REFLECTOR: Electric fuel valves

[Jim Sower]

That's true.  My point was that if for whatever reason (catastrophic 
total electrical failure, failure of the valve actuator, whatever), the 
fact that if you have a tank "permanently" deselected does not a serious 
(or even significant) problem.


Jim Agnew wrote:

>Actually Jim these valves take about 250 milliseconds to transfer position and
>no power after the transfer.  So unless you have a total electric failure you
>have time to change them.  Since I have a small backup battery a total power
>failure would still allow me to switch.
>
>Jim
>
>--- Jim Sower <canarder at frontiernet.net> wrote:
>
>  
>
>>That's true.  I would have preferred solenoid valves that would fail 
>>open.  However, as a practical matter, with the valves powered by the 
>>main buss, if you can't move the valve one of two things are happening:  
>>a) you have a serious electrical failure and are heading for the nearest 
>>airport you can land at, and should have more than sufficient fuel in 
>>the tank that IS transferring (it was, after all, the one with too much 
>>fuel in it) to get you there;  or  b) the valve failed closed and would 
>>not open when you saw your tanks were even again, so now you have half 
>>as much fuel as you thought, which should be more than adequate to get 
>>to a decent en route alternate.
>>So in the cosmic scheme of things, it really doesn't matter ... Jim S.
>>
>>KeithHallsten wrote:
>>
>>    
>>
>>>No, these need power to move, so they fail in the last position selected.
>>>This is in contrast to typical solenoid valves, which are spring loaded to
>>>one position (either open or closed) and need continuous power to phold them
>>>in the other position.
>>>
>>>Keith Hallsten
>>>
>>>
>>>----- Original Message ----- 
>>>From: "Scott Derrick" <scott at tnstaafl.net>
>>>To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>>Sent: Friday, October 29, 2004 4:33 PM
>>>Subject: Re: REFLECTOR: Uneven fuel draw
>>>
>>>
>>> 
>>>
>>>      
>>>
>>>>jim,
>>>>
>>>>Are you saying these are fail closed?
>>>>
>>>>Scott
>>>>
>>>>At 10:59 AM 10/29/2004, you wrote:
>>>>   
>>>>
>>>>        
>>>>
>>>>>Don't recall.  They are from JCW and are fuel tank selector valves.  They
>>>>>have supply and return for two tanks.  That's SIX nipples.  I only used
>>>>>two and plugged the other four.  I used them because the guy who sold
>>>>>     
>>>>>
>>>>>          
>>>>>
>>>them
>>> 
>>>
>>>      
>>>
>>>>>to me made me an offer I couldn't refuse.  I was seriously considering
>>>>>manual valves from Wicks for about $10 but wire is easier to string than
>>>>>cable.  There used to be solenoid valves that failed open at JCW but
>>>>>they're not there any more.
>>>>>Think about the manual valves too .... Jim S.
>>>>>
>>>>>
>>>>><mailto:PVTPIL8 at aol.com>PVTPIL8 at aol.com wrote:
>>>>>     
>>>>>
>>>>>          
>>>>>
>>>>>>Canarder Thanks for the info what were the valve part numbers.
>>>>>>Steve
>>>>>>
>>>>>>
>>>>>>       
>>>>>>            
>>>>>>