Evening star. [volume] (Washington, D.C.) 1854-1972, 1928-01-01
MOTOR WORLD OWES
IMMENSE DEBT TO
FEDERAL EXPERTS
Continued from Eighth Page)

lioah ApHstsk 49,
walls is probably the largest fac,Cr In
the drag internal friction places on
an automobile engine. The bureau
has not gone into this matter extern
sively in automobile engines, but 1t
has with regard to aviation engines,
where much the sane factors are IN
vOlved. A report published recently
summarizes the results of the friction
measurements made as part Of the
performance test If aircraft engines
I'm the altitude laboratory of the bu-
reau. On the basis of these results
the probable influence upon friction
OF various factors Is discussed, includ-
ing temperature of air entering the
engine. atmospheric pressure. throttle
opening, engine speed. jacket water
temperature and compression ratio.
Part OF the report deals with measure
ments of the friction OF a group OF
pistons used in n truck engine and
differing from each other In such re-
spects as length. clearance. area OF
thrust face, location of thrust face,
etc. These results indicate the com.
rlexity of the subject of piston fric-
ton and the difficulty of predicting
adequately the magnitude OF the
change in friction which would result
from a change in piston design.
Soap Aims have often rendered no
table service To science and in quite
diversified fields. a new and important
use of the childs playthinS has just
been made at the bureau. where. in
the form of a common soap bubble
filed with a charge of explosive gases.
to be investigated and fired by spark
from the center. 1t permits. because
- oil nd r.
ency, a continuous photogra phic rec
ord to be made of the process of the
explosive reaction from the instant
the ignition spark passes to the in
slant the reaction il completed. The
Photographic plates show that instead
of being haphaZard. erratic process.
as might be inferred. the explosive re.
action. under the condition of con-
slant pressure provided by the bubble.
In a law abiding and orderly process.
AZ symmetrical AZ any known explo.
sion All the relationships shown by
the use of the lowly soap bubble are
indispensable TO n better understand
ing OF the gas engine. Its use mas
revealed for the first time data CON
corning the kinetics trates, Of gaseous
explosions In terms Of the compost
ton Of those gases.
i mas NtlnN u ttaA tts- iiRiVSt tNNC IA
which the zone OF reaction. the flame,
liherates the energy Of the explosive
gases in which II Is rropagated Is
proportional 10 the product Of the con.
aentrations Of the active gases the
tame is entering.
Many Tire Facts Found.
Ingenuity is great thing when
applied In the right direction. That
these painstaking men at the Bureau
OF Standards are not lacking in THIS
trait Is shown by the fact that when
the other day they were not satisfied
with the instrument tests showing tire
wear under varying loads they ran the
tire under test up against strong
piece Of sheet glass and actoallS
watched Its performance through the
glass Their inquiries into tires have
gone very far. and out Of them nave
come many vi the standard recon
mendatinns for the rubber tfeads that
carry - 0oD. 900 ears over American
roadway~. Here are the bureaus rec
concentrations for tire care
Keen your shoes" properly Inflated,
Do not run nat" farther than
See that all wheels are in correc,
alignment.
Remember that oil. grease. sunlight
and heat are enemies of rubber.
Snare tubes should be carried In
wrapped packages.
Avoid the use OF bent ar rusty rims.
II chains are necessary. apply them
loosely.
Have cuts In pneumatci tires
promptly repaired
Adjust brakes 80 they operate even
~ on all wheels,
Drive carefully aud avoid bumps
particularly at high speed
Did YOU know that hot and cold
weather affect the efficiency al your
brakes Perhaps you noticed after
your brakes were frightened they
Grabbed quickly after running short
aistspc. due Ia the swelling AZ the
material under the heat OF friction,
The bureau has found that there IN a
nronounced decrease In coet'icien 81
friction when the Innings are operated
Under test conditions when cause
rapid increase of temperature ot s~N
srul hundred degrees, Its tests III
trake efficiency have developed a sim
ple and accurate type ~ INDICATING
acceieroneter for testing the btak'ns
efficiency OF motor vehicles Mot"
than a thousand of these devices are
now In use throughout the country
while In cooperation with the S"rtets
NJ Automotive Engineers nh'efhh
brake safety code has heen drawn w
This code has been adopted ny many
states, and probably viii het"he UNI
versal