US Hawks Hang Gliding Association

Something analogous will have to be done by aviators. This is preferably
accomplished by first building a gliding machine of the type which is intended
for the flying machine and testing it personally on a sandy hillside to develop
its defects in stability and to learn its control. This was the course recommended
to the French aviators by myself in a paper published in "Aerophile" for August,
1903. At first they accepted the advice and made a lot of gliding experiments
with moderate success, on the sand hills near Berck, but they became impatient
at the slow progress accomplished, tried other methods, such as going up as a
kite towed by a launch, and then they were tempted by the light motors to "get
ahead of the Wrights," oblivious to the fact that the latter had spent three years
in gliding before they ventured to put on a motor. Now, M. Leon Delagrange,
after making quite a number of short flights (the longest about 200 feet) with
his motor flying machine, has found it advisable to go with M. Voisin, the
cleverest of the French flying machine pilots, to experiment with a gliding
apparatus on the sand hills near Le Touquet.

The mode of conducting such experiments has been described by the various
experimenters. It consists in first testing the apparatus as a kite and measuring
accurately the "lift," the "drift," the "head resistance" and the location of the
"centre of pressure" at various angles of incidence. If the relations between these
conditions prove unsatisfactory they can be altered by changing the cross section
by trussing the ribs. Then glides can be made by running and jumping into a
head wind, noting carefully the angle of descent, which should he finally as
flat as possible with adequate stability.

It is great sport; the chances of accident are not great to careful men who
proceed step by step, and it enables the aviator to develop gradually the best
shapes of surfaces and framing for his particular design ; while, more important
than all, it gives him experience and skill to manage his motor flying machine
when he finally comes to the point of testing it.