The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1903-05-31

In the National Geographic Maya
zine" for June there will be published
for the first time detailed account of
the principles of tetrahedral kite con-
struction by Dr. Alexander Graham Bell.
inventor of the telephone bearing his
name who is trying to solve the prob
lem of aerial navigation by the applica-
ton OF those principles.
The article concludes with the fol-
lowing statement. which is self-ex-
planatory, when coupled with the fact
that patents are now pending in this
and in other countries for his inven-
lions
at is not my object in this communi-
caticn to describe the experiments that
Fave been made in my Nova Scotia
laboratory, but simply to bring to your
attention the Importance of the tetrahe
dral principle in kite construction"
1nasmuch as the patents have not been
cttained, DR.. Bell does not think it
wise to discuss at this time the actual
results of a practical nature accom-
pljshed. but simply deals with the prin-
oiple involved
Four Years Experimenting.
Since April. 1892" says DR.. Bell, 81
Lave been continuously at work on ex-
periments relating to kites. Why. I do
not know. excepting. perhaps, because
o. the intimate connection of the sub
joct with the flying machine problem
II have had the feeling that a prop
erly constructed flying machine should
be capable of being flown as kite;
and, conversely. that a properly
structed kite should be capable of use
as flying machine when driven by its
own propelIers. 1 am not SO sure. how
ever, of the truth of the former propo-
sition as ] am of the latter
Given a kite, so shaped as to DC suit
able for the body of a flying machine
and so efficient that it will fly we'll in u
good breeze (say twenty miles an hour
when loaded with weight equivalent
to that of man and engine; then 1t
seems to me that this same kite pro-
vided with an actual engine and man N
place of the load and driven by its own
propellers at the rate of twenty miles
an hour, should be sustained in calm
air as flying machine So far as the
pressure of the air is concerned. it is
surely immaterial whether the air
moves against the kite or the kite
against the air.
Kite Should Fly Steadily.
1.-THE point ] have had specially in
mind is this-that the equilibrium Of
the structure in the air should be per-
feet; that the kite should fly steadily.
and not move about from side to side or
dive suddenly when struck by a squall
and that when released II should drop
slowly and gently to the ground without
material oscillation. 1 have also con-
sidered IL important that the frame
work should possess great strength. with
little weight
Il believe that in the form of struc-
ture now attained the properties of
strength. lightness and steady flight have
been united in a remarkable degree.
1T is only within the last few years
that improvements in kite structure have
been seriously considered, and the re-
cent developments in the art have been
largely due 10 the efforts of one man
Laurence Hargrave. OF Australia
''HargraVe realized that the structure
best adapted for what is called a good
kite would also be suitable as the basis
for the structure Of a lying machine.
His researches. published by the Royal
Society OF New South Wales, have at
traeted the attention of the world and
form the starting point for modern re-
searches On the subject in Europe and
America
HaTgrave's Kites.
"Hargrave introduced what is known
as the cellular construction of kites.
He constructed kites composed OF many
cells. but found no substantial improve
ment in many cells over two alone:
and a kite composed OF two rectangular
cells. separated by a considerable space
is now universally known as the 'Har-
grave box kite.
The front and the rear cells are con-
nected by a framework. so that a con-
siderable space is left between them
This space is an essential feature OF the
kite: on II depends the fore-and- aft sta
bility Of the kite. The greater the space
the more stable is the equilibrium OF
the kite in a fore and-aft direction. the
more II tends to assume a horizontal po-
s:tion IN the air and the less II tends
10 dive or pitch like vessel in rough
sea. Pitching motions or oscillations
are almost entirely suppressed when the
space between the cells is large.
Each cell is provided with vertical
sides. and these again seem TO be es-
sential elements OF the kite contributing
TO lateral stability. The greater the ex-
tent OF the vertical sides the greater is
the stability in the lateral direction and
the less tendency has the kite to roll or
move from side to side or turn over in
the air.
Milestone in Progress.
I'm looking back over the line of ex-
periments in my own laboratory" Mr.
Bell says. Il recognize that the adoption
OF triangular cell was step in ad-
vance, constituting indeed, one OF the
miIestones OF progress. one of the points
that stand out clearly against the hazy