This is the first thread/question on my upcoming mini series of questions, sorry about the length.
I am at the point of not knowing what things to improve on to get better. We are doing graphite as that is what our local scout races are but will venture into oil soon. I don’t have a test track locally so that limits actual testing.
This is the first year my son and I have been involved with the PWD. He took first in his den, found this place made improvements and took first at the district (wolf division) and also set a new track record. Since there hasn’t been any information put out about a local council race I sent in his car (open scout/graphite) and an adult (graphite) car to the Mid America race.
I didn’t have any expectations of winning since we are new and both running stock tires and axles that were prepped at home. I wanted to see where we lined up with some of the country’s best racers that were using aftermarket parts against our stock parts. I figured this would be a good indicator of our prep process quality. I did consider buying DD4H axles and tires but the timing of me getting them in, prepped, and installed didn’t allow for it.
At the MA my son finished 10th out of 18 with an average time of 3.0205. We were only able to see one of his races online, (hopefully they will get all the video’s posted soon so they can all be reviewed) but it was enough to see that the lighter tires make a HUGE impact on starting speed. The one race I got to see had my son and the race winner next to each other. By the time the cars made it one car length off the starting pin, he was trailing by almost a ¼ car length, and by the time they hit the transition to the straight away he was more than a half a car length behind the winner.
My car finished 27th out of 64 in the adult graphite division with an average time of 3.0286. I was a little bummed that his car time beat mine, as based on weight placement alone my car should win all things being equal. Then I realized that we ran on two separate tracks so comparing the times is not a good comparison. I did have a couple last minute catastrophes with my car. The DFW was rubbing the fender and had to do some last minute sanding where I think paint and balsa dust were introduced into the hub, then just before I boxed the cars up to be shipped (at my office) I realized my scale readings from the night before were off and had to do make some weight reductions. Ended up pulling a row of tungsten cubes and bars and replacing them with putty (didn’t have enough cubes with me and the bar was too heavy. So I think the weight distribution was heavier on the NDFW when it had been on the DFW side.
I was pleased with our race finishes, but hoped for better times. I am going to do some investigating to verify the alignment is still correct, that the drift and tire spacing remained where it was set, double check the weight, and do a visual inspection of everything including the condition of the tires. When I got the cars back Wednesday I noticed a significant amount of graphite in the bottom of my son’s car shipping box and there was some in the bottom of my box as well. It is impossible to know if it happened when shipping to the race or on the return shipping back to us. I did a couple timed wheel spins on both of the cars for grins and giggles.
I realize that the wheel spin test is considered by many as not being a good indicator of prep or speed but without a track to test on it is all I have to go by currently.
I noticed a major reduction in spin time from where they were before shipping to the race, which was concerning since one car only ran 4 races and the other 6 races. I also looked closely at my son’s race times, with each race his time improved (3.0265 race #1 to 3.0172 race #6). My car’s four race times were fairly consistent. Between the graphite in the shipping boxes and the increase in speed with each race of my son’s car I thought maybe I was adding to much graphite and/or the graphite in the shipping box may have helped or hurt the cars speed. More graphite in my son’s box and his times got better with each race. Less graphite in my shipping box and my times were not great but were consistent.
I thought that by taking a car and adding graphite to the wheels then doing a timed spin test might help me to figure out if I am adding to much or not enough and that maybe the results would show me a clear add graphite/spin - add graphite/spin ratio. I was also hoping that maybe it help me to know when to stop spinning the tire to distribute or sluff off graphite after the last round of graphite was added so that in the future the cars could start racing just before the spin duration peaked.
Because I haven’t had a chance to really examine the two MA cars yet I decided to do a test on another car I had built that had been prepped similarly to both the MA cars. This car beat my son’s car on the district’s 49 foot track by a car length, but was run only once just for fun. I’m sure there was some tire spinning done between the one race and now a month later.
The test:
I understand that most of the variables in this test method are not fixed – finger pressure, force, and initial spin speed, how long it takes me to start the timer after spinning, accurate measurement of a “puff” of graphite, how much graphite makes it into the bore vs. remaining on the outside of the tire. Again I am trying to work with what I have available to me at the moment and thought I could gather at least some meaningful data.
Without any additional graphite added I took three separate spin times on each of the three operable tires to establish a base line the average was:
DFW (21) seconds, high time of (23), low time of (19)
RR (25) seconds, high time of (25), low time of (24)
LR (24) seconds, high time of (25), low time of (22)
There was no noticeable tire chatter. The car was held vertically (top of car body facing me with the front wheels at the top & rear wheels at the bottom. The car was also slightly tilted so that the tires migrated toward the axle head. This was the best position to eliminate toe in/out (slop between hub and axle) vibration. Guess it would have been easier to say that’s how the tires appeared to spin the best and straightest – LOL.
