The Salt Lake herald-Republican. [volume] (Salt Lake City, Utah) 1909-1918, 1909-09-26
Mechanical Principles Of the Aeroplane

of the main plane and steers it from
side to side by swinging the tail around
in the direction he desires to go, like a
rudder on a ship.
The monoplane does not have as
much plane surface as the biplane, but
on the other hand it does not have so
much weight to carry. It is also less
susceptible to cross currents OF winds
and other disturbing elements in the
air, because there is less fiat surface
for these to strike against.
The development In aeroplanes viii
be compelled to wait, more or less, upon
the progress in gas engine construction.
In their present state gas engines are
liable to stop without the least notice,
as any owner of an automobile will tes-
tify, and when the engine stops IN an
aerOplane it is most likely to come
down to earth with more or less OF a
thud. There is no getting out and
crawling under the machine, like the
chaUffeurs do, to where the trouble is.
X X X
No Chance Given for Repairs.
To insure absolute safety, the aero
plane engine must run every second OF
the time the machine is in the air. II
anything breaks, the operator cannot
leave his seat to see where the trouble
is, for that would OveTbalance the ma
chine. And gas engines are disgusting
| ~ obstinate sometimes. They stop, dead
still, without an instant's notice, and
! apparently with no more reason than
animates a balky horse. It's no use
talking about the future of aerOplanes,
then. until the future of gas engines is
/ determined The progress of one is alb
| sOlutely dependent on the progress OF
| the other, unless, of course, some new
/ method is found to turn the prOpellers.
The question may arise, and often
| does in a discussion of aerOplanes, as
| to why the prOpellers prOpeL To a
mind unfamiliar with mechanical terms
| it is difficult to explain the exact action
| of revolving prOpellers on the air.
! Briefly, it may be said that the air
/ pressure against all objects is some fiji
] teen pounds to the square inch. Thus
/ the air presses against the palm and
| the back of your hand at that rate, the
| two pressures exactly balancing each
| other. Remove the air adjacent to the
| palm of your hand and the pressure
/ from the back would be fifteen pounds
| for every vacant square inch on the
| other side, and the strain on the back
of your hand would be equivalent to
that caused by lifting a weight as
| heavy as fifteen multiplied by the num-
| Der of square inches unoccupied by air,
X X X
PIcpeIIers Create Their Own Vacuum.
Thus, when the aeroplane propellers
are revolving they are constantly biting
into the air in front of them and push
| ing it behind them. In this way they
| create a partial vacuum in front, and
what they take away from in front is
added behind, thus to the fifteen
pounds per square inch that is already
bearing against the blades from behind
is added the number of pounds pressure
that they are able to subtract from the
pressure in front, making, we will say
! twenty-five pounds pressure to the
| square inch behind, and only five il
front. 1t is in response to this pressure
from behind that the machine moves
forward
If the prOpelleTs could whirl rapidly
enough they could create an absolute
| vacuum in front and have thirty
pounds per square inch on every incl
Of their back surface. II this condition
were possible, OF if engines powerful
enough and propellers strong enough t.
with stand that pressure could be made
an aeTOplane. according to such experts
as the Wrights, could be sent through
the air at a rate of 500 miles an hour.