Mailing List lml@lancaironline.net Message #44620
From: Dave Schroder <schroder@timesync.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Gear cylinder hydraulic gaskets
Date: Wed, 31 Oct 2007 17:47:33 -0400
To: <lml@lancaironline.net>
Mario and Terrance,
Better yet, why not a manual retract system like the early Mooneys?
dave
----- Original Message -----
Sent: 10/30/2007 2:03 PM
Subject: [LML] Re: Gear cylinder hydraulic gaskets

Mario,
Sounds like an excellent idea.  Neat, compact linear actuators with built-in adjustment, available from robotics spinoffs... not expensive.
Eliminate much time/labor?  Replace the switches, sequencers, limiters, many-piece-lines, pump, etc., with three actuators and one up-down switch?
Wouldn' be re-inventing the wheel (gear).  I heard the 10,000 Bell P-39, -63, -59s were electric gears.
 
Terrence LNC2 N211AL
----- Original Message -----
Sent: Tuesday, October 30, 2007 07:27 AM
Subject: [LML] Re: Gear cylinder hydraulic gaskets

Hello,
 
Just a thought, has anyone on the list researched if with the new electric motors and batteries available today one could build an electric gear retract system, maybe like the garage door oppeners kind of thing technology?.
 
No more leaks here and there get rid of complexity of a mechanical/hydraulic system, no more pistons, gaskets, pumps etc.
 
Mario LNC2


To: lml@lancaironline.net
Date: Mon, 29 Oct 2007 15:35:01 -0400
From: matt.hapgood@alumni.duke.edu
Subject: [LML] Re: Gear cylinder hydraulic gaskets

Wonderful.  I did the EXACT same thing in May.  Rebuilt all three gear cylinders due to 1 slight leak.  Result.  Massive hydraulic leak problems that persist to this day.  I’ve now replaced two entire cylinders and may need to replace the third… 

 

I’m at a loss, frustrated, and in desperate need of a shop in the southeast that will help me TROUBLEshoot the problem (as opposed to continually replacing cylinders).

 

Matt

 

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of kneaded pleasures
Sent: Monday, October 29, 2007 1:59 PM
To: lml@lancaironline.net
Subject: [LML] Gear cylinder hydraulic gaskets

 

Matt Reeves wrote back in late August:

 

"I have a Lancair 320.  I just found a leak coming out of the end of the left main hydraulic cyl on the high side.  It is not coming out of the fittings, it's actually coming out of the end where the stop jam is.   It's just a small leak but I rebuilt this cylinder once already cause I thought there was an internal leak so my opinion is this is a defective cylinder."

 

Matt:  The problem is probably not with the cylinder - or your workmanship!  It is probably due to a wrong piston gasket being included in the cylinder rebuild kit.  I had an identical problem with one cylinder and chose to rebuild all three gear cylinders at the same time.  After ordering rebuild kits (just gaskets in the kits) I installed the new gaskets and two leaked after rebuild.  I removed them and critically reexamined the supplied materials and my workmanship. (Meanwhile, I reordered from Lancair two more gasket kits.) I then noted that the newly-supplied leaking gaskets differed from both the very old rotted gaskets that I had originally removed and also differed from the two newest gaskets that I had just received from Kit Components.  (The gasket that I am targeting here is the gasket that surrounds the piston as it extends/withdraws from the cylinder.) 

 

The differences in these gaskets are easy too see and measure.  The new and correct gaskets are the same as the very-old, original and now rotted gaskets.  They have an O-ring embedded inside of the plasticized gasket. {I "dis-sected" (the word is not "di-sected") an old gasket to observe this.}  Writing on the good/proper/desired gasket is illegible to me.  However, writing is very clear on the IMPROPER gasket and it reads, "USA   .375   MP I     K3E.1".  Further, the good/non-leaking gasket stands noticeably higher on a flat surface - perhaps four or five mils higher than the poor/leaking gasket (probably important at 2000 psi).

 

Summarizing, don't throw away your leaking cylinders before you first check to ensure that the correct replacement gasket is installed.  Look for the tell-tail embedded "O ring" that is prominently visible on the top of the correct gasket.     Greg Nelson 



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