Drag - A Basic History

The history of drag calculation is interesting. Before 1904, that is before Prandtl introduced the concept of boundary layer, people did not know how to compute drag. Most analysis based on ideal flow or hydrodynamic theory until that time would calculate the drag of any object to be zero, in spite of the fact that everyone new drag was not zero. If you recall the Wright brothers flew in 1903. Luckily for them they were experimentalists. If they depended on the lift and drag calculations to help them choose the airfoil, they would not have flown for some more time.

Consider flow around a cylinder