REFLECTOR:RG Pressure Switches
Al Gietzen
reflector@tvbf.org
Thu, 8 Apr 2004 09:56:20 -0700
This is a multi-part message in MIME format.
------=_NextPart_000_0001_01C41D4F.BE494030
Content-Type: text/plain;
charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Subject: REFLECTOR:RG Pressure Switches
=20
While we are talking about pressure switches, is anyone having problems =
with
the up pressure switch chattering - i.e., pump cutting on and off =
repeatedly
as the gear is being retracted. Duane says just increase the setting =
until
it quits. I have adjusted my high side/up pressure switch several times =
but
the problem persists. I guess I need to put the gauge back on it and =
see
just how high the setting is now.
=20
Ronnie Brown
173 Elite RG
=20
What I learned years ago while working on the retract system and =
measuring
pressures; is that the adjustment screw does not adjust the nominal =
pressure
point of the switch. That number is given on the label. It does adjust =
the
'bandwidth'; i.e., the difference in the pressure where the switch =
closes
and where it opens.
=20
I don't recall now (I've written about this before, so maybe it's in the
archives) but I think turning counterclockwise CCW narrows the =
bandwidth,
clockwise CW increases. Ronnie - you may find that increasing the =
bandwidth
(turning the screw on the high pressure switch CW) will alleviate the
problem. I believe also that the likelihood of the pump not running in =
the
'down' direction ("hanging up") due to pressure balance, is reduced by
narrowing the bandwidth (CCW adjustment) on the low pressure switch.
Warning - I may not have this all correct from memory, but with a little
experimentation, you can verify. =20
=20
I also think it has been determined that the "hanging up" is more likely =
the
result of temperature differential expansion than bleeding past the
cylinders. The fluid is incompressible, and it doesn't take much =
expansion
is the lines to change the pressure significantly. I guess this doesn't
help much, except maybe to be aware that if you put the gear up when =
things
were pretty cool, there may be a greater likelihood they won't go down =
if
the temp is then 20-30 degrees higher.
=20
FWIW,
Al
=20
=20
----- Original Message -----
From: "Jack Sheehan" <j.f.sheehan@larc.nasa.gov>
To: <reflector@tvbf.org>
Sent: Thursday, April 08, 2004 10:46 AM
Subject: Re: REFLECTOR:Follow up on my bad landing
=20
=20
| Could you explain what you mean by "Hung Up"? I have experienced the
| problem of placing the gear switch in the down position and nothing
| happening. The problem can be resolved by pushing the reset button.
| Do not push the reset button with the switch in the up position. I
| discussed the problem with Scott Swing and the explanation about the
| high and low pressure seems correct the system can bleed pressure to
| the other side. therefore when you place the switch in the down
| position the pressure switch already thinks the gear is in the down
| position. The pressure switches have adjustment screws on the top. I
| adjusted the pressure by about a 1/4 turn of the screw for the down
| switch ( which is the outboard switch or the switch closer to the
| fuselage) It was OK for a while then it did it again so another 1/4
| turn. It has been fine since.
| Having had this problem I can not put the gear switch down without
| wondering if it is going to work therefore I pay particular attention
| to the lights
| Sorry for your mishap and hope you get back flying soon
|
| Jack
| N55XL
| _______________________________________________
| To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
|
| Visit the gallery! www.tvbf.org/gallery
| user:pw =3D tvbf:jamaicangoose
| Check new archives: www.tvbf.org/pipermail
| Check old archives: =
http://www.tvbf.org/archives/velocity/maillist.html
=20
=20
_______________________________________________
To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
=20
Visit the gallery! www.tvbf.org/gallery
user:pw =3D tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
------=_NextPart_000_0001_01C41D4F.BE494030
Content-Type: text/html;
charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
<html>
<head>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Dus-ascii">
<meta name=3DGenerator content=3D"Microsoft Word 10 (filtered)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Nimrod;
panose-1:2 4 5 3 5 4 1 2 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:Nimrod;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 62.3pt 1.0in 62.3pt;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=3DEN-US link=3Dblue vlink=3Dpurple>
<div class=3DSection1>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Subject:
REFLECTOR:RG Pressure Switches</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>While
we are talking about pressure switches, is anyone having problems =
with</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>the
up pressure switch chattering - i.e., pump cutting on and off =
repeatedly</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>as
the gear is being retracted. Duane says just increase the setting =
until</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>it
quits. I have adjusted my high side/up pressure switch several =
times but</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>the
problem persists. I guess I need to put the gauge back on it and =
see</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>just
how high the setting is now.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Ronnie
Brown</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>173
Elite RG</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>What I =
learned years
ago while working on the retract system and measuring pressures; is that =
the
adjustment screw does not adjust the nominal pressure point of the
switch. That number is given on the label. It does adjust =
the ‘bandwidth’;
i.e., the difference in the pressure where the switch closes and where =
it
opens.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'> </span><=
/font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>I don’t =
recall
now (I’ve written about this before, so maybe it’s in the =
archives)
but I think turning counterclockwise CCW narrows the bandwidth, =
clockwise CW increases.
