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This got ugly...

Discussion in 'General Pinewood Derby Discussion' started by karlaj, Feb 8, 2021.

  1. karlaj

    karlaj Pinewood Ninja

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    First, huge thanks to all y'all for help and feedback! Truly made a big difference unlearning a bunch of crap and getting better. But, having internalized the entire contents of about 10 years of data, forum information, and developed a machine-learning algorithm to sort fact from fiction (ok, I'm lying about that), I was reminded by my son that sometimes good enough is good enough.

    Pack race was actually a double pack race. I worked with my son to employ a few more things than we have in the past (better axel polishing, magnification, wheel bores, alignments, tuning board). But, what got him excited was that I let him bandsaw his own car, with dad nervously standing over his shoulder. The plan was to have him do all the steps and maybe use dd4h parts as needed (and they were nice to compare to as standards), but he just took ownership and wanted it to be his car and didn't care to spend THAT much time fixing EVERYTHING. So, that's how we rolled.

    And of course he ran away with it and won by 0.04s. Questions were asked (these cars only use graphite, right?). He also trashed every other Masters car except one (guess who). He had fun with it, and that's what mattered.

    What was also satisfying was seeing a kid I'd helped out last year improved as well (to 4th). Now I've got more knowledge to pass along to that family as well since I know they care.

    So, my son's pushing to go all in for his final district races and build a new car with a no-holds, in-it-to-win-it attitude. (he calls John the "Utah Guru") I'm pretty sure we've left a fair chunk of speed on the table, and I'm looking forward to us finding it over the next couple of months.

    ps. I'll update with pics when I get the cars back!
     
    Jupiter 2.9 and Loud2ns like this.
  2. Jupiter 2.9

    Jupiter 2.9 Workshop Leader Pro Racer

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    Send them into one of the "League race" test tracks. Data.
    Congratulations
     
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  3. karlaj

    karlaj Pinewood Ninja

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    I peeked around today but couldn’t find the new schedule. I’m totally ready to give it a try (current car v. new hotness), even if we’re the last two. Just gotta find when and where.
    And yep, Data always beats a thousand expert opinions.
     
  4. Loud2ns

    Loud2ns District Champion

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    Here is the schedule for NPWDRL.

    All start times are 5:30pm MT unless otherwise noted.

    Ice Series
    February 5th
    March 5th
    April 2nd
    June 4th - Ice Series Finals

    May 14th - Pinewood Derby Nationals at Mid America hosted by NPWDRL & APR


    Fire Series
    July 9th
    August 6th
    September 3rd
    October 1st - Fire Series Finals

    MOTM Finals Race - Nov. 5-6
     
  5. karlaj

    karlaj Pinewood Ninja

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    Thanks, finally found it. Some websites need updating. ;-)

    Watching the video of the scouts race, the speeds from the bottom cars are beyond us (we also run 42' best track, so comparable?). I knew the top was not reachable, but I'm not sure where to pick up 0.07s just to reach the very back of this pack. Do folks get feedback on their cars, or just times? TIA -karlaj
     
  6. T-Bone Racing

    T-Bone Racing District Champion

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    No track is exactly the same. Scout tracks and league tracks won’t be comparable even if they’re the same size.
     
  7. Castoro Racing

    Castoro Racing Council Champion Pro Racer

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    You will get times of course and there are a ton of guys always willing to give feedback and guidance. Most of us love talking about PWD non stop and enjoy getting new people into the hobby. Do your best, send it in, make friends and ask questions. That's helped me a catch up pretty quick.
     
  8. karlaj

    karlaj Pinewood Ninja

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    ok, first NPWDRL race in the books last night. Not unhappy with results, though we weren't good. We were Purple and Beskar, if you watch the Scout class.

    My takeaways:
    1. there is almost nothing that can be done with a standard PWD kit that will be raceable at the league level.
    2. Tracks can be WILDLY different. (3.17 pack, 3.07 league) I know that's not news, but it's still pretty unbelievable.
    3. Our faster car was much faster (0.05s). So dd4h parts >>>>> PWD kit (see above).

    I'll be curious how to improve. The race vid shows on the downslope our friction is a bit higher than the better cars. On the flat, we're not bad but had one run on the white track where we wiggled (but so did many others, maybe slightly more steer). So friction high, alignment meh to my untrained eye.

    We're restricted b/c this car has to race at districts with tall wheels (remove flashing, but leave the step), standard size axles, graphite only, but rail running is ok. John's body, axles, wheels. Axles polished with wet 2000 grit + brasso. Wheel bores got novus2 + red rocket (full cure). Tuned 4"/4'. I intentionally didn't pledge the axles to see how far back we're starting (others said maybe a .002s). But how much time am I giving up with the wheels? Sub 3 seems not far! TIA!
     
  9. B_Regal Racing

    B_Regal Racing PWD Royalty Pro Racer

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    Since you are using John's block, there is no need to talk about alignment, narrowing the DFW side for a rail rider, 3 wheels vs. 4 wheels, weight of the body, or weight placement within the body. Thin to win - do not add fins or anything decorative on the body. Fenders do help, both leading and trailing. Most league racers make them out of balsa, but it can be daunting if it is your first time. These are a nice alternative and really can be faster if the balsa fenders are not shaped correctly.

    https://www.derbydad4hire.com/Dynasty-High-Performance-GEE-DIAMOND-Fenders-GEED.htm
    https://www.derbydad4hire.com/Dynasty-High-Performance-GEE-DIAMOND-TRAILING-Fenders-GEEDT.htm

    If you have to use stock axles, be carefully not to over polish them. Remove the burrs on the head, but I would leave the crimp marks on the shaft and just polish it. It keeps the diameter larger to prevent wiggling. Also know that scout axles are bent and the rear is best when tuned. Turn the rear axles, one at a time and check the speed on a test track. You will need to put a "k-house" groove in the axle head to allow the axles to be adjusted with a regular screwdriver. You will see the speed increase and decrease by a large margin with each little twist of a rear axle. Once you find the best position of both rear axles, you can take them out, re-prep and put the axles back in the same position. Finding a track to test on will almost become a necessity as scout axles are just horrible.

