New-York tribune., 1908-08-30
SCIENCE0F AEROPLANES
Grezo Out of american Gliding Kite
Principles of AUiatiOn.

1t is probable that the casual observer watching
the government aeropanss In practice flights viii
find no great difference between them All the
heavier than air flying machines that have re-
rnained more than few seconds in air have
grown of American gliding kite. 1t Is there
possible to describe the typical aeropiane OF
1903 pretty accurately.
The typical aeroplane is exceedingly light
framework of thin strips with vanished silk
stretched tight over the top and the bottom max
ing long narrow kites. held nearly level. one
over the other. This structure Is mounted across
q short chassis with bicycle wheels, go that when
the vehicle the kites come on edgewise. Ike
knife blades. into the air. Upon the stfn frame OF
the chassis the seat for passengers the motors
and the shafts of the propellers. which whired
in the Rudders either at the front or the
rear of the chassis When the engine is set going
and the propellers thrust the aeropiane ahead 1t
the ground its wheels until 1T gathers
such speed that the kites, tilted just little at the
front take the air and rise. Somewhere. 'front.' OF
| rear is a fiat broad plane that causes the aero
plane to rise to dip when hinged at angles
Swinging from side to side in the rear is rud-
| der that the aviator uses to turn his ma
chine in its course. There may. be tail to steady
| the flight Either by small hfnsing planes at the
sides by making the outer rear corners OF the
| kites flexible that they bend up or down-up on
one side, the other-the kite structure can
be made lean when rounding turns. and to come
| to a level when the machine tips for any reason
| All these devices worked by wires from a
wheel, by levers by other controlling mechanism
at the aviators seat. The control of the motor is
| also under his hand.
The government aeroplanes finished machines
| Every piece of material IN them has been shaped
| after calculation of weight and strength The
| small parts designed as to be interchange
| able The fabric of the wings may be rolled UP.
| and the framework. made in sections. taken apart
| Hollow steel joints that screw or bolt together
| make II rigid when assembled again.
The wings Of an aeropl6ne things Of beauty
Narrow carefully curved and tapered ribs OF hick-
ory are sewed into the silk so that they are COW
cred i in the border of henstitched handker-
chief The fabric also rounds the strip at the 'front.'
| edge II is stretched tight as a board and then
vanished with guncotton mixture that hardens
| like thin film OF celluloid The curving ribs i'm
part a shape 10 the under surfaces OF the
| great wings. Through the translucent silk the fine
| ribs show like the veins IN dragon fy's wing
But there Is more than beauty in the shapes The
surface curving OF an aeropiane wing is all in an
/ Know the right and your machine Will n.y.
/ To explain why the shapes Of supporting wings In
! aeropanes and of the blades OF aerial propelers
mean so much is bring UP the whole fascinating
! new science of dynamics of the air. which made
! the flying machine possible
! Take a down feather and flip it from the thumb
/ as boy shoots n marble II the thumb springs
/ quickly enough tho feather will shoot away for
/ four inches, then spring back two. II has fol-
lowed the movements of a little mass OF air tnat
| was thrown by the thumb. was stopped by the arr
/ in front OF II, and sprung back oy the ar 3 per
feet elasticity under pressure The wonderful quail
ty Of viscostv in the air is shown when loco
motive sends rings of smoke from its stack The
air rolls upon itself cohering and passing through
other air with very little friction. Throw feather
into the whirl OF an electric fan II win at times
sail through the blades. so on for few inches.
then whiri back through the centre, zigzag about
and finally strike the straight way onward Tne
air masses have been in a turmoil momentum
and elasticity and viscosity took part in their
direction. Take a card and let IT slide obiiquely
from the hand. 1t viii Invariably turn over and
/ over backward Laws not understood in their
( completeness govern this molten through the
changing Of pressures different parts Of the sur
face as it strikes the air obIiquely at different
angles.
/ The wing of the aeroplane. slightly inclined.
strikes the air in its swift onward rush and forces
II downward But the air does not move quickly.
II is inert inclined to stay together In masses and
flow evenly and the obliQue wing is also rarity
ing the air above. so that there is more pressure
below than on the upper surface Of the wing
There comes a point. the speed of the aeroplane
Increases where the weight of the machine cannot
make the air move quickly enough anu "lsie II
cannot sink in its fight.
/ The air. however. does not press up equally on
the wing The front surface of the plane strikes IT
downward and II has taken downward direction
when the back surfaces arrive Here is where
the curved surfaces in. Long experimentation
with differently shaped wings. at different speeds
and different angles has taught. 10 some degree OF
exactness what curves should be given to support
ing p1anes The narrow wings and the propeller
blades have been found to be most efficient
Worlds Work
DEMOCRATIC SPLIT AT ossINikG.