Ronnie – you may find that increasing the bandwidth (turning =
the
screw on the high pressure switch CW) will alleviate the problem. =
I
believe also that the likelihood of the pump not running in the =
‘down’
direction (“hanging up”) due to pressure balance, is reduced =
by narrowing
the bandwidth (CCW adjustment) on the low pressure switch. Warning =
–
I may not have this all correct from memory, but with a little =
experimentation,
you can verify. </span></font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'> </span><=
/font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>I also think =
it has
been determined that the “hanging up” is more likely the =
result of
temperature differential expansion than bleeding past the =
cylinders. The
fluid is incompressible, and it doesn’t take much expansion is the =
lines
to change the pressure significantly. I guess this doesn’t =
help
much, except maybe to be aware that if you put the gear up when things =
were pretty
cool, there may be a greater likelihood they won’t go down if the =
temp is
then 20-30 degrees higher.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'> </span><=
/font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>FWIW,</span></=
font></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack =
face=3DVerdana><span
style=3D'font-size:11.0pt;font-family:Verdana;color:black'>Al</span></fon=
t></p>
<p class=3DMsoPlainText><font size=3D2 color=3Dblack face=3DNimrod><span
style=3D'font-size:11.0pt;color:black'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>-----
Original Message -----</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>From:
"Jack Sheehan" =
<j.f.sheehan@larc.nasa.gov></span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>To:
<reflector@tvbf.org></span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Sent:
</span></font>Thursday, April 08, 2004 10:46 AM</p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Subject:
Re: REFLECTOR:Follow up on my bad landing</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Could you explain what you mean by "Hung Up"? I have =
experienced the</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
problem of placing the gear switch in the down position and =
nothing</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
happening. The problem can be resolved by pushing the reset =
button.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Do not push the reset button with the switch in the up position. =
I</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
discussed the problem with Scott Swing and the explanation about =
the</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
high and low pressure seems correct the system can bleed pressure =
to</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
the other side. therefore when you place the switch in the =
down</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
position the pressure switch already thinks the gear is in the =
down</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
position. The pressure switches have adjustment screws on the top. =
I</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
adjusted the pressure by about a 1/4 turn of the screw for the =
down</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
switch ( which is the outboard switch or the switch closer to =
the</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
fuselage) It was OK for a while then it did it again so another =
1/4</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
turn. It has been fine since.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Having had this problem I can not put the gear switch down =
without</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
wondering if it is going to work therefore I pay particular =
attention</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
to the lights</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Sorry for your mishap and hope you get back flying =
soon</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Jack</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
N55XL</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
_______________________________________________</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
To change your email address, visit</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>http://www.tvbf.org/mailman/listinfo/reflector=
</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Visit the gallery! www.tvbf.org/gallery</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
user:pw =3D tvbf:jamaicangoose</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Check new archives: www.tvbf.org/pipermail</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>|
Check old archives: =
http://www.tvbf.org/archives/velocity/maillist.html</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>______________________________________________=
_</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>To
change your email address, visit =
http://www.tvbf.org/mailman/listinfo/reflector</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Visit
the gallery! www.tvbf.org/gallery</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>user:pw
=3D tvbf:jamaicangoose</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Check
new archives: www.tvbf.org/pipermail</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Check
old archives: =
http://www.tvbf.org/archives/velocity/maillist.html</span></font></p>
</div>
</body>
</html>
------=_NextPart_000_0001_01C41D4F.BE494030--