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Need help finishing a four on the floor car.

Discussion in 'Building tips' started by Larry c, Mar 10, 2021.

  1. Larry c

    Larry c Lurking

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    My friends son has no Dad so I was asked to help him build a car by this Friday's weigh in. The little guy has a Mom and three sisters and is a great kid that needs some confidence. Here is what We've got so far.

    Rules
    basic rules plus these
    All 4 wheels touch at the same time
    standard BSA wheels and axles. You cannot remove material from them or change their shape. You can sand and polish them to remove burs.
    Beyond that, I think everything is up the creativity of the boys.

    Below is a picture of our first run at building something. I did order the pro driller tool from pinewood. Plan on canting the rear axles 2.5 degrees. As for the front we were going to shoot for a rail car with the passenger side axle bent to allow a 3-4" steer into the rail over a 4 foot run. The other front I was going to either keep straight or bend also slightly toed out and try and get it to where it's barely touching. The wheel base will end up around 5 3/8". Also the tires have been prepped (lathed and coned). We will use pledge with the pipe cleaners and then graphite. I'm planning on distributing the extra weights in the pocket to get the COG between 3/4" and 1 ". I have extra tungsten on the way. Not sure how best to place the weights from side to side weighting and how to secure them to the wood. The vinyl is a sticker used on airplane wings that will wrap around the entire car.
    Any help is much appreciated as I've tried to read everything I could on the forum and appreciate the information I've gained so far.


    car.jpg IMG_1281.jpg
     
    Last edited: Mar 10, 2021
  2. T-Bone Racing

    T-Bone Racing District Champion

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    If you plan on building a second car, and can make the adjustment, a 3 degree cant is typically what you want in the rear.

    To secure the weights, try running a piece of tape from the end of the weight pocket, and then wrap it around the back and leave a little bit on the top. You can also use a little bit of school glue to secure them, this way, you can get them out.

    Another huge thing for scout cars is the rear axles. Rotating the position after they’re installed makes a difference! If you can, tune them and see if the car sounds better rolling on a table of some sort.
     
    karlaj likes this.
  3. bracketracer

    bracketracer PWD Royalty Pro Racer

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    Just for clarification, regarding the wheel rules you said "You cannot remove material from them or change their shape." but then you said you have lathed and coned wheels. Are you sure those are going to be accepted?

    When you go to set the steer on a four touching car, set it first with the fourth wheel not touching. When you get the number you're looking for, then lower the fourth wheel until it rolls but does not change the steer you set.
     
    Castoro Racing likes this.
  4. Keith A.

    Keith A. Pack Champion

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    Whoa, is this actually effective? With all other things being equal, does a rail-rider with 4 touching actually perform better than a proper aligned straight car?
     
  5. karlaj

    karlaj Pinewood Ninja

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    What bracketracer said sounds right. Tune the car w/ 3 touching, get the wheel barely touching but not affecting the steer (guessing weight on 4th wheel is below 1 gram). Rail-riding vs straight? I'm pretty new here but unfortunately, I can tell you from experience that straight is slower b/c our car bounced around the rails alot. But I'm happy to be shown otherwise.
     
  6. TRE

    TRE PWD Royalty Pro Race Winner Pro Racer

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    You will never get the car to run straight..a rail rider is always faster
     
  7. bracketracer

    bracketracer PWD Royalty Pro Racer

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    You've heard the expression that the shortest distance between two points is a straight line? Well, a rail rider is your best shot at running a straight line down the track. Regarding three vs four wheel touching, you'll give up about .010 sec on a 42ft BestTrack having the fourth wheel down but if the rules require four touching, I feel the alignment technique I posted gives the best result. If you have four mini scales to set the car on, you should see a little less than the bare wheel weight on that fourth scale. We had to run stock weight wheels so the bare wheel would be around 2.5g, the scale would show 2.0-2.1g. If you don't have enough weight showing, the wheel may not roll reliably for check in.
     
    Keith A. likes this.

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