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WWII aircraft tach, will it work?

Discussion in 'The Hokey Ass Message Board' started by meferflatheads, May 3, 2010.

  1. meferflatheads
    Joined: Jun 29, 2009
    Posts: 38

    meferflatheads
    Member
    from Oregon

    I found a WWII aircraft tachometer at the swap meet and picked it up for 15 bucks,I thought the price was right even if it doesnt work. Well, out of couriosity, I hooked it up, and it moved. It did not read right, but it still moved. So Iam thinking the thing needs 24 volts to work right, and I have a 12 volt system. Does anybody know if this can be made to work for a v8 12 volt system?
     
  2. UnsettledParadox
    Joined: Apr 25, 2007
    Posts: 1,107

    UnsettledParadox
    Member

    dunno if it will work, have any pics?!
     
  3. KIRK!
    Joined: Feb 20, 2002
    Posts: 12,032

    KIRK!
    Member

    My guess is that an early tach like that would need a sending unit to work.
     
  4. Best bet I would think would be to get a solid ID on it as to make and model and then find out how it works. I wouldn't be surprised if someone who was handy with electronics could rig you up a sender out of the stuff you used to be able to buy at Radio Shack -
     
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  5. meferflatheads
    Joined: Jun 29, 2009
    Posts: 38

    meferflatheads
    Member
    from Oregon

  6. meferflatheads
    Joined: Jun 29, 2009
    Posts: 38

    meferflatheads
    Member
    from Oregon

    how do I post a picture?
     
  7. meferflatheads
    Joined: Jun 29, 2009
    Posts: 38

    meferflatheads
    Member
    from Oregon

  8. big creep
    Joined: Feb 5, 2008
    Posts: 2,945

    big creep
    Member

    photobucket account. post there and then copy and paste image here.
     
  9. ZRX61
    Joined: Jul 10, 2006
    Posts: 175

    ZRX61
    Member
    from The AV

    You'l need the tach generator to go with it.
     
  10. F&J
    Joined: Apr 5, 2007
    Posts: 13,217

    F&J
    Member


    go to the bottom below reply, then click GO Advanced to get a new page..

    Then you go to the part of the page to click on 'Manage Attachments'

    click that to get the browse button to link to your files
     
  11. VonWegener
    Joined: Nov 19, 2009
    Posts: 784

    VonWegener
    Member

    Doesn't such a tach redline at 3000RPM? Most airplane engines turn very slow because when their props go supersonic they lose their ability to move air.
    That distinctive sound on takeoff by a WWII trainer plane called T6 is the prop tips going supersonic.
     
  12. 375instroke
    Joined: Dec 7, 2005
    Posts: 30

    375instroke
    Member
    from seattle,wa

    How many cylinders did the original motor have? That's very important.
     
  13. Pete1
    Joined: Aug 23, 2004
    Posts: 1,764

    Pete1
    Member
    from Wa.

    Most of those tachs ran off of a small rotary transmitter/generator
    and were 24 volt. It is possible to build a solid state sender but it
    isn't going to be easy or cheap. If it is only a 3 or 4 thousand maximum
    reading, you could make a new face and recalibrate to any rpm max.
    Again, not easy.
     
  14. rainh8r
    Joined: Dec 30, 2005
    Posts: 792

    rainh8r
    Member

    A friend of mine makes digital conversions for old tachs, so having a sender isn't really a necessity if you want it to work. Let me know if you're interested and I'll get you the contact info.
     
  15. Chevy Gasser
    Joined: Jan 23, 2007
    Posts: 695

    Chevy Gasser
    Member

    All aircraft radial engines have an uneven number of cyls.
     
  16. scottybaccus
    Joined: Mar 13, 2006
    Posts: 4,109

    scottybaccus
    Member

  17. Hal_396
    Joined: Apr 14, 2009
    Posts: 310

    Hal_396
    Member

    Not that this is a big deal but aircraft use 28 VDC.
     
  18. Chevy Gasser
    Joined: Jan 23, 2007
    Posts: 695

    Chevy Gasser
    Member

    O.K. We'll get technical. Single banked radial aircraft engines have an uneven number of cylinders. So a double bank 3 cyl. is 6 cyls. and a double banked 5 cylinder is 10 cyls.
    It is still a cool deal and would be neat to have. It may even work but maybe not accurately. The cool factor overrides innacuracy in my book.
     
  19. Warpspeed
    Joined: Nov 4, 2008
    Posts: 528

    Warpspeed
    Member

    All four stroke radial engines must have an odd number of cylinders ON EACH BANK.
    Sure there are multi row radials with even numbers of cylinders, but not single row.

    *edit*. You beat me to it Chevy.
     
  20. CadillacBob
    Joined: Jul 12, 2009
    Posts: 14

    CadillacBob
    Member

    If you can get me the part number and the manufacturer off of the data plate, I can help determine what it will take to hook that bad boy up.

    I am an aircraft instrument technician and work with this stuff every day. While there are a myriad of variations in tachometers, and this one might not work for your application, we may be able to find one that will.

    Let me know what you find out and I'll work with you to get the info you need.

    A couple of years ago, we converted a WWII temp gauge and bulbs to work with a Lincoln Flathead V8 that went into Hudson Joe's roadster project. That turned out REALLY nice!

    Bob
     
  21. gbones32coupe
    Joined: Jan 1, 2007
    Posts: 577

    gbones32coupe
    Member

    can you buy a cheapy tach and swap the insides?
     
  22. jandersonheads
    Joined: Feb 10, 2010
    Posts: 33

    jandersonheads
    Member

    I had a shop in my town convert a MECHANICAL tach to a 6 volt positive ground tach for me. ANYTHING is possible. Don't give up on it. It would be really cool. PM me if you want the name of the shop that did it for me. Very reasonable pricing.
     
  23. meferflatheads
    Joined: Jun 29, 2009
    Posts: 38

    meferflatheads
    Member
    from Oregon

    O.K. i think i got a picture on here

    [​IMG]
     
  24. meferflatheads
    Joined: Jun 29, 2009
    Posts: 38

    meferflatheads
    Member
    from Oregon

    General Elecrtic
    BU. AERO US NAVY TACHOMETER, MARK V
    F.F.S.C.No 88-I-2500
    MFRS Part No8D113 AAT22
    this is what is on the id tag
     
  25. Warpspeed
    Joined: Nov 4, 2008
    Posts: 528

    Warpspeed
    Member

    What sort of car engine has a red line of 3,000 rpm ? And three sweeps of the dial as you are accelerating up through the gears might be a bit confusing too. That pointer is going to move damned fast. I just cannot see how it is going to be useful in any sort of road application.
     
  26. I'll give you $20 for it since all the experts here are saying its useless :D
     
  27. rotorwrench
    Joined: Apr 21, 2006
    Posts: 633

    rotorwrench
    Member

    I still work on the old Bell 47 helicopters on occasion and they use the same basic tachometer generators that were used on the round motors of the WWII era. Hell a lot of them have AN (ARMY/NAVY standard) or MS (military standard) part numbers on them. The tach generator generates a current (actually an alternating current like an alternator) that is calibrated to make the indicator movement for the correct rpm. They require no outside electrical connection other than for a post light next to the indicator to light them up for night flying. They usually have three wires or two wires with an interconnected shield running between the tach/gen and the indicator.
     
    Last edited: May 5, 2010

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