKA Grayhawk
 
In=20 a message dated 1/29/2013 6:54:27 A.M. Central Standard Time, chris_zavatson@yahoo.com=20 writes:
Wolfgang,<= /SPAN>
I seem to = recall=20 you dismissed the idea of a three-way valve previously.
<<That's a sound and positive fix.
- - However it requires changing the dump valv= e,=20 running a return line and pump modification (replace the=20 reservoir).
...................................
Wolfgang>>
<<..........Automatic = action by=20 my module can prevent these problems for both up and down gear=20 operation.
Wolfgang>>
&nb= sp;
Could you = please=20 explain how your module will prevent the gear extension lock-up=20 failures.  Recall Lorn's photo after his extension failure and g= ear=20 up landing.  Both pressure gauges showed around 500 psi.  T= he=20 system is hydraulically locked with one switch open and one=20 closed.
 
Chris Zavatson
N91CZ
360std, 1,400 hrs
&nb= sp;
From:=20 Wolfgang <Wolfgang@MiCom.net>
<= B>To:=20 lml@lancaironline.net=20
Sent: Saturday, January 26, 2013 11:24 AM
Subject:=20 [LML] Re: Thermal influence on Hydraulic Pressure
 
This=20 has been covered at great length before. Some take the position that = "real=20 pilots" don't need anything but the dump valve.
I=20 have proposed two answers,
1)=20 replace the dump valve that only opens a port between the HI and LO s= ides=20 with a dump valve that dumps back to the pump reservoir.
2)=20 install a small electric module I make across the pressure switches= =20 that runs the pump to relieve the over pressure in the "wro= ng"=20 line automatically.
<= /DIV>
 
Wolfgang
-----=20 Original Message -----
From:=20 Charles=20 Brown
<= SPAN=20 style=3D"FONT-FAMILY: 'Arial', 'sans-serif'; COLOR: black; FONT-SIZ= E: 10pt">To:=20 lml@lancaironline.net= =20
<= SPAN=20 style=3D"FONT-FAMILY: 'Arial', 'sans-serif'; COLOR: black; FONT-SIZ= E: 10pt">Sent:=20 Saturday, January 26, 2013 2:07 AM
<= SPAN=20 style=3D"FONT-FAMILY: 'Arial', 'sans-serif'; COLOR: black; FONT-SIZ= E: 10pt">Subject:=20 Re: [LML] Re: Thermal influence on Hydraulic Pressure
<= /DIV>
 
This has happened to me even at the beginnin= g of a=20 flight, if the temps in the hangar have gone from cold on a previou= s=20 day, to warm on flight day.  I guess cold temps shrink the flu= id=20 and suck more from the reservoir into the lines, and when it warms,= the=20 pressure builds on both sides of the system, so that the "up" and "= down"=20 pressure switches are both open and the gear won't move until I pop= the=20 bleed valve.
 
Nasty when the gear won't retract just after= =20 blasting off into a low overcast.
 
Charley Brown
Legacy #299  200 hr
 
On Jan 25, 2013, at 7:23 AM, randy snarr=20 wrote:
 
. I= dont=20 like having to open the dump valve but it is necessary once in a wh= ile=20 especially when it is cold. The pressures on both sides of the syst= em=20 climb due to the engine heat and the gear sometimes will not move= =20 without dumping the pressure.
 
 


--
For=20 archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html<= /A>
 
 =20


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