Agreed, in the real world, CFD is where the effort is put. The windtunnel is used to correlate the results. The variables in track testing are unlimited, so it would be hard to pinpoint if it was a car change, or some other variable.
Wind drag on body
- Thread starter Pinewood Outlaw
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I’m all for simulation and optimization... the more factors you can include in the simulation the better. Regarding real world vs virtual you need both to better understand the nuances that exist in racing these little cars.
Unless someone does CFD themselves, or knows someone willing to do it for them, I doubt a pinewood derby racer would be willing to pay a professional CFD consultant to perform the task. CFD is very expensive, you are talking 1000's USD for a single simulation and easily five figures for any sort of parametric optimization analyses. Aerodynamics is just one small variable in a pinewood derby car, and I doubt people want to drop that much money on one small variable (probably with little room for improvement) when there are many others which are much easier and cheaper to improve upon.
How many F1 racing teams are using CFD? All of them, spending millions on it. One of the Formula 1 rules limits the computing power of the supercomputers used for their CFD analyses, which tells you how important it is.
How many F1 racing teams are using CFD? All of them, spending millions on it. One of the Formula 1 rules limits the computing power of the supercomputers used for their CFD analyses, which tells you how important it is.
The question should be, how many national champion pinewood derby racers would use CFD, or other vehicle simulation, if they had the resources to?
From real world experience, I did some extensive testing on the full length fenders vs the traditional X3 design. I have yet to see a statistical difference between the two styles in actual data, but it is so hard to compare two different cars that are built the same, notwithstanding the fender design (too many variables). In my own experience, the full fendered cars are more susceptible to air disturbances caused by traffic than is the X3 fendered cars, but, it be interesting to see a graphical representation of what is really going. Most assuredly that my own tests are too small of a sample size to truly know which is better.
And to answer the question, I would absolutely use CFD if I could.
And to answer the question, I would absolutely use CFD if I could.
I am 2018 NPWDRL MOTM UNLIMITED CHAMPION...... and l’ve used CFD to optimize my designs of my 3D Printed Car bodies. My point earlier is that the simulations shown here are missing important factors.
I had not realized how close these cars are together, less than an inch of space between them (3.5" pitch). With cars on both sides, (mathematically, infinite cars side by side) the total drag force increases by 14% vs. the car being all alone.
Using a race calculation script I wrote, I calculate the time difference on a 42' besttrack would be ~ 5 ms.
The results for both cases are also not steady, as there is vortex shedding which causes turbulent fluctuations in drag force. These vortex shedding cause side to side vibrational forces on the order of about +- 0.5 mN, which is pretty small.
Using a race calculation script I wrote, I calculate the time difference on a 42' besttrack would be ~ 5 ms.
The results for both cases are also not steady, as there is vortex shedding which causes turbulent fluctuations in drag force. These vortex shedding cause side to side vibrational forces on the order of about +- 0.5 mN, which is pretty small.
What would the data look like with
What would the data look like with Plank Fenders in traffic? Thanks
I don't know what plank fenders would look like in traffic. I wouldn't use them just cuz they are ugly, and probably heavy. I'm lazy so I don't build balsa fenders, I just 3D print them, so they are more dense than balsa.
I thought you guys already had simulator software available? Doesn't Doc Jobe have that "virtual race" program? Mine is written in the program "Mathcad 15.0", so others would need that software to use the code.
I thought you guys already had simulator software available? Doesn't Doc Jobe have that "virtual race" program? Mine is written in the program "Mathcad 15.0", so others would need that software to use the code.
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