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Lowest hanging fruit on scout cars?

Discussion in 'General Pinewood Derby Discussion' started by karlaj, Nov 21, 2020.

  1. karlaj

    karlaj Pack Champion

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    Hi Folks,
    Now that I've taken a couple weeks to digest the last 7+ years of discussion, I'm finally ready to jump into the shark tank. Apologize for the long post, but maybe this will spur some discussion!

    Looking for low-hanging fruit. 5kidsracing's guide was pretty helpful, I assume his methods are well-accepted for scouts?

    I should preface that I'm just looking at scout-legal racing for now. My son is pretty clever and enjoys the process and designing his cars, but mostly he enjoys winning. I've figured out enough to put us into contention at the district, but we're consistently ~0.01-0.02+ behind the best. Track isn't consistent year-to-year, nor particularly well-maintained.

    Our rules are graphite, wheels+axles from an official pwd box, only mold projections on wheels removed (no lathe turning to reduce running surface or reduce weight). That cuts down the number of dd4h's products I can use, but I think there's plenty of speed to be found there.

    I think the basics are fairly clear. Slim body, rear-weighted, rail running, polishing axles and hubs. Anything to add?

    The first 2 aren't a problem. I have tungsten and even cast bismuth-tin alloy into cavities. If you've seen my lava car, you'll know I have to work with weird car shapes.

    Wheels are my weakest point. I hunt for the best-balanced wheels, and can usually get pretty good ones but it's a pain. I'm planning to order Dynasty BASX Tall. I think I still need to polish and burnish, so I've got novus2 (that stuff's amazing) and will grab Red Rocket and graphite.
    But I'm bad at polishing hubs. I've tried HobELube and a regular q-tip in a slow drill, but I don't think that's helped. The novus2 should help, and I've seen enough videos to practice that. But I think I'm losing speed rubbing the car body, maybe at the nail head too, but dont' see how to polish those effectively. Maybe I'm overthinking it. Is there >0.01s to be won here?

    I'm making my tuning board. I hope that tuning to ~6" drift /4' is the winning formula for us due to the shoddy tracks. Or, do we aim for 4"? Can't test beforehand. (and in the past I've used the infamous treadmill, but I've learned my lesson there) I have the basic axle jig, so I can at least drill straight holes, but don't have anything fancier so won't attempt to drill canted holes bc no way they'll be true+straight. I still think this will easily drop ~0.01+ s, and seems like the easiest low-hanging fruit. And it's something my son and I can work on together!

    Axle polishing I feel ok on. I've got files, sandpaper, and leather. These already come out mirrored. I'm adding brasso because it won't hurt. I'll probably order DD4H's speed axles, since I don't think BSA elite axles would be allowed (axles must be from a kit). Maybe a couple 0.001's? Anyone found more speed than that?

    Thoughts? And thanks in advance!
    -karlaj

    p.s. I can't access the dd4h site from my computer (all browsers: This site can't be reached), only my phone. Seems odd.
     
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  2. ljo

    ljo District Champion

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    If rules allow for canted wheels, do it! If I didn't have provisions to drill canted axle holes,, I would buy a predrilled body and not feel guilty about it. Another recommendation is the place rear axle holes 5/8" from the back with an overall wheelbase of 4.75-5". If the track is rough you may be able to use less steer with a 5 inch wheel base.
     
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  3. karlaj

    karlaj Pack Champion

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    Good thoughts. Canted wheels are allowed. But we have a max 4.5" wheelbase, and I remember them checking that. I will look into the pre-drilled body with wheels back -- nothing stipulating we have to use the axle slots, so maybe we won't!
     
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  4. Eric Scheid

    Eric Scheid Bent Axle

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    Totally agree with above. Will help a lot with stability. Get a lighted magnifying lens to inspect wheels and axles. The pipe cleaners and q tips leave a lot of lint. Also having your own digital scale (or 3 so you can check each wheel) is good. Get this: jig-a-loo on eBay. spray prepped and clean axles. Let dry. Don’t spray the wheels.
     
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  5. karlaj

    karlaj Pack Champion

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    Eric, thanks for the feedback.

    You mean canted axles for stability? OK, I'm definitely going to look into pre-drilled bodies more. Canted also makes alot of sense--wider wheel stance is better, so every mm helps.

    I found my son's magnifying glass--and just playing around with that I definitely see plastic bumps in the wheel bores, but they actually look fairly smooth (to my surprise). Maybe better mag will let me see more flaws. Seems like a pretty easy thing to quickly smooth the insides with novus2 before doing any kind of spin test for roundness with an old axle. I'm getting a jewelers loupe (loop?), so I hope that will up our game.