    If you can buy straight aftermarket axles and use them, its highly recommended. You NEVER want to bend the rear axles. With straight aftermarket axles and John's body, the rear is plug and play

    Using stock wheels will be tough. Some are far worse than others, mostly due to runout. You would need a special gauge to check for runout, which would not be available to you unless you know a league racer. You can search through a bunch of wheels to find wheels with the least runout, but it would be better served to buy something like this:

    https://www.derbydad4hire.com/The-Dynasty-BASX-set-of-4-wheels-W-BASX.htm

    Leave the double step if it is in the rules. These wheels would satisfy any rule set out there (I'm not going to get into the debate of buying wheels vs an adult who has the capability to turn a nicely trued machined wheel). John would just true the wheel and save you $$$ from searching for good ones (by purchasing multiple sets) and save the cost of a gauge. If you ever have noticed some cars are very noisy going down an aluminum track, it could likely be a result of wheel runout (assuming the edges were properly prepped). Quiet cars are typically faster than those that are noisy.

    Polish the bore, edges that touch the track, and the hubs, removing the machining marks. The hubs of my wheels (and to some degree, the inside and outside edges) look very much like the bores. Edges and hubs are often overlooked. Polish the treads bumps of the front wheel.

    For the body, just know that spray paint is heavy. Most league racers cover the car with either monokote trim sheets or vinyl. Use pin striping for decoration.

    Polish the washers as well. If you can not use washers, find some thin clear Teflon tape / PTFE film with adhesive backing and use it as a friction plate. To me, its not a washer, but more of a sticker, so this fits most rules out there unless the rules state that the wheel must touch the wood. It's plug and play - super easy to apply.

    Set your steer to approximately 5" over 4'. I know this is more than what is recommended, but the extra friction will not be as costly if you car wiggles on one or more passes. Scout cars can be unpredictable, especially those you are racing against. If the inner edge of the front wheel is polished properly and you are racing on a nice aluminum track, the friction created with the extra inch of steer will be negligible at this level. You can always fine tune the steer as the cars races more.

    Make sure your car weighs 5.03 to 5.04oz if weighed on a 1/10 ounce scale; otherwise, get the car as close to 5oz as possible. Get 13 to 15 grams of weight on the front wheel. Cover all openings with either metal tape or packing tape (I always use lightweight metal tape).

    Before the race, make sure your wheels are absolutely clean. Do not put graphite on the surface of your wheels but you might encourage others to do so to give you an edge. :) Clean wheels will always be faster than dirty wheels. Use a nail file block or something similar (DD4H sells exactly what you need). I have taken scout cars (assuming they are built somewhat correctly), cleaned the wheels and have gain 5 or 6 thousandths almost every time, and in some cases, over 1 hundredth of a second.

    https://www.derbydad4hire.com/Pro-Wheel-Tread-Cleaner-T-PWTC.htm

    Race here. Send cars in, get a time, adjust, and race again. In the beginning, you are racing yourself. You ALWAYS pick up speed by racing - the more you race, the faster you will become. You should be able to easily break 3 seconds just with the tips above.
     
    Last edited: Mar 6, 2021
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  10. karlaj

    karlaj Pinewood Ninja

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    thank you Regal.
    In no particular order:
    We’re using John’s wheels, the ones you rec’d. Polished and prep’d with novus2 and red rocket. They’re relatively heavy but nothing I can do about it. Depending who I’ve asked, this could be 0.04s or less than 0.01s. Checked with jewelers loop and look very, very shiny and clean. Same the inner and outer hubs. Of everything, I’ve made biggest strides in speed here. and we definitely cleaned wheels before sending in, but I don’t have that tread cleaner yet.

    Also have John’s speed axles, as those are as far as we can go. Way rounder and smoother than box axles.

    No washers allowed. Teflon tape is an interesting idea for the front wheel. I’ll dig around more on that! Got a brand? Could be the single biggest thing I can still do.

    Our front weight had me nervous at 17-18g. We’ve never gone that light before! But it seems like we can bump down even more and be ok. We have to run std wheel base, but seems normal for Scout class. Will move the weights around for next month and try again, but can’t imagine we’re too far off here.

    The steer is also easy to bump up a bit. My rear gaps were fairly tight, but I think that’s ok. And, our district race will be either an old wood track or a long 49’ best track most likely. Both probably best to slightly oversteer than under.
    Thanks again!!!
     
  11. B_Regal Racing

    B_Regal Racing PWD Royalty Pro Racer

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    PM me an address...I'll send you some. Put it on the DFW and the rears. I have s small amount from when my son raced in scouts. If I have a wheel, I could send that as well for comparison.

    Gaps are tricky. I have had cars that like them lose whereas others like them tight. I can not explain why that is.
     
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  12. karlaj

    karlaj Pinewood Ninja

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    PM sent.

    You aren't lying about paint being heavy. When planning, we left a good margin to adjust w/ tungsten putty, but the several layers of paint and clear coats added a lot and we juuuust fit under. Another lesson learned there.
     

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