Indian Tipi/Smoke Flaps
Preferably, the structure is erected in such an orientation that the prevailing wind tends to blow toward the back of the tipi. In this manner, the smoke flaps define an opening which is generally downwind, and this improves the draught in the interior of the tipi, so that smoke from a fire built on the ground within the tipi will be drawn up to the peak, and out through the flue opening between the smoke flaps.
It is not essential that the smoke flaps be an exact shape, since their configuration is a matter of choice. The lower corners of the smoke flaps need not be provided, for example, and the flaps can merely be triangular with the vertical edge extending directly from the pocket to the bottom of the flue opening. Where the corners are provided, however, they can be tied out to a tie-pole by cords, thus preventing the smoke flaps from flapping.