The Pensacola journal. (Pensacola, Fla.) 1898-1985, 1920-04-12
GAS BOILS AT
Mile ALTITUDE
TESTS MADE BY MAJOR SCHROE.
DER TEACH AIR SERVICE PER-
SOHAL INTERESTING FACTS.

The Air Service Information Bureau
has issued bulletin on phase of
Major Schroeder's flight. The infor-
nation is interesting to all pilots, ex-
pilots and internal combustion en-
gineers. The bulletin follows:
Considerable trouble has been. ex-
perienced by Mayor Schroeder during
his big altitude flights on account of
the failure of his sylphon pump to
deliver gasoline to the carburetor at
high attitudes. Upon installation of
the Schroeder flowmeter in the gaso-
line feed system he discovered boiling
of the gasoline at attitudes from 5000
feet and up This indicated by bubbles
appearing in the glass tube of the
fowmeter at about 5000 feet. These
bubbles increasing in number and con-
sequent failure of the pump itself
Experiments in the laboratory of the
material section, engineering division,
reproduced this situation exactly on
reducing the pressure on the gasoline
to pressures corresponding to atmos-
pherio pressures at various attitudes,
and an analysis of the gasoline by
distillation process showed the gaso-
line to be casing head gasoline rather
than straight run. AS casing head
SdSOllnG mas d 1OWeT
point than called for by specifica-
tions Nos. 3511-B covering domestic,
3512 for export. and 3513-A for fight
ing gasolines, the conclusion was inn
mediately arrived at that a gasoline
having a higher initial boiling point
and consequently conforming more
closely to the specifications would stop
the boiling that had been experienced.
Consequently a gasoline conforming to
specification No. 3511-B was ordered
from the Sun Oil Company and used
by Major Schroeder in his last two
flights with no trouble whatever ex-
perienced due to boiling. The matter
of condemning the gasolines used at
the field on the ground of not meet
ing specifications had been under con-
sideration for sometime, but had not
been decided upon definitely as it was
something of an advantage to be able
to use the ordinary high test gaso-
line on sale at all filling stations.
However, this instance together
with trouble experienced in the dyna-
mometer laboratory and increasing
complaints about evaporation losses
at the hangers led to condemnation of
the casing head gasoIines and i'm
mediately increased the quality of the
meet specifications.
The principal lesson drawn from this
series Of experiences is the wide
spread prevalence of an incorrect i'm
preston among air service person
mel concerning the efficiency of the
specific gravity test of gasoline. Most
all air service personnel regard a
gravity OF IS baume, or specific grav-
ity of .721 as establishing beyond
shadow of a doubt the efficiency and
general good qualities of the gaso-
line. This, however, is not correct
as two gasolines,-one straight run
and the other blended casing head
can be given identical specific gravi-
ties but very different distillation
curves, that is to say plotted curves
which give the initial boiling points,
the final boiling point, and the inter
mediate points. The casing head gaso-
line will show considerably less power
delivered in the motor after it gets
there, than does the straight run gaso-
line. BY strait run is meant that
fraction from a crude petroleum dis
tiiling off between such points as are
designated to constitute the fraction
known as gasoline.
Inspection of specifications Nos.
3511-B. 1912 and 351S-A, will disclose
named as a requirement OF either of
the three gasolines but that entire de-
pendence is placed on the distilIation
curve, Specific gravity is of value