Tag Archives: douglas

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