Re: Drafting in Bicycle Races

[brian whatcott <inet@INTELLISYS.NET>]

At 05:54 9/15/99 -0400, Ed Schweber wrote:
> Hi:
>
>    In bicycle races one rider will ride closely on the tail of the rider in
> front of him so that he will be riding in the "air resistance shadow" of the
> front rider.
>
> ... Does the front rider in any way need a greater power
> output to maintain the same speed by virtue of having someone drafting
> behind him?
>
>    I am looking forward to any responses.
>
> Ed Schweber

This answer is meant to be provocative rather than definitive.

  Bairstow, taking advantage of the technical reports of the ACA
(Advisory Committee on Aeronautics) showed a table of comparitive
drag of two wires in line astern at various gaps, using the drag
of a single wire as 1.0 in his book.

The row showing the angle between the wind and the plane containing
 the two wires of zero, for various seperations in diameters
between centers:

Seperation        1 diam  2      3      4      5      6
Relative          0.20    0.29   0.44   0.67   0.70   0.72
drag of pair

(Beware! Wires of differing diameters scale steeply.)

"The front member of a pair of wires has a very large shielding
effect on the rear member, and the resistance of the pair may be
much less than either wire seperately."

Bairstow, Applied Aerodynamics,  Longmans. 1920

(By this time, the aeronautical advance of the European nations was
so marked, that the Congress was finally moved to set up a national
research arm modelled somewhat on the ACA [Britain] called NACA.)

brian whatcott <inet@intellisys.net>
Altus OK