X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 03 Oct 2009 20:36:55 -0400 Message-ID: X-Original-Return-Path: Received: from a2s34.a2hosting.com ([74.126.18.170] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTPS id 3873390 for lml@lancaironline.net; Sat, 03 Oct 2009 15:44:40 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.126.18.170; envelope-from=lorn@dynacomm.us DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=dynacomm.us; h=Received:Subject:From:X-Priority:Message-Id:Date:Content-Type:To:Mime-Version:X-Mailer; b=UV+6+bj88GBzIQVhwZew3ded55OArPelCwyhyf+pPFNRDYsCAkwnNoaQ0vNzvNgSgYaNt4oAYxMcsAUcmfGQwtZZqF1W23ZQ4XeImxtNFM2UaYoJ3PH9yxjeaRX+AuTC; Received: from adsl-76-226-10-87.dsl.sfldmi.sbcglobal.net ([76.226.10.87] helo=[192.168.1.64]) by a2s34.a2hosting.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.69) (envelope-from ) id 1MuAWU-00024J-5n; Sat, 03 Oct 2009 15:44:07 -0400 Subject: Lancair 320/360 hydraulic system questions and fixes From: Lorn H Olsen X-Priority: 3 X-Original-Message-Id: X-Original-Date: Sat, 3 Oct 2009 15:44:02 -0400 Content-Type: multipart/alternative; boundary=Apple-Mail-1--733547618 X-Original-To: Lancair List Mime-Version: 1.0 (Apple Message framework v1074) X-Mailer: Apple Mail (2.1074) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - a2s34.a2hosting.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - dynacomm.us --Apple-Mail-1--733547618 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes Lancair 320/360 hydraulic system questions and fixes There have been instances of gear operation failure in the Lancer 320/360. I have looked into this, spoken with Lorn Olsen-LNC2 owner, Brian Anderson-product manager at OilDyne for the 108 pump, Ross-320/360 specialist at Lancair, Christopher Zavatson-Lancair owner, Randy Stuart-Lancair owner and believe I have the answers. Gear operation failure is usually due to both HI/UP and LO/DN hydraulic pressures being above their respective pressure switch settings preventing operation of the pump. This happens because hydraulic fluid gets trapped in the lines and with a temperature rise, pressures exceed normal conditions. The pump used is an OilDyne 108 series with the "LB" circuit. http://www.parker.com/literature/Literature%20Files/euro_cylinder/v4/108_1301-uk.pdf Earlier models were 108AM/19-CLB3VT-11-08, Lancair # 637715 and later models are 108AMS32-CZZ3V-14-08 Lancair # 642666. The pump has check valves that operate with a 1:5 pressure ratio. The ZZ in the newer pump is still an LB circuit but with a slightly modified back pressure circuit. Looking at the pressure port side of the pump housing, the left port is labeled "U" and had the higher pressure output. The right hand one is labeled "D" and has the lower pressure output. The back pressure circuit is powered by pressure from the "D" port connected to the rod side of the cylinders as shown on page 9 of the product literature link above. This is problem # 1. This is backwards from the way the 320/360 needs it ! The Lancair 320/360 requires "U" pressure on the rod side of the cylinders to raise the gear using the higher pressure. For the back pressure valve to operate properly, the spool valve needs to be flipped around. This is why there have been reports of the spool being in backwards. With this corrected, everything works and all is right with the world. You can check your own system. You will need pressure gages in the HI and LO side to do this. Put the plane up on jacks. Power the gear up. With the dump valve, induce a leak from HI side to LO side. Note the pressure on the LO side stays at zero. Power the gear down. With the dump valve, induce a leak from HI side to LO side. Note the pressure on the HI side rises a bit and then goes back to zero. - - - This is because the pressure has to leak back past the pump gears before it gets to the pressure relief valve. This is expected operation when the spool valve is in properly and stays where it was last pressured. Most of the time things work all right but there continue to be reports of gear actuation failure. Problem #2 is that vibration and pump internal leakage can move the spool valve off it's position of all to one side or the other while the pump is not running. When this happens, the check valves close