REFLECTOR: Hydraulic Pump Leak..fluid levels

[Alex Balic]

You would think that, but remember that when the cylinders are extended, the
fluid volume is the volume of the cylinder bore x stroke, when the cylinders
are retracted, the fluid volume is the volume of the cylinder bore x stroke
minus the volume of the rod(s) - so there is a significant volume
difference- this type of difference is also taken into  account in the
calculations of cylinder power, since on the out stroke, you get full power,
but on the return stroke, you do not, since you must subtract the rod end
area from the  total piston area.

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of Jeff Clough
Sent: Monday, December 13, 2004 7:20 PM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Hydraulic Pump Leak..fluid levels


Does the hydraulic fluid level change THAT much between 'up' and 'down'
cycles?  I would think that the amount of driving (extending) fluid
would nearly equal the fluid driven out of the cyclinders and returned
back to the reservoir and same for the retraction cycle(once all the air
bubbles are out of the system and it is in 'steady state') .. JEFF C.

johnward wrote:

>Also shouldn't the fluid level be determined during the drop check when the
>gear is retracted?  I believe the reservoir might be overfilled when the
>hydraulic piston is retracted in the cylinder if it's filled on the extend
>cycle.
>
>John Ward
>----- Original Message -----
>From: "Pat Shea" <xl340hp at yahoo.com>
>To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>Sent: Monday, December 13, 2004 5:42 PM
>Subject: Re: REFLECTOR: Hydraulic Pump Leak
>
>
>
>
>>Okay, I obviously should have thought that thru before
>>posting...
>>
>>I recall someone dealing with leaking cap in the past
>>& was curious how they dealt with it since mine is
>>leaking some from just ground ops. Agreed, if the cap
>>is the only vent source, you're gonna need it! One
>>thought was to raise the vent opening further from the
>>fluid level (i.e. seal the cap slots and use a vent
>>tube stemming from the cap). Ronnie, since you're
>>flying and don't seem to have any problems, maybe
>>running with the reservoir only 1/2 full is the
>>ticket! I'll try that first...
>>
>>Thanks, Pat
>>
>>
>>
>>>The vents really need to be left open.  You can see
>>>the fluid go up and down in the reservoir as the gear
>>>is retracted and extended.  The difference is the
>>>piston rods that displace fluid as they go into the
>>>cylinders. I agree, seal the vents and you could have
>>>a real mess!
>>>
>>>
>>
>>
>>
>>
>>
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