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From: Jasper
Date: 6/14/03
Time: 10:24:59 PM
Remote User:
John: Anmd while you could have had the shop manual specification of a 1994 Bronco fresh off the assembly line, you can not know the actual dimensions of the Bronco in question after months of driving and wear and tear."
Jasper: Not so. Every production vehicle has a “build tolerance.” That mean you can’t count on the precise specifications of any vehicle in a “shop manual.” It also means that if you know the build tolerance you can tell how far off from the specifications (package engineering) the vehicle can be. You can’t build a production vehicle that’s more than a half-inch out of package. The parts won’t fit together. Normal wear and tear won’t change these dimensions a quarter inch. In packaging a vehicle, half a millimeter is too much (because you have to allow for the build tolerance in real-world assembly plants).
John: Here's my point: you don't have anything analogous to your chalk marks to denote the exact position OJ left the Bronco when he pulled out of the DRiveway.
Jasper: Wrong. A side view photo showing the rear of the Bronco and the north side of the driveway along with other photos of the driveway and Bronco gives you all the reference points you need to make a mechanical drawing.
In design there is a thing called a theoretical intersection (ask a draftsman) that gives you a precise point to work with. Extend the line on the side of the driveway nearest the Bronco past the Rockingham curb. Extend the line on the curb past the extended line for the driveway. Where they cross is your “theoretical intersection.” Almost all vehicles have some sweep (curve) in the bumpers in plan view (top view). The farthest point on the bumper is at the centerline. Draw a line from this point to the curb perpendicular to the curb and measure this true intersecting point on the curb to the theoretical intersection of the curb and the driveway. Now you can measure the distance of the curb to the rear of the bumper to a fraction of an inch. That’s your first point (chalk mark fore and aft).
All of the photos showing the relationship between the tires and the curb have greatly exaggerated perspective. However there is a white strip running the length of the curb so the proportions are identical. That means you can make an isometric plan view drawing showing the front and rear passenger side tires in proper relationship to each other and the curb (or the stip). Draw a line perpendicular to the curb to the centerline of the front wheel. Do the same thing with the rear wheel. Now you can measure how far each tire is from the curb and compute the angle. At different times O.J. may have driven farther forward or gotten closer to the curb. If so the angel would have been different. These are your other two points (in and out chalk marks). The only way anyone could have hit that zone, even within the VERY liberal deviations I gave you was to pull in directly from the driveway.
John: There's a saying in the ARmy: "Opinions are like noses; everybody has one." Well, that's not exactly what they say, but I'd ratheer call you a 'nose'.
Jasper: Very good :0)