For this testing I used a model stock car, postal scale (weight in grams), blow dryer with a concentrator nozzle attachment, a plexiglass box. The car was attached inside the plexiglass box and a hole was made for the blow dryer to point at the nose of the car. I performed 10 trials each of different combinations of speed (high & low), temperature (high, medium, & low), and angle of air flow (none, 45 degrees, 90 degrees, and 180 degrees. I recorded each of these results in my log book and later converted these results to equivalent force on a life-sized stock car.
My findings proved that the faster air speed and lower temperature had the most downforce on the stock car. Surprisingly, the 45-degree angle showed the most change in downforce. The high temperature and low speed air flow with 90-degree or 180-degree angles resulted in the least amount of change to the car's weight.
I conclude that studying the air flow over a stock car is important because it can affect the results of a race. To my surprise the 45-degree angle showed the most amount of downforce on the car, in a real race, this would only happen when the car was banked in a steep turn. This could be one of the reasons why oval race tracks are slanted on the turns. My recommendation for the future would be to use a stronger source of air to test the effects. My converted results did not meet the actual force on a car in a race.
This project is about amount of downforce on a stock car with speed, temperature, and angle of air flow as variables.
Science Fair Project done By Peter N. Fettis