    In my case, "Only dry lubricants, such as graphite, may be used. Oils and silicone sprays are prohibited.". So we're graphite-only. My understanding is extra coatings like pledge would be forbidden. (it's a silicone spray, even though there's no way for them to check!) Red Rocket seems ok, as it's dry. Plus, Jig is for oil lubrication unless I'm mistaken. I guess no-oil is good, b/c it simplifies my prep.
     
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  6. Eric Scheid

    Eric Scheid Bent Axle

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    Ok it seems perhaps jig is off your options. I consider it the last part of prep rather than a “lube”. I use it pre graphite because it dries. If that is wrong others will chime in.

    yes angle in the rear does many good things including putting gravity on your side as the wheels work towards the heads instead of wobble. Becomes important to prep that interface. You cannot get rid of mass related friction but you can reduce where you have to fight.
     
  7. Brian Stanley

    Brian Stanley Workshop Leader Pro Racer

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    Pledge is a wax, same as Red Rocket, neither are lubricants.
     
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  8. karlaj

    karlaj Pack Champion

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    This is what I found on the SC Johnson website for lemon pledge (attached). It says unambiguously that it has silicone oil, and that’s part of why it works well. So, for our scout races it’s out, and I have to find speed elsewhere.

    Now if we start doing league races, you can bet it’s going on! And then I’ll only get smoked by 0.1s instead of 0.15!
     

    Attached Files:

  9. Loud2ns

    Loud2ns Rail Runner

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    Could you post your rules for lubricant?
     
  10. Brian Stanley

    Brian Stanley Workshop Leader Pro Racer

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    Red Rocket contains silicone as well.
     
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  11. karlaj

    karlaj Pack Champion

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    Oh, that’s good to know. Thanks for the heads up!
     
  12. karlaj

    karlaj Pack Champion

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    Sure—It’s brief: “Only dry lubricants, such as graphite, may be used. Oils and silicone sprays are prohibited."

    Or i think it was also explained: “if it flows, it don’t goes (on your car).” I’m willing to push into waxes and powders, but if they leave a liquid film after application/curing then its out.

    and I hope nobody misunderstands me—I’m not trying to be combative, I just wanna work within my rule, even if they’re silly and unenforceable.
     
  13. Mojo Racing

    Mojo Racing National Contender Pro Racer

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    If it is as you are thinking it is, they are saying no axle polish because it was a liquid to start with... they are not saying that. They mean it in the sense of your main lubricant... which is graphite in your case.

    They aren't going to ask what wax you are using, or what you put onto your axles. They are looking to see if you are using graphite or if you are using an oil for a lube.

    Use Lemon Pledge, and graphite, you will be within your rules. Even the stupidest rules that I have seen in cub packs, and I have seen a LOT of them, don't say you can't prep your axles.
     
  14. karlaj

    karlaj Pack Champion

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    thanks Mojo. Upon reflecting, I think you’ve nailed it. No need to further rethink this.
     
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  15. Mojo Racing

    Mojo Racing National Contender Pro Racer

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    Happy to help. :D
     
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  16. karlaj

    karlaj Pack Champion

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    I put together my tuning board using an old 5' closet shelf. Marked it off, then ran several of our older cars to see how they were really running. To my surprise, they ran really straight--probably too straight (<1" steer / 4'). Am I correct in thinking that this would result in inconsistent times? I.e. when setup straight it's good; but if it's off a bit, there's not enough steer to correct it and it'll bounce around?

    And now I'm just wondering how much time we gave up over the last 2 years to a treadmill. That's probably good news, actually, because we should see pretty big gains getting that fixed.

    So, how deep does this rabbit hole go?
     
  17. Gso125 Racing

    Gso125 Racing Workshop Leader Pro Race Winner Pro Racer

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    Glad you’re using a tuning board now. Treadmills scare me in more than one way hahaha
     
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  18. Loud2ns

    Loud2ns Rail Runner

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    This is where I was going to go........I'm just not as eloquent as Mojo.
     
    Last edited: Nov 23, 2020
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  19. Loud2ns

    Loud2ns Rail Runner

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    Possibly...... if the car had the wiggles it could be due to not enough steer and that would give inconsistent times.
    How aggressive are you weighting the car?

    Deep, very very deep. Lol
     
  20. karlaj

    karlaj Pack Champion

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    just under and inch in front of the axle.
     

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