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Originally Posted by kach22i
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These assesments are complete BS. Here's an excerpt from the SAE paper on the Charger Daytona development:
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The wind tunnel development of the Daytona low form drag front end included a wide spectrum of nose configurations. The nose configurations investigated fell into two broad categories: a 9 in. extension and an 18 in. extension. Both basic shapes were developed with respect to achieving a minimum axial force [N.B. "axial force" = drag]. The results of this investigation are presented in Fig. 7. The data indicate the 9 in. extension without a front undernose spoiler is superior to the 18 in. extension without spoiler. However, the 18 in. extension with spoiler is significantly better than the 9 in. extension with spoiler. The phenomenon is probably caused by two effects:
1. The spoiler chord on the 9 in. extension is less than on the 18 in. extension for an equal distance from the nose.
2. With the spoiler installed, more air is forced over the nose surface. The upper surface of the 18 in. extension is more favorable from a drag standpoint than the 9 in. extension.
The results in Fig. 7 explain the selection of the 18 in. extension for the Daytona Aerodynamic Package.
The effectiveness of front undernose spoilers is very sensitive to front end shape. This point is illustrated in Fig. 8 where the spoiler effectiveness as a function of yaw angle is presented for the 1969 race car and the Charger Daytona. Spoiler effectiveness is defined as the force coefficient with the spoiler minus the force coefficient data without the spoiler. The incremental axial force coefficient data indicate the spoiler on the Daytona nose is 4.5 times as effective in reducing axial force as the 1969 spoiler at zero yaw angle. Similar results are seen on lift. These data indicate the spoiler-nose combination is a highly interactive aerodynamic system and must be approached and handled as such.
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1. A variety of shapes were trialed
2. The engineers used existing studies on nose shape and spoilers as a starting point for their research
3. The front spoiler reduced both lift and drag--on both the 1969 blunt-nose and 1970 streamlined-nose cars
4. Nose design was just one part of a 5-part approach to a complete aerodynamic package to improve the Charger