The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1904-04-24


could be achieved the difficulty was
passed. for the matter of motor and
propeller would be relatively easy. To
this problem. therefore, DR.. Bell direct
ed his attention.
Triangular Cells Used.
His first modification OF the Hargrave
type was a kite formed of triangular
cells. The box cells of the former did
not lend themselves readily to combina-
ton, and did not fly well together Yet
DR.. Bell had already concluded that
his hope lay in combining number of
small kites. rather than in building one
of gigantic size. BY combining the small
kites he could outwit the law regulating
the proportion between increased weight
and increased lifting power, which had
been shown to be so exceedingly unfair
to the latter. The box cells would not
lend themselves to this scheme. The
adoption of the triangular cell followed
the trial and abandonment of cells Of
various other shapes and types. Cir
cular cells, polyagonal cells Of six,
eight and twelve sides, with cells Of
many other shapes. were tried. found
lacking. and thrown away.
Into the chaos of disbursement thus
evolved. the idea OF the triangular cell
came TO Dr. Bell with the grace Of a
benediction- It proved Immediately an
an immense advantage over the rectan-
gular Hargrave, being stronger In con-
struction, lighter in weight, and offering
less head resistance TO the wind. The
triangular cell needed bracing in one
direction only, on its fat surface: in a
transverse direction it is self-braced, so
that Internal bracing. which causes
head resistance. was found 20 be unnec-
essary.
Problem But Half Solved.
But the problem. even now. was only
/ half solved. Combinations OF triangu-
lar kites must be arranged in two sets,
with a powerful connecting framework.
The larger the sets. the farther apart
they must be, and the connecting
| frame. therefore. becomes exceedingly
stout and heavy Further Improvement
was necessary. The necessity Of even
the limited amount Of bracing that re-
NAMED as an inherent weakness Of the
| triangular cell was TO be obviated, and
some method OF doing away with the
heavy connecting framework was a pa
! tent need. DR.. Bell reasoned that a
cell could be made seif-bracing in
every direction by making IL triangu-
lar in all directions or tetrahedral In
form. This was the germ OF the sue
cessful idea.
/ Astonishing results We're attained.
/ They are summed up as follows by Gil
/ bert H. Grosvenor, editor OF the Ma
/ tional Geographical Magazine" and DR..
Bells assistant in most of his inves-
legations:
The Wonderful Tetrahedral.
''First-A tetrahedral cell has aston
ishing strength even when composed Of
very light wooden stocks. AS. DR.. Bell
has expressed It; 1T is not simply
braced in two directions in space like
a triangle. but in three directions like
solid. II l may coin word, 1t possesses
three-dimensionaI strength: not two-di-
sional strength like a triangle. or one
dimensional strength like a rod. 1t Is
the skeleton Of solid, not Of surface
or q line
'Second-A large kite constructed Of
tetrahedral cells is as solid as small
one, for it is likewise self-braced in all
directions.
'Third-A kite built Of tetrahedral
cells is an almost perfect flyer; Il is
steady in squalls, a good litter and flies
/ almost directly overhead. Tetrahedral
cells when combined do not interfere
with each other in the least or hurt each
others flying ability as box or triangu-
/ lar cells do when combined.
] 'Fourth-By the use OF the tetrahedral
cell il is possible TO build kites unlim-
tied In size and in which, however gi-
| gantIc the kite, the ratio of supporting
surface 20 weight remains the same as
in small kite. The successive doub-
ling in size OF the kite may be carried
on indefinitely without the weight in
creasing faster than the winged sur
face The cells all act in harmony; no
part OF kite built OF tetrahedral cells