Tag Archives: 1930s

Even More ALC Markings

ALC24ST — ca. 1935.  Alcoa Aluminum advertisement, Aviation, May 1935, pg. 9. (Image also reproduced in Aero Digest article below.)  Link:  http://archive.org/stream/Aviation_Week_1935-05-01#page/n42/mode/1up

ALC24ST — ca. 1936.  Douglas fuselage frame in “Development of Aluminum for Aircraft,” C.F. Nagel, Jr., Aluminum Company of America, Aero Digest, Feb. 1936, pg. 27.  Link: http://archive.org/stream/aerodigest2819unse#page/n148/mode/1up

ALC 24ST — ca. 1936.  “Spot Welding vs. Riveting,” Aviation, Oct. 1936, pg. 29.  Link:  http://archive.org/stream/Aviation_Week_1936-10-01#page/n14/mode/1up

ALC24ST — ca. 1937.  “Thrills of the Navy Test Pilots,” Popular Mechanics, Aug. 1937, pg. 227.  Link: http://archive.org/stream/bub_gb_79oDAAAAMBAJ#page/n123/mode/2up

ALC24ST — ca. 1937.  Alcoa Aluminum advertisement, Aviation, Nov. 1937, pg. 9.  Link: http://archive.org/stream/Aviation_Week_1937-11-01#page/n4/mode/1up

ALC24ST — ca. 1938.  Rear cover, Curtiss Fly Leaf, December 1938.  Link:  http://p40hawksnest.co.nf/Curtiss/CFL/CFL38Dec.html

ALC24ST — ca. 1939.  “Slots Are Here to Stay,” Kurt Rand, Popular Aviation, Oct. 1939.  Link:  http://books.google.com/books?id=NR6fckxHa4UC&pg=PA51#v=onepage

ALC24ST — ca. 1940.  “Are You Qualified?”, Hurd Barrett, Flying Magazine, Oct. 1940. pg. 32.  Link: http://books.google.com/books?id=CJVLeVu8dxMC&lpg=PA1&pg=PA32#v=onepage

ALC24SRT — ca. 1940.  “Assembling of a DC-3 / C-47 aircraft, ca.1940,” California Historical Society Collection.  Link:  http://digitallibrary.usc.edu/cdm/ref/collection/p15799coll65/id/10435

ALC24ST — ca. 1940.  “A man working on fuselage in the factory,”  George Strock/The LIFE Picture Collection/Getty Images.  Link:  http://www.gettyimages.com/license/50452689 (Another source: http://www.google.com/culturalinstitute/beta/asset/-/7gHD1-EtIoRKOA.)

ALC24SO — ca. 1940. “29th March 1940: At the Lockheed Aircraft Corporation at Burbank, California, large numbers of high-speed twin-engined planes, part of a previous British order, are being produced,” Photo by Fox Photos/Getty Images. Link:  http://www.gettyimages.com/license/3293948

ALC24SO — ca. 1940. HPM Fastraverse Presses advertisement, Aviation, June 1940, pg. 67. Link:  http://archive.org/stream/Aviation_Week_1940-06-01#page/n34/mode/1up

ALC24ST — ca. 1941.  “Curtis Wright,” Dmitri Kessel, April 1941.  Link:  http://www.google.com/culturalinstitute/beta/asset/curtis-wright/CQF4HZsxtsB_9Q

ALC24ST — ca. 1941.  Multiple photographs, “Glenn Martin Plane Factory,” George Strock, January 1941. Links: 1, 2, 3, 4, 5, 6, 7, 8 

ALC24ST — ca. 1941.  “B-17E Flying Fortress Camera Pit Below Radio Compartment.”  Link:  http://www.boeingimages.com/archive/B-17E%20Flying%20Fortress%20Camera%20Pit%20Below%20Radio%20Compartment-2F3XC569VIN.html and http://www.boeingimages.com/archive/B-17E%20Flying%20Fortress%20Camera%20Pit%20Below%20Radio%20Compartment-2F3XC56983J.html

ALC24ST — ca. 1942.  Although other aluminum markings were introduced in the early 1940s, the leading edge of this wing still shows faded “ALC24ST” markings.  Link: http://www.loc.gov/resource/fsa.8b05338/

ALC24ST — unknown [DC-3].  Handbook of Instructions for the Transport Model DC3-277B for American Airlines, Inc., Douglas Aircraft Company, Inc., pgs. 11, 34, 64, 89, 106A, 145.  Link: http://www.avialogs.com/viewer/avialogs-documentviewer.php?id=3248

ALC24ST — unknown [P-36].  P-40 Warhawk in Detail, Part 1: Y1P-36 through P-40C, Bert Kinzey, pg. 26. 



1930s and Early 1940s ALCOA Aluminum Markings

Documented examples of 1930s and early 1940s aluminum markings. Click each image to enlarge.