and fluid is trapped in both the HI and LO sides of the system. Temperature increase, cylinder leakage and dump valve leakage can all cause both sides to exceed pressure switch settings. (If there is leakage, the pump runs and can building pressure in both sides) The thermostatic relief valve settings in the pump will prevent line pressures from exceeding about 1500 psi. So, the fix is to prevent the non-action side pressure from increasing above it's pressure switch setting due to heat soak or leakage and bring it down if it does. This can be accomplished in two ways. 1 ) Hydraulic only = = = Add an accumulator to each HI and LO side to absorb the temperature induced volume/pressure increase. I initially thought 5 cu.in. units (Parker # AD007B25T9A1) with a precharge of about 100-200 psi would work even though they were larger than needed. Upon further examination, I considered a length of flexible (expandable) hose added to the system since that would be much easier to install. I just needed to figure out the required length. After rounding up expansion numbers from AeroQuip on their 303-5 and 303-8 hose and other details; 303-5 ID=1/4" 303-5 hose expansion = 0.094cc / in at 1000 psi 303-5 hose expansion = 0.123cc / in at 2000 psi 303-5 hose expansion = 0.149cc / in at 3000 psi 303-8 ID = 13/32" 303-8 hose expansion = 0.100cc / in at 600 psi 303-8 hose expansion = 0.137cc / in at 1250 psi 303-8 hose expansion = 0.171cc / in at 2000 psi Hydraulic fluid volume in the LNC2 is about 27 cu in ; 6.4 cu in in the lines, ; 20.6 cu in the actuators with door actuators Hydraulic fluid thermal expansion coefficient = .0005 / deg.F Aluminum thermal expansion coefficient = .0000123 / deg.F (negligible for this purpose) Modulus of elasticity of hydraulic fluid = 250,000 (compression under pressure - psi per percent reduction in volume - negligible for this purpose) I calculated that about 8ft of 303-5 with AN4 fittings would provide the desired volume expansion from heat soak. Fluid in the non-action side of the system = 3.2 cu in. 8ft of 303-5 line = 4.71 cu in Fluid in the non-action side of the system with added line = 7.9 cu in (ignoring volume of removed line segment) Extrapolated volume increase in the added line at 300 psi = 0.065cc / in Volume increase = 0.065 / 2.54^3 x 96 = 0.381 cu in Delta T allowance = 0.381 / (7.9 x 0.0005) = 96.5 degF with 300 psi increase Replace an existing piece of line with a 3 loop coil under each seat pan, one plumbed into the HI side and the other plumbed into the LO side and bleed the system. There are other details but these are the basics. These are initial calculations and have not yet been tested. - - - I consider this solution really just an engineering exercise. CAUTION If there is a leak in a cylinder or the dump valve, there will still be a problem that can render the gear inoperative leaving only emergency dump valve use. The action side can leak into the non-action side, the pump will turn on to bring the action side pressure back up, the leak will continue until both sides are above the pressure switch setting. Should heat soak come into play after that, the pressures can continue up to 1500 psi, the thermostatic relief valve setting of the pump. 2 ) Electric only = = = This will address actuation failure in either direction. Rewire the system so the pump will run in the direction set by the gear switch even though both pressure switches are open (high pressure). This will build up pressure inside the pump causing the shuttle to move to one side and open the other side's check valve releasing the undesired pressure. I have designed a circuit board that has 2 relays and can be wired into the pressure switches of the existing system. It will be about 2" x 2" x 1". If I get at least 5 requests, I will make a batch of units for those interested. The electric only solution can overcome the leak problem and is my desired installation. If anyone wants more details or has comments, feel free to email me Wolfgang@MiCom.net Wolfgang Franke -- Lorn H. 'Feathers' Olsen, MAA, ASMEL, ASES, Comm, Inst DynaComm, Corp., 248-345-0500, mailto:lorn@dynacomm.us LNC2, FB90/92, O-320-D1F, 1,635 hrs, N31161, Y47, SE Michigan --Apple-Mail-1--733547618 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii

