PRODUCTION OF A NEW-TYPE PROPELLER AT AERO NATIONAL ENTERPRISE IN PRAGUE-VYSOCANY

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00810A006200420004-6
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 3
• Document Creation Date: December 21, 2016
• Document Release Date: August 18, 2008
• Sequence Number: 4
• Publication Date: April 13, 1955
• Content Type: REPORT

Approved For Release 2008/08/18: CIA-RDP80-0081OA006200420004-6
CENTRAL INTELLIGENCE AGENCY
INFORMATION REPORT
This material contains information affecting the Na-
tional Defense of the United States within the mean-
ing of the Espionage Laws, Title 18, U:8.C. Secs. 793
and 794, the transmission or revelation of which in
any manner to an unauthorized person is prohibited
by law. `
S-E-C-R -E-T
NOFORN
COUNTRY Czechoslovakia
SUBJECT Production of a New-Type Propeller
at Aero National Enterprise in Prague-
Vysocany
REPORT
DATE DISTR.
NO. OF PAGES 3
REQUIREMENT NO. RD
REFERENCES
THE SOURCE EVALUATIONS IN THIS REPORT ARE DEFINITIVE.
THE APPRAISAL OF CONTENT IS TENTATIVE.
(FOR KEY SEE REVERSE)
13 April 1955
1. Aero National Enterprise in Prague-Vysocany (Plant No. AP-1103-B) has been
producing propellers of a new type since the summer of 1953. The daily
production varies from 20 to 23 propellers with a labor force of about
210 workers. The propellers are tested in a wind tunnel belonging to the
plant; it has an inside diameter of 3,600 millimeters.
2. The propellers are constructed entirely of silumin, with an integral
gradient and wing profile. The profile of this new propeller, compared
to that of standard construction, has the advantage of reducing to a
minimum the negative load. The air flows very lightly along the axial
direction of the propeller, with the result that the eccentric movement
of the air itself is almost completely eliminated.
3. The propeller has two blades. Each bladeis cast under a pressure of 45
kilograms per square centimeter and is kept in an annealing oven for a
long period. The reduction of the casting temperature to room temperature
lasts generally from 36 to 48 hours. Then the blades are carefully checked
before undergoing additional processes.
4. The rough grinding and finishing is done automatically by means of milling
machines which work in accordance with a steel model, with a precision up
to one-tenth of a millimeter. This m*es it possible to turn out two blades
of the same propeller which are equal in form, as well as in weight. The
two blades are then fitted into a special propeller hub. The weight dif-
ference between the two blades has a tolerance of 0.05 grams.
5. The surfaces of the propeller blades are then cleaned and polished, and
the propeller is tested in the wind tunnel. The annotations regarding the
wind-tunnel tests are then engraved on the propeller hub and the entire
propeller assembly is duly marked by.'the final testing commission.
S-E-C-R-E-T
NOFORN
STATE ][ ARMY X NAVY X AIR L'i X FBI AEC
Approved For Release 2008/08/18: CIA-RDP80-0081 OA006200420004-6
 Approved For Release 2008/08/18: CIA-RDP80-0081 OA006200420004-6
S-E-C-R-E-.T
NOFORN
6. Measurement of the propellers is as follotirs: Diameter of the circle
formed by the rotating blades of the propeller: 3,120 millimeters.
Maximum thickness of the blades at a distance of 270 millimeters from the
circle described above: 385 millimeters. Average inclination of the
positive surface (lower) at a distance of 150 millimeters from the tip
of the blade: angle - (aipha)of 13? 30'. Average inclination of the
positive surface (lower) at a distanc(' of 525 millimeters from the axle
of the propeller hub: angle - (alpha l)of 53:.
S-E-C-R-E-T
NOFORN
Approved For Release 2008/08/18: CIA-RDP80-0081 OA006200420004-6
 Approved For Release 2008/08/18: CIA-RDP80-00810A006200420004-6
S-E-C-R-E-T
NOFORN
-3-
Annex: Sketch of Integral Silumin Propeller
Scale: 1:17
F - Propeller blades of silumin
H - Propeller hub
N - Elousing of driving shaft
S-E-C-R-E-T
NOFORN
Approved For Release 2008/08/18: CIA-RDP80-00810A006200420004-6