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Thread: Vacuum system installation

  1. #1
    janboc's Avatar
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    Vacuum system installation

    I decided to get rid off old electric AI and go into vacuum system in my PA-18 with O-320-B2B engine - registered in normal category. Can you recommend me all the necessary parts and gauges?
    TNX
    J

  2. #2
    Crash's Avatar
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    Garmin 296. Crash

  3. #3

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    Look in a 18 parts manaul. They are very helpful and affordable. Everything you need to know in detail is listed there -correctly.

  4. #4
    T.J.'s Avatar
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    As long as your not flying in the ice much, go with a venturi. Trouble free, no moving parts and no ADs on them.

  5. #5

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    Crash is right. The venturi works well at around 100 mph; it can drive all three gyros. But I wonder if the feds will ever figure out that it is airflow you need, and not inches. There is no engineering data on the venturis.

    The Garmin is a wonderful backup. While not legal for IFR flight, it has a horizontal flight director that makes an ILS a real snap! The HSI presentation is hard to beat when things get tight.

    Also, what about those new $2000 solid state AHRS deals? Sure, they are not TSO, but I bet they will be in a couple of years! Save weight, look great! The solution! Glass is saving the airlines big bucks, and has been for about 20 years.

  6. #6
    janboc's Avatar
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    Definetly I need to have something "legal", once a year in(p)sector puts his head in the cabin Btw. I use GPS as a backup.
    Parts manual for PA-18 shows different installations from the past and will be tough to get all the items.
    I loooked to the various manufacturers (God bless google) like Airwulf, Sigmatec, RC Allen - most of them has pumps, gauges, hoses, filters etc - but I want to have the working configuration that will work for a copule of years.

  7. #7
    Aviator's Avatar
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    Agree go with venturi. No pumps, no regulators, no valves, no suction gauges, no failures, no maintenance $. One gyro, one venturi; two gyros, two venturis; no sharing, no cross over. KISS principle.

    BTW, to avoid having to answer the same stupid question over and over, stick a sign over the venturi that says " NO, IT'S NOT A HORN"

  8. #8
    Aviator's Avatar
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    Need venturi advice.

    The other day ATC gave me a heading to fly. Easy for you to say - I grumbled. My whiskey compass is reliable +/- 180*. Anyway, it looks like I'll have to go for gyros if I want to fly in "civilized" airspace. I can't afford electric, don't want a vacuum pump, and have no room for low-suction AN gyros. So I'm thinking dual 9" venturis, one on the left, one on the right just above the cowl gills, merged into a 1/2 x 3/3 x 3/8 wye, a regulator, then branched off to two 3/8 lines, one for an AH, the other for a DG + needle-valve and T&B. All air intakes from one common filter. Or dual 8" venturis and no regulator.

    My present 4" venturi pulls 2.9" Hg @ 80mph - taken directly off the venturi. I'm told 9" super venturis pull about 6-7" @ 75mph.

    Any thoughts? Experience?

    Thanks

  9. #9
    mvivion's Avatar
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    Whatever you do, stay away from RC Allen gyros. Unless they've improved a lot recently, you'll be spending a lot of time and $ replacing them. Personally, I would stick with a GOOD quality electric AI, especially if all you need is the AI.

    MTV

  10. #10

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    Go digital with a RCA2600-2 It is not cheap but dirt simple and in the long run cheaper and a lot lighter than trying to stick in a vacuum system.
    DENNY

  11. #11
    Cub Builder's Avatar
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    I'd recommend a Dynon D1 or D2 unless you are getting set to fly IFR with it. Clips into a 3 1/8" instrument hole or onto a RAM mount. Only uses milliamps of power and weighs a whopping 7 oz. Provides loads of information, including heading, GPS altitude, vertical speed, pitch, roll, slip/skid, turn rate and GPS speed. Also has 4 hrs of battery life if the power goes off. I find the roll on mine to sometimes drift off 3 or 4 degrees before it corrects itself, but I've been flying with a D1 for a little over a year in my other plane and love it. The D2 provides a g meter and wi-fi if you like to display this stuff on your tablet.

    -CubBuilder

  12. #12

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    Another good choice my buddy has one and loves it
    DENNY

  13. #13
    skywagon8a's Avatar
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    All solid state. All in one 3-1/8" instrument. Weighs next to nothing. All electric using almost no electricity. Works great. Gets the compass information from your GPS. http://trutrakap.com/product/gemini/

    I have the early version in my Cub and would have no hesitation in recommending to others.
    N1PA

  14. #14
    RaisedByWolves's Avatar
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    Quote Originally Posted by Aviator View Post
    Need venturi advice.

    The other day ATC gave me a heading to fly. Easy for you to say - I grumbled. My whiskey compass is reliable +/- 180*. Anyway, it looks like I'll have to go for gyros if I want to fly in "civilized" airspace. I can't afford electric, don't want a vacuum pump, and have no room for low-suction AN gyros. So I'm thinking dual 9" venturis, one on the left, one on the right just above the cowl gills, merged into a 1/2 x 3/3 x 3/8 wye, a regulator, then branched off to two 3/8 lines, one for an AH, the other for a DG + needle-valve and T&B. All air intakes from one common filter. Or dual 8" venturis and no regulator.

    My present 4" venturi pulls 2.9" Hg @ 80mph - taken directly off the venturi. I'm told 9" super venturis pull about 6-7" @ 75mph.

    Any thoughts? Experience?

    Thanks
    Why not a garmin portable GPS? You can have pretty accurate heading and alt. my compass can be a pita sometimes and not show the right heading. Plus you wouldn't have to add a bunch of weight.



    Mine had an attitude indicator and dg when I got it. Powered by a Venturi. It sucked. It was mounted on the boot cowl, left side. I think that's the stock location. Didn't work that great, pulled it all when I got it. No need for it. I won't be flying IFR in that airplane, and it didn't seem to reliable.

  15. #15
    Steve Pierce's Avatar
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    I'm with Tom, that is what I use.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  16. #16
    Aviator's Avatar
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    Thanks for all the advice, folks.

  17. #17
    kiwicubber's Avatar
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    I’m restoring a PA-18A-150 with a vacuum system and Univair don’t have the regulator valve part no. 756 764. Can anyone suggest an alternative regulating valve please?

    cheers Bill
    Bill and Neroli.
    www.supercub.co.nz

  18. #18
    wireweinie's Avatar
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    Rapco or Tempest. Different part numbers are different hose sizes and number of connections.

    Web
    Life's tough . . . wear a cup.
    Thanks kiwicubber thanked for this post
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  19. #19
    hotrod180's Avatar
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    I've got 2 vacuum regulators, a Pesco and a Manning Maxwell & Moore.
    PM me if youre interested.
    Cessna Skywagon-- accept no substitute!
    Thanks kiwicubber thanked for this post
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