X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 04 Oct 2009 05:07:08 -0400 Message-ID: X-Original-Return-Path: Received: from imr-da04.mx.aol.com ([205.188.105.146] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3873684 for lml@lancaironline.net; Sun, 04 Oct 2009 01:03:41 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.146; envelope-from=Sky2high@aol.com Received: from imo-da02.mx.aol.com (imo-da02.mx.aol.com [205.188.169.200]) by imr-da04.mx.aol.com (8.14.1/8.14.1) with ESMTP id n94530OD024634 for ; Sun, 4 Oct 2009 01:03:00 -0400 Received: from Sky2high@aol.com by imo-da02.mx.aol.com (mail_out_v42.5.) id q.c6c.5808a538 (29672) for ; Sun, 4 Oct 2009 01:02:54 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Sun, 4 Oct 2009 01:03:50 EDT Subject: Re: [LML] Lancair 320/360 hydraulic system questions and fixes X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1254632629" X-Mailer: AOL 9.1 sub 5006 X-Spam-Flag:NO X-AOL-SENDER: Sky2high@aol.com -------------------------------1254632629 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Another analysis/solution using Occam's Razor: Both pressure switches have somehow sensed a high enough pressure condition where their switch contacts conducting electricity to the selected up or down function relay remain in the open position and the pump will not start to operate. Down - as long as the hi pressure conditions are static, nothing will happen. Cracking the dump valve will clear the problem because spring forces (nose, gear doors) and gravity will destabilize the system pressures and the pump will start. Then close the dump valve and continue on as though nothing went awry. Uh, still check for three green. Up - The system pressures are static because the gear is locked into position not allowing any fluid to pass from one side to the other or return to the reservoir. Deaf pilots notice this condition because the pump indicator doesn't come on and climb performance doesn't improve. Cracking the dump valve has no effect. Any momentary pump operation will resolve the problem by moving the shuttle/poppet valves. One way to accomplish this is to bring a 2 conductor wire, each connected to a side of the Up pressure switch, forward to a momentary push on switch located within the pilot's reach. Depressing this switch will short across the pressure switch contacts and allow the pump power relay to operate as long as the button is held. This should require only a few moments. Excessive system pressure is avoided because each side has a relief valve inside the pump (set approximately 400 psi above the pressure switch for that circuit). My personal preference is biased for such a manual system (KISS) since the underlined "somehow" is not definitive enough for automatic electrical solutions. Scott Krueger AKA Grayhawk PS If such a switch is used, it should be protected from accidental activation and it should not bypass the "squat" switch function. Gear up on the ground is as bad as landing before extension. Be careful out there. In a message dated 10/3/2009 7:37:57 P.M. Central Daylight Time, lorn@dynacomm.us writes: 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_ (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_ (mailto:Wolfgang@MiCom.net) Wolfgang Franke -- Lorn H. 'Feathers' Olsen, MAA, ASMEL, ASES, Comm, Inst DynaComm, Corp., 248-345-0500, _mailto:lorn@dynacomm.us_ (mailto:lorn@dynacomm.us) LNC2, FB90/92, O-320-D1F, 1,635 hrs, N31161, Y47, SE Michigan = -------------------------------1254632629 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Another analysis/solution using Occam's Razor:
 
Both pressure switches have somehow sensed a high enoug= h=20 pressure condition where their switch contacts conducting electricity= to=20 the selected up or down function relay remain in the open position and the= pump=20 will not start to operate. 
 
Down - as long as the hi pressure conditions are static, nothing= will=20 happen.  Cracking the dump valve will clear the problem because sprin= g=20 forces (nose, gear doors) and gravity will destabilize the syste= m=20 pressures and the pump will start.  Then close the dump valve and con= tinue=20 on as though nothing went awry.  Uh, still check for three green.
 
Up - The system pressures are static because the gear is locked= into=20 position not allowing any fluid to pass from one side to the other or= =20 return to the reservoir.  Deaf pilots notice this condition because= the=20 pump indicator doesn't come on and climb performance doesn't improve. = ;=20 Cracking the dump valve has no effect.  Any momentary pump operation= will=20 resolve the problem by moving the shuttle/poppet valves.  One way to= =20 accomplish this is to bring a 2 conductor wire, each connec= ted=20 to a side of the Up pressure switch, forward to a momentary push= on=20 switch located within the pilot's reach. Depressing this=20 switch will short across the pressure switch contacts and= allow=20 the pump power relay to operate as long as the button is held.  This= should=20 require only a few moments.  Excessive system pressure is avoided bec= ause=20 each side has a relief valve inside the pump (set approximately 400 psi ab= ove=20 the pressure switch for that circuit). 
 
My personal preference is biased for such a manual system=20 (KISS) since the underlined "somehow" is not definitive enough for=20 automatic electrical solutions.   
 
Scott Krueger AKA Grayhawk
 
PS If such a switch is used, it should be protected from accidental= =20 activation and it should not bypass the "squat" switch function.  Gea= r up=20 on the ground is as bad as landing before extension.  Be careful out= =20 there.
 
In a message dated 10/3/2009 7:37:57 P.M. Central Daylight Time,=20 lorn@dynacomm.us writes:

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 own= er,=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=20 LO/DN hydraulic pressures being above their respective pressure switch= =20 settings preventing operation of the pump. This happens because hyd= raulic=20 fluid gets trapped in the lines and with a temperature rise, pressures= exceed=20 normal conditions.
 
The pump used is an OilDyne 108 series with the= "LB"=20 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=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 circ= uit.=20 Looking at the pressure port side of the pump housing, the left port is= =20 labeled "U" and had the higher pressure output. The right hand one is la= beled=20 "D" and has the lower pressure output. The back pressure circuit is powe= red by=20 pressure from the "D" port connected to the rod side of the cylinde= rs as=20 shown on 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 hi= gher=20 pressure. For the back pressure valve to operate properly, the spool val= ve=20 needs to be flipped around. This is why there have been reports of the= spool=20 being in backwards.
 
With this corrected, everything works and all is rig= ht with=20 the world.
You can check your own system. You will need pressur= e gages=20 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.=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 the= n 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=20 properly and stays where it was last pressured.
Most of the time things work all right but there con= tinue 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 oth= er=20 while the pump is not running. When this happens, the check valves close= and=20 fluid is trapped in both the HI and LO sides of the system. Temperature= =20 increase, cylinder leakage and dump valve leakage can all caus= e both=20 sides to exceed pressure switch settings. (If there is leakage, the pump= runs=20 and can building pressure in both sides) The thermostatic relief valve= =20 settings in the pump will prevent line pressures from exceeding abo= ut=20 1500 psi.
 
 
So, the fix is to prevent the non-action side pressu= re 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=20 LO side to absorb the temperature induced volume/pressure=20 increase.
 
I initially thought 5 cu.in. units (Parker #=20 AD007B25T9A1) with a precharge of about 100-200 psi would work even thou= gh=20 they 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 an= d=20 303-8 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 .000= 0123 /=20 deg.F (negligible for this purpose)
Modulus of elasticity of hydraulic fluid =3D 25= 0,000=20 (compression under pressure - psi per percent reduction in vol= ume -=20 negligible for this purpose)
 
I calculated that about 8ft of 303-5 with AN4 f= ittings=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 adde= d=20 line =3D 7.9 cu in (ignoring volume of removed line segment)=
Extrapolated volume increase in the added line at 30= 0=20 psi =3D 0.065cc / in
Volume increase =3D 0.065 / 2.54^3 x 96 =3D 0.3= 81 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=20 the LO side and bleed the system.
 
There are other details but these are the=20 basics.
These are initial calculations and have not yet been= =20 tested.
 
- - - I consider this solution really just an engine= ering=20 exercise.
 
CAUTION
If there is a leak in a cylinder or the dump valve,= there=20 will still be a problem that can render the gear inoperative leavin= g=20 only emergency dump valve use.
The action side can leak into the non-acti= on side,=20 the pump will turn on to bring the action side pressure back up, the lea= k 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 15= 00=20 psi, the thermostatic relief valve setting of the pump.
 
2 ) Electric only =3D =3D =3D This will ad= dress=20 actuation failure in either direction. Rewire the system so the pump wil= l run=20 in the direction set by the gear switch even though both pressure switch= es are=20 open (high pressure). This will build up=20 pressure  inside the pump causing the shuttle to move to one side= and=20 open the other side's check valve releasing the undesired=20 pressure.
 
I have designed a circuit board that has 2=20 relays and can be wired into the pressure switches of the existing= =20 system. It will be about 2" x 2" x 1". If I get at least 5 requests, I= will=20 make a batch 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,=20 ASMEL, ASES, Comm, Inst
DynaComm,=20 Corp., 248-345-0500, mailto:lorn@dynacomm.us
LNC2, FB90/92, O-320-D1F= , 1,635=20 hrs, N31161, Y47, SE=20 Michigan

=3D -------------------------------1254632629--