A drag count is a dimensionless unit used by aerospace engineers where 1 drag count is equal to a of 0.0001.

Definition

A drag count is defined as:

where:

is the drag force, which is by definition the force component in the direction of the flow velocity,
is the mass density of the fluid,
is the speed of the object relative to the fluid and
is the reference area.

The drag coefficient is used to compare the solutions of different geometries by means of a dimensionless number. A drag count is used as a more user-friendly measurement as the coefficient of drag is usually much less than 1. A drag count of 200 to 400 is typical for an airplane at cruise. A reduction of one drag count on a subsonic civil transport airplane means about 200 lbs more in payload.


This article uses material from the Wikipedia article Drag count, which is released under the Creative Commons Attribution-Share-Alike License 3.0.