Welcome! Becoming a registered user of ShortWingPipers.Org is free and easy! Click the "Register" link found in the upper right hand corner of this screen. It's easy and you can then join the fun posting and learning about Short Wing Pipers!

Page 1 of 3 123 LastLast
Results 1 to 10 of 26

Thread: Why Positive Pressure Fuel Caps on 180hp Conv

  1. #1

    Join Date
    Aug 2015
    Posts
    275
    Post Thanks / Like

    Default Why Positive Pressure Fuel Caps on 180hp Conv

    Quote Originally Posted by pmanton View Post
    Why the ram air vents on the fuel tanks?

    Thanks
    Paul
    Salome, AZ
    Quote Originally Posted by stevesaircraft[bri] View Post
    Required for Trimmer fuel system and 0-360 conversion...

    Brian


    Sent from my iPhone using Tapatalk
    Quote Originally Posted by Stephen View Post
    Bug catchers
    Yep. I've flown an O-360 Super Cub wide open for an hour many times with plain flat vented caps and the engine never hiccuped, that was with the maule moeller 1/4" NPT fuel valve and 3/8 fuel line, is that what the Timmer uses? I would be affraid of them catching bugs and blocking fuel flow.
    Last edited by Tp109; 10-04-2017 at 10:39 AM.

  2. #2
    Steve Pierce's Avatar
    Join Date
    Nov 2007
    Location
    Graham, Texas, United States
    Posts
    9,944
    Post Thanks / Like
    Blog Entries
    1

    Default Re: Andy's Pacer restoration thread...

    Quote Originally Posted by Tp109 View Post
    Yep. I've flown an O-360 Super Cub wide open for an hour many times with plain flat vented caps and the engine never hiccuped, that was with the maule moeller 1/4" NPT fuel valve and 3/8 fuel line, is that what the Timmer uses? I would be affraid of them catching bugs and blocking fuel flow.
    The vented fuel caps were needed to meet the FAA requirements of 150% max fuel flow at all flight attitudes. The STC on the Super Cub also includes venting the two tanks together so you have a redundent vent.

  3. #3
    Clayton Harper's Avatar
    Join Date
    Dec 2007
    Location
    Seabrook, TX
    Posts
    1,256
    Post Thanks / Like

    Default Re: Andy's Pacer restoration thread...

    Eddie T. told me that when he started with STC, that a stock fuel system would not even meet the minimums for 150 HP engine. I guess it was sort of "grandfathered" along from the 135 HP days. Wouldn't one have to have the bugs plug both in the same flight to have problem. I'M thinking in 50+ years of flying I have not had even one pitot plugged. What me worried?
    Last edited by Clayton Harper; 10-04-2017 at 08:12 PM.
    The only true wisdom is in knowing you know nothing.
    Socrates

  4. #4

    Join Date
    Aug 2015
    Posts
    275
    Post Thanks / Like

    Default Re: Andy's Pacer restoration thread...

    Quote Originally Posted by Steve Pierce View Post
    The vented fuel caps were needed to meet the FAA requirements of 150% max fuel flow at all flight attitudes. The STC on the Super Cub also includes venting the two tanks together so you have a redundent vent.
    I knew the 150% flow was why, read that here before.. I didnt realize the plane I flew may have had the tanks vented together.. that might explain why I could run the O-360 wide open without ramair gas caps.
    Last edited by Tp109; 10-04-2017 at 09:02 PM.

  5. #5
    59pacer's Avatar
    Join Date
    Feb 2010
    Location
    Mulgoa, Australia
    Posts
    269
    Post Thanks / Like

    Default Re: Andy's Pacer restoration thread...

    When I rebuilt our 160hp Pacer, I did fuel flow checks for my own satisfaction. I did it as per the FARs, and found both tanks met the 150% requirement, even though the left was better than the right (surprise!). The right tank has pickups front and rear, the tubing layout is stock standard, the fuel caps are original, but the fuel valve is the newer Univair (Andair) valve.

  6. #6

    Join Date
    Aug 2015
    Posts
    275
    Post Thanks / Like

    Default Re: Andy's Pacer restoration thread...

    Quote Originally Posted by 59pacer View Post
    When I rebuilt our 160hp Pacer, I did fuel flow checks for my own satisfaction. I did it as per the FARs, and found both tanks met the 150% requirement, even though the left was better than the right (surprise!). The right tank has pickups front and rear, the tubing layout is stock standard, the fuel caps are original, but the fuel valve is the newer Univair (Andair) valve.
    I cant see how Timmer didnt meet the 150% either, I've drained fuel out of my front gascolator several times into a 2 gal can, I dont believe it took anywhere near 6 minutes to fill a two gal can, but even if it did take 6 minutes to fill a 2 gallon jug that's 20 gallons per hour.

    I wonder how the FAA calculates that 150%?


    With only 5 gallons in the left tank the rate was right at 2 minutes 8 seconds per gallon, filled the 2 gallon can in 4:16, which is 28 gallons an hour, thats greater than 200% of max O-360 fuel burn. I must not be testing it the way the FAA does.
    Last edited by Tp109; 10-05-2017 at 09:59 AM.

  7. #7
    Clayton Harper's Avatar
    Join Date
    Dec 2007
    Location
    Seabrook, TX
    Posts
    1,256
    Post Thanks / Like

    Default Re: Andy's Pacer restoration thread...

    Tp109, I believe, I have reported what Eddie Trimmer told me correctly. I did not witness the test, so it is just a report. You have been around here for over 2 years, and after following your math I can tell you are sharp. Who are you? Where are you from? How about helping out with the cost of running this web site?
    The only true wisdom is in knowing you know nothing.
    Socrates

  8. #8
    Steve Pierce's Avatar
    Join Date
    Nov 2007
    Location
    Graham, Texas, United States
    Posts
    9,944
    Post Thanks / Like
    Blog Entries
    1

    Default Re: Andy's Pacer restoration thread...

    Engine manufacturers specify the full power fuel flow. An O-360 should flow 22.5 gallons an hour at all flight attitudes and all usable fuel levels.

  9. #9
    Pacer42Z's Avatar
    Join Date
    Feb 2008
    Location
    Winchester, VA
    Posts
    287
    Post Thanks / Like

    Default Re: Andy's Pacer restoration thread...

    Quote Originally Posted by Steve Pierce View Post
    The vented fuel caps were needed to meet the FAA requirements of 150% max fuel flow at all flight attitudes. The STC on the Super Cub also includes venting the two tanks together so you have a redundent vent.
    Steve, how can I vent my two main tanks together? Is there a schematic somewhere I can use?

    Juergen
    Pacer N3342Z

  10. #10
    Steve Pierce's Avatar
    Join Date
    Nov 2007
    Location
    Graham, Texas, United States
    Posts
    9,944
    Post Thanks / Like
    Blog Entries
    1

    Default Re: Andy's Pacer restoration thread...

    There was a Jensen STC to install a nylon plug in the fuel selector with a both position and it called out welding a nipple into each filler neck to vent the two tanks together. They are no longer in business.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •