The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1903-05-31
DIR. ALEXANDER G. BELL
TELLS OF KITE TRIALS
Problem Not Yet Solved, But Is Encouraged by
Experiments Thus Far

fluence of gravity, and the vertical sur
faces prevent it from turning over in
the air. ObliQue aeroplanes may there
fore conveniently be resolved into hori-
zontal and vertical equivalents-that Is,
into supporting surfaces and steadying
surfaces
Triangular Cells.
While theoretically the triangular
cell is inferior in lifting power to Har-
graves four-sided rectangular cell.
practically there is no substantial diff
ference. So far as l can judge from OBJ
servation in the field kites constructed
on the same general model as the Har-
grave box kite. but with triangular cells
instead Of quadrangular, seem to fly as
well as the ordinary Hargrave form and
at as high an angle.
Triangular cells also are admirably
adapted for combination into a com
pound structure. in which the aeroplane
surfaces do not interfere with one
another For example. three triangular
celled kites tied together at the corners
form compound cellular kite. which
files perfectly we'll.
The weight of the compound kite is
the sum of the weights of the three
kites of which it is composed, and the
total aeroplane surface Is the sum of
the surfaces of the three kites. The
ratio OF weight to surface, therefore. is
the same in the larger compound kite as
IN the smaller constituent kites. con-
sidered individually
Tetrahedral Kites.
Passing over in silence multitude
nous experiments IN kite construction
carried on in my Nova Scotia labora-
tory. l come to another conspicuous
I-oint of advance-another milestone of
pIogress-the adoption OF the triangular
construction in every direction Qongi-
tudinally as we'll as transversely). and
the clear realization of the fundamental
Importance of the :N,leton of a terra
hebron, especially the regular terra
kedron. as an element of the structure
or framework of kite or flying ma
chine.
"A tetrahedron is a form of solid
bounded by four triangular surfaces.
In the regular tetrahedron the
boundaries consist of four equilateral
triangles and six equal edges. In the
skeleton form the edges alone are rep
resented and the skeleton OF regula.
tctrahedron is produced by joining to-
gether six equal rods end to end so as
TO form four equilateral triangles.
Upon this mode of construction an
empty space OF octahedral form is left IN
the middle of the kite. which seems to
have the game function as the space be-
tween the two cells of the Hargrave box
kite. The tetrahedral kites that have
the largest central spaces preserve their
equilibrium best In the air.
Ratio of Weight to Surface.
The ur-celled kite weighs four
times as much as one cell and has four
times as much wing surface. the six
teen-celled kite has sixteen times as
much weight and sixteen times as much
wing surface. and the sixty four-celed
kite has sixty-four times as much weight
aud sixty-four times as much wing sur
face. The ratio of weight to surface.
therefore. is the same for the larger
kites as for the smaller.
''Tetrahedral kites combine in a mark
ed degree the qualities of strength, light
ness. and steady flight; but further ex-
periments are required before deciding
that this form Is the best for kite or
that winged cells without horizontal
aeroplanes constitute the best arrangn-
mentor aero surfaces
II have flown this kite in calm by
attaching the cord-in this case
manila rope-to galloping horse. On
releasing the rope the kite descended
so gently that no damage was done TO
the apparatus by contact with the
ground.
Almost a Disaster.
IAN attempt which almost ended dis
astrously was made to fly this kite In
good sailing breeze, but squall struck
it before il was let go. The kite went
Up, lifting the tv men who held il
of their feet. OF course they let go in
stantly and the kite rose steadily in
the air until the flying cord Ia manila
rope three-eighrns of an inch in dia-
meter made an angle with the horizon
or about As degrees. when the rope
snapped under the strain.
Kites of this type have much great
er lifting power than one would at first
sight suppose. The natural assump-
ton Is that the winged superstructure
alone supports the kite in the air and
that the boat body and floats represent
mere dead load and head resistance. But
this is far from being the case. Boat
shaped bodies having V-shaped cross
IL ar
and expose considerable surface to the
wind l have successfully flown a boat
OF this kind as kite without any super
structure whatever. and though II did
not fly well, it certainly supported 1T
self In the air. thus demonstrating the
fact that the boat surface is an ele-
ment OF support in compound struc-
lures"
TUNE NUMBER OF FASHIONS"