Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1919-09-07
alRPLANES AND GRAVITY
DISCUSSED BY EXPERT
Who Sends Him Letter of
Inquiry.
SCIENTIFIC CALCULATIONS
Aviator's Sustaining Force Is Pro-
duccd by Rapid Motion of the
Machine Through Air, Much Like
That Which Keeps Kite Flying.

"Does an airpiane violate the law
Aof grayitvr'-r + = asks. How did
Fyou come to imagine that an airplSne
8could violate the law OF gravitation'
sYou Nigh, as we'll suppose That bird
sviolates it. Yc7, YOU are evidently los
isno means singular in entertaining SGGh
"a notion. cor two or tbree others nave
asked the same question. II seems
plain tina, this great law is not as
be. In fact. however. ihcre are some
s peculiar Things shout IT, Wh.tA 20"
52Could hardly be blamed Tor not Nnc"
g9ing. unless YOU are student "i
\ piS fyet .,s.,,e. everyeoay knows tina,
Mthe force called SravitAiion. OF gravity.
makes any heavy object mat Is un
supported from beneath. fall toward
eths sropnd; Sr 'ow"Td ~ tn,n eeh i",r,r
8 which the force tends HU: When tue
3.body is supported. as by table, gravity
Jdraws upon Il JUST ihg same. .Ht ,t'
distance OF the ;A5lt exceeds the sTaN!-
National force. and me efteci OF the
.flatto- is feI; simply in the form @:
,lStcady pressure.
& No Violation of Grnvity Inv.
Il There is here no violation or the
B. law for the body oocys hE preSsln-
% ,oIa '2 nb i'e. j jaiT' Tq iRe "a ab!}
.swere taken away. When the body is
supported. o. Kept from falling, We
call the eHsct produced Upon s,I +!
a; the effect Of gravity IS called acc .e?a-
dion. Technically ih!s means nc IN
crease OF velocity mat gravity impartS
10 the body during each second OF
: it's fall For objects near the cArth.s
surface tais increase, or Acyel.r"t 'on'
us 4 constant quantity, amountuS TO
K about - feet PEI second--per second.
!. c., the velocity OF ia.in- rod!
tneglecting air resistance increases
81 feet every successive second
In scientitc calculations The acceleva-
ton OF gravity is thing OF Immense
importance. and scientiic men haIE
you asked a Pho. how fast a body
would be going after ii mao fall,Hi one
right Kind OF PAD. and was Also IN a
hurry, Sixty - From what has
been said above. sec II !ou can figure
ing understood ihat atmospheric re
: Sistancc is neglected.
Obcys Lnws of GrnVitntion.
When an airpiane is IN niEhi' it.
same way that the BODY supported by
the table obeys it-viz". by presS.uS
With It's wHisni n Hn0a the a,r 'q A.
resis; This pressure, c;HNcept, IN sma !
part, the airpiane would fall If II mad
not a aGd fs means 81 Sgpr OF Inc M
would increase, until, IN certain CIR.
cums;anccs. it might become great
enough to balance the pun Of gravity,
then there Mould hc no violation Of
the law.
means of support is which enables the
airplanc effectively 20 rest its weight
upon upon ne ~o, ,hin NJ air Is fore de- de-
plane ahead at such = speed that the
upward component of the air resist
ance. or air pressure, eonais the down
ward pull OF gravity. The effect may
be likened to that OF "a wind on a Kite
The kite would fan in calm. bat
its sloping surface. balances the down
ward effect of its weight, so that IL
scars in. spite Of It's constant obedience
to gravity. which never ceases 20 inn
part The same weight TO il. The weigh,
is balanced by another force that is all
In the case OF the ,a!rpisne the
rapid motion or the machine through
the air; in that OF the kite it IS the
rapid motion OF the air that produces
The sustaining force The ON j. the
equivalent OF the other, because ,ct.on
T. and reaction must always bc equal
Another Curious Fact.
Here is another curious fact about
grarltation-it acts with practical in
s.antansousn.s ., al distance. If
other' 100000 miles. both would bc
thu sam. instant although the amount
OF that attraction would b 10000 times
greater on the nearc1 than. on the
Ii results from the fnstsntancous ac-
zion Of gravity that Il a pro5ectile -
shot straight UPWARD = begins 80 ial.
"S" has it's sra..p on j, from the very
beginning Ipiling i back a tn. rate
Of 81 f"ct per second Al that the force
derived from the pow dor ls able 30 do
is 20 start the p!oJect.le upward .t
n greater speed than that and ihe n1u',
me initial Upward y'loc ~ exceed &
The velocity Of iall du" to "g'' 4ucuulu-
lates g. more feet evcry second SO thai
s. III = ..hls' " Ih.."s ~ |.1!iHifisrf ''H'
comes ana then rcy5rEC- -. motion p;
the body. bringing back 10 .altr