Lancair 320/360 hydraulic system questions and=20 fixes

There have been instances of gear operation = failure in the=20 Lancer 320/360. I have looked into this, spoken with Lorn Olsen-LNC2 = owner,=20 Brian Anderson-product manager at OilDyne for the 108 pump,=20  Ross-320/360 specialist at Lancair, Christopher Zavatson-Lancair = owner,=20 Randy Stuart-Lancair owner and believe I have the answers.
 
Gear operation failure is usually due to both = HI/UP and LO/DN=20 hydraulic pressures being above their respective pressure switch = settings=20 preventing operation of the pump. This happens because hydraulic = fluid gets=20 trapped in the lines and with a temperature rise, pressures exceed = normal=20 conditions.
 
The pump used is an OilDyne 108 series with = the "LB"=20 circuit. http://www.parker.com/literature/Literature%20Files/eu= ro_cylinder/v4/108_1301-uk.pdf
Earlier models were 108AM/19-CLB3VT-11-08, Lancair = # 637715=20 and later models are 108AMS32-CZZ3V-14-08 Lancair # 642666. The pump has = check=20 valves that operate with a 1:5 pressure ratio. The ZZ in the newer pump = is=20 still an LB circuit but with a slightly modified back pressure = circuit.=20 Looking at the pressure port side of the pump housing, the left port is = labeled=20 "U" and had the higher pressure output. The right hand one is labeled = "D" and=20 has the lower pressure output. The back pressure circuit is powered by = pressure=20 from the "D" port connected to the rod side of the cylinders as = shown on=20 page 9 of the product literature link above.
 
This is problem # 1. This = is backwards=20 from the way the 320/360 needs it ! The Lancair 320/360 requires = "U"=20 pressure on the rod side of the cylinders to raise the gear using the = higher=20 pressure. For the back pressure valve to operate properly, the spool = valve needs=20 to be flipped around. This is why there have been reports of the spool = being in=20 backwards.
 
With this corrected, everything works and all is = right with=20 the world.
You can check your own system. You will need = pressure gages in=20 the HI and LO side to do this.  
 
Put the plane up on jacks.
 
Power the gear up.
With the dump valve, induce a leak from HI side to = LO side.=20
Note the pressure on the LO side stays at = zero.
 
Power the gear down.
With the dump valve, induce a leak from HI side to = LO=20 side.
Note the pressure on the HI side rises a bit and = then goes=20 back to zero.
- - - This is because the pressure has to leak = back past the=20 pump gears before it gets to the pressure relief valve.
 
This is expected operation when the spool valve is = in properly=20 and stays where it was last pressured.
Most of the time things work all right but there = continue to=20 be reports of gear actuation failure.
 
Problem #2 is that vibration and pump = internal leakage=20 can move the spool valve off it's position of all to one side or the = other while=20 the pump is not running. When this happens, the check valves close and = fluid is=20 trapped in both the HI and LO sides of the system. Temperature increase,=20= cylinder leakage and dump valve leakage can all cause both = sides to=20 exceed pressure switch settings. (If there is leakage, the pump runs and = can=20 building pressure in both sides) The thermostatic relief valve = settings in=20 the pump will prevent line pressures from exceeding about 1500 = psi.
 
 
So, the fix is to prevent the non-action side = pressure from=20 increasing above it's pressure switch setting due to heat soak or = leakage=20 and bring it down if it does.
 
This can be accomplished in two ways.
1 ) Hydraulic only =3D =3D =3D Add an accumulator = to each HI and LO=20 side to absorb the temperature induced volume/pressure = increase.
 
I initially thought 5 cu.in. units (Parker #=20= AD007B25T9A1) with a precharge of about 100-200 psi would work even = though they=20 were larger than needed.
 
