From the book
Modifying the Aerodynamics of Your Road Car (paraphrased pg 56):
Spray a film of water onto the area of interest until it is damp. Then dusted with clay that sticks in a thin film to the wet panel (bentonite is suggested). Then spray with some more water (there should be an even coating of clay) and drive the car. The process is repeated until the airflow pattern is revealed in the clay.
Also says this method is really good for identifying separation and reattachment areas. There are pictures, but unless I scan or take a picture of the picture with my phone I don't know how to share them.
I haven't tried it before.
I am going to try and replicate this (see video) to make a camera mount for tuft testing on my car.
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1973 Fiat 124 Special
1975 Honda Civic CVCC 4spd
1981 Kawasaki KZ750E
1981 Kawasaki KZ650 CSR
1983 Kawasaki KZ1100-A3
1986 Nissan 300zx Turbo 5 spd
1995 Chevy Astro RWD (current project)
1995 Mercury Tracer
2017 Kawasaki VersysX 300
2022 Corolla Hatchback 6MT
https://www.youtube.com/channel/UC6s...LulDUQ8HMj5VKA