Air and there

Barry Taylor’s great letter (“Not so slippery”) in OBA 52 will not come as a great surprise to people who know aerodynamics. To the general public, airflow is full of “myth-conceptions” as they often believe that it is only the air pressure in front that matters, but air penetration isn’t the problem. Drag is frontal area X coefficient of drag (C/D). The frontal air pressure doesn’t increase greatly but seems to as the air pressure behind decreases, giving an imbalance. Chin-on-the-tank riding is not much use if the knees, elbows and legs are increasing the frontal area. Years ago, a wedge-fronted outfit was found to be faster with the airing removed. Most air passes around the sides of a moving vehicle and only some goes over the top. Years ago in England, similar tests were done to that mentioned by Barry and the best C/D turned out to be the Volkswagen Kombi, but of course it had a lot of frontal area. The E-Type Jaguar was worse but We stand corrected. For the record, the outright win in the 1972 Advertiser Three Hour race went to Garry Thomas and Gordon Doble (Honda CB750) on 150 laps. 500 class winners were John Inkster/ Lyn Carle (Honda CB500) and the Lightweight class went to Denny McCormack/Chas Maddern (Suzuki T250). – Ed