Mailing List lml@lancaironline.net Message #46158
From: LHenney <LHenney@charter.net>
Sender: <marv@lancaironline.net>
Subject: 360 gear dump valve idea Transcon Record...
Date: Wed, 13 Feb 2008 00:18:12 -0500
To: <lml@lancaironline.net>

Randy,

 

Yup, Chuck, chunk or clunk it.  Make sure it doesn’t land in your plane. Mine also had the ¼ al tube in the reservoir.  However, it was removed after it was found sunk in the reservoir some time back.  I’m thinking the tube is irrelevant because the flow of 1 directional (to the reservoir).

 

The allen plug of which we speak is betwixt the high and low pressure ports.

 

Larry

PS:  The T shuttle still doesn’t make sense to me.  The idea that pressure on the high pressure side would open the low pressure back to the reservoir is NOT intuitively obvious to this observer.

 

 


From: randy snarr [mailto:randylsnarr@yahoo.com]
Sent: Monday, February 11, 2008 5:09 PM
To: lml@lancaironline.net
Subject: Re: [LML] /360 gear dump valve idea Transcon Record...

 

Larry,
What does the ball and spring do?
Does the ball and spring get chucked or chunked, or maybe clunked. Anyway, do you remove them? If memory serves, there is an allen plug somewheres in the vicinity of the high and low ports. Is that where the below mentioned  ball and spring are to be found and replaced with the tube to the bottom of the reservoir?
Randy.

LHenney <LHenney@charter.net> wrote:

Bryan, Gary, Randy S’s.,

 

Bryan, yes the ball and spring get chunked.

Gary, I’m incompetent at computer sketching but it is a one liner.  Perhaps S.Kruger could help me.  My thought is that a 3 way dump valve will directly replace the existing dump valve.  As far as the sketch is concerned, I would draw a line from the new dump valve to the center port of my pump.  A piece of plane ole ¼” tubing slips in the pump and down to near the reservoir bottom.

A possible option for the dump valve is :

3-Way Gear Dump Valve

Long Beach Valve and Fitting

3940 Gilman St

Long Beach, CA 90815

(562) 494-6694

(562) 494-0493 fax

Part Number:  B-42XHS4-BKB

 

HOWEVER:  this whole 3 way dump valve may just be a feel good solution.   In the final analysis it may be just fine as far as safety of gear extension (electric or freefall) is concerned.  So far there have been no indications that anyone’s gear has hesitated to come down after cracking the dump valve (in it’s existing design).  As I mentioned one other time, the loss of the physical handle combined with the unique high to low pressure bleeding could pose a problem.

 

AND:  Randy Stuarts external T shuttle sounds to be an elegant and simple correction for the quirk which would preclude the need for the 3 way valve.  Have you got a vendor and part that you are considering?  We’d love the data.  Do the 2 ends of the T go High and low pressure connections and the third leg directly to the pump return port?

 

Disclaimer:  The above discussion is from a list of things I’m trying to get accomplished on my speeder.  I have not done any of the aforementioned projects to my plane (weight penalty, budget, time, honey do’s, etc).  I haven’t even got the darn gages installed which have been sitting in my hangar for a week.  I do appreciate the feedback from those with more time on there hands.

 

Did anybody notice that Bruce Hammers transcontinental speed record of Mar 06 got walloped by a blistering 30 mph.  New record 288 mph by a Questair Venture!  Say it isn’t so……..

 

Larry

Very Prompt Lancair 360LH


From: Bryan Wullner [mailto:vonjet@gmail.com]
Sent: Friday, February 08, 2008 2:14 PM
To: lml@lancaironline.net
Subject: Re: [LML] FW: [LML] 235/320/360 gear dump valve idea

 

Randy,

When I removed the plug in my pump a spring and a steel ball came out.  Do I remove these and then Install the 1/4" return line to this port?

Bryan



On Feb 7, 2008 10:34 AM, LHenney <LHenney@charter.net> wrote:

Randy,

 

Hold off on the machine work.  Your pump is designed with a third port (between the two now in use).  It is threaded and ready for your return line.  A ¼ " tubing can be installed as a down tube in the tank (mine came with the tube installed).

 

Also, Randy Stuarts idea of a T shuttle sounds very, very interesting.  I don't completely know what a T shuttle valve is however.  Thus, I'm grappling with check valve analogies and getting a lot of "how would that work?" thoughts.   Does this mean pressure on up circuit triggers opening of shuttle from down circuit, therefore T goes to third port???  I'm tempted to like this idea.  Additionally, could second T also tie in to third port and allow 3 way dump common path to reservoir.  Please tell us more R. Stuart…..

 

Larry Henney

N360LH

Much less chirping lately after changing out pump O rings; Lancair also got more pressure gauges in stock and shipped mine.

 


From: Sky2high@aol.com [mailto:Sky2high@aol.com]
Sent: Wednesday, February 06, 2008 2:49 PM
To: lml@lancaironline.net
Subject: Re: [LML] 235/320/360 gear dump valve idea

 

Randy,

 

Remember that the reservoir needs a small vent hole so that air pressure or vacuum does not build up in the reservoir itself.  Usually the vent is in the filler cap or its threads.

 

Scott Krueger AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Pilot not TSO'd, Certificated score only > 70%.

 

 

In a message dated 2/6/2008 11:29:13 A.M. Central Standard Time, randylsnarr@yahoo.com writes:

With the way the hydraulic system is currently designed, you equalize the pressure on the high and low sides when it is opened. For those of us who have pressure gauges, you can see that you can have significant pressure on the system even when the valve is opened. I want to be able to not only equalize the pressure between the high and low sides of the hydraulic system with the dump valve but also release the pressure on both sides.

Today I purchased a 3 way valve to do just that. The idea  is to open the valve  connecting  the high and low sides and also releasing the pressure back to the tank.
I will most likely run a low pressure line like nylaflow back to the pump and make spin up a custom fitting on the lathe out of aluminum to go into the dipstick hole and terminate the return line there. I will make a needle dipstick checker that will screw into the same fitting for checking fluid level.
If you wanted to do it the easy way, you could always just dump the low pressure line out the belly of the airplane onto the ground. It would take very little fluid to drop the pressure and there would be no need to deal with connecting the low pressure fluid line to the tank.

I hate pulling the airplane out of a cool hanger into the warm sunshine and watching the gear pressures rise to 6-700 lbs before the master switch is turned on! We all know what happens when they hit 900. Yep no gear retraction as the upper limit has been tripped by the system pressure.
My new valve would fix that!!!
I hope...

 

 

 

 

 


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