The evening herald. [volume] (Albuquerque, New Mexico) 1914-1922, 1915-07-10
Difficulties of StabHizing
Aeroplane Discussed BY Wright

Some phases OF f~ore-and-aft or
longitudinal equilibrium IN flying are
discussed hy Orville Wright In a re-
cen publication ~ the Smithsonian
institution. entitled stability of Aero
planes Mr.. wright SAYS that a ny
ina machine IL balanced in three d.
rec~tions-abOut an imaginary axis
fore aud AFT IN It's line Of motion. re.
ferred to az lateral equilibrium.
about another axis extending IN n lat
: eral direction from tip to tip OF the
WINS. known as ~fore-and-aft or long
itudinal equilibrium; and about a ver-
teal axis. which Is generally referred
to AZ steering, although lis most Inn
portant function IL that OF lateral
equilibrium. Although a beginner
finds most diniculty In mastering the
/ latter control. II Is his lack Of knowl-
(, edec OF certain features OF the fore
and-aft equilibrium which leads 60
most Of the serious accidents.
In an ideal nying machine the cen
ter of grayitS would Ne IN the line
Of the center 81 resistance Co forward
movement and also In the line of
thrust. but In practice this - o al
ways feasible. since the machine must
be built IN land safely las we'll az 10
ny. In nyilg. a low center of gray
ity. that Is. one below the center ~
support. causes an osciilating nos
ment about the lateral axis like that
OF a pendulum. which lends to form
a disturbing turning movement. On
the other hand. a high enter of gray
iiy tends to cause the machine TO roll
over In landing. and consequently a
compromise Is adopted.
The wi principal methods used IN
preserving ~f0rc-Gnd-an equilibrium
have been shifting ~ weight So az 90
keep the center OF gravity in line with
the changing center Of lit. and the
utilization Of auxiliary surfaces,
known AZ elevators. 90 keep the center
of pressure in line with % fixed center
Of gravity. The first method has
been found impracticable on account
of the impossibility OF shifting large
weights qdickly enough. but the sec
0nd is used IN most OF the modern
flying machines.
Flsing machines Of the latter type
should nave their auxiliary surfaces
located In the 'front.' or rear. ana az
FAY ie possible from the main Dear
ing planes, because tho greuter the
distance the greater s. the leverage.
and consequently the smaller the
amount of furfacs required. 30 parts
of either the muiu surface or auxiliary
surface should DO exposed on their
uppc. sides 10 90 way Co create "A
downward pressure for maintaining
equilibrium, since such @ pressure re-
quires twice the propeller thrust a.
overcome il that en- equal carried
weight would require.
The downward pressure ~ air S.
used 60 some extent, however. on ace
count of its adaptaullitY. iu producing
more ar less Inherent stable aero
planes. Mr. Wright descr.bes an in
hcreutly stable acropl3ne is one in
which equilibrium b. maintained by
IA IrrunReueui. OF surfaces So placed
that when q rhrfeft ~ air strikes one
part 81 the machine creating % pres
sure that would tr1d Goo disturb the
equilibrium, the same current strik-
ing another part Droates 60 aaluu.iug
pre- are boz the opposite direction.
This romuensating OF correcting pres.
sure Is secured without the mcablu-
iHai movement uf ANS part ui the mu-
chine. While This system VIII cone
tfol 5 machine Go SOME extent. b. dee
ponds SOP much ou variation In course
and speed as lo render 10 Inadequate
Co meet the demands ut o. practical
living machine
IN order to secure greater dynamic
efficiency and greater -muncuEcrlru
ability auxiliary surface mechanic l