After running the base line spin test I added 4-6 good puffs of graphite working each puff into the hub by tapping, slowing turning, and/or moving the tire up and down on the axle. After the graphite was worked in I did 10 timed spins with the resulting mode (most recurring number in the set) being:
DFW (25) seconds, high time of (28), low time of (20)
RR (24) seconds, high time of (30),low time of (22)
LR (26) seconds, high time of (28), low time of (22)
A second round of 4-6 puffs of graphite worked into the hub as done previously was done. Resulting 10 spin time modes:
DFW (22) seconds, high time of (28),low time of (20)
RR (22) seconds, high time of (23), low time of (19)
LR (24) seconds, high time of (28), low time of (23)
A third round of adding graphite as before after ten spins yielded the following modes:
DFW (22) seconds, high time of (25),low time of (21)
RR (22) seconds, high time of (23),low time of (19)
LR (18) seconds, high time of (19), low time of (17)
What I find interesting and frustrating is that after the second round of adding graphite the spin times were slower. In the third round of adding graphite the spin times modes were the same except the LR that was noticeably shorter, AND now there was excessive tire chatter present. It was also clear when adding the third round of graphite the hubs seems to be getting “full”, meaning that more resistance was felt when tapping and turning the tire to get the graphite into the hubs.
Noticing the decrease in spin times and thinking too much graphite was added I expanded the timed spins to 20. The mode results for spins 11-20 are:
DFW (19) seconds, high time of (21), low time of (17)
RR (20) seconds, high time of (24), low time of (20)
LR (19) seconds, high time of (20),low time of (17)
What did I learn with this testing? Other than spending a lot of time and wasting a bunch of DD4H graphite that I am now even more lost in my understanding of how much and how often should be added than before I started the test. Although the test car was not run in a full 6 round race, it was run once over a month ago and did have some occasions where the tires were spun. I would have guessed that the second round of adding graphite would have resulted in the best spin times but it did not.
While prepping before sending the cars off I noticed while adding graphite to the two Mid America cars that the first round of graphite just after burnishing seemed to result in the best spin times. This observation isn’t documented with a stop watch but by using a mental count. It might be worthwhile to document spin times on the next fresh tire/axle combo I put together. But even if the best spin times come after only on round of adding graphite I wouldn’t think there would be enough in the hub to sustain it through 6 races.
I am pretty sure I read on this site that for the initial graphite prep after burnishing, graphite is added with the axle inserted, spun six times, with that process being done three times. This testing shows adding graphite/spinning three times is far too much, at least as a reprep process.
Input is welcome, tips from your proven burnish and graphite process is also very welcome. If it is top secret and you are willing to share I welcome PM’s as well! Other testing methods or constructive criticism of this test is also welcome.
More posts in my mini series of questions coming soon!
I am at the point of not knowing what things to improve on to get better. We are doing graphite as that is what our local scout races are but will venture into oil soon. I don’t have a test track locally so that limits actual testing.
This is the first year my son and I have been involved with the PWD. He took first in his den, found this place made improvements and took first at the district (wolf division) and also set a new track record. Since there hasn’t been any information put out about a local council race I sent in his car (open scout/graphite) and an adult (graphite) car to the Mid America race.
I didn’t have any expectations of winning since we are new and both running stock tires and axles that were prepped at home. I wanted to see where we lined up with some of the country’s best racers that were using aftermarket parts against our stock parts. I figured this would be a good indicator of our prep process quality. I did consider buying DD4H axles and tires but the timing of me getting them in, prepped, and installed didn’t allow for it.
At the MA my son finished 10th out of 18 with an average time of 3.0205. We were only able to see one of his races online, (hopefully they will get all the video’s posted soon so they can all be reviewed) but it was enough to see that the lighter tires make a HUGE impact on starting speed. The one race I got to see had my son and the race winner next to each other. By the time the cars made it one car length off the starting pin, he was trailing by almost a ¼ car length, and by the time they hit the transition to the straight away he was more than a half a car length behind the winner.
My car finished 27th out of 64 in the adult graphite division with an average time of 3.0286. I was a little bummed that his car time beat mine, as based on weight placement alone my car should win all things being equal. Then I realized that we ran on two separate tracks so comparing the times is not a good comparison. I did have a couple last minute catastrophes with my car. The DFW was rubbing the fender and had to do some last minute sanding where I think paint and balsa dust were introduced into the hub, then just before I boxed the cars up to be shipped (at my office) I realized my scale readings from the night before were off and had to do make some weight reductions. Ended up pulling a row of tungsten cubes and bars and replacing them with putty (didn’t have enough cubes with me and the bar was too heavy. So I think the weight distribution was heavier on the NDFW when it had been on the DFW side.
I was pleased with our race finishes, but hoped for better times. I am going to do some investigating to verify the alignment is still correct, that the drift and tire spacing remained where it was set, double check the weight, and do a visual inspection of everything including the condition of the tires. When I got the cars back Wednesday I noticed a significant amount of graphite in the bottom of my son’s car shipping box and there was some in the bottom of my box as well. It is impossible to know if it happened when shipping to the race or on the return shipping back to us. I did a couple timed wheel spins on both of the cars for grins and giggles.
I realize that the wheel spin test is considered by many as not being a good indicator of prep or speed but without a track to test on it is all I have to go by currently.
I noticed a major reduction in spin time from where they were before shipping to the race, which was concerning since one car only ran 4 races and the other 6 races. I also looked closely at my son’s race times, with each race his time improved (3.0265 race #1 to 3.0172 race #6). My car’s four race times were fairly consistent. Between the graphite in the shipping boxes and the increase in speed with each race of my son’s car I thought maybe I was adding to much graphite and/or the graphite in the shipping box may have helped or hurt the cars speed. More graphite in my son’s box and his times got better with each race. Less graphite in my shipping box and my times were not great but were consistent.
I thought that by taking a car and adding graphite to the wheels then doing a timed spin test might help me to figure out if I am adding to much or not enough and that maybe the results would show me a clear add graphite/spin - add graphite/spin ratio. I was also hoping that maybe it help me to know when to stop spinning the tire to distribute or sluff off graphite after the last round of graphite was added so that in the future the cars could start racing just before the spin duration peaked.
Because I haven’t had a chance to really examine the two MA cars yet I decided to do a test on another car I had built that had been prepped similarly to both the MA cars. This car beat my son’s car on the district’s 49 foot track by a car length, but was run only once just for fun. I’m sure there was some tire spinning done between the one race and now a month later.
The test:
I understand that most of the variables in this test method are not fixed – finger pressure, force, and initial spin speed, how long it takes me to start the timer after spinning, accurate measurement of a “puff” of graphite, how much graphite makes it into the bore vs. remaining on the outside of the tire. Again I am trying to work with what I have available to me at the moment and thought I could gather at least some meaningful data.
Without any additional graphite added I took three separate spin times on each of the three operable tires to establish a base line the average was:
DFW (21) seconds, high time of (23), low time of (19)
RR (25) seconds, high time of (25), low time of (24)
LR (24) seconds, high time of (25), low time of (22)
There was no noticeable tire chatter. The car was held vertically (top of car body facing me with the front wheels at the top & rear wheels at the bottom. The car was also slightly tilted so that the tires migrated toward the axle head. This was the best position to eliminate toe in/out (slop between hub and axle) vibration. Guess it would have been easier to say that’s how the tires appeared to spin the best and straightest – LOL.
After running the base line spin test I added 4-6 good puffs of graphite working each puff into the hub by tapping, slowing turning, and/or moving the tire up and down on the axle. After the graphite was worked in I did 10 timed spins with the resulting mode (most recurring number in the set) being:
DFW (25) seconds, high time of (28), low time of (20)
RR (24) seconds, high time of (30),low time of (22)
LR (26) seconds, high time of (28), low time of (22)
A second round of 4-6 puffs of graphite worked into the hub as done previously was done. Resulting 10 spin time modes:
DFW (22) seconds, high time of (28),low time of (20)
RR (22) seconds, high time of (23), low time of (19)
LR (24) seconds, high time of (28), low time of (23)
A third round of adding graphite as before after ten spins yielded the following modes:
DFW (22) seconds, high time of (25),low time of (21)
RR (22) seconds, high time of (23),low time of (19)
LR (18) seconds, high time of (19), low time of (17)
What I find interesting and frustrating is that after the second round of adding graphite the spin times were slower. In the third round of adding graphite the spin times modes were the same except the LR that was noticeably shorter, AND now there was excessive tire chatter present. It was also clear when adding the third round of graphite the hubs seems to be getting “full”, meaning that more resistance was felt when tapping and turning the tire to get the graphite into the hubs.
Noticing the decrease in spin times and thinking too much graphite was added I expanded the timed spins to 20. The mode results for spins 11-20 are:
DFW (19) seconds, high time of (21), low time of (17)
RR (20) seconds, high time of (24), low time of (20)
LR (19) seconds, high time of (20),low time of (17)
What did I learn with this testing? Other than spending a lot of time and wasting a bunch of DD4H graphite that I am now even more lost in my understanding of how much and how often should be added than before I started the test. Although the test car was not run in a full 6 round race, it was run once over a month ago and did have some occasions where the tires were spun. I would have guessed that the second round of adding graphite would have resulted in the best spin times but it did not.
While prepping before sending the cars off I noticed while adding graphite to the two Mid America cars that the first round of graphite just after burnishing seemed to result in the best spin times. This observation isn’t documented with a stop watch but by using a mental count. It might be worthwhile to document spin times on the next fresh tire/axle combo I put together. But even if the best spin times come after only on round of adding graphite I wouldn’t think there would be enough in the hub to sustain it through 6 races.
I am pretty sure I read on this site that for the initial graphite prep after burnishing, graphite is added with the axle inserted, spun six times, with that process being done three times. This testing shows adding graphite/spinning three times is far too much, at least as a reprep process.
Input is welcome, tips from your proven burnish and graphite process is also very welcome. If it is top secret and you are willing to share I welcome PM’s as well! Other testing methods or constructive criticism of this test is also welcome.
More posts in my mini series of questions coming soon!
