Evening star., 1948-06-10
JET XS-1 Passes
Sound Barrier
In Level Flight
Rocket Ship Betters
76O Miles Per Hour
On Many Occasions
By John A. Giles

Secretary of Air Symington
announced today that the Air
Force experimental rocket plane
xS-1 was flown much" faster
than the speed of sound many
times in flight testing last Octo-
ber" at Muroc Airbase in Cali
fornia.
Mr.. Symington told a news confer
ence that so far as he knows nc
other plane has achieved in leveI
flight supersonic speed, that is
faster than the 760-miles- per- -hou1
speed of sound.
IF any other aircraft has broken
the speed of sound, it has not been
on the fiat QeveD to the best of our
knowledge-it would have been in a
dive" Mr.. Symington said in reply
to a question.
The first and only pilot to fly the
XS-1, a Bell plane, beyond the So
called sonic wall is Capt. Charles E
Yeager, 25, fighter pilot, who de-
stroyed 13 German planes while
serving with the Air Force.
Capt. Yeager, a native of Myra
w. Va. is test pilot assigned tc
the Air Materiel Command at
Wright Field, Ohio.
Plane Contracts Awarded.
At the same time, Secretary
Symington announced the award
ing of contracts to aircraft manu-
facturers for a total of 2,201 planes
of which 1914 will be jet-propelled
The contracts are being made un-
der a ST ,345 ,165, 900 allotment from
current funds recently approved by
Secretary of Defense Forrestal and
will provide for the delivery OF
planes in the fiscal year 1851.
Included in the contracts were
243 bombers, LAOS fighters and $50
transports. training and air-sea
rescue aircraft.
The announcement of the rocket
plane speed record confirmed an
earlier story published in the maga-
zine Aviation Week last December
%. The Air Force sought to have
the magazine prosecuted on the
grounds the information was a TOP
secret and its publication aided for
eign countries, but Attorney Gen.
eral Clark ruled on May q that this
did not constitute violation OF
Federal law.
Although military classification
does not have the force of law in
peacetine outside of the military
establishment, there are certainly
obviously justif1able reasons for it,
observance Mr.. Symington sale
today. :"The premature publication
data on experimental aircraft per-
mits other nations to benefit from
our research and places them on
parity with us on the practical ap'
pIication of such information in ths
development Of military types o.
aircraft"
Asks Research Protection.
Mr.. Symington asked the CO.
operation of news media in protect
ing the results cf research until TIT
military advantage had been OBJ
tanned.
The Air Force hopes for con
tinuance of the spirit of co-opera
ton which media representative
have observed in this field in th'
past he said. THE information
that the XS-1 has flown faster thar
the speed of sound many times i
all the Air Force can release witt
regard to performance"
The 760-mile-an-hour speed o
sound is based on a temperature O
SO degrees Fahrenheit at sea level
1t varies up to 100 miles an hour II
either direction as the temperature
rises or falls. Once across the soune
barrier frontier, aeronautlcal en-
gineers have stated, military avia'
ton will be confronted with innum'
cradle new problems which must be
solved before super-sonic warfare
can be regarded as practical.
The XS-1 is powered by foul
rocket motors, and is launched from
the under part of bomber, usuall3
the B-29. This assist solves take
off problems, conserves fuel anc
lengthens the range of the ship,
More Such Planes on Order.
Mr.. Symington said the Air Force
had two such planes, one OF then
on loan to the National Association
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