NO. 8 I914 TESTS OF THE LANGLEY "aERODROME" ABBOT 3 



In January 1942, Mr. Fred C. Kelly, of Peninsula, Ohio, com- 

 municated to me a list of differences between the Langley plane as 

 tested in 1914 and as tested in 1903, which he had received from 

 Dr. Wright. This list is given verbatim below. The Institution accepts 

 Dr. Wright's statement as correct in point of facts. Inferences from 

 the comparisons are primarily the province of interested experts and 

 are not discussed here. 



COMPARISON OF THE LANGLEY MACHINE OF 1903 WITH THE 

 HAMMONDSPORT MACHINE OF MAY-JUNE, 1914. 



LANGLEY, I903. 



HAMMONDSPORT, I914. 



WINGS. 



1 Size: ii'6"x22'6" (L.M. p. 206) 



2 Area: 1040 sq. ft. (L.M. p. 206) 



3 Aspect Ratio: 1.96 



4 Camber: 1/12 (L.M. p. 205) 



5 Leading Edge: Wire 1/16" di- 

 ameter (L.M. P1.66) 



6 Covering : Cotton fabric, not var- 

 nished. 



7 Center Spar: Cylindrical wood- 

 en spar, measuring lY' dia. for 

 half its length and tapering to i" 

 at its tip. (L.M. p. 204), Located 

 on upper side of wing. 



8 Ribs : Hollow box construction. 

 (L. M. Plates 66,67) 



Size: io'ii^"x22'6" 



Area : 988 sq. ft. 



Aspect Ratio: 2.05 



Camber: 1/18 



Leading Edge : Cylindrical spar i^" 

 dia. at inner end, tapering to l" dia. at 

 outer end. 



Covering : Cotton fabric, varnished. 



Center Spar: Cylindrical spar about 

 ii" dia. at inner end, tapering to about 

 i" dia. at outer end. Located on upper 

 side of wing. This center spar was 

 reinforced (i) by an extra wooden 

 member on the under side of the wing, 

 which measured i"x iV' and extended 

 to the 7th rib from the center of the 

 machine; and (2) by another wooden 

 reinforcement on the under side ex- 

 tending out about one-fourth of the 

 length of the wing. 



Ribs: Most of the original Langley 

 box ribs were replaced with others 

 made at Hammondsport. (Manly let- 

 ter, 1914). The Hammondsport ribs 

 were of solid construction and made 

 of laminated wood. That part of the 

 rib in front of the forward spar was 

 entirely omitted. 



