I had a coworker ask me to help his son on his first derby car. He's a Tiger but he's super competitive in everything, just like his dad. I asked his dad for a copy of the rules. It was just half a page, the upshot was that there had to be four touching, use the slots, wheels are untouched, AND NO BENT AXLES. Oh geez. OK. I'll skirt the discussion on how stupid that is to require four touching but allow no easy method to achieve that goal. And I'll also not point out that bending a front axle is free and any scout can do it easily with a hammer and a screwdriver. OK, so I asked him to drop off the block so I could square it up ahead of time. I made some test drills on scrap planks to get the alignment at least pretty close. I settled on drilling the RF hole 2.5 degrees down and 1.25 degrees forward and the LF at 2.5 degrees down and 1 degree towards the rear with the LF hole .005" higher than the RF to take some load off of the LF. Rears were 3 degree cant and when I checked them on my new test fixture I was happy to see that they were "LB approved perfect" LOL. I drilled his actual block right above the slots and deepened the slots to meet the holes. Then I trimmed off the bottom of the block.
Build day comes and the little guy is very excited to start. I ask him if he's thought about what he wants his car to look like. He says "Dad says thin to win!" LOL. So I cut the block down to a 5/16" plank and hand it to him. I direct him to the sander and he and his dad shape the nose to a point. Then we go to the mill and he carefully cut his weight pockets. I had to get a step stool for him because he couldn't reach the handles! LOL. Normally we cut in lightening pockets now but by this point his attention span is growing short so we leave the plank otherwise unlightened. I gave his dad some pointers on axle polishing and some supplies and they leave. During the week, they get the graphics applied, put nail polish where the wheels would rub, and polish the axles. According to the rules the wheels have to remain untouched and three of his actually look really good so we swapped out the one wobbly wheel. They bring the pieces back when they're ready and we add weight to get it to 4.99 ounces. The pack does their weigh in on a hundredth ounce scale so there's no .044 ounce fudge factor this time. I applied a coat of tungsten disulphide powder to the bores, then his dad and I burnished the graphite and install three of the wheels. We roll it down the tuning board on three wheels and the drift is a little light. Even though the axles aren't bent, they are oval shaped so I turn the RF axle a fraction CCW until the drift adjusts to 5" in 4'. We put the LF wheel on and the drift reverts to about 3" so we turn the LF axle a bit until the drift comes back to 5". The track's always set up so we gave it a few runs to break in the graphite. It was about .020 off the fastest four touching car we've ran but that car had bent front axles and polished wheels. We figured that with those rules it'd probably be good enough to at least get the little guy a trophy. We didn't want to overdo it and blow everyone else out of the water in his first race.
Fast forward to the weekend. My son, a Webelo II, has his last derby. I get a call from the Tiger's dad asking how race day went for us. My son won his rank and the overall and picked up the trophy for fast lap of the day. He tells his son the results and the boy's reply was "Dad, if I don't win fastest lap of the day, it's all your fault 'cause you helped!" LOL. I told you he was competitive!
So his race day comes and he handily wins his rank to advance to the finals. In the finals, the car keeps laying down consistent 3.6 second runs to take the overall and fast lap. I asked what the MOV was just to see how close we were since I'd never seen those rules before. Next fastest lap was 3.77 so he was about .110 faster a lap! Ooops! So much for not blowing them out of the water! LOL. I'm curious to see if they change the rules for next year.
Build day comes and the little guy is very excited to start. I ask him if he's thought about what he wants his car to look like. He says "Dad says thin to win!" LOL. So I cut the block down to a 5/16" plank and hand it to him. I direct him to the sander and he and his dad shape the nose to a point. Then we go to the mill and he carefully cut his weight pockets. I had to get a step stool for him because he couldn't reach the handles! LOL. Normally we cut in lightening pockets now but by this point his attention span is growing short so we leave the plank otherwise unlightened. I gave his dad some pointers on axle polishing and some supplies and they leave. During the week, they get the graphics applied, put nail polish where the wheels would rub, and polish the axles. According to the rules the wheels have to remain untouched and three of his actually look really good so we swapped out the one wobbly wheel. They bring the pieces back when they're ready and we add weight to get it to 4.99 ounces. The pack does their weigh in on a hundredth ounce scale so there's no .044 ounce fudge factor this time. I applied a coat of tungsten disulphide powder to the bores, then his dad and I burnished the graphite and install three of the wheels. We roll it down the tuning board on three wheels and the drift is a little light. Even though the axles aren't bent, they are oval shaped so I turn the RF axle a fraction CCW until the drift adjusts to 5" in 4'. We put the LF wheel on and the drift reverts to about 3" so we turn the LF axle a bit until the drift comes back to 5". The track's always set up so we gave it a few runs to break in the graphite. It was about .020 off the fastest four touching car we've ran but that car had bent front axles and polished wheels. We figured that with those rules it'd probably be good enough to at least get the little guy a trophy. We didn't want to overdo it and blow everyone else out of the water in his first race.
Fast forward to the weekend. My son, a Webelo II, has his last derby. I get a call from the Tiger's dad asking how race day went for us. My son won his rank and the overall and picked up the trophy for fast lap of the day. He tells his son the results and the boy's reply was "Dad, if I don't win fastest lap of the day, it's all your fault 'cause you helped!" LOL. I told you he was competitive!
So his race day comes and he handily wins his rank to advance to the finals. In the finals, the car keeps laying down consistent 3.6 second runs to take the overall and fast lap. I asked what the MOV was just to see how close we were since I'd never seen those rules before. Next fastest lap was 3.77 so he was about .110 faster a lap! Ooops! So much for not blowing them out of the water! LOL. I'm curious to see if they change the rules for next year.
