REFLECTOR: FUEL FEED

[Jim Sower]

I did have something "very wrong".  And the factory put it there when 
they fixed the damage for the seller before the airplane came to me.  
I've got it fixed now.  My point in all of this was to lay out all of 
the stuff that I tried that was /supposed/ to fix it, but didn't.  Back 
before last spring (when I installed the de-selector valves) I was back 
and forth here for *months* looking for help to try and figure this 
out.  I tried everything anyone suggested (except 1/2" lines from the 
strakes to the sump, which were not suggested IIRC).  None of it 
worked.  I finally came up with something that did.  I still don't know 
what caused the problem because it's still there.  But now I have a work 
around that overcomes the problem.

That was the best I could do ... Jim S.

Scott Derrick wrote:

> Jim,
>
> Obviously you have something really wrong or should I say "very 
> different" from the factory configuration.
>
> The proof is in the pudding.
> Find and correct that difference and your fuel flow would be per design.
>
> Scott
>
> Jim Sower wrote:
>
>>
>>
>> Scott Derrick wrote:
>>
>>> A leaking gas cap can cause uneven fuel flow but is not the prime 
>>> culprit. A bit of fuel valve lube applied to the O ring once a year 
>>> will insure this doesn't happen.
>>>
>>> A miss-rigged airplane is most likely the cause. Shim your rudders 
>>> so the ball is right in the middle and you will get perfect fuel flow.
>>
>>
>> That's what I thought.  It's the first thing I did.  Leveled the 
>> airplane w/laser level, checked the ball centered, flew a couple of 
>> test hops and shimmed it to perfectly centered ball.  Had no 
>> measurable effect AT ALL on assymmetric transfer.
>>
>>>
>>> To test, be sure your turn and bank is installed correctly first, 
>>> garbage in garbage out. Then fly, this is the fun part.. Once you 
>>> see an uneven condition, press on the rudder that will put the ball 
>>> in the middle. If you want to even up the tanks fast, press on the 
>>> correct rudder so the ball is on the other side for a couple 
>>> minutes, you'll see the fuel even up and even go into the opposite 
>>> imbalance if you keep the rudder depressed. Then hold the rudder so 
>>> the ball is centered, fuel will flow as it was designed to.
>>
>>
>> At full rudder deflection I was able to transfer maybe 1/2 gal / 
>> min.  Took 10 minutes to transfer five gallons (that was on a GOOD 
>> day.  Other days it was less.
>>
>> Sometimes nothing at all seems to work ... but I finally fixed it ... 
>> Jim S.
>>
>>>
>>> Scott
>>>
>>> Tom Martino wrote:
>>>
>>>> Well, now that I’m in my test flying mode ... I will really be 
>>>> asking a lot of questions.
>>>>
>>>> Here are some of them, as they relate to my fuel system:
>>>>
>>>> 1. What makes the fuel tanks feed unevenly to the header 
>>>> tank/engine? (My right tank is feeding twice as fast as my right 
>>>> tank.)
>>>>
>>>> 2. Will that cause a problem when the fast-feeding tank runs out?
>>>>
>>>> 3. I used the larger vent lines for my tanks and tied them al 
>>>> together with a manifold, then vented the entire system out through 
>>>> the top of my firewall in the engine compartment (about four inches 
>>>> below my naca duct). Do you think the system gets enough venting 
>>>> there?
>>>>
>>>> 4. Is there a need for a “whistle” hole in any of the tank vents 
>>>> ... for additional venting (like we do with the crankcase breather?
>>>>
>>>> Any help is appreciated from my more experienced Velocitologists J
>>>>
>>>> Tom
>>>>
>>>> N173EX
>>>>
>>>> (A mere 6 hours)
>>>>
>>>> ------------------------------------------------------------------------ 
>>>>
>>>>
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>>
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> _______________________________________________
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>