Recent content by CAD_Jockery

Turbulence off of, and behind the rear wheels probably creates more drag, than the squared off tail of the chassis itself. Plus, how much would the wake of turbulence from the rear wheels, negate any gain from a tapered rear chassis?

A trip, or "gurney" would be interesting to test. My gut says a full width trip, would increase drag, but a series of vortex generators my help.

The question should be, how many national champion pinewood derby racers would use CFD, or other vehicle simulation, if they had the resources to?

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.

I think the key to CFD_Engineer's statement, was "streamlined". If all of the cars on track are aero efficient, there should be less wake. When dealing with the wake from other cars, you would have to run cases with the opponent's car at various positions ahead, and behind your car, and vary...

Here are some images from a non-fendered car, that Corvid ran CFD on (http://www.corvidtechnologies.com ). https://www.aeriusphoto.com/OurRaceCarsSpeedwaybikesKartin/First-race-car/

Also of note, those runs were done with the car straight. A rail rider is actually in yaw going down the track, thus, their is some side force on the car. In theory, the side force would help hold the car against the rail, so you could dial a bit of steer out of the car, and reduce the rolling...

Correct, you're turning the air less, and not hitting a second frontal face (the second fender).

First time poster, but I thought I'd share a bit. A friend was doing a new OpenFOAM CFD install, and wanted some data to run, to test it, so I sent him some pinewood derby fender designs. The baseline was the fender set my nephew ran in 2018, which was his 3rd generation car. Wood chassis is...