Evening star., 1951-02-05
Space Ship Might Melt
At Required High Speed
Navy Experiments Show
Problem of Friction Heut
By Thomos R. Henry

At speed far below that necessary
for missile or a space ship to leave
the Earth 1t could become wisp Of
vapor
This is conclusion from wind tunnel
experiments at the Naval Ordnance Lab
oratory in which air flow was produced at
velocity of eight times the speed Of
sound. This would be about 5000 feet
second in dry air at ordinary tenn
peratures, but it greatly slowed down at
very low temperatures.
The effect on an object of air flowing
past it at such speed Is the same as if
it were itself moving through air at the
same velocity. It was found that the
surface temperature would be raised sew
eral thousand degrees in few seconds.
This involved extremely complicated
computing with one of the new mechan-
lcal brains which performed in few
weeks a mathematical job which would
have required man 10 years.
Steel Was Used.
The material involved was steel, such
as forms the castings of shells. Tests were
moving at the simulated speed of close
to miles second. It has been cal
culated that to leave the Earth against
the force of gravity and actually escape
into outer space it would be necessary
for an object to move at rate of
miles second. 1t could not quite escape
at miles second but would become q
satellite of the Earth, like the Moon.
1t is difficult to imagine any material
which could withstand such tempera-
ture. The heating. however, would be on
the surface and there were no calcula-
tions as to the rate this would penetrate
10 iy,fo orin ~ e.;11
The Navy experiments were not con-
cerned with overcoming gravity entirely
but with quite practical problems which
might arise in future ordnance design.
X
Both featherweight and elastic con-
crete now can be produced.
This is revealed by DR.. Wallace r.
Brode of the United States Bureau Of
Standards in review Of the available
structural materials of the future. The
new concretes, he points out, may weigh
only about a fifth as much as ordinary
concrete used for building. At the same
time their resistance. to transmission Of
heat Is less than a tenth that of the
building material now in use.
The result is achieved, he points out,
by using such materials as perlite and
materials as gravel in the concrete mix
ture. Perlite is the glass-like material
left after a volcanic eruption. Vermiculite
is an aberant form of mica.
Already, he points out, lightweight
cements are being produced by three
methods. These mostly depend on sub
stituting scme lighter weight materials
for sand and crushed stone A light
WEIGHT ho [a I,xy
whipping all into mixtures which con-
tain minute amounts of soaps or resins.
This traps air in amounts ranging from
to 6 per cent of the volume of the
concrete.
Gas Can Be Produced.
Another method is to include in the
cement materials which react chemically
with other constituents to produce q
gas. Most often used is powdered alumni
mum which reacts to produce hydrogen.
This markedly increases the volume of
the cement-water mixture Much of the
highway construction is now with such
blown-up concrete. --4>sr
1t also now is possible, Dr. Brode says
in prediction of future materials pre-
pared for the Franklin Institute, to
prepare concrete which is virtually
elastic. The tendency to break under
strains and stresses is major objection
to use of the material
The new material is reinforced, with
special attention paid reinforcement in
those places where the stress is antici-
pated.
ut is material quite distinct from
reinforced concrete since it is an elastic
material" he says.