All known photographs of aluminum markings from the 1930s show Alcoa Alclad aluminum was marked “ALC24ST” and “ALC24SRT”.

Photographs show “ALC24ST” and “ALC24SRT” markings on aluminum in aircraft from:

  • Boeing
  • Douglas
  • Lockheed
  • Severski
  • Glenn L. Martin Co.

Boeing XB-17 (Model 299):

Boeing XB-17[Click Image to Enlarge]

Douglas DC-3:

douglas_dc3_upload[Click Image to Enlarge]

Seversky P-35:

seversky[Click Image to Enlarge]

Unknown Glenn L. Martin Co. Aircraft:

glenn-martin-unknown-aircraft[Click Image to Enlarge]

Unknown Douglas Aircraft:

unknown-douglas-co-aircraft-upload[Click Image to Enlarge]

Caltech Thesis:

alc24st-thesis[Click Image to Enlarge]

Earhart’s Electra:

alc24st-earhart-mechanics2[Click Image to Enlarge]
alc24st-engine-mount copy[Click Image to Enlarge]

Lockheed Electra:

  • Marking: ALC24ST
  • Font: serif
  • Aircraft: Electra
  • Company / Factory: Lockheed
  • Date: N/A
  • Source: “Lockheed Aircraft Corp. Report No. 421”. (Internal pages include dates from 1934 to 1936.)
  • Notes: Via private communication. No online source at this time.

electramanual2[Click Image to Enlarge]
electramanual1[Click Image to Enlarge]

Aircraft Template Development (1942):

lockheed-electra-image-one-inset[Click Image to Enlarge]
wing-image-book-inset[Click Image to Enlarge]

NACA TN No. 752, Investigation of Sheet-Stiffener Panels (1940):

test-specimen-dunn-alclad[Click Image to Enlarge]

George Arnold Photo:

alc24srt-china-inset[Click Image to Enlarge]

NACA TN 883 (1943):

  • Marking: ALC24ST
  • Font: serif
  • Aircraft: N/A
  • Company / Factory: Alcoa
  • Publication Date: 1943
  • Source: “TESTS OF ALUMINUM ALLOY STIFFENED SHEET SPECIMENS CUT FROM AN AIRPLANE WING”, Marshall Holt, TECHNICAL NOTES, NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS No. 883, Aluminum Company of America, Washington, January 1943. (http://hdl.handle.net/2060/19930081583)
  • Notes:

press-test-1of2[Click Image to Enlarge]
press-test-2of2[Click Image to Enlarge]


TBD Devastator:

tbd[Click Image to Enlarge]

Boeing 314 Clipper:

boeing-clipper[Click Image to Enlarge]

Airplane Metal Work, Vol. 2 (1941):

24so-image[Click Image to Enlarge]
alc24st-image[Click Image to Enlarge]

F-10-G Fleet:

fleet-1934[Click Image to Enlarge]

Mech. Prop. of Flush-Riveted Joints (1940):

  • Marking: N/A
  • Font: serif
  • Aircraft: N/A
  • Company / Factory: N/A
  • Publication Date: 1940
  • Source: Bruggeman, Wm. C. & Roop, Frederick C., “Mechanical Properties of Flush-Riveted Joints”. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc65026/.
  • Notes:

naca pg39 high_res[Click Image to Enlarge]

To Do:
– Add Lockheed Electra
– Add DC-2 example
– Add examples from the Alcoa Aluminum book
– To add: http://www.edcoatescollection.com/ac3/Airline/TWA%20Douglas%20DC-2.html

Other Sources to Investigate:
– Marking regulations. War Dept. TM: http://babel.hathitrust.org/cgi/pt?id=uc1.b3241791;view=2up;seq=16
– Airplane Metal Work: http://babel.hathitrust.org/cgi/pt?id=mdp.39015019904690;view=2up;seq=36
– Aircraft Sheet Metal: http://babel.hathitrust.org/cgi/pt?id=mdp.39015024027636;view=2up;seq=40
– PC and ALC abbrev.: http://babel.hathitrust.org/cgi/pt?id=uc1.$b317251;view=2up;seq=118
– Color markings (British?): http://babel.hathitrust.org/cgi/pt?id=mdp.39015063583184;view=2up;seq=14
– General discussions of abbreviations: ( http://babel.hathitrust.org/cgi/pt?id=uc1.$b65154;view=2up;seq=66, http://babel.hathitrust.org/cgi/pt?id=wu.89090519133;view=2up;seq=124, http://babel.hathitrust.org/cgi/pt?id=mdp.39015049832671;view=2up;seq=208, http://babel.hathitrust.org/cgi/pt?id=wu.89090515669;view=2up;seq=88, http://babel.hathitrust.org/cgi/pt?id=wu.89090515388;view=1up;seq=424 )
– Too small to read: http://babel.hathitrust.org/cgi/pt?id=uc1.$b317215;view=2up;seq=100