Upon further examination, I considered a length of = flexible=20 (expandable) hose added to the system since that would be much easier to=20= install. I just needed to figure out the required length.=20 After rounding up expansion numbers from AeroQuip on their 303-5 = and 303-8=20 hose and other details;
 
303-5 ID=3D1/4"
303-5 hose expansion =3D 0.094cc / in at 1000=20= psi
303-5 hose expansion =3D 0.123cc / in at 2000=20= psi
303-5 hose expansion =3D 0.149cc / in at 3000=20= psi
 
303-8 ID =3D 13/32"
303-8 hose expansion =3D 0.100cc / in = at 600=20 psi
303-8 hose expansion =3D 0.137cc / in at 1250=20= psi
303-8 hose expansion =3D 0.171cc / in at 2000=20= psi
 
Hydraulic fluid volume in the LNC2 is about 27 cu=20= in ;  6.4 cu in in the=20 lines, ; 20.6 cu in the actuators with = door=20 actuators
Hydraulic fluid thermal expansion = coefficient =3D .0005 /=20 deg.F
Aluminum thermal expansion coefficient =3D = .0000123 / deg.F=20 (negligible for this purpose)
Modulus of elasticity of hydraulic fluid =3D = 250,000=20 (compression under pressure - psi per percent reduction in = volume -=20 negligible for this purpose)
 
I calculated that about 8ft of 303-5 with = AN4 fittings=20 would provide the desired volume expansion from heat soak.
 
Fluid in the non-action side of the system =3D = 3.2 cu=20 in.
8ft of 303-5 line =3D 4.71 cu in
Fluid in the non-action side of the system with = added=20 line =3D 7.9 cu in (ignoring volume of removed line = segment)
Extrapolated volume increase in the added line at = 300=20 psi =3D 0.065cc / in
Volume increase =3D 0.065 / 2.54^3 x 96 =3D = 0.381 cu=20 in
Delta T allowance =3D 0.381 / (7.9 x 0.0005) =3D = 96.5 degF with=20 300 psi increase
 
Replace an existing piece of line with a 3 = loop coil=20 under each seat pan, one plumbed into the HI side and the other plumbed = into the=20 LO side and bleed the system.
 
There are other details but these are the = basics.
These are initial calculations and have not yet = been=20 tested.
 
- - - I consider this solution really just an = engineering=20 exercise.
 
CAUTION
If there is a leak in a cylinder or the dump = valve, there will=20 still be a problem that can render the gear inoperative leaving=20 only emergency dump valve use.
The action side can leak into the = non-action side,=20 the pump will turn on to bring the action side pressure back up, the = leak will=20 continue until both sides are above the pressure switch setting. Should = heat=20 soak come into play after that, the pressures can continue up to = 1500 psi,=20 the thermostatic relief valve setting of the pump.
 
2 ) Electric only =3D =3D =3D This = will address actuation=20 failure in either direction. Rewire the system so the pump will run in = the=20 direction set by the gear switch even though both pressure switches are = open=20 (high pressure). This will build up = pressure =20 inside the pump causing the shuttle to move to one side and open the = other=20 side's check valve releasing the undesired pressure.
 
I have designed a circuit board that has 2=20 relays and can be wired into the pressure switches of the existing = system.=20 It will be about 2" x 2" x 1". If I get at least 5 requests, I will make = a batch=20 of units for those interested.=20
 
The electric only solution can overcome the=20= leak problem and is my desired installation.
 
If anyone wants more details or has comments, feel = free to=20 email me Wolfgang@MiCom.net
 
Wolfgang Franke
 
Lorn H. = 'Feathers' Olsen, MAA, ASMEL, ASES, Comm, Inst
DynaComm, = Corp., 248-345-0500, mailto:lorn@dynacomm.us
LNC2, FB90/92, O-320-D1F, 1,635 = hrs, N31161, Y47, SE = Michigan

= --Apple-Mail-1--733547618--