until any tendency to sag, no matter how slight it may
be, is overcome.

Putting on the Cloth.

We are now ready to put on the cloth covering which
holds the air and makes the machine buoyant. The kind
of material employed is of small account so long as it is
light, strong, and wind-proof, or nearly so. Some aviators
use what is called rubberized silk, others prefer
balloon cloth. Ordinary muslin of good quality, treated
with a coat of light varnish after it is in place, will answer
all the purposes of the amateur.

Cut the cloth into strips a little over 4 feet in length.
As you have 20 feet in width to cover, and the cloth is
one yard wide, you will need seven strips for each plane,
so as to allow for laps, etc. This will give you fourteen
strips. Glue the end of each strip around the front
horizontal beams of the planes, and draw each strip back,
over the ribs, tacking the edges to the ribs as you go
along, with small copper or brass tacks. In doing this
keep the cloth smooth and stretched tight. Tacks should
also be used in addition to the glue, to hold the cloth to
the horizontal beams.

Next, give the cloth a coat of varnish on the clear, or
upper side, and when this is dry your glider will be
ready for use.