Hi all!
We took home top prize at the pack race today thanks to the wonderful advice from this sub. Unfortunately we didn't get any sub 3 second times which I think is partly due to the wheel prep. The body was a thin wedge 5/8" in the back and 3/8" in the front. Manually routed out the body using a dremel. Body was about 9 grams total after routing. On the underside toward the back I drilled 5 holes for tungsten cylinders (3 behind the rear axle and 2 in front). I only used the two holes in front of the axles though because of weight limitation and COG concerns. I filled over all the holes with epoxy putty. Eventually I placed clear packing tape over the entire bottom portion. On top I used a 3.5oz canopy positioned as far back as possible. I then drilled into the back of the car which connected to an empty cavity that was drilled from the underside to sneak in some last minute tungsten putty. This is why I have black duct tape covering the back. My COG was slightly over 1/2" from the rear axle. I canted the rear wheels at 2.5 degrees and used a 1.5 degree bent front axle with about 4" of steer over 4 feet. Front non-dominant wheel was bent up as I didn't have room to drill a raised straight axle. The wheels and axles where purchased on amazon. Wheels were derby dust Xlite 1.5 grams. 3 straight axles were derby dust and bent axle was 1.5 degree bent axle from pinewood pros. The decorations on the car was an afterthought, we just wanted speed. Unfortunately I didn't do any wheel bore prep other than burnishing graphite. I attempted to polish one wheel with Meguiar's plastX but completely bent the bore and got scared. Next year we'll try a 3 stage polishing system.
Overall I was happy with the way it raced. Averaged about 3.085 seconds. The next fastest car was about 3.15 so we had a comfortable advantage. I'm assuming a good wheel bore polish could potentially take us down under 3 seconds next year. Any comments or criticism would be great! thanks again for all the tips!
We took home top prize at the pack race today thanks to the wonderful advice from this sub. Unfortunately we didn't get any sub 3 second times which I think is partly due to the wheel prep. The body was a thin wedge 5/8" in the back and 3/8" in the front. Manually routed out the body using a dremel. Body was about 9 grams total after routing. On the underside toward the back I drilled 5 holes for tungsten cylinders (3 behind the rear axle and 2 in front). I only used the two holes in front of the axles though because of weight limitation and COG concerns. I filled over all the holes with epoxy putty. Eventually I placed clear packing tape over the entire bottom portion. On top I used a 3.5oz canopy positioned as far back as possible. I then drilled into the back of the car which connected to an empty cavity that was drilled from the underside to sneak in some last minute tungsten putty. This is why I have black duct tape covering the back. My COG was slightly over 1/2" from the rear axle. I canted the rear wheels at 2.5 degrees and used a 1.5 degree bent front axle with about 4" of steer over 4 feet. Front non-dominant wheel was bent up as I didn't have room to drill a raised straight axle. The wheels and axles where purchased on amazon. Wheels were derby dust Xlite 1.5 grams. 3 straight axles were derby dust and bent axle was 1.5 degree bent axle from pinewood pros. The decorations on the car was an afterthought, we just wanted speed. Unfortunately I didn't do any wheel bore prep other than burnishing graphite. I attempted to polish one wheel with Meguiar's plastX but completely bent the bore and got scared. Next year we'll try a 3 stage polishing system.
Overall I was happy with the way it raced. Averaged about 3.085 seconds. The next fastest car was about 3.15 so we had a comfortable advantage. I'm assuming a good wheel bore polish could potentially take us down under 3 seconds next year. Any comments or criticism would be great! thanks again for all the tips!
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