Awana race

[RockChalkRscing]

This is me saying thank you to everyone here. We got tons of advice here and through trial and error built not only a winner but a record breaker. Chloe's awana grand prix car ran a 2.35 in the race of champions. Link to the finals below.

This is a few months old but I started to get the bug again and have a few ideas on helping her defend her title next year. We noticed a few things about how other cars performed and identified a few things we could do to be better.

One glaring fact was we were consistent. She ran 2.42 in her four heat races with no drop off. The 2.35 was on her 7th run when I believe the oil had reached the optimum state. So basically I had slightly over lubed. Compared to the graphite cars we rocked as they slowed after every run.

Also, I have no idea how long the track is from memory but I'm sure you guys will know. And is this 2.35 time about right? I mean how much can I try to improve on our next build.

We were able to build bodies that weighed .8oz allowing for a huge amount of weight in the back. We three wheeled, rail rided our way to a win on lightened wheels rolling on polished axles and a modified oil process.

We learned a ton, my daughter loved science and talked to everyone about how we used it to go faster.

Thanks again for all the advice.

 

[Peregrine Racing]

Congrats and thanks for sharing the video.

 

[DerbyDad4Hire]

Awesome work!

 

[derbydentist]

Sounds like a great car there! Looks like you smoked em! Looks like a freedom track- most likely 32 feet long. You asked if there was a way to improve for next year - I think most pro racers try to have their car bodies under 10 grams- that should allow you to get an even bigger engine in the back- which can mean more speed! Great job

 

[RockChalkRscing]

Thanks. I cut several bodies using a laser last year and just weighed one we didn't use at 12.5g. So ive got room to get better. I'm positive I can get closer to 10g if not under. I didn't shape the nose to a wedge, just rounded it. There is some meat on the bone still we could trim. We may build a few and mail in to a race or two. Each with a different "test" setup. Awana race isn't for some time so we can test and tune.

 

[Wolfram Racing]

WOW! 2.35?!? We've been building cars on a 32 foot Freedom track for several years now. The closest time I have to that is 2.44xx from an unlimited style car with razor style bearing wheels and a solid rear axle. That is a crazy fast time.

 

[bracketracer]

WOW! 2.35?!? We've been building cars on a 32 foot Freedom track for several years now. The closest time I have to that is 2.44xx from an unlimited style car with razor style bearing wheels and a solid rear axle. That is a crazy fast time.

If you read on here long enough, you’ll find many, many posts asking something to the effect of “What’s a good time on X brand or X length of track?” And the response is always the same. It’s just impossible to compare times on two different tracks unless you run the same car on both tracks. The track in the video above appears to possibly be using a homemade timer in a wooden frame so that adds another huge variable. What it boils down to is that if your car won the race, on that track, on that day, against the other cars that showed up, then you were fast enough! Lol

 

[RockChalkRscing]

I talked to the director weeks before when we helped kids build cars and asked what was fast. His answer was anything under 2.5 was quick. Challenge accepted. ;-) I helped assemble and test on it. We were in the 2.45 range before lube a week before hand. The track is dirty, unpolished but not to banged up. I have no idea on the timer. I'm going to ask if I can clean and polish the track this year. Lots of graphite stains at the top. Hoping it will help all cars.

I have the laser cutter schedule for next week. Should cut 6 bodies then and start playing with them. I will reduce the weight of the bodies compared to last year, try a 1.5 by .5 weight vs cubes from last year and work the wheels and axles like last year but with less oil. Our cars last year weren't pretty. We may work on that too. My daughter is already playing around with the CAD file for her laser cuts. I have to find a sander to do some more work. May need to try a harbor freight one.

 

[Wolfram Racing]

I talked to the director weeks before when we helped kids build cars and asked what was fast. His answer was anything under 2.5 was quick. Challenge accepted. ;-) I helped assemble and test on it. We were in the 2.45 range before lube a week before hand. The track is dirty, unpolished but not to banged up. I have no idea on the timer. I'm going to ask if I can clean and polish the track this year. Lots of graphite stains at the top. Hoping it will help all cars.

I have the laser cutter schedule for next week. Should cut 6 bodies then and start playing with them. I will reduce the weight of the bodies compared to last year, try a 1.5 by .5 weight vs cubes from last year and work the wheels and axles like last year but with less oil. Our cars last year weren't pretty. We may work on that too. My daughter is already playing around with the CAD file for her laser cuts. I have to find a sander to do some more work. May need to try a harbor freight one.

Cleaning the track helps on ours. Even when it doesn't look dirty...wipe it down.
I understand that you can't compare times from one track to another, or even the same track if it's moved, but there is a range of expected variance for the same type of track. A time of 2.35 is fast on a 32 foot Freedom...no doubt. If you ran the car on my test track, I'd bet it's a fast car more than I'd bet it's a slow one. In other words...nice job on the car!
Don't know what laser cutter you are using, but I would make some test coupons first and then compensate for beam width in the cad files. I found that mine were coming out on average 0.010 less than the cad file was designed. If I did a scoring pass with low power, it was measuring correct, but the full power run must be burning away some extra material as it cuts. So any critical areas where the dimension was important, I'd add that amount to the dxf and they were coming out much better. Use the same material for the coupons you intend to use for the car. The tolerance is different if I cut acrylic, balsa, birch, basswood, etc.

 

[RockChalkRscing]

We use a Epilog 75w laser cutter. its free to use at the local library. they also have 3d printers and routers. its part of a makers space here in the comunity. I have to book it about a month in advance though so my cuts are a bunch at once. Either that or camp out and wait for a cancellation.

What I found was set the frequency to a higher setting than hard woods for cuts. Most of the time people use plywood or oak in there and the settings they recommend dont fit pine or bass. I start the power level at 100% but adjust the speed. It took 5 test cuts to get ours right this time. Last year the laser was a 40w unit so the settings were different. Our settings this year were 2000hz 100% power and 30% speed on the 75w epilog laset cutter. for plywood they recommend 750hz. odd I thought.

 

[Wolfram Racing]

?? Depends on what kind of cuts your looking to do. I usually stick to high frequency to get smooth cuts, the extra flame and smoke is piped to an air scrubber that has worked wonderfully so far...we might upgrade the cutter at the end of the year to a 100/120W. This one was an experiment to see if we could/would use it. I kind of giggled because I was cutting Derby bodies for the very first test cuts before our ME's even got to it. I had 4 bodies cut before they got to play with their new toy...Hehehe. I think I use it more than anyone now.

 

["The Fonze"]

I give my students this catch phrase to remember.

‘The slower the speed the deeper the cut’
but then fine tune it by adjusting the power.

 

[RockChalkRscing]

I kind of giggled because I was cutting Derby bodies for the very first test cuts before our ME's even got to it. I had 4 bodies cut before they got to play with their new toy...Hehehe. I think I use it more than anyone now.

I laugh too as my cuts and files are simple rectangles where others are bringing in projects that snap together and form art or really unique pieces. I thought I was the poop when I figured out how to cut and engrave at the same time so I could mark lines for the axles across the bodies. I've learned a ton since I started.

They have two at the local library (a 40w Zing and a 75w Helix both by Epilog) and they are always booked. I have to plan cuts a month out almost. its right down the street from my job so I can go over lunch and cut though. Oh, and getting it on the weekend is like winning the lottery. I'd love to own one of my own some day but that's a ways out.

I cut 6 bodies yesterday, the weights ranged from 7.7g to 5.6g. I thought that was a rather wide range. I wonder if I had one dense piece of bass wood and one rather light one in my two pack.