Is it better to make a three wheel car or change car from graphite to oil. Don't know the process at all, but can get the DVD. Thx
Lose wheel or graphite
- Thread starter Rocket car
- Start date
Paper beats rock....oh wait I wondered for a minute!
Get the DVD, best investment you can make to learn oil.
Get the DVD, best investment you can make to learn oil.
if your car already has graphite you will need to remove the wheels and axels clean them with 91% alcohol then use the oil. go to DD4H get the good stuff
If I could only do one I would go with a 3 wheel rail runner instead of oil if it is a scout race.
Three wheels are not mentioned is our district rules. Oil is technically illegal . If I pull the wheel off and install a pin they will give me the anal exam for sure. So that's why it's an either or. Thx
My granddaughter got plenty of questions and pleas to the judges from other competitors in the open division with three wheels at the districts. The open rules allow "anything goes", except propulsion devices. You can add any weight you want. Some cars had 10 oz. The three wheels will get more questions in the scout division. The question needs to addressed before the rules are published. Just build a car that will beat everyone even if someone else tries to sneak lighter wheels in. Graphite is getting very fast.
I have been playing around with unlimited weight with last years SR cars. There is a point of deminiting returns. 12 oz is too much. I haven't found the perfect weight yet, but I think it will be about 7 or 8 oz. Did the same with a bearing car. I got very little return after 5.5 oz. About 5/1000 with 6 oz. No more speed with 7 oz. BTW, a 5oz bearing car beat the heck out of the SR with 7 or 12 oz by over 12 inches.
IMO, go with the 3 wheel rail runner. Although the DVD is very informative and will teach you everything about oil, using oil is a time consuming learning process. Unless you have time to test and perfect your oil prep process it is better to stick with graphite. Go with DD4H graphite it is incredibly fast.
I agree with Oparennen. The ideal weight for those races that allow any weight is anywhere from 5.4 to 7. Beyond that the car slows quickly on the straights.
OPA, I am doing the same tests for an unlimited weight race coming up in a month. I can totally support your finding that just running the bearing car can not be beat. I am working on a heavy car I think I can increase the speed up to just over 12 oz.. This needs to take place without increasing the height of the car or one will lose speed due to more drag and instability.. As weight gets added, the COM will move to the center of the car, and you also need to keep it so it still runs on three wheels.
Now we also have the rule no lead- and so I am also working on a good system that can keep the cost of 12 oz to lower than tungsten costs and still fit. Then I will try to win the race with the heavy car- and after the race, when I can control what cars are on the track, I will show what the bearing car can do. Because it is in a old rotten wood track, I do not want to run the bearing next to just any car, and I am not going to let them use my aluminum track with Mad Max cars of unknown height.
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Now we also have the rule no lead- and so I am also working on a good system that can keep the cost of 12 oz to lower than tungsten costs and still fit. Then I will try to win the race with the heavy car- and after the race, when I can control what cars are on the track, I will show what the bearing car can do. Because it is in a old rotten wood track, I do not want to run the bearing next to just any car, and I am not going to let them use my aluminum track with Mad Max cars of unknown height.
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Txchemist,
You are right on about the COM and the drift. With the 12oz car, I kept making test runs, starting with 12 inch veer, and moving down. I ended up with the best time of 2.945 with a drift of only 1.5 inches, and 3 wheels. My track time of 2.945 times .995 would be NPWDRL track in Utah. I am sending the car to a son in Olympia, Washington. I cut a 1/32 piece of sheet-lead(which you can cut with sissors) exactly to fit the bottom of the car , from the rear to just in front of the front axels (12.5 oz), (vs. 2.850 for a 6 oz bearing car) . Then I ironed on a piecd of Monokote to cover the lead completely. I have a second car I will also send, that I am working on now, and it will be 8 oz, but the same shape all around.
You are right on about the COM and the drift. With the 12oz car, I kept making test runs, starting with 12 inch veer, and moving down. I ended up with the best time of 2.945 with a drift of only 1.5 inches, and 3 wheels. My track time of 2.945 times .995 would be NPWDRL track in Utah. I am sending the car to a son in Olympia, Washington. I cut a 1/32 piece of sheet-lead(which you can cut with sissors) exactly to fit the bottom of the car , from the rear to just in front of the front axels (12.5 oz), (vs. 2.850 for a 6 oz bearing car) . Then I ironed on a piecd of Monokote to cover the lead completely. I have a second car I will also send, that I am working on now, and it will be 8 oz, but the same shape all around.
OK, I made a series tests of excess weight using one of my last year's SR cars (IROCZ, 9 inches, 6 oz, all the weight to the rear, raised NDW, other 3 wheels using DD5H's Cheetahs, with a 6 inch between axels). During the year, the car was always first of 2nd place.
At 7 oz, 14 inch drift, the car picked up almost 1/100th
At 8 oz, 7 inch drift, the car picked up another 1/100th
I changed the drift to 4 inches, and picked up another 100th
At 9 oz, the car became slower. I made all kinds of changes and tests, but could never equal the 8 oz time.
As I mentioned above, I tried the same with a bearing car, and 5.5 ounces was the optimum. AND the bearing car was over 12 inches faster than the heavy SR car.
I decided not to test an SS car, because almost all the unrestricted races that I am aware of make tests of SS (BSA) cars unnecessary.
At 7 oz, 14 inch drift, the car picked up almost 1/100th
At 8 oz, 7 inch drift, the car picked up another 1/100th
I changed the drift to 4 inches, and picked up another 100th
At 9 oz, the car became slower. I made all kinds of changes and tests, but could never equal the 8 oz time.
As I mentioned above, I tried the same with a bearing car, and 5.5 ounces was the optimum. AND the bearing car was over 12 inches faster than the heavy SR car.
I decided not to test an SS car, because almost all the unrestricted races that I am aware of make tests of SS (BSA) cars unnecessary.
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