Aircraft Zero-lift Drag Coefficient at Take-off with Gear Down

The aircraft drag polar is expressed as:

..\Images\IMG00029_shg.gif

For parabolic drag polars:

..\Images\INFO0272_wmf.gif

where:

..\Images\INFO0273_wmf.gif

is the wing aspect ratio.

..\Images\INFO0274_wmf.gif

is the Oswald's efficiency factor.