REFLECTOR: Hydraulic Pump Leak..fluid levels

[Jeffrey Clough]

Ahhh...good points!

Alex Balic wrote:

>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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