REFLECTOR: Gear dump valve

[Brian Michalk]

What about a pressure relief valve with a small orifice in series?

http://www.mcmaster.com/ctlg/DisplCtlgPage.asp?ReqTyp=CATALOG&CtlgPgNbr=433&CtlgEdition=&RelatedCtlgPgs=433,434&sesnextrep=606455415545954&ScreenWidth=1280&McMMainWidth=1071

The orifice(around .010) would maintain the very high pressures while 
there is hydraulic flow.  Once the pump stops, the pressure would drop 
down to that of the relief valve.  The ones at the link are 125 PSI or 
so.  I don't know if that's high enough to hold up the gear.

Ron Brown wrote:
> I believe there is a lot more pressure across the opening valve just as 
> you crack the valve.  After all, 1500 psi or so is used to raise the 
> gear.  The pressure switch cuts the pump off, but there is still 1500 
> psi there.  The pump will run again when this pressure drops a few 
> pounds.  Now, if you slowly open the valve until the gear starts to 
> drop, you are bleeding 1300-1500 psi fluid across the ball and seat.
>  
> Mine worked fine during the building process and then the rapid cycling 
> of the pump after the 2nd landing.  Perhaps there was a piece of trash 
> that damaged the valve.  Tightening the stem packing did not remedy the 
> problem.  I ordered and installed a new valve - problem fixed for 215 
> hours of flight.
>  
> Ronnie