Mailing List lml@lancaironline.net Message #38622
From: randy snarr <randylsnarr@yahoo.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Electrical /Hydraulic system questions lancair 235/320
Date: Tue, 21 Nov 2006 01:58:14 -0500
To: <lml>
Scott,
Thanks for the reply. If the ground was bad to the
dimmer system why would the flickering go away when
the alternator is turned off?
I do also have a little alternator whine in the
headset that also goes away when the alternator is
turned off.
That is a good point though. I will take a closer look
to see if other lights not running through the dimmer
are doing the same thing. If so I will look closer at
the regulator. If not I will investigate the dimmer. I
should have already done that.

I am using the suzuki samuri alternator with the
voltage reg removed. I have a seperate Ford style
regulator. The battery is an RG25 by concord.

As for the low side hydraulic pressure, shouldn't that
side be open to the resevoir when the gear is up
keeping that side at 0? I am not entirely sure how the
hyd pump operates as it relates to pressure on the
oppisite side of the system when it is running.
When I originally installed and tested the gear I
could open the dump valve and move a gear leg by hand
up and down with little resistance. Now when I do the
same thing (open the dump valve on the jack stands and
push the gear up by hand) I notice there is some
resistance or building pressure as the gear leg is
pushed up into the wing. I am not sure what has
changed or if this is normal. With the dump valve
open, what would cause the building resistance? I
would think that whatever the position of the gear,
the opposite side should be open to the resevoir at
the pump. Randy..

--- Sky2high@aol.com wrote:

 

Randy,
 
Flickering Lights
 
The voltage regulator is certainly a possibility. How about a loose  connection to your light dimming circuitry or a bad
ground there?   What alternator, regulator and battery are you using?
 
Lo side pressure
 
It is hard to imagine the low side fluid expanding
since there is so little  of it available when everything is sucked up. However, if the stops are,  uh, not rigid, it is conceivable that the up side fluid
pressure  rise could push the piston further, maybe thru fluid expansion in
the nose  wheel well actuators that are heated by lower cowling air
entering the  well during flight.  The ambient temperature rise in the main gear  wells
doesn't seem high enough to have much of an effect except that it isn't  helping
relieve any pressures.  Maybe Chris has more useful  information.  Luckily
your pressures are different enough that the dump  valve relieves the
lo side enough to allow the pump to come on.
 
 
Scott Krueger  AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

A man  has got to know his limitations.

 
In a message dated 11/20/2006 9:16:51 A.M. Central
Standard Time,  randylsnarr@yahoo.com writes:

I  haven't posted in a while as I have been busy
flying
and completing my  interior.
I will post a few pics when I am completed to keep the
grinding, sanding crowd motivated.

Anyway, I was flying recently  near dark and I had
the
panel switch lights on. Can someone tell me why  my
lights flicker with the alternator on? When I turn the  alternator off the flicker goes
away.
Is this just a bad voltage regulater  or something
else?
Ironicly my wifes Lexus suv started doing the  same
thing. Maybe it is her fault!

2nd question. I have experienced  the same issue as
some have documented regarding the gear not  coming
down without recycling the dump valve. I flew on
Friday and  noticed something interesting. Here are the facts:

Depart from  PVU
50 deg f
4500 ft field elev
cruised at 12.5 for 1.2 hrs to a  warmer place
decend to 4000 ft new atmosphere temp near 65 f

I  have gauges on the high and low side of the hyd
system
After take off  they idicated low-0 and high-1300 or
so.
After decending to a warmer  atmospheric conditions
both  the high and low side of the hydraulic  system
had significantly risen. low 400 psi and high  1700
psi.

What happens in my case is the system pressure rises
in  cruise on the high and low side. The lower side
exceeds the high pressure  switch and the gear does
not
come down. I open the dump valve and then  close it
and
the gear acts normally. My question relates the down  side witht he gear up.
It would seem to me that that side should always stay
at 0 relieving pressure back to the resevoir in the
pump.

At  first I thought I may have a leak somewhere
allowing the pressure to sneak  past the high side
to
the low side in cruise. I do not believe that  is
happening to me as both the high and low sides rise.


Can someone  give me some idea where to start?











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