jhefner

It is true that throughout history, there have been things that were streamlined and looked like they had been wind tunnel tested; but were nothing but styling. (Much of the Art Deco fad streamlining was of this nature.) Then, there were things that were really optimized for aerodynamics, with wind tunnel testing, etc.

Chysler actually built a wind tunnel, and used it to find an optimum shape for it's Airflow. One they learned was that the typical car of the 1930s was more aerodynamic when driven backwards than when it was driven forwards. To prove the point, they actually drove a car around backwards (Wikipedia says it was a car with the steering and drive axles reversed; I always heard it was a conventional car driven backwards cross country.)

Anyway, others at the time and later also used wind tunnel testing to fine tune their designs. What set the Audi 5000s (which was released first) and Ford Taurus apart was that the entire car was optimized for the lowest practical Cd. The following is the list that I can come up with off the top of my head of the changes they did to achive it:

1. Flush mounted headlights and window glass
2. Flush door frames and door handles
3. Much, if not all of the radiator cooling air came through slots under the bumper, rather than through the grill. Attention was even paid to airflow in the engine compartment.
4. Smoothing the underside of the car as much as possible; by rearranging and shaping components such as the oil and transmission pans, exhaust system, and rear axle.
5. Optimizing the stance (front height vs. rear height) of the car for lowest Cd.
6. Optimizing windshield angle and frontal area. Of course, no longer can one easily reach anything in the engine compartment; with everything jammed in as tight as possible.
7. Smooth sides with a minimum of fender flare and smooth hubcaps.
8. Smooth tail with an optimized trunk height and shape.

Anyway, the end result was truly stunning; and stood out compared to their comtemporaries. I think the work in the automotive industry also made wind tunnel testing more assessable to designers in other industries, including the cycling industry; prior to that; it was mostly used by the aerospace industry. Of course, nowdays, there are places where we can go to have ourselves and our positioning on our bikes wind tunnel tested if we so desire.

I was looking at cycling videos on youtube awhile back, and one of them showed a modern TT bike being tested in a wind tunnel. The video was taken from inside the control room; where you could see the displays on the desk. One of them showed what looked like the Cd for bike alone; it registered 0.32.

A drag coefficient of 0.32 was good for a car back in the 1980s; and it is still pretty good today. I was amazed to see that they got a bare bicycle, with all that machinery hanging on it, down to 0.32 as well.

Anyway, when carbon fiber began to catch on big time in the 1990s; then I think the drive to push weight down began once again, as they attempted to make more and more parts out of it instead of AL or Ti. From an aerodynamic point of view, I think they are a point where they were with weight back in the 1980s; you would have to go with a prone position or some other radical ideas to get radical improvements nowdays.

GV27, I really enjoyed your posting on the race scene in CO during the 1980s. I was in college at the time, and studying to be a mechanical engineer so I could work in the aerospace industry (or so I hoped.) I wasn't paying much attention to the bicycle racing scene; so thanks for your look back at what I missed.

-James