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    1. Kit: , by (Yearly Subscriber) Jo NZ is offline
      Builder Last Online: Jan 2020 Show Printable Version Email this Page
      Model Scale: 1/8 Rating:  Thanks: 1
      Started: 12-25-19 Build Revisions: Never  
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      Bloody Mary is a hillclimber, built in the UK by John and Richard Bolster in 1929, when they were both schoolboys. It has a wooden (ash) chassis and was originally powered by a single JAP V-twin of 750cc. Through the years, pre-war, it was refitted with bigger engines and ended up with two 1000cc JAP KTOR V-twins, mounted in tandem. It competed until 1959, when it was put on display at the Montagu Motor Museum - and it's still there. It appears these days at events like Goodwood - the picture below is a from recent visit.

      Bloody Mary in 1/8 scale scratch build-bm1-jpg
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  1. Jo NZ's Avatar Yearly Subscriber
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    Jo
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    The engines used in the final version, the JAP (for J.A. Prestwich) KTOR engine are more usually found at the front end of the Morgan 3 wheeler or mounted in a Brough Superior motorbike. It can be easily recognised by the external ohv valve springs.
    Luckily there are still drawings available for most of the engine (only because the microfilms were found in a gutter!) so I started by trying to make a cylinder barrel. The fins are a problem (getting them deep enough) but I could use a slitting saw on a rotary table, which would take forever (four barrels to make!). I tried a shorter slot using a lathe tool. I'll try it in place to see whether the fin depth is going to be seen. Here's the engines in situ

    Bloody Mary in 1/8 scale scratch build-img_0241-jpg

    And the trial cylinder - note that I miscalculated the pcd of the head bolts, so there are grooves down the bottom of the cylinder....

    Bloody Mary in 1/8 scale scratch build-img_3262_1-jpg

    Bloody Mary in 1/8 scale scratch build-img_3264_1-jpg

    It looks like it should work, although I will probably cut the head fins full depth.

    Now the chassis - I found some cedar of the right size (it scales out to about 3.75" by 1.8") and used brass sheet for the corner gussets

    Bloody Mary in 1/8 scale scratch build-img_3285-jpg

    The front springs are quarter elliptic and cord wrapped.

    Bloody Mary in 1/8 scale scratch build-img_0237-jpg

    The leaves are cut from 0.4mm brass sheet, the wrapping is crochet cotton (found in the sewing box).
    I discovered on about the fifth look at the photo (after I'd wrapped it of course) that I'm short by one leaf. There should be another long leaf on top of the one with the eye....

    Bloody Mary in 1/8 scale scratch build-img_3280-jpg

    Jo


    Bloody Mary in 1/8 scale scratch build
    Last edited by Jo NZ; 12-25-19 at 10:41 PM.
    QUOTE QUOTE #2

  2. JunkGTZ's Avatar VIP/Sponsor
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    Larry
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    Seeing the original front suspension doesn’t make a soul confident that it handled well or was safe racing up hills, but the fact that it was run until 1959 says one of two things. Either it actually functioned much better than it looked, or it was owned and driven by a succession of very crazy people! This is going to be fun to follow. You’re off to a great start.
    QUOTE QUOTE #3

  3. Jo NZ's Avatar Yearly Subscriber
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    Jo
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    The front suspension is actually from a GN. Mary held several hill records over the years, so was pretty quick - all in the hands of John Bolster. I suppose that with a solid (chain driven) rear axle you wouldn't have too much time to worry about the front end...


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #4

  4. ThierryD86's Avatar Yearly Subscriber
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    Thierry
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    Taken my pop-corn cone and a pint of cider and will stay stuck in front of the screen...really blown away by these promising starts...Thanks for sharing, Jo NZ
    QUOTE QUOTE #5

  5. Jo NZ's Avatar Yearly Subscriber
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    Thierry, you're welcome. I must revisit your Bugatti Thread, as I need quite a lot of chain (bike chain). There is a chain drive between the motors, then from the rear motor to the gearbox, and then from the gearbox to the back axle. Has anyone ever taken a photocopier apart? I think that there might be small size roller chain in some of them.


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #6

  6. Jo NZ's Avatar Yearly Subscriber
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    Jo
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    Now for the front spring mount. Not the most common type!
    The parts

    Bloody Mary in 1/8 scale scratch build-img_3286-jpg

    The bit that looks like a boat and the slotted T are silver soldered to make the bottom clamp plate. Everything seems to hang off this, which is why I've silver soldered it

    Bloody Mary in 1/8 scale scratch build-img_3296-jpg

    This bracket is important as it is the sole support for the friction damper/bottom radius arm, the hydraulic damper and the brake lever

    Bloody Mary in 1/8 scale scratch build-img_0238-jpg

    I made some M1.4 threaded rod to hold it all together. The rods are soft soldered into the bottom clamp plate

    Bloody Mary in 1/8 scale scratch build-img_3289-jpg

    Bloody Mary in 1/8 scale scratch build-img_3293-jpg


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #7

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