Fuel System Plumbing Question

Discussion in 'Pitts Miscellaneous' started by SamSwift, May 8, 2018.

  1. May 8, 2018 #1

    SamSwift

    SamSwift

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    Hey all,

    My S-1 is set up for racing at Reno, not aerobatics. Therefore, no inverted fuel and oil setups.

    Given that info, here is how my plane is currently plumbed and I'm wanting some expert advice if this is correct, or just overly complex, or just plain old incorrect.

    I have the standard 19-gal fuel tank, an electric fuel pump, and an Airflow Performance FM-200 servo.

    My biggest questions/concerns/curiosity is why the fuel comes through the firewall and into a "T" fitting prior to entering the electric fuel pump, then exiting the fuel pump into another "T" fitting. Seems like a lot of T's in the system.

    Thanks for taking a look.

    fullsizeoutput_8ad5.jpg
     
  2. May 8, 2018 #2

    Morphewb

    Morphewb

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    Looks to me that your fuel pump won't allow free flow through it when it is off. There is a one way valve, maybe two, in this system that I can see.

    The easiest solution would be to spend the money for a Weldon pump or similar style that allows free flow through the pump and does away with all the extra complicated system you have there. Of course this is also the most expensive solution. Andair also makes a pump that has flow through capabilities when on or off.

    At least that's what I see going on here. Hard to tell with just one picture.

    http://www.aircraftspruce.com/catalog/eppages/andairfuelpump.php?recfer=14168

    Try this from the Aircraft Spruce site. It's the Andair pump. In, out, internal bypass when off, no extra lines and check valves. You can see other options including the Airflow Performance pump which to me is a manufactured version of the setup you already have.
     
    Last edited: May 8, 2018
  3. May 8, 2018 #3

    Dave Baxter

    Dave Baxter

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    I believe Ben is correct, it was/is not uncommon to see automotive type boost pumps installed in aircraft, and most will not free flow fuel when not pumping, and need a one way check valve in the system in order for it to work correctly. Also the newer boost pumps made by Airflow Performance are smaller and a bit less complicated. Dave
     
  4. May 8, 2018 #4

    PittsDriver68

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    And I will add the suggestion that you move the electric boost pump behind the firewall. A hot pump in the engine compartment will reward you with vapor lock, especially racing at Reno's 5000' field elevation. Piper ran into pump overheating in Cherokees at sea level during the summer and had to put a heat shield around the pump.

    Best of luck,

    Wes
     
  5. May 8, 2018 #5

    dimcuesta

    dimcuesta

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    Ditto on the pump relocation + switching to Airflow Performance. A hot pump will also fail prematurely.
     
    ernstfokker likes this.
  6. May 8, 2018 #6

    Morphewb

    Morphewb

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    I think the Airflow Perf unit to be the least desirable of all that's available with the flow through feature. It's not that inexpensive compared to the other less complicated versions available from other manufacturers.
     
  7. May 9, 2018 #7

    Vic Zubot

    Vic Zubot

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    Is that teflon tape I see on your 90 degree fitting on your fuel system. Teflon tape is a no no in your fuel system.
     
  8. May 9, 2018 #8

    SamSwift

    SamSwift

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    Yes. The entire fuel system is being revamped for reliability and all of that was done by a prior owner. It’s being yanked out.

    Sam
     
  9. May 9, 2018 #9

    SamSwift

    SamSwift

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    Thanks everyone. I think I’m going with the Andair product. As always, thanks for your knowledge!

    Sam
     
  10. May 14, 2018 #10

    TxSkyBolt

    TxSkyBolt

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    I still have an older model, never used Andair pump and installation kit for sale.
     
  11. May 14, 2018 #11

    smizo

    smizo

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    youll be very happy with the andair pump......
     
  12. May 14, 2018 #12

    SamSwift

    SamSwift

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    I may be contacting you about that. PM me if you have a price in mind.

    sam
     
  13. May 15, 2018 #13

    cashflyer

    cashflyer

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    For assembling pipe thread joints, maybe you want to try Titeseal 55.
    That is what is approved by Robinson for use in the fuel system assembly, and is relatively easy to find.
     

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