Evening star., 1950-08-07
Automatic Parachute
Solves Altitude Problem
Opens Only After Set Delay
And at the Proper Height
By Thomos R. Henry

A new automatic parachute developed
by the Air Force is believed largely to
have solved the problem Of escape from
aircraft at high attitudes or high speed.
It opens only after an appropriate
delay after leaving the plane and at
proper distance above the earth without
need for Judgment on the part Of the
parachutist.
With the automatic parachute all that
Is required Of a pilot Is to get out Of the
plane and pull the ball-type handle con-
nected by cable to the automatic release,
which then takes over and opens the
parachute only after he has dropped to
a safe altitude. If the bail-out is made
at high speed and low altitude. the auto
matte release provides flve-second de-
lay which allows the pilot to clear the
plane and slow down to q safe speed
before the parachute opens.
The release Is designed to control
automatically the opening Of the para
chute by means Of both time and alti-
tude delay. The timer is adjustable
from one to 26 seconds, but it usually
provides delay Of from five to seven
seconds. This is sufficient to reduce the
velocity Of the fall, for example, to 130
miles an hour at 10000 feet and to 100
miles an hour at sea level from an
initial velocity Of 600 miles an hour.
Mechanism Is Set Beforehand.
The altitude control mechanism, how
ever, prevents operation Of the para
chute release above preset height. Be-
fore the plane takes off, this element is
set for an altitude 5000 feet higher than
the highest point of the terrain over
which it is expected to fly. II this high
est point, for example, is 1000 feet, the
altitude control mechanism is set for
$4,000 feet. Should it become necessary
to bail out at 10000 feet. the parachute
will not open until after a free fall Of
$4,000 feet.
At 10000 feet the shock of the para
chute opening is four times as great as
at sea level Also if the parachute opens
at this altitude, the descent will take
longer; and lack Of oxygen and extreme
cold may well prove fatal.
First intensive study Of the chemistry
OF human teeth is underway at the
United States Bureau Of Standards
This eventually may lead to methods
of reversing the decay process, which is
essentially breakdown Of the calcium
structure, and remineralization. It is
now known, according to bureau re-
port on the work, that great differences
exist in the resistance of different teeth,
even in the same mouth, to decalcifica-
ton; and these differences are thought
to be associated in some way with the
manner in which the hard, calcified
tooth structures are deposited in the
first place. AS yet, however, no salts
factory association between tooth Struc-
ture and resistance to decay has been
established.
Precise Measurements Made.
The bureau scientists are making for
the first time precise measurements Of
the hardness Of tooth enamel and dem
tine and studying the abrasion and de-
Qualification of tooth structures due to
the chemical and wearing action Of vari-
out tooth pastes and powders. They
are taking pictures of the tooth struc-
lures with the electron microscope, which
reveals them in greater detail than ever
before possible.
There is suspicion that very minute
traces Of rare elements, far too small to
be determined by any ordinary chemical
procedure. may have very great effect
on tooth decay. For the first time 1t Ii
expected that it will be possible to
